Corneal topography. Medical search

The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.

A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)

The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)

Gas lasers with excited dimers (i.e., excimers) as the active medium. The most commonly used are rare gas monohalides (e.g., argon fluoride, xenon chloride). Their principal emission wavelengths are in the ultraviolet range and depend on the monohalide used (e.g., 193 nm for ArF, 308 nm for Xe Cl). These lasers are operated in pulsed and Q-switched modes and used in photoablative decomposition involving actual removal of tissue. (UMDNS, 2005)

Refraction of LIGHT effected by the media of the EYE.

Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)

A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.

A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.

A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.

Diseases of the cornea.

Surgical procedures employed to correct REFRACTIVE ERRORS such as MYOPIA; HYPEROPIA; or ASTIGMATISM. These may involve altering the curvature of the CORNEA; removal or replacement of the CRYSTALLINE LENS; or modification of the SCLERA to change the axial length of the eye.

Partial or total replacement of all layers of a central portion of the cornea.

The use of an aberrometer to measure eye tissue imperfections or abnormalities based on the way light passes through the eye which affects the ability of the eye to focus properly.

Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.

Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.

A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.

The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.

A quantitative prediction of the biological, ecotoxicological or pharmaceutical activity of a molecule. It is based upon structure and activity information gathered from a series of similar compounds.

Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)

The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)

A surgical technique to correct REFRACTIVE ERRORS of the EYE, such as MYOPIA and ASTIGMATISM. In this method, a flap of CORNEAL EPITHELIUM is created by exposure of the area to dilute alcohol. The flap is lifted and then replaced after laser ablation of the subepithelial CORNEA.

A refractive error in which rays of light entering the eye parallel to the optic axis are brought to a focus behind the retina, as a result of the eyeball being too short from front to back. It is also called farsightedness because the near point is more distant than it is in emmetropia with an equal amplitude of accommodation. (Dorland, 27th ed)

Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)

The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.

Hydrophilic contact lenses worn for an extended period or permanently.

Zernike representation of corneal topography height data after nonmechanical penetrating keratoplasty. (1/329)

PURPOSE: To demonstrate a mathematical method for decomposition of discrete corneal topography height data into a set of Zernike polynomials and to demonstrate the clinical applicability of these computations in the postkeratoplasty cornea. METHODS: Fifty consecutive patients with either Fuchs' dystrophy (n = 20) or keratoconus (n = 30) were seen at 3 months, 6 months, and 1 year (before suture removal) and again after suture removal following nonmechanical trephination with the excimer laser. Patients were assessed using regular keratometry, corneal topography (TMS-1, simulated keratometry [SimK]), subjective refraction, and best-corrected visual acuity (VA) at each interval. A set of Zernike coefficients with radial degree 8 was calculated to fit two model surfaces: a complete representation (TOTAL) and a representation with parabolic terms only to define an approximate spherocylindrical surface (PARABOLIC). The root mean square error (RMS) was calculated comparing the corneal raw height data with TOTAL (TOTALRMS) and PARABOLIC (PARABOLICRMS). The cylinder of subjective refraction was correlated with the keratometric readings, the SimK, and the respective Zernike parameter. Visual acuity was correlated with the tilt components of the Zernike expansion. RESULTS: The measured corneal surface could be approximated by the composed surface 1 with TOTALRMS < or = 1.93 microm and by surface 2 with PARABOLICRMS < or = 3.66 microm. Mean keratometric reading after suture removal was 2.8+/-0.6 D. At all follow-up examinations, the SimK yielded higher values, whereas the keratometric reading and the refractive cylinder yielded lower values than the respective Zernike parameter. The correlation of the Zernike representation and the refractive cylinder (P = 0.02 at 3 months, P = 0.05 at 6 months and at 1 year, and P = 0.01 after suture removal) was much better than the correlation of the SimK and refractive cylinder (P = 0.3 at 3 months, P = 0.4 at 6 months, P = 0.2 at 1 year, and P = 0.1 after suture removal). Visual acuity increased from 0.23+/-0.10 at the 3-month evaluation to 0.54+/-0.19 after suture removal. After suture removal, there was a statistically significant inverse correlation between VA and tilt (P = 0.02 in patients with keratoconus and P = 0.05 in those with Fuchs' dystrophy). CONCLUSIONS: Zernike representation of corneal topography height data renders a reconstruction of clinically relevant corneal topography parameters with a marked reduction of redundance and a small error. Correlation of amount/axis of refractive cylinder with respective Zernike parameters is more accurate than with keratometry or respective SimK values of corneal topography analysis. (+info)

Changes in corneal wavefront aberrations with aging. (2/329)

PURPOSE: To investigate whether corneal wavefront aberrations vary with aging. METHODS: One hundred two eyes of 102 normal subjects were evaluated with videokeratography. The data were decomposed using Taylor and Zernike polynomials to calculate the monochromatic aberrations of the cornea for both small (3-mm) and large (7-mm) pupils. RESULTS: For a 3-mm pupil, the amount of total aberrations (Spearman rank correlation coefficient r(s) = 0.145; P = 0.103) and spherical-like aberrations (r(s) = -0.068; P = 0.448) did not change with aging, whereas comalike aberrations exhibited a weak but statistically significant correlation with age (r(s) = 0.256; P = 0.004). For a 7-mm pupil, total aberrations (r(s) = 0.552; P < 0.001) and comalike aberrations (r(s) = 0.561; P < 0.001) significantly increased with aging, but spherical-like aberrations showed no age-related changes (r(s) = 0.124; P = 0.166). Simulated pupillary dilation from 3 mm to 7 mm caused a 38.0+/-28.5-fold increase in the total aberrations, and the extent of increases significantly correlated with age (r(s) = 0.354; P < 0.001). Pupillary dilation influenced the comalike aberrations more in the older subjects than in the younger subjects (r(s) = 0.243; P = 0.006), but such age dependence was not found for spherical-like aberrations (r(s) = 0.141; P = 0.115). CONCLUSIONS: Comalike aberrations of the cornea correlate with age, implying that the corneas become less symmetrical along with aging. Spherical-like aberrations do not vary significantly with aging. Pupillary dilation markedly increases wavefront aberrations, and those effects are more prominent in older subjects than in younger subjects. (+info)

Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system. (3/329)

AIMS: To map the thickness, elevation (anterior and posterior corneal surface), and axial curvature of the cornea in normal eyes with the Orbscan corneal topography system. METHODS: 94 eyes of 51 normal subjects were investigated using the Orbscan corneal topography system. The anterior and posterior corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, island, and unclassified patterns, and the axial power maps were grouped into round, oval, symmetric bow tie, asymmetric bow tie, and irregular patterns. The pachymetry patterns were designated as round, oval, decentred round, and decentred oval. RESULTS: The thinnest point on the cornea was located at an average of 0.90 (SD 0. 51) mm from visual axis and had an average thickness of 0.55 (0.03) mm. In 69.57% of eyes, this point was located in the inferotemporal quadrant, followed by the superotemporal quadrant in 23.91%, the inferonasal quadrant in 4.35%, and the superonasal quadrant in 2.17%. Among the nine regions of the cornea evaluated (central, superotemporal, temporal, inferotemporal, inferior, inferonasal, nasal, superonasal, and superior) the central cornea had the lowest average thickness (0.56 (0.03) mm) and the superior cornea had the greatest average thickness (0.64 (0.03) mm). The mean simulated keratometry (SimK) was 44.24 (1.61)/43.31 (1.66) dioptres (D) and the mean astigmatism was 0.90 (0.41) D. Island (71.74%) was the most common elevation pattern observed in the anterior corneal surface, followed by incomplete ridge (19.57%), regular ridge (4.34%), irregular ridge (2.17%), and unclassified (2.17%). Island (32.61%) was the most common topographic pattern in the posterior corneal surface, following by regular ridge (30.43%), incomplete ridge (23. 91%), and irregular ridge (13.04%) patterns. Symmetric bow tie was the most common axial power pattern in the anterior cornea (39.13%), followed by oval (26.07%), asymmetric bow tie (23.91%), round (6. 52%), and irregular (4.53%) patterns. In the pachymetry maps, 47.83% of eyes had an oval pattern, and round, decentred oval, and decentred round were observed in 41.30%, 8.70%, and 2.18% of eyes, respectively. CONCLUSION: The information on regional corneal thickness, corneal elevation and axial corneal curvature obtained with the Orbscan corneal topography system from normal eyes provides a reference for comparison with diseased corneas. The Orbscan corneal topography system is a useful tool to evaluate both corneal topography and corneal thickness. (+info)

Proposed classification for topographic patterns seen after penetrating keratoplasty. (4/329)

AIMS: To create a clinically useful classification for post-keratoplasty corneas based on corneal topography. METHODS: A total of 360 topographic maps obtained with the TMS-1, from 95 eyes that had undergone penetrating keratoplasty (PKP), were reviewed independently by two examiners in a masked fashion, and were categorised according to a proposed classification scheme. RESULTS: A high interobserver agreement (88% in the first categorisation) was achieved. At 12 months post-PKP, a regular astigmatic pattern was observed in 20/85 cases (24%). This was subclassified as oval in three cases (4%), oblate symmetric bow tie in six cases (7%), prolate asymmetric bow tie in six cases (7%), and oblate asymmetric bow tie in five cases (6%). An irregular astigmatic pattern was observed in 61/85 cases (72%), subclassified as prolate irregular in five cases (6%), oblate irregular in four cases (5%), mixed in seven cases (8%), steep/flat in 11 cases (13%), localised steepness in 16 cases (19%), and triple pattern in three cases (4%). Regular astigmatic patterns were associated with significantly higher astigmatism measurements. The surface asymmetry index was significantly lower in the regular astigmatic patterns. CONCLUSIONS: In post-PKP corneas, the prevalence of irregular astigmatism is about double that of regular astigmatism, with a trend for increase of the irregular patterns over time. (+info)

Reassessment of the corneal endothelial cell organisation in children. (5/329)

AIM: To assess uniformity of the corneal endothelial cell mosaic in children. METHODS: 36 healthy children (5-11 years old, 16 boys, 20 girls) were assessed by specular microscopy. Endothelial cell density (ECD) was calculated from measured cell areas, and the number of sides/cell noted. RESULTS: Average values for ECD and cell areas were 3987 cells/mm(2) (95% CI 3806 to 4168 cells/mm(2)) and 278 (SD 85) mm(2) respectively, with normal distribution (COV 28. 2%, range 17.4 to 39.2%) and with the average percentage of six sided cells being 66.6% (8.8%). Cell area was positively correlated to number of cell sides (p <0.01, r(2)=0.993), but the percentage of six sided cells was negatively correlated to ECD (p <0.01, r=0.493). CONCLUSION: A high ECD occurs in children, but this does not mean there is a high percentage of "hexagons". (+info)

Pterygium-induced corneal astigmatism. (6/329)

BACKGROUND: Previous work has suggested an association between increasing size of pterygium and increasing degrees of induced corneal astigmatism. OBJECTIVES: To assess the quantitative relation between pterygium size and induced corneal astigmatism using a computerized corneal analysis system (TMS II) and slit-lamp beam evaluation of pterygium size, and to conclude whether corneal astigmatism is an early indication for surgical intervention. METHODS: We evaluated 94 eyes of 94 patients with unilateral primary pterygium of different sizes, using TMS II and slit-lamp beam measurements of the size of the pterygium (in millimeters) from the limbus to assess parameters of pterygium size with induced corneal astigmatism. Best corrected visual Snellen acuity was performed. RESULTS: Primary pterygium induced with-the-rule astigmatism. Pterygium extending > 16% of the corneal radius or 1.1 mm or less from the limbus produced increasing degrees of induced astigmatism of more than 1.0 diopter. Significant astigmatism was found in 16.16% of 24 eyes with pterygium of 0.2 up to 1.0 mm in size, in 45.45% of 22 eyes with pterygium of 1.1 up to 3.0 mm in size (P < or = 0.0004), and in 100% of 3 eyes with pterygium of 5.1 up to 6.7 mm in size (P = 0.0005). We found that visual acuity was decreased when topographic astigmatism was increased. CONCLUSIONS: When primary pterygium reaches more than 1.0 mm in size from the limbus it induces with-the-rule significant astigmatism (> or = 1.0 diopter). This significant astigmatism tends to increase with the increasing size of the lesion. Topographic astigmatism tends to be improved by successful removal of the pterygium. These findings suggest that early surgical intervention in the pterygium may be indicated when the lesion is more than 1.0 mm in size from the limbus. (+info)

Effect of disagreement between refractive, keratometric, and topographic determination of astigmatic axis on suture removal after penetrating keratoplasty. (7/329)

BACKGROUND/AIMS: Post-keratoplasty astigmatism can be managed by selective suture removal in the steep axis. Corneal topography, keratometry, and refraction are used to determine the steep axis for suture removal. However, often there is a disagreement between the topographically determined steep axis and sutures to be removed and that determined by keratometry and refraction. The purpose of this study was to evaluate any difference in the effect of suture removal, on visual acuity and astigmatism, in patients where such a disagreement existed. METHODS: 37 cases (from 37 patients) of selective suture removal after penetrating keratoplasty, were included. In the first group "the disagreement group" (n=15) there was disagreement between corneal topography, keratometry, and refraction regarding the axis of astigmatism and sutures to be removed. In the second group "the agreement group" (n=22) there was agreement between corneal topography, keratometry, and refraction in the determination of the astigmatic axis and sutures to be removed. Sutures were removed according to the corneal topography, at least 5 months postoperatively. Vector analysis for change in astigmatism and visual acuity after suture removal was compared between groups. RESULTS: In the disagreement group, the amount of vector corrected change in refractive, keratometric, and topographic astigmatism after suture removal was 3.45 (SD 2.34), 3.57 (1.63), and 2.83 (1. 68) dioptres, respectively. In the agreement group, the amount of vector corrected change in refractive, keratometric, and topographic astigmatism was 5.95 (3.52), 5.37 (3.29), and 4.71 (2.69) dioptres respectively. This difference in the vector corrected change in astigmatism between groups was statistically significant, p values of 0.02, 0.03, and 0.03 respectively. Visual acuity changes were more favourable in the agreement group. Improvement or no change in visual acuity occurred in 90.9% in the agreement group compared with 73.3% of the disagreement group. CONCLUSIONS: Agreement between refraction, keratometry, and topography was associated with greater change in vector corrected astigmatism and was an indicator of good prognosis. Disagreement between refraction, keratometry, and topography was associated with less vector corrected change in astigmatism, a greater probability of decrease in visual acuity, and a relatively poor outcome following suture removal. However, patients in the disagreement group still have a greater chance of improvement than worsening, following suture removal. (+info)

Corneal topography by keratometry. (8/329)

AIMS: To investigate the ability of a telecentric keratometer to describe the asphericity and curvature of convex ellipsoidal surfaces and human corneas. METHODS: 22 conicoidal convex surfaces and 30 human corneas were examined by conventional keratometry. Additional keratometric measurements were made when the surface was tilted in the horizontal plane relative to the instrument optical axis. This resulted in a series of radius measurements derived from different regions of the surface. These measurements were used to determine the apical radius and the p value of the horizontal meridian of each surface. The results were compared with those derived from measurements using the EyeSys videokeratoscope and form Talysurf analysis. The method was repeated on 30 human corneas and the results compared with those of a videokeratoscope. RESULTS: For the aspheric buttons, the keratometric and the EyeSys results tended to give higher values for both apical radius and the p values than those of the Talysurf analysis. The best agreement was between the Talysurf and the keratometer where the results were not significantly different. For the human corneas, the apical radii were significantly different comparing the keratometer with the videokeratoscope but the p values were not significantly different. CONCLUSION: The keratometric method for assessing curvature and asphericity appears to hold promise as a method for quantifying the corneal topography. (+info)

Corneal pachymetric topography. Ophthalmology 101:432-438, 1994. Reinstein DZ, Silverman RH, Raevsky T, Simoni GJ, Lloyd HO, ... Arc-scanning very high-frequency ultrasound for 3-D pachymetric mapping of the corneal epithelium and stroma in laser in situ ... This system allowed demonstration of the importance of arc-scanning for corneal analysis and led to the subsequent development ... Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing, Ophthalmology, 101: 140- ...

https://en.wikipedia.org/wiki/Ronald_Silverman

The gold standard diagnostic test for PMD is corneal topography. However, it may not be as specific as corneal pachymetry, ... Pellucid marginal degeneration is diagnosed by corneal topography. Corneal pachymetry may be useful in confirming the diagnosis ... if corneal topography is used for diagnosis, it should be in conjunction with clinical findings of peripheral, inferior corneal ... Corneal topography may show a "crab claw-like" appearance, a finding that is seen in both keratoconus and in pellucid marginal ...

https://en.wikipedia.org/wiki/Pellucid_marginal_degeneration

Corneal topography (April 4, 2006). *Charles Schepens (April 9, 2006). *Iridodialysis (October 15, 2006) ... Copyedit : Fungal keratitis, Blepharochalasis, Phthiriasis, Eye trauma, Optic neuropathy, Keratoglobus, Corneal ulcer, Cone ... Cleanup : Conjunctivitis,Conjunctivochalasis, Corneal dystrophy, Eye surgery, Oculoplastics, Rubeosis iridis, Conjunctival ... concretion, Iridoplegia, Corneal ulcer, Corneal abrasion, Ocular tilt reaction. * ...

https://en.wikipedia.org/wiki/Wikipedia:EYE

Kiely PM, Carney LG, Smith G (October 1983). "Menstrual cycle variations of corneal topography and thickness" (PDF). American ... Leach NE, Wallis NE, Lothringer LL, Olson JA (May 1971). "Corneal hydration changes during the normal menstrual cycle--a ...

https://en.wikipedia.org/wiki/Feminizing_hormone_therapy

... anterior corneal) astigmatism is measured through the use of techniques such as keratometry and corneal topography. One method ... Corneal topography may also be used to obtain a more accurate representation of the cornea's shape. An autorefractor or ... Corneal Topography and Imaging at eMedicine Graff, T (1962). "Control of the determination of astigmatism with the Jackson ... "Classification of normal corneal topography based on computer-assisted videokeratography". Archives of Ophthalmology. 108 (7): ...

https://en.wikipedia.org/wiki/Astigmatism

Preliminary investigation of the corneal topography. The test maps a patient's cornea for raised areas and surface ... a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium. The outer layer of ... "CORNEAL REFRACTIVE SURGERY (ICD9 V802A/V802B)" (PDF). January 2006. Retrieved August 16, 2013.. Archive index at the Wayback ... Granular corneal dystrophy type II. Possible complications[edit]. Some complications that can be temporary or permanent include ...

https://en.wikipedia.org/wiki/Photorefractive_keratectomy

"Corneal topography and Schirmer testing in eyes with the Hudson,-,Stahli line". Eye. 16 (3): 267-70. doi:10.1038/sj.eye.6700028 ... It lies in the corneal epithelium. Usually it has about 0.5 mm in thickness and is 1-2 mm long. It is generally horizontal, ... Fleischer ring - corneal iron depositions in keratoconus Ophthalmology Myron Yanoff, Jay S. Duker Edition 3, illustrated ...

https://en.wikipedia.org/wiki/Hudson–Stahli_line

Is the future of refractive surgery based on corneal topography or wavefront? "Ocular Surgery News". August 1, 2000, page 26. ... Both the depth of the corneal incisions and the degree of central corneal flattening correlated with the laser energy applied. ... Those with Fuchs' corneal endothelial dystrophy, corneal epithelial basement membrane dystrophy, retinal tears, autoimmune ... or corneal topography machine, to measure their surface contour. Using low-power lasers, a topographer creates a topographic ...

https://en.wikipedia.org/wiki/LASIK

Corneal topography indices after corneal collagen crosslinking for keratoconus and corneal ectasia One-year results. J Cat ... Refractive Corneal Surg. 1994;10:571-574. Hersh PS, Schwartz-Goldstein B. Summit PRK Topography Study Group. Corneal topography ... "Corneal topography indices after corneal collagen crosslinking for keratoconus and corneal ectasia: One-year results". Journal ... Summit PRK Topography Study Group. Corneal topography of phase III excimer laser photorefractive keratectomy: Optical zone ...

https://en.wikipedia.org/wiki/Peter_Hersh

The corneal thickness from mild (> 506 μm) to advanced (< 446 μm). Increasing use of corneal topography has led to a decline in ... A more definitive diagnosis can be obtained using corneal topography, in which an automated instrument projects the illuminated ... The corneal transplant surgeon trephines a lenticule of corneal tissue and then grafts the donor cornea to the existing eye ... Maguire LJ, Bourne WM (August 1989). "Corneal topography of early keratoconus". American Journal of Ophthalmology. 108 (2): 107 ...

https://en.wikipedia.org/wiki/Keratoconus

"Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system". Br J Ophthalmol. 83 ...

https://en.wikipedia.org/wiki/List_of_examples_of_lengths

"Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system". The British Journal ...

https://en.wikipedia.org/wiki/Orders_of_magnitude_(length)

Corneal topography may also be used to obtain a more accurate representation of the cornea's shape. An autorefractor or ... It is typically characterized by an aspherical, non-figure of revolution cornea in which the corneal profile slope and ...

https://en.wikipedia.org/wiki/Astigmatism_(optical_systems)

The specific application of UVA for each patient takes into account the refractive error and corneal topography. The major ... PiXL is a high-fluence corneal collagen cross-linking administered in a customizable pattern and intensity in order to flatten ... or steepen the cornea through corneal strengthening. ...

https://en.wikipedia.org/wiki/PiXL

Preliminary investigation of the corneal topography. The test maps a patient's cornea for raised areas and surface ... a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium. The outer layer of ... "CORNEAL REFRACTIVE SURGERY (ICD9 V802A/V802B)" (PDF). January 2006. Retrieved August 16, 2013.. Archive index at the Wayback ... The amount of corneal hazing after surgery is also decreased with brush technique.[12] The platelet activating factor LAU-0901 ...

https://en.m.wikipedia.org/wiki/Photorefractive_keratectomy

Corneal and Retinal Topography: computerized tests that maps the surface of the retina, or the curvature of the cornea. ...

https://en.wikipedia.org/wiki/Tadpole_pupil

Corneal topography and pachymetry are used to screen for abnormal corneas. Furthermore, some people's eye shape may not permit ... Customized Transepithelial No-touch (C-TEN) is an innovative strategy for corneal surgery that avoids any corneal manipulation ... such as corneal topography. While refractive surgery is becoming more affordable and safe, it may not be recommended for ... It involves cutting a flap in the cornea and pulling it back to expose the corneal bed, then using an excimer laser to ablate ...

https://en.wikipedia.org/wiki/Refractive_surgery

Corneal topography is considered a more quantitative test, and for purposes of aligning a toric IOL, most surgeons use a ... which is calculated by the internal programming of the corneal topography machine, to determine the astigmatic meridian on the ... including manifest refraction or corneal topography. Manifest refraction is the familiar test where the eye doctor rotates ... It is believed to have a lesser effect on corneal endothelium. The main complication with this type is their tendency to cause ...

https://en.wikipedia.org/wiki/Intraocular_lens

He has also done extensive research in corneal crosslinking and topography-guided PRK for keratoconus, procedures he introduced ... Applications of Corneal Crosslinking, Refractive Eyecare for Ophthalmologists, Ethis Publishing, March 2010. http://www. ...

https://en.wikipedia.org/wiki/Raymond_Stein

... have demonstrated the ability of OCT systems to depict pathology within the cornea as well as disorders of corneal topography. ... Direct corneal elevation measurements using multiple delay en face optical coherence tomography. J Biomed Opt. 2008 Sep-Oct;13( ... High-speed optical coherence tomography of corneal opacities. Ophthalmology. 2007 Jul;114(7):1278-85. Plesea et al. ...

https://en.wikipedia.org/wiki/OCT_Biomicroscopy

As the inflammation is reduced, the stroma appears to be thin and the corneal topography changes to show an area of depression ... The corneal response to the treatment appears to be as expected until the four-day mark where the corneal inflammation and ... It could also show corneal edema which leads to thickening the corneal to 30%. Extensive conjunctival injection, which is an ... corneal abrasion and infectious corneal ulcer. Now, in order to diagnosis Christmas eye, it's essential to take a look at the ...

https://en.wikipedia.org/wiki/Christmas_eye

A modern development of the concept is found in corneal topography, in which analysis of the reflected image is passed to a ... The automated instrument can produce colour-coded contour maps of the eye's topography or even three-dimensional visualisations ... If the patient is suffering from astigmatism or from a corneal dystrophy, the rings will be distorted. ...

https://en.wikipedia.org/wiki/Keratoscope

... however corneal topography is a practical test (technique) as the condition worsens. Pterygium should be differentiated from ... "Facts About the Cornea and Corneal Disease , National Eye Institute". The National Eye Institute (NEI). May 2016. Archived from ... Other conditions that can look similar include a pinguecula, tumor, or Terrien's marginal corneal degeneration. Prevention may ... as it invades the cornea with the potential of obscuring the optical center of the cornea and inducing astigmatism and corneal ...

https://en.wikipedia.org/wiki/Pterygium_(conjunctiva)

Central corneal power can be measured by keratometry or corneal topography. Corneal radius of curvature relates to corneal ... which uses the pre-LASIK corneal power for the calculation of the ELP, and the post-LASIK corneal power for the calculation of ... corneal topographers) cannot obtain accurate measurements in eyes that have undergone corneal refractive surgery. Most manual ... The central corneal power is the second important factor in the calculation formula. To simplify the calculation, the cornea is ...

https://en.wikipedia.org/wiki/Intraocular_lens_power_calculation

Rabinowitz, YS; McDonnell, PJ (1989). "Computer-assisted corneal topography in keratoconus". Refractive & Corneal Surgery. 5 (6 ... custom topography-guided transepithelial PRK combined with corneal collagen cross-linking, or corneal transplant. When cross- ... Abnormal corneal topography compromises of keratoconus, pellucid marginal degeneration, or forme fruste keratoconus with an I-S ... "Post-LASIK ectasia treated with intrastromal corneal ring segments and corneal crosslinking". Digital Journal of Ophthalmology ...

https://en.wikipedia.org/wiki/Post-LASIK_ectasia

It is also the principle used in corneal pachymetry, the mapping of corneal topography, done prior to refractive eye surgery ...

https://en.wikipedia.org/wiki/Scheimpflug_principle

However, it was not until computerized corneal topography became available during the 1990s that it became possible to apply ... In June 2002, the FDA granted approval for overnight wear of a type of corneal reshaping called "Corneal Refractive Therapy" ( ... 2001 Aug;108(8):1389-99 Macsai, M.D., Marian S. (January 2005). "Corneal Ulcers in Two Children Wearing Paragon Corneal ... Each patient presented with a bacterial corneal ulcer after wearing CRT contact lenses for less than 6 months. In the first ...

https://en.wikipedia.org/wiki/Orthokeratology

... tomography Elastography Electrical impedance tomography Optoacoustic imaging Ophthalmology A-scan B-scan Corneal topography ...

https://en.wikipedia.org/wiki/Medical_imaging

... corneal topography MeSH E01.370.380.225 - electroretinography MeSH E01.370.380.235 - eye movements MeSH E01.370.380.235.280 - ... moire topography MeSH E01.370.350.600.631 - photography, dental MeSH E01.370.350.600.635 - photomicrography MeSH E01.370. ...

https://en.wikipedia.org/wiki/List_of_MeSH_codes_(E01)

Corneal topography. *Optical coherence tomography. *Electrodiagnosis: Electrooculography. *Electroretinography. * ...

https://en.wikipedia.org/wiki/Ishihara_Test

Corneal topography. *Optical coherence tomography. *Electrodiagnosis: Electrooculography. *Electroretinography. * ... Keratomileusis, from Greek κέρας (kéras: horn) and σμίλευσις (smileusis: carving),[1] or corneal reshaping, is the surgical ... Before the advent of the excimer laser, keratomileusis was performed using a cryolathe, which froze thin flaps of corneal ...

https://en.wikipedia.org/wiki/Keratomileusis

Corneal topography. *Optical coherence tomography. *Electrodiagnosis: Electrooculography. *Electroretinography. * ...

https://en.wikipedia.org/wiki/Ophthalmoscopy

Corneal topography. *Optical coherence tomography. *Electrodiagnosis: Electrooculography. *Electroretinography. * ... Corneal collagen cross-linking[edit]. Corneal collagen cross-linking may delay or eliminate the need for corneal ... Corneal transplantation, also known as corneal grafting, is a surgical procedure where a damaged or diseased cornea is replaced ... Intrastromal corneal ring segments[edit]. In corneal disorders where vision correction is not possible by using contact lenses ...

https://en.wikipedia.org/wiki/Keratoplasty

Corneal topography. *Optical coherence tomography. *Scanning laser ophthalmoscopy. Some of these techniques[example needed] are ...

https://en.m.wikipedia.org/wiki/Imaging_studies

Corneal topography. *Eye disease. *List of keratins expressed in the human integumentary system ...

https://ml.wikipedia.org/wiki/കോർണിയ

Corneal opacity. *Corneal topography. *Corrective lens. *Cover test. *Cup-to-disc ratio ...

https://en.wikipedia.org/wiki/Category:Ophthalmology

Corneal topography. *Optical coherence tomography. *Electrodiagnosis: Electrooculography. *Electroretinography. * ...

https://en.wikipedia.org/wiki/Optokinetic_drum

The Ophthalmological Hospital[5] is the hospital that performs more transplants and corneal uptake in Brazil. It was honored at ... with higher relief and the rocks of the Parana Sedimentary Basin and gently rolling topography with lower altitudes. The ...

https://en.wikipedia.org/wiki/Sorocaba

Corneal topography. *Cranial ultrasound. *CT Gastrography. *Current density imaging. D. *Depth kymography ...

https://en.wikipedia.org/wiki/Category:Medical_imaging

... applications of corneal Crosslinking 1999 World's first wavefront-guided laser treatment on the human eye 2002 First topography ... His work and research interests include corneal surgery, especially refractive corneal surgery, surgery of the anterior segment ... He habilitated at the Free University of Berlin in 1987 with his scientific paper "Refractive corneal surgery" and was ... Eyes 1988 World's first Holimum YAG laser PRK thermokeratoplasty 1989 First clinical studies on PRK 1995 Invention of Corneal ...

https://en.wikipedia.org/wiki/Theo_Seiler

... computerized corneal topography, endothelial microscopy, ultrasound pachymetry, b-scan sonography, keratometry and ... Corneal cross-linking with riboflavin (vitamin B2) and UV-A light is a surgical treatment for corneal ectasia such as ... "Corneal collagen crosslinking: A clinical update". Corneal Collagen Cross-Linking on National Keratoconus Foundation website. ... In this group, the most common side effects are haziness of the cornea, punctate keratitis, corneal striae, corneal epithelium ...

https://en.wikipedia.org/wiki/Corneal_cross-linking

In 79% of these cases, sealers did not check the corneal reflex to ensure that the seals were dead prior to hooking or skinning ... There are also words referring to seasons, topography, place names, legends, and kinship relationships based on the seal. One ... of the sealers recorded on the four videotapes failed to palpate the skull or check the corneal reflex before proceeding to ... including checking for a corneal reflex and bleeding animals immediately after clubbing." In 2005, the World Wildlife Fund (WWF ...

https://en.wikipedia.org/wiki/Seal_hunting

"Fast Facts, Geography, Topography". navajobusiness.com. Retrieved 27 July 2017. Comerford, Kevin. "Checkerboard Reservation, ... Other symptoms include corneal anesthesia and scarring, acral mutilation, cerebral leukoencephalopathy, failure to thrive, and ...

https://en.wikipedia.org/wiki/Navajo_Nation

"CXL, topography-guided, customized ablation Tx for keratoconus and post-LASIK". Archived from the original on 2016-03-10. " ... He performs complex corneal collagen and cross-linking (CXL) procedures for keratoconus patients, combined with excimer laser ... He went on to complete his post-doctoral fellowship training in corneal transplantation, cataract surgery and laser refractive ... In 2015, Wallerstein and Cohen launched a new laser vision procedure called Laser PresbyVision™, a corneal-based treatment ...

https://en.wikipedia.org/wiki/Avi_Wallerstein

Sun XC, Bonanno JA (2003). "Identification and cloning of the Na/HCO(3-) cotransporter (NBC) in human corneal endothelium". Exp ... 2003). "Identification of membrane topography of the electrogenic sodium bicarbonate cotransporter pNBC1 by in vitro ...

https://en.wikipedia.org/wiki/Electrogenic_sodium_bicarbonate_cotransporter_1

Corneal pachymetry Corneal reflex Corneal tattooing Corneal topography Eye disease Keratometry List of keratins expressed in ... For corneal epithelial diseases such as Stevens Johnson Syndrome, persistent corneal ulcer etc., the autologous contralateral ( ... The most common corneal disorders are the following: Corneal abrasion - a medical condition involving the loss of the surface ... Corneal dystrophy - a condition in which one or more parts of the cornea lose their normal clarity due to a buildup of cloudy ...

https://en.wikipedia.org/wiki/Cornea

While corneal topography relies on reflected light from the front (anterior) of the cornea, a technique called corneal ... Computerized corneal topography can be employed for diagnostics. It is, in fact, one of the exams the patients have to undergo ... Corneal Topography measuring and modifying the cornea - Schanzlin 1992, page 4-5 Gullstrand A (1909). "Procedure of rays in the ... Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for ...

https://en.wikipedia.org/wiki/Corneal_topography

... this presentation helps identify and interpret corneal topographies in patients scheduled for cataract surgery and demonstr ... Led by a team of topography experts, ...

https://www.aao.org/annual-meeting-video/evaluating-corneal-topography-in-patients-slated-c

Other: Topography guided Excimer Laser treatment and Corneal Cross Linking Other: Corneal Cross Linking Phase 3 ... Other: Topography guided Excimer Laser treatment and Corneal Cross Linking A topography guided excimer laser treatment will be ... Patients will receive a standard corneal cross linking treatment. Other: Corneal Cross Linking A standard corneal cross linking ... Corneal Cross Linking and Topography Guided Excimer Laser Treatment. The safety and scientific validity of this study is the ...

https://www.clinicaltrials.gov/ct2/show/NCT01682993

... central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A.Results: After a mean 15 ± 6.5 (range 6-24 ... The combination of customized PRK and corneal CXL provided safe and effective results in the management of corneal ... and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously ... 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided ...

https://www.dovepress.com/simultaneous-topography-guided-prk-followed-by-corneal-collagen-cross--peer-reviewed-article-OPTH

Home Clinical Education Webinars Corneal Tomography and Topography for the Cataract and Refractive Surgeon ... this webinar will address how the cataract and refractive surgeon can best optimize topography and tomography to achieve better ...

https://ascrs.org/clinical-education/webinars/2016-webinar-corneal-tomography-and-topography-for-the-cataract-and-refractive-surgeon

Forty-three eyes of 22 patients who underwent topography-guided FS-LASIK for myopic correction were included. The ... To observe the epithelial remodeling over a 9-mm diameter cornea induced by topography-guided femtosecond laser-assisted in ... Stromal surface topography-guided custom ablation as a repair tool for corneal irregular astigmatism. J Refract Surg. 2015;31: ... Stromal surface topography-guided custom ablation as a repair tool for corneal irregular astigmatism. J Refract Surg. 2015;31: ...

https://www.healio.com/ophthalmology/journals/jrs/2019-2-35-2/%7Bb0771793-f62e-417b-a73f-802b3541cd28%7D/longitudinal-and-regional-non-uniform-remodeling-of-corneal-epithelium-after-topography-guided-fs-lasik

Findings from anecdotal case reports are supported by clinical studies to highlight the relevance of advances in corneal ... including Placido disk-based corneal topography, Scheimpflug corneal tomography, ocular wavefront analysis, and corneal ... "Corneal topography does augment sensitivity to detect keratoconus in many cases with normal biomicroscopy and normal corrected ... Corneal tomography or topography: When to make the clinical decision. @media screen and (max-width: 468px) { .video-detail .doc ...

https://www.ophthalmologytimes.com/view/corneal-tomography-or-topography-when-make-clinical-decision

Combined topography-guided PRK and corneal collagen cross-linking are a safe and effective option in the management of mild and ... nonrandomized interventional study including 20 eyes of 14 patients with grade 1-2 keratoconus that underwent topography-guided ... i,Purpose.,/i, To evaluate effectiveness of simultaneous topography-guided photorefractive keratectomy and corneal collagen ... The device collects corneal topography, ocular wavefront, autorefraction, and pupillometric data. The topography is Placido- ...

https://www.hindawi.com/journals/joph/2015/321953/

Find any required new, refurbished or used Corneal Topography System Equipment or device. ... used Corneal Topography System Equipment for sale or auction. ... Corneal Topography System may also be referred to as : ... Corneal , Keratography System, Video , Computer Assisted Corneal Topography System , Computed Corneal Topography System ... Tips for buying Corneal Topography System. *Facilities should consider several parameters prior to making the purchase, ...

http://www.medwow.com/used-corneal-topography-system-equipment/281.med?DBPARAM6438=128945

Su Ah Kim, Kui Dong Kang, Ji Sun Paik, Su Kyung Jung, Suk-Woo Yang; Effect of Orbital Decompression on Corneal Topography in ... Corneal topography (Orbscan II), Hertel exophthalmometry, and intraocular pressure were measured at 1 month before and 3 months ... Corneal topographic parameters analyzed were the total astigmatism(TA), steep axis(SA), central corneal thickness(CCT), and ... Effect of Orbital Decompression on Corneal Topography in patients with thyroid ophthalmopathy ...

https://iovs.arvojournals.org/article.aspx?articleid=2335748

Differentiating Keratoconus and Corneal Warpage by Analyzing Focal Change Patterns in Corneal Topography, Pachymetry, and ... Lim L Wei RH Chan WK Tan DT . Evaluation of keratoconus in Asians: role of Orbscan II and Tomey TMS-2 corneal topography. Am J ... Computer-assisted corneal topography devices have become indispensable for diagnosing subclinical/clinical KC and for ... Progression of Keratoconus by Longitudinal Assessment with Corneal Topography You will receive an email whenever this article ...

http://iovs.arvojournals.org/article.aspx?articleid=2188463&resultClick=1

Purpose To assess the refractive improvements and the corneal endothelial safety of an individualised topography-guided regimen ... Refractive improvements and safety with topography-guided corneal crosslinking for keratoconus: 1-year results ... Refractive improvements and safety with topography-guided corneal crosslinking for keratoconus: 1-year results ... corneal collagen crosslinking (CXL); n=25). Visual acuity, refraction, keratometry (K1, K2 and Kmax) and corneal endothelial ...

https://bjo.bmj.com/content/101/7/920

Aladdin HW 3.0-Biometry, Corneal Topography and Premium IOLs by Ike Ahmed, MD ... shares his viewpoint on accurate biometric values and a comprehensive analysis of the corneal surface. ...

http://www.topconmedical.com/about/publications/aladdin-hw-30-biometry-corneal-topography-and-premium-iols.htm

Learn about corneal topography, an important component of a contact lens examination which keeps track of changes within the ... However, corneal topography has revolutionized corneal shape analysis. Instead of just measuring two points, a corneal ... During my annual contact lens exam, my doctor charges an extra fee for corneal topography. What is corneal topography? ... What Is Corneal Topography? Print By Troy Bedinghaus, OD , Medically reviewed by a board-certified physician ...

https://www.verywellhealth.com/what-is-corneal-topography-3421836

The global corneal topography systems market growth is anticipated, owing to a number of factors such as increased prevalence ... Corneal Topography Systems Market Size, Share and Global Trend By Type of Product (Placido-Based Systems, Evaluation-Based ... Corneal topography systems are also known as videokeratography or photokeratoscopy refers to a computerized test, non-invasive ... Systems, Interferometric Systems, Others), By Application (Corneal Disorders, Cataract Surgery Evaluation, Contact Lens Fitting ...

https://www.fortunebusinessinsights.com/enquiry/request-sample-pdf/corneal-topography-systems-market-101136

... subepithelial corneal power and topography for disease diagnosis ... Methods and systems to measure corneal epithelial thickness and ... subepithelial corneal power and topography for disease diagnosis uspto.gov May 23 2017. Ophthalmology , Patents ... subepitheila corneal power and topography. The systems and methods disclosed herein are non-invasive, non-contact and automated ... This invention discloses methods and systems for measuring corneal epithelial thickness and power, stromal thickness, ...

http://www.octnews.org/articles/7044944/methods-and-systems-to-measure-corneal-epithelial-/

... may be reasonable and medically necessary in the following clinical situations. * corneal ulcers ... Corneal topography is performed with a non-contact instrument called a corneal topographer. These instruments work by ... Important clinical functions of corneal topography include the following. * earlier and more accurate diagnosis of corneal ... Corneal Topography. Many eye diseases affect the physical features and shape of the anterior surface of the cornea. These ...

https://www.bondfamilyeyecare.com/treatment-of-eye-disease/diagnostic-tests/corneal-topography/

Your personal data will be used to support your experience throughout this website, to manage access to your account, and for other purposes described in our privacy policy.. ...

https://www.ophthalmicmart.com/tag/corneal-topography/

Corneal topography is a process for mapping the surface curvature of the cornea, similar to making a contour map of land. The ... Corneal Topography?. Corneal topography is not a routine test. Rather, it is used in diagnosing certain types of problems, in ... Assisted Corneal. Topography. Corneal topography is a process for mapping the surface curvature of the cornea, similar to ... Corneal Topography. Work?. The corneal topographer is made up of a computer linked to a lighted bowl that contains a pattern of ...

http://eyehealthconsultants.com/how-we-help-you/hi-tech-eye-diagnostics/computer-assisted-corneal-topography.html

Medmont E300 Corneal Topographer. View Video. The Medmont E300 Corneal Topographer gives accurate mapping of the corneal ... Coverage extends from a minimum ring diameter of 0.25mm to beyond 10mm, which is ideal for detailed assessment of corneal ... Using 32 concentric rings with 9,600 measurement points and 102,000 analyze points, the E300 provides detailed topography data ...

http://www.shattky.co.nz/shattky/how_we_help/eyecare_technology/corneal_topography.htm

... , as the name might suggest, is an imaging technique used to map out the curvature of your cornea (the front ... Diagnosing and monitoring corneal conditions such as Keratoconus. *Investigation of astigmatism for contact lenses and before ...

https://www.maskelloptometrists.com/corneal-topography/

Example of placido based corneal topography. This image depicts a large quantity of "with-the-rule" corneal astigmatism. The ... Example of placido based corneal topography. This image depicts a large quantity of "with-the-rule" corneal astigmatism. The ... Corneal topography. This test, completed by approximately 93% of surgeons performing refractive procedures, is used to assess ... Corneal scarring/haze (, 1-2%). *. Although LASEK may carry a decreased rate of corneal haze relative to PRK, it may still ...

https://emedicine.medscape.com/article/1222702-treatment

Corneal Topography Testing. Duration: 30 seconds. A corneal topographer is a specialized computerized equipment that is used to ... Corneal Topography Testing. Corneal Topography Testing. David Mitchell, OD, discusses Corneal Topography Testing ...

https://www.healthchoicesfirst.com/videos/corneal-topography-testing

Hans Lewis has a distinguished career working at the intersection of healthcare and technology for more than 13 years. He looks after the Partnership and Strategy for DocMode. Prior to the Creation of DocMode.org in 2009, Hans worked in the field of Healthcare Advertising as a Copywriter and followed up as a Sponsorship Head in Medical Events. In the initial years of DocMode, he was the Freelance contributing editor for TMCnet covering articles predominantly in Healthcare IT. He is a Tech autodidact and is also the project Head of the award-winning and patented clinical nutrition management app www.iNutrimon.com Graduated in Advertising, he has a Masters in Philosophy from Mumbai University. Yoga and Logic is his interest areas ...

https://docmode.org/courses/course-v1:aios+AIOS008+2017_May_AIOS008/about

The range of corneal topography measurement (D) in this study was from 32.8D to 46.3D. The mean corneal topography measurement ... The factors that influence a normal corneal topography are not well understood. Factors that may change the corneal curvature ... Therefore, the factors evaluated in this study were cornea topography changes by corneal topography measurement. ... Corneal topography changes following strabismus surgery. 1Universiti Sains Islam Malaysia. Purpose - to determine whether ...

http://www.eyepress.ru/article.aspx?20849

The range of corneal topography measurement (D) in this study was from 32.8D to 46.3D. The mean corneal topography measurement ... The factors that influence a normal corneal topography are not well understood. Factors that may change the corneal curvature ... Therefore, the factors evaluated in this study were cornea topography changes by corneal topography measurement. ... The differences between corneal topography measurement was done using the repeated measure analyses. Results. A total of 17 ...

https://eyepress.ru/article.aspx?20849

These data demonstrate that the PAR CTS is both highly accurate and reproducible in determining topography of spheres that ... The PAR Technology Corneal Topography System Refract Corneal Surg. Jan-Feb 1992;8(1):88-96. ... The PAR Technology Corneal Topography System (PAR CTS) is a prototype of a new computer-assisted corneal imaging device. The ... Conclusions: These data demonstrate that the PAR CTS is both highly accurate and reproducible in determining topography of ...

https://pubmed.ncbi.nlm.nih.gov/1554645/?dopt=Abstract

... a very strong lens responsible for as much as 75% of the eyes ... Computerized Corneal Topography The cornea functions as a very strong lens responsible for as much as 75% of the eyes focusing ... The computerized corneal topography measures this important surface giving us a color coded display containing detailed ... The greatest advantage of the computerized corneal topography is that it can detect conditions too subtle or invisible to even ...

https://eyefreedom.com/computerized-corneal-topography/

Corneal Topography. Topographical map of the front surface of the eye shows the doctor how much and where your astigmatism lies ... Instead of ultrasound, this computer uses a mild beam of laser to measure the axial length and corneal measurements.This has ... The usual measurements are corneal, white to white,and axial length. These numbers are placed in two or more computer programs ...

https://www.rockymountaineye.com/specials/

Corneal topography is interpreted much like other topography maps. The cool shades of blue and green represent flatter areas of ... Corneal topography is used in the diagnosis and management of various corneal curvature abnormalities and diseases such as:. * ... The purpose of corneal topography is to produce a detailed description of the shape and power of the cornea. At Ezekiel Eyes we ... Corneal topography is a process for mapping the surface curvature of the cornea, similar to making a contour map of land. The ...

https://ezekieleyes.com/corneal-topography/

Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. (wikipedia.org)
Nevertheless, topography in itself is a measurement of the first reflective surface of the eye (tearfilm) and is not giving any additional information beside the shape of this layer expressed in curvature. (wikipedia.org)
To investigate the longitudinal changes in corneal topographic indices over time in patients with mild keratoconus (KC) and to determine predictive factors for the increase in corneal curvature. (arvojournals.org)
Corneal topography is a process for mapping the surface curvature of the cornea, similar to making a contour map of land. (eyehealthconsultants.com)
The Medmont E300 Corneal Topographer gives accurate mapping of the corneal curvature and that is integrated into Medmont Studio software environment. (shattky.co.nz)
Corneal Topography, as the name might suggest, is an imaging technique used to map out the curvature of your cornea (the front, clear part, of your eye). (maskelloptometrists.com)
This test, completed by approximately 93% of surgeons performing refractive procedures, is used to assess the shape and the curvature of the corneal surface. (medscape.com)
This test, using either scanning slit-beam or Scheimpflug technology, gives information about corneal thickness and posterior corneal curvature, in addition to the anterior corneal curvature information that is presented on standard corneal topographic maps. (medscape.com)
In this system, the corneal curvature was divided into 12 spots and measured in diopters (D) prior to the operation, 6 weeks postoperation and 12 weeks postoperation. (eyepress.ru)
From Fig., we could observe that there were at certain points in which the corneal curvature decreased at 6 weeks postoperation but increased again after 12 weeks postoperatively however there was no significant difference in corneal topography changes over time after horizontal muscle strabismus correction surgery with Wilks' Lambda = 0.971, F=2.895 and p=0.058. (eyepress.ru)
Factors that may change the corneal curvature measured using corneal topography in a normal eye include accommodation and external forces such as those exerted by the eye lid [6]. (eyepress.ru)
Suture and muscle placement are the mechanical forces that may alter the corneal curvature. (eyepress.ru)
If a muscle is placed too close to the limbus or tied to the sclera under tightly, the corneal curvature might be altered [2]. (eyepress.ru)
Although it has been reported that there are changes of the corneal curvature following extraocular muscle surgery, the effect was also known to be transient [2, 7]. (eyepress.ru)
These data demonstrate that the PAR CTS is both highly accurate and reproducible in determining topography of spheres that approximate the curvature of the human cornea. (nih.gov)
Corneal topography provides us with the most detailed possible information about the curvature of the eye and potential eyesight and eye disease issues. (ezekieleyes.com)
Computerized analysis of the diameter of the ring reflections can measure radius of curvature at specific points and across the entire corneal surface as a whole. (la-sight.com)
The even, symmetric curvature creates a topography map with very little variation across the surface. (la-sight.com)
Topography and photokeratoscope maps can disclose pathologic conditions such as keratoconus , in which there is distortion of surface curvature, significant topographic asymmetry, and abnormal steepening of the central area of the cornea (orange and red in the map). (la-sight.com)
Conductive Keratoplasty for Changing Corneal Curvature 11. (ophthabooks.eu)
Corneal topography is a computer assisted diagnostic tool that creates a three-dimensional map of the surface curvature of the cornea. (salandvision.com)
A computer-guided device creates a 3-D image map of your cornea to measure corneal power, curvature, and thickness. (dukehealth.org)
Small variations in corneal curvature originating from genetic disease, or post-surgical complications, can affect vision negatively. (vistaeyecareco.com)
he also proposed to photograph the image generated and to represent it on a diagram, which was aimed to analyze the variations in the curvature observed in the corneal surface. (biomedcentral.com)
He joined the discs to his photokeratoscope and examined the corneal photographs using a microscope in order to calculate the corneal curvature by a numerical algorithm. (biomedcentral.com)
The flattest, or lowest overall dioptric power is likely to be the most accurate measurement of corneal curvature. (thefreedictionary.com)
Although the primary aim of corneal cross-linking (CXL) is to stop the progression of keratoconus ectasia, it may, as a welcomed side effect, also result in a decrease in corneal curvature and in a flattening of the apex. (biomedcentral.com)

It is, in fact, one of the exams the patients have to undergo prior to the Cross-linking and the Mini Asymmetric Radial Keratotomy (M.A.R.K.). For example, the KISA% index (keratometry, I-S, skew percentage, astigmatism) is used to arrive at a diagnosis of keratoconus, to screen the suspect keratoconic patients and analyse the degree of corneal steepness changes in healthy relatives. (wikipedia.org)
Topography guided laser treatment enables the surgeon to correct higher order aberrations in corneas with irregular astigmatism. (clinicaltrials.gov)
Keratoconus is a chronic bilateral noninflammatory corneal degeneration, characterized by localized corneal thinning and corneal steepening, leading to irregular astigmatism and impaired visual acuity [ 1 ]. (hindawi.com)
Topography-guided PRK to correct ametropia and irregular astigmatism in form fruste and frank keratoconus was introduced over a decade ago [ 7 - 9 ] with good results. (hindawi.com)
When dealing with corneal abnormalities, such as keratoconus or irregular astigmatism, specialists should decide whether a corneal topography system is more valuable than a keratometer. (medwow.com)
This study was performed to evaluate the changes of corneal astigmatism in patients undergoing orbital decompression surgery. (arvojournals.org)
Corneal topographic parameters analyzed were the total astigmatism(TA), steep axis(SA), central corneal thickness(CCT), and anterior chamber depth(ACD). (arvojournals.org)
Using Astig PLOT TM , the mean surgically induced astigmatism (SIA) was 0.21±0.88D with the axis of 46±22° which suggest that decompression surgery did change the corneal shape and induced incyclotorion of the steepest axis. (arvojournals.org)
There is a significant change in corneal astigmatism after orbital decompression surgery and this change is sufficient to affect the optical function of the cornea. (arvojournals.org)
This corneal thinning induces irregular astigmatism, myopia, and protrusion, which leads to mild to marked impairment in vision quality. (arvojournals.org)
These conditions can produce corneal shape anomalies such as irregular astigmatism that result in visual impairment. (bondfamilyeyecare.com)
This image depicts a large quantity of "with-the-rule" corneal astigmatism. (medscape.com)
This analysis attempts to depict optical aberration of the corneal surface in an effort to find irregular astigmatism and refractive error. (medscape.com)
This information is useful to evaluate and correct astigmatism, monitor corneal disease, and detect irregularities in the corneal shape. (ezekieleyes.com)
In cases of severe astigmatism, special lenses can be used during cataract surgery as a result of the topography. (augenklinik-bern.ch)
and provides a visual display of corneal astigmatism. (la-sight.com)
The topography study above shows a normal cornea with very minimal astigmatism. (la-sight.com)
The topography study above also shows a normal cornea, this one with a bit more regular (symmetric) astigmatism. (la-sight.com)
We retrospectively collected corneal topographies of the study group with clinically manifested keratoconus and the control group with regular astigmatism. (arvojournals.org)
Keratoconus is a noninflammatory corneal disease characterized by stromal thinning, anterior protrusion, and irregular astigmatism. (arvojournals.org)
[ 5 ] Photorefractive keratectomy (PRK) has been used successfully for hyperopia but has problems of regression, induced astigmatism, and corneal haze, thereby limiting its usefulness to the correction of mild hyperopia only. (medscape.com)
The investigators' purpose is to study the induced refractive change caused by different 2.8-mm corneal incision locations in phacoemulsification, because the investigators hypothesize that the effect may be different for nasal, temporal, and superior location, although they are considered astigmatism neutral. (clinicaltrials.gov)

After topography-guided FS-LASIK, the 9-mm diameter epithelial thickness showed a longitudinal and regional non-uniform redistribution. (healio.com)
Optical coherence tomography (OCT) is a non-contact method of measuring the corneal epithelial thickness with good repeatability and reproducibility. (healio.com)
Scheimpflug corneal tomography is a three-dimensional imaging technique that characterizes the anterior/posterior corneal surfaces, along with corneal thickness distribution. (ophthalmologytimes.com)
One such report described a case of unilateral ectasia identified in a patient who had been referred for treatment of keratoconus in his right eye.14 Unilaterality of the ectatic disease was confirmed by extensive diagnostic evaluation, including Placido disk-based corneal topography, Scheimpflug corneal tomography, ocular wavefront analysis, and corneal segmental tomography with epithelial thickness mapping by very high frequency digital ultrasound and spectral-domain OCT. (ophthalmologytimes.com)
The unoperated eye would be considered a good candidate for LASIK based on findings from standard screening methods, which included a normal front surface topography and central corneal thickness of 542 µm," he said. (ophthalmologytimes.com)
4 Because KC progresses, contour and thickness measurements by corneal topography taken over time can help track the disease course. (arvojournals.org)
This invention discloses methods and systems for measuring corneal epithelial thickness and power, stromal thickness, subepitheila corneal power and topography. (octnews.org)
A pachymeter is a device used for the exact measurement of corneal thickness (accuracy 1 to 5 micrometers (μm) This is relevant for the correct determination of the intraocular pressure by tonometry, since the measured value is influenced by the corneal thickness in most common methods. (augenklinik-bern.ch)
With the result of the corneal thickness the actual intraocular pressure can be calculated. (augenklinik-bern.ch)
After applying an anesthetic drop to the cornea, a small pencil touches the corneal surface and measures the thickness using ultrasound. (augenklinik-bern.ch)
The surgeon replaces only certain layers of your cornea with donor tissue in these alternatives to full-thickness corneal transplant. (dukehealth.org)
If the corneal thickness is less than 400 microns, instill Photrexa drops (riboflavin without dextran) every 5 to 10 seconds until the corneal thickness increases to at least 400 microns. (ophthalmologytimes.com)
Keratoconus patients with a minimal corneal thickness of 400 μm were offered CXL in case of confirmed disease progression. (biomedcentral.com)
You will see the doctor after watching the 3 videos and he will advise you what type of LASIK can be done depending on your corneal thickness and your degree of shortsightedness (doesn't mean you are suitable for the most expensive one). (lesterchan.net)
There is a negative correlation between optic disc size and corneal thickness and biomechanical properties. (scielo.br)
Working with Dan Reinstein, Dr. Silverman developed software for processing 3-D scans of the cornea that allowed measurement and mapping of corneal thickness as well as the thickness of the stroma and epithelium. (wikipedia.org)
Use of ultrasonic pachymetry for measurement of changes in corneal thickness in mouse corneal transplant rejection. (biomedsearch.com)
The aims of this study were to (1) evaluate a pachymetry technique to measure changes in mouse corneal thickness and (2) correlate increases in transplant thickness with clinical and histological features of rejection. (biomedsearch.com)
Graft transparency was graded and corneal thickness measured by pachymetry on alternate days. (biomedsearch.com)
Stromal cellularity increased with increasing corneal thickness up to approximately 300 microm. (biomedsearch.com)

This blade is a finer tool than the microkeratome used in laser assisted in situ keratomileusis (LASIK) so that it enables the surgeon to cut through the outer corneal epithelium without penetrating deeper corneal layers, specifically the Bowman layer, which promotes scar tissue formation. (medscape.com)
Allows your doctor to examine the cellular structure of your cornea and to see normal and abnormal cells in the various corneal layers (epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium) as well as infectious cells such as fungi and amoeba. (dukehealth.org)
17. Alvarado J, Murphy C, Juster R. Age-related changes in the basement membrane of the human corneal epithelium. (ssmj.ru)
This study investigates the use of single-fit lenses for ortho-k and how they effect the corneal epithelium. (clspectrum.com)
LASEK and PRK permanently change the shape of the anterior central cornea using an excimer laser to ablate (remove by vaporization) a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium . (wikipedia.org)
With PRK, the corneal epithelium is removed and discarded, allowing the cells to regenerate after the surgery. (wikipedia.org)
19],[20] Normal corneal nerves are important in maintaining the homeostasis of corneal epithelium, but their injury can cause corneal dystrophy , which may be one pathogenesis for diabetic keratopathy. (thefreedictionary.com)
The technique involves topical application of riboflavin/dextran solution onto eye after removal of corneal epithelium. (bioportfolio.com)

Tomographic normal values for corneal elevation and pachymetry in a hyperopic population. (ssmj.ru)
CONCLUSION: In vivo graft pachymetry provides a new and reliable way to objectively diagnose rejection in the mouse model of corneal transplantation. (biomedsearch.com)

This treatment involves administering riboflavin eye drops, which penetrate into the corneal stroma. (drholzman.com)
CXL aims to mitigate the progression of this distortion by strengthening the corneal stroma. (ophthalmologytimes.com)
Uptake is confirmed by a homogeneous green fluorescence throughout the corneal stroma and by the presence of a yellow/green flare in the anterior chamber. (ophthalmologytimes.com)
Photrexa is a relatively hypotonic solution which swells the corneal stroma, the goal of which is to protect the endothelium from damage by the riboflavin/UV interaction. (ophthalmologytimes.com)
These masks were centered on the exposed corneal stroma between the laser beam and the eye, successively starting with the 4.5-mm mask, followed by the 4-mm mask, and, finally, the 3.5-mm mask, to allow the final ablation pattern to reveal a central graduated steepening comprised of 3 concentric rings. (medscape.com)
Transparent lenses on the patient's corneal stroma allowed visualization of the fixation light. (medscape.com)
New blood vessels originating from the corneal veins and extending from the limbus into the adjacent CORNEAL STROMA. (bioportfolio.com)
Neovascularization in the superficial and/or deep corneal stroma is a sequel to numerous inflammatory diseases of the ocular anterior segment, such as TRACHOMA, viral interstitial KERATITIS, microbial KERATOCONJUNCTIVITIS, and the immune response elicited by CORNEAL TRANSPLANTATION. (bioportfolio.com)
The principle of the procedure is to induce collagen crosslinking of the corneal stroma by the using riboflavin/UVA-treatment. (bioportfolio.com)

The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK) and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus. (dovepress.com)
To evaluate effectiveness of simultaneous topography-guided photorefractive keratectomy and corneal collagen cross-linking in mild and moderate keratoconus. (hindawi.com)
Prospective nonrandomized interventional study including 20 eyes of 14 patients with grade 1-2 keratoconus that underwent topography-guided PRK using a Custom Ablation Transition Zone (CATz) profile with 0.02% MMC application immediately followed by standard 3 mw/cm 2 UVA collagen cross-linking. (hindawi.com)
Combined topography-guided PRK and corneal collagen cross-linking are a safe and effective option in the management of mild and moderate keratoconus. (hindawi.com)
Corneal collagen cross-linking has found a broad international application for keratoconus in recent years [ 2 , 3 ]. (hindawi.com)
The combination of ultraviolet A (UVA) light with riboflavin as a photosensitizing agent produces interfibrillar cross-linking between corneal stromal collagen fibers, thus increasing corneal rigidity and halting the ectatic process. (hindawi.com)
The aim of this study is to evaluate the effectiveness of combined corneal collagen cross-linking and topography-guided PRK in cases of mild and moderate keratoconus using an advanced ablation software with the Quest laser platform (Nidek, Gamagori, Japan). (hindawi.com)
Patients with FFKC who seek laser vision correction should be dissuaded from having LASIK (sculpting under a thin flap of superficial tissue), but may be candidates for PRK, which renders teh sculpting on the outermost layer of corneal collagen. (la-sight.com)
Accelerated corneal collagen cross-linking yielded results similar to those of conventional cross-linking while markedly reducing exposure time with the same treatment dose, according to a study.The case series study included 39 eyes of 22 patients with keratoconus. (linkoph.com)
On the heels of the recent FDA approval of corneal collagen crosslinking, some surgical pearls are provided for the treatment of progressive keratoconus and corneal ectasia. (ophthalmologytimes.com)
Teaneck, NJ -Corneal collagen crosslinking (CXL) is a treatment designed to decrease the progression of keratoconus, a disease typified by distortion of the normal corneal optical dome secondary to biomechanical structural weakening. (ophthalmologytimes.com)
Magdy Ezzat Khallaf ,Mohamed Ahmed El Mallah ,Rasha Hassan Ismail , Topography-guided photo-refractive keratectomy followed by corneal collagen cross-linking for keratoconus, Egypt. (who.int)
Prospective, randomized multicenter study to determine the safety and effectiveness of performing corneal collagen cross-linking (CXL) using riboflavin and UVA light in eyes with ectasia a. (bioportfolio.com)
To compare the clinical outcome 2 years after corneal collagen cross-linking (CXL) with conventional and accelerated ultraviolet A (UVA) irradiation using riboflavin with hydroxypropyl methylcellulose. (bioportfolio.com)

Another report presented the case of a patient who developed post-LASIK ectasia despite being considered at low risk based on preoperative topographic evaluation.12 Findings from corneal tomographic and biomechanical measurements identified ectasia risk in the fellow unoperated eye. (ophthalmologytimes.com)
The system produces a true topographic map (elevation map) by analyzing a projected grid on the corneal surface, as opposed to a placido disk reflection, and utilizes the technique of raster photogrammetry to define elevation points on the corneal surface. (nih.gov)
Shown above is a topography study reflecting mild topographic asymmetry. (la-sight.com)
Computer software digitizes these data points to produce a printout of the corneal shape, using assorted colors to identify different elevations, much like a topographic map of the earth displays changes in the land surface. (salandvision.com)
The DL models had fair accuracy for keratoconus screening based on corneal topographic images. (arvojournals.org)
As you look at the bowl, the topography machine uses a series of data points to measure the "highs and lows" of your cornea, creating a corneal map that's similar to a topographic map of geographic features. (drleaks.com)
In a retrospective study, 3rd-order to 6th-order HOAs from preoperative and 3-month postoperative corneal topographic maps of eyes that had hyperopic LASIK using the Visx Star S2 and Visx Star S3 laser systems were calculated. (nih.gov)

For patients with an atypical corneal shape, VK is a helpful process, particularly for refractive surgery and contact lens candidates. (medwow.com)
Orbscan Corneal Mapping in Refractive Surgery 6. (ophthabooks.eu)
Corneal topography provides a detailed "map" of your cornea that's important for contact lens fitting, laser refractive surgery, and diagnosing and managing issues that affect the cornea. (drleaks.com)
Placido disk corneal topography (PDCT) is the gold standard procedure to detect and diagnose corneal aberrations (i.e., keratoconus), analyze pre- and postoperative results of refractive surgery, and aid in contact lens fitting. (scielo.br)

The third in the ASCRS Phaco FUNdamentals series, this webinar will address how the cataract and refractive surgeon can best optimize topography and tomography to achieve better surgical results and will discuss anterior segment imaging. (ascrs.org)
To observe the epithelial remodeling over a 9-mm diameter cornea induced by topography-guided femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia correction using spectral-domain optical coherence tomography (SD-OCT). (healio.com)
Corneal tomography represents a major advance for diagnosis, prognosis, and treatment planning, but there remains a need for classic imaging technologies, such as Placido topography, along with a comprehensive clinical evaluation, said Renato Ambrósio Jr., MD, PhD. (ophthalmologytimes.com)
Dr. Ambrósio said that a classic question about tomography relates to whether it is a more sensitive modality than Placido disk-based topography to detect mild forms of keratoconus and screen for ectasia risk prior to refractive laser vision correction (LVC). (ophthalmologytimes.com)
The integrated Scheimpflug-based corneal tomography and biomechanical analysis provided with the Pentacam and Corvis systems (both Oculus) generates the Tomographic and Biomechanical Index (TBI), which was developed to enhance diagnostic sensitivity, he said. (ophthalmologytimes.com)
Objective: The aim was to compare the corneal topography and tomography parameters of macular corneal dystrophy (MCD) granular corneal dystrophy (GCD) and lattice corneal dystrophy (LCD) patients obtained by Scheimpflug imaging system. (thefreedictionary.com)
Optic disc area and geometry was accessed by HRT III ( Heidelberg Retina Tomography - Heidelberg eng ), Pentacam (Oculus) was used for accessing IOP and corneal parameters and ORA ( Ocular Response Analyze - Reichert) was utilized to access corneal biomechanical properties. (scielo.br)

Several case reports and small uncontrolled trials have been published on the combination of this treatment with corneal cross linking (CCL) in patients with ectatic corneal diseases. (clinicaltrials.gov)
This randomized study will evaluate the safety and efficacy of a combined treatment of corneal cross linking with a partial topography guided excimer laser treatment in eyes with progressive ectatic corneal diseases. (clinicaltrials.gov)
Your corneal surgeon will conduct a thorough examination of your eye and its structures using a variety of imaging devices to help diagnose any corneal disorders or diseases. (dukehealth.org)
Corneal topography typically is only performed in patients who may be at risk for certain eye diseases or conditions, who wear or want to wear contact lenses, or who have vision issues that the doctor feels might be related to or involve the cornea. (drleaks.com)
Review 8+ years of Clinical experience of surgical management of Keratoconus and other ectatic diseases using Topography Guided PRK + Corneal Crosslinking. (wcea.education)
Detection of ectatic corneal diseases based on Pentacam. (ssmj.ru)
This new technology permits earlier diagnosis of many corneal diseases, provides vital information to eye surgeons for preoperative and post-operative decision making and provides helpful information for the fitting of contact lenses. (uic.edu)
Corneal irregularities in ectatic diseases such as keratoconus degrade the eye's optical quality and visual performance because of the increase in higher order aberrations (HOA) [ 1 ]. (biomedcentral.com)
We will also examine for any potentially sight-threatening conditions such as corneal ulcers, glaucoma, retinal diseases, and optic nerve disorders. (np.edu.sg)

In the quest for enhanced ectasia diagnosis, we have to go beyond topography, which only provides two-dimensional information about the front surface of the cornea,' said Dr. Ambrósio, professor of ophthalmology, Federal University of the State of Rio de Janeiro (UniRIO), Brazil. (ophthalmologytimes.com)
Corneal Ectasia Post-Lasik: The Orbscan Advantage 5. (ophthabooks.eu)
When it comes to treating corneal ectasia or keratoconus, corneal cross-linking is an effective method . (drholzman.com)
In corneal ectasia, average maximum keratometry improved by approximately 0.7 D. (ophthalmologytimes.com)
The optical quality in progressive keratoconus deteriorates due to ectasia and distortion of the corneal shape and optics. (biomedcentral.com)
The purpose of this evaluation is to assess the safety and efficacy of riboflavin-UVA induced cross-linking treatment for corneal ectasia due to keratoconus and LASIK keratectasia. (bioportfolio.com)
Corneal ectasia is a relative weakness in the structure of the cornea, which produces a progressive change in its shape which results in visual distortion. (bioportfolio.com)

A corneal topographer projects a series of illuminated rings, referred to as a placido disc, onto the surface of the cornea, which are reflected back into the instrument. (verywellhealth.com)
Instead of just measuring two points, a corneal topographer can measure hundreds and even thousands of data points to build a much more precise color map of the overall steepness of the eye in any location the doctor is interested in. (verywellhealth.com)
A corneal topographer will be able to show how rough the surface is and how a dry eye may be affecting your vision. (verywellhealth.com)
Corneal topography is performed with a non-contact instrument called a corneal topographer. (bondfamilyeyecare.com)
Using computerized imaging technology, the 3-dimensional map produced by the corneal topographer aids an ophthalmologist in the diagnosis, monitoring, and treatment of various visual conditions. (eyehealthconsultants.com)
The corneal topographer is made up of a computer linked to a lighted bowl that contains a pattern of concentric rings. (eyehealthconsultants.com)
A corneal topographer is a specialized computerized equipment that is used to map the surface of the eye. (healthchoicesfirst.com)
All measurements were obtained with Haag-Streit corneal topographer. (eyepress.ru)
At Ezekiel Eyes we use computerized imaging technology, and the 3-dimensional map produced by the corneal topographer aids us in the diagnosis, monitoring, and treatment of various visual conditions. (ezekieleyes.com)
In our practice, we use the E300 Corneal Topographer from Medmont (and distributed in the United States by Nidek, Inc). The E300 analyzes 102,000 corneal points with a standard deviation of error of less than 2 microns and is capable of measuring the cornea from limbus to limbus. (optometricoffice.com)
began studying this issue by re-purposing the corneal topographer to measure the surface profile of four commercially available brands of soft, simultaneous-designed, multifocal contact lenses. (specialeyesqc.com)
Corneal scans using our Zeiss Atlas 9000 Corneal Topographer allows our doctors to view the cornea in a more detailed way than is afforded with only our biomicroscopes. (vistaeyecareco.com)
The information the corneal topographer provides is useful in monitoring disease, diagnosing disease, fitting custom contact lenses, and is used in Myopia Management . (vistaeyecareco.com)
The corneal topographer picks up the distortion of the cornea that is typical of this disease and leads to our ability to diagnose the cause of vision loss. (vistaeyecareco.com)
The first fully automated corneal topographer was called Corneal Modeling System (CMS-1), developed by Computed Anatomy Inc. (New York, USA). (biomedcentral.com)

A development of keratoscopy, corneal topography extends the measurement range from the four points a few millimeters apart that is offered by keratometry to a grid of thousands of points covering the entire cornea. (wikipedia.org)
Visual acuity, refraction, keratometry (K1, K2 and K max ) and corneal endothelial morphometry were assessed preoperatively and at 1, 3, 6 and 12 months postoperatively. (bmj.com)
Keratometry: Before computerized corneal topographers were invented, a keratometer was used to measure a small area in the central cornea. (verywellhealth.com)
The primary efficacy criterion was a difference in the change in maximum keratometry on corneal topography analysis between treatment and sham control groups. (ophthalmologytimes.com)
The mean number of days until stability is reached in the soft lens wearers is: 10.7 10.4 days for manifest refraction, 16.2 17.5 days for keratometry and 28.1 17.7 days for topography. (constantcontact.com)
Objective: To determine the effect of 23-gauge pars plana vitrectomy on corneal dioptric power through a comparison of difference in preand postsurgery keratometry. (thefreedictionary.com)

During my annual contact lens exam, my doctor charges an extra fee for corneal topography. (verywellhealth.com)
Coverage extends from a minimum ring diameter of 0.25mm to beyond 10mm, which is ideal for detailed assessment of corneal pathologies and accurate contact lens fitting. (shattky.co.nz)
Corneal mapping allows us to evaluate important corneal characteristics necessary for an optimal contact lens fit. (optometricoffice.com)
Assessing Soft Multifocal Contact Lens Centration With the Aid of Corneal Topography. (specialeyesqc.com)
Following the procedure, a protective contact lens will be placed over the eye while the corneal tissue regenerates. (drholzman.com)
Fungal keratitis is of growing concern amongst contact lens wearers, and is a serious and painful corneal disease caused by a fungal organism. (newsightlasikcenter.com)
The contact lens consultation begins with asking about your visual demands and lifestyle, followed by measurement of your corneal dimensions. (np.edu.sg)
It also can be used before contact lens fittings and corneal transplants and for patients with other corneal problems. (clevelandclinic.org)

The corneal topograph owes its heritage to the Portuguese ophthalmologist Antonio Placido, who, in 1880, viewed a painted disk (Placido's disk) of alternating black and white rings reflected in the cornea. (wikipedia.org)
Example of placido based corneal topography. (medscape.com)
In placido-based topography, a series of light rings is projected onto the eye, outlining the cornea. (medscape.com)
This review article attempts to compare the Scheimpflug with the Placido disc systems, stresses the value of elevation-based topography and the importance of posterior float. (edu.au)
Current corneal topography is based on the development of the Goode keratoscope by Antonio Placido da Costa [ 3 ], who developed it in 1880. (biomedcentral.com)
Corneal topographers based on this technology, also called videokeratoscopes, are based on the application of the principles of convex mirrors' geometrical optics to an instrument in which the rings or Placido discs with known size and spacing are reflected on the anterior surface of the cornea. (biomedcentral.com)

To highlight the misalignment between the center of the multifocal optics and a patient's visual axis, Dr. Lampa first performed corneal topography for 18 subjects without contact lenses on the eye. (specialeyesqc.com)
Corneal topography involves measuring subtle variations in a patient's corneal curvatures. (vistaeyecareco.com)
Later, in the mid-nineteenth century, the Goode keratoscope appeared and enabled a corneal examination using the lateral reflection of a bright square object projected onto the patient's cornea. (biomedcentral.com)

In a 71 eye study, we noted an improvement in corneal topography indices using Scheimpflug imaging, including the keratoconus index (KI), index of surface variance (ISV) and index of vertical asymmetry (IVA). (ophthalmologytimes.com)
METHODS: Corneal data were acquired using a rotating Scheimpflug camera before and 1 month and 3 months after DSEK. (biomedsearch.com)

In India, ocular trauma, infectious keratitis, corneal ulceration and post-infectious keratitis corneo-iridic scars contribute significantly to the paediatric ocular morbidity whereas in adults, the major causes of corneal blindness include bacterial, fungal or viral keratitis, hereditary corneal dystrophy and eye injuries. (thefreedictionary.com)

Since then, several studies have evaluated the simultaneous use of topography-guided PRK followed immediately by CXL in progressive keratoconus [ 9 , 11 - 13 ]. (hindawi.com)
Purpose To assess the refractive improvements and the corneal endothelial safety of an individualised topography-guided regimen for corneal crosslinking in progressive keratoconus. (bmj.com)
Thirty-seven patients (50 eyes) with progressive keratoconus planned for corneal crosslinking were included. (bmj.com)

You may be a candidate for corneal transplantation if you have been diagnosed with keratoconus, which causes your cornea to become thin and cone-shaped, or when an inherited corneal dystrophy, such as Fuchs' dystrophy, results in vision-impairing corneal swelling and clouding. (dukehealth.org)
You may also be a candidate for corneal transplantation if your cornea has been damaged by infection, scarring, or trauma. (dukehealth.org)
BACKGROUND/AIMS: Diagnosis of rejection in the mouse model of corneal transplantation is based on subjective judgement of loss of graft transparency. (biomedsearch.com)

Study subjects were strabismus patients under the care of Eye Clinic, Universiti Kebangsaan Malaysia medical centre, planned for strabismus correction involving horizontal rectus muscles and cooperative for corneal topography and objective refraction. (eyepress.ru)

However, prices have fallen substantially over time, bringing corneal topographs into the budget of smaller clinics and increasing the number of patients that can be examined. (wikipedia.org)
Topography Guided Excimer Laser Surface Ablation in Combination With Corneal Cross-linking (CCL) in Patients With Progressive Ectatic Corneal Disorders. (clinicaltrials.gov)
Patients will receive a topography guided laser treatment in combination with a standard corneal cross linking treatment in the same session. (clinicaltrials.gov)
Forty-three eyes of 22 patients who underwent topography-guided FS-LASIK for myopic correction were included. (healio.com)
The TBI was developed by Dr. Ambrósio and colleagues in a multicenter study including one randomly selected eye from subgroups of patients with normal (n = 480) or keratoconic corneas (n = 204) and using the random forest method with leave-one out cross-validation, an efficient artificial intelligence technique for classification.1 The study also included 94 eyes with normal topography from patients with VAE. (ophthalmologytimes.com)
Several adjuvant therapies in combination with CXL have been proposed in an effort to develop a technique that can offer patients keratectasia corneal stability together with improved functional vision, including intracorneal rings [ 5 ] and phakic intraocular lenses [ 6 ]. (hindawi.com)
Corneal topography becomes a crucial step in determining the correct lens parameters for our patients. (optometricoffice.com)
Using corneal mapping to look at the distribution of power becomes important when fitting patients for myopia control. (optometricoffice.com)
Patients who choose corneal cross-linking with topography-guided PRK can rest assured knowing they are receiving the most predictable treatment available. (drholzman.com)
Methodology: the present study was designed to evaluate simultaneous topography-guided partial PRK and CXL as a therapeutic intervention in patients with KC. (who.int)
The purpose of the study was to analyze corneal topography in patients with cataract after previous anterior radial keratotomy Material and Methods. (ssmj.ru)
Optimization of the calculation of the optical power of the toric IOL in patients with cataracts and altered corneal topography. (ssmj.ru)
Overall, our novel approach of combined EK and MICS can be performed for patients with Fuchs' corneal dystrophy and dense cataract. (thefreedictionary.com)

By incorporating full corneal topography and wavefront analysis of the cornea the ALADDIN addresses the limitations of conventional biometers. (topconhk.com)

A topography guided excimer laser treatment will be performed prior to CCL in one session. (clinicaltrials.gov)
After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A. (dovepress.com)
Each technique focuses on creating an epithelial flap under which an excimer laser is used to sculpt the corneal tissue. (medscape.com)
While corneal cross-linking (CXL) aims at stopping disease progression, "CXL-Plus" combines CXL with excimer laser ablation to improve visual function. (biomedcentral.com)
Central Corneal Regularization (CCR) represents a therapeutic excimer laser modality specifically designed to smoothen the ectatic corneal shape and to reduce higher order aberrations (HOA). (biomedcentral.com)

A comprehensive ophthalmological examination was performed, including the topography of the cornea using a Pentacam HR apparatus (Oculus, Germany) with the determination of elevation points of the anterior cornea. (ssmj.ru)
Normative Pentacam anterior and posterior corneal elevation measurements: effects of age, sex, axial length and white-to-white. (ssmj.ru)
Qualitative analysis selected 10 EyeSys and 15 Pentacam topographies used in the quantitative evaluation. (scielo.br)

The factors that influence a normal corneal topography are not well understood. (eyepress.ru)
A normal corneal topography study is shown above. (la-sight.com)

Duke corneal surgeons have extensive experience and perform hundreds of corneal transplants each year using the latest advances. (dukehealth.org)

The mechanism of topography-guided ablation is the fitting of an ideal corneal shape (usually a sphere) under the present topography map with the ablation of tissue in between. (hindawi.com)
However, the fact that cross-linked corneas may have a different ablation rate from normal corneas-which could lead to unpredictable PRK results-and the hypothesis that the removal of the cross-linked corneal tissue by the PRK procedure could decrease the stiffening effects of the CXL treatment in addition to the increased possibility of haze formation after PRK were serious limitations [ 3 ]. (hindawi.com)
The corneal topography map is used in conjunction with other tests to determine exactly how much corneal tissue will be removed to correct the visual defect. (eyehealthconsultants.com)
The outermost layer of the cornea is removed, allowing the eye drops to penetrate the corneal tissue with ease. (drholzman.com)
There are several types of corneal transplant procedures to remove damaged, unhealthy cornea tissue. (dukehealth.org)
During this procedure -- also called penetrating keratoplasty (PK) -- the corneal transplant surgeon removes all layers of the diseased cornea and replaces it with clear, healthy cornea tissue from a donor. (dukehealth.org)
Restores vision by removing the severely damaged or diseased cornea and replacing it with an acrylic artificial cornea and donor corneal tissue that is sutured in place. (dukehealth.org)
the pattern and sequence selected to allow a cloud of ablated corneal tissue particles to dissipate in one place before contacting that place again with another laser shot. (google.com)

A standard corneal cross linking procedure will be performed in this arm. (clinicaltrials.gov)
They introduced a two-step procedure with CXL performed first and topography-guided PRK after a 1-year interval [ 2 ]. (hindawi.com)
Corneal topography is a procedure used to monitor and measure changes that may occur to the shape and integrity of the cornea of your eye. (verywellhealth.com)
Outcome measured was changes of the corneal topography before strabismus correction surgery and after the procedure. (eyepress.ru)
At the ophthalmology practice of Dr. Andrew E. Holzman in Washington, D.C. , we offer corneal cross-linking with topography-guided PRK to reduce the risk of regression and other complications following the procedure. (drholzman.com)
A minimally invasive procedure, corneal cross-linking, also called CXL, is used in the treatment of keratoconus, a condition that causes the cornea to bulge. (drholzman.com)
Because corneal cross-linking itself is minimally invasive, undergoing this procedure at the same time as PRK does not result in any additional post-operative discomfort. (drholzman.com)
If you are considering vision correction surgery, combining corneal cross-linking with your procedure can offer significant benefits. (drholzman.com)
The procedure is typically recommended when less-invasive corneal disease treatments, such as special glasses or contact lenses, and medications to reduce swelling cannot halt the progression of your corneal disease. (dukehealth.org)

Instead of ultrasound, this computer uses a mild beam of laser to measure the axial length and corneal measurements.This has its ownprogram for calculating the proper intraocular lens powers. (rockymountaineye.com)
To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography . (bvsalud.org)

Centration Analysis of Ablation Over the Coaxial Corneal Light Reflex for Hyperopic LASIK. (specialeyesqc.com)
The technique routinely used for hyperopic LASIK uses a 110- to 160-µm thick corneal flap and a wide ablation with a peripheral blend zone. (medscape.com)

Schnyder dystrophy is a slowly progressive corneal dystrophy with autosomal dominant inheritance. (thefreedictionary.com)
This situation went on for another year before she was eventually diagnosed with corneal dystrophy in 2011. (thefreedictionary.com)
PC-2 or Jackson-Lawler syndrome is characterized by natal or prenatal teeth (15-50%), numerous steatocystomas and various other cystic lesions (25%), hair abnormalities (9-25%), and corneal dystrophy (8%), in addition to clinical features of PC-1 but with less severe keratodermas. (thefreedictionary.com)
The increased ROS levels and the oxidative stress both play a crucial role in the development of Fuchs endothelial corneal dystrophy , keratoconus, and granular corneal dystrophy type 2. (thefreedictionary.com)

This device was a variant that allowed a precise measurement of the anterior corneal surface through the projection of a circular plate onto the cornea. (biomedcentral.com)
To evaluate the effects of hyperopic laser in situ keratomileusis (LASIK) on anterior corneal higher-order aberrations (HOAs) (3rd to 6th orders). (nih.gov)
The surgically induced changes in anterior corneal HOAs and the differences between the HOA changes in corneas treated with and without active eye tracking were analyzed. (nih.gov)

Corneal topography does augment sensitivity to detect keratoconus in many cases with normal biomicroscopy and normal corrected visual acuity and is also efficient for identifying clinical keratoconus," he said. (ophthalmologytimes.com)
Conclusions Individualised topography-based crosslinking treatment centred on the ectatic cone has the potential to improve the corneal shape in keratoconus with decreased spherical refractive errors and improved visual acuity, without damage to the corneal endothelium. (bmj.com)
Outcome measures will be induced corneal refractive change (Fourier power vector analysis), ISV change, and visual acuity, at 6 months. (clinicaltrials.gov)
In addition to corneal transparency, regularity of the anterior surface is an important factor in visual acuity after DSEK. (biomedsearch.com)

Findings from anecdotal case reports are supported by clinical studies to highlight the relevance of advances in corneal imaging to help evaluating the cornea. (ophthalmologytimes.com)
Computer-assisted corneal topography devices have become indispensable for diagnosing subclinical/clinical KC and for evaluating disease progression. (arvojournals.org)
The morphological characterization of the cornea using corneal topographers is a widespread clinical practice that is essential for the diagnosis of keratoconus. (biomedcentral.com)
Early and late clinical landmarks of corneal dystrophies. (medlineplus.gov)

After allowing lenses to settle and confirming appropriate fit with a slit lamp exam, each of the subjects then underwent corneal topography while wearing five different commercially available soft multifocal contact lenses. (specialeyesqc.com)

Longitudinal changes in the corneal topography quantitative indices can be used as predictors of KC progression. (arvojournals.org)
Finally, the main valuation indices, which are provided by the corneal topographers and used for the diagnosis of keratoconus, are also defined. (biomedcentral.com)
This article discusses the current technologies of corneal topographers and is aimed at: i) describing how they enable the main morphological measurements that produce the pathology of keratoconus on the corneal surface to be performed and ii) enumerating the main assessment indices provided by the topographers and used to diagnose keratoconus. (biomedcentral.com)
Corneal elevation and keratoconus indices in a 40- to 64-year-old population: Shahroud Eye Study. (ssmj.ru)

Surprisingly, little is known about the effect of CXL-Plus on HOA: Just a single study measured the changes in higher-order aberrations [ 5 ], but without distinguishing between the aberrations of the anterior and posterior corneal surface. (biomedcentral.com)

Corneal Topography in Cataract Surgery. (ophthabooks.eu)

The main outcome measures were changes in refractive errors and corneal endothelial cell density. (bmj.com)
No corneal endothelial cell loss was seen after either treatment. (bmj.com)

The endothelial camera is used to measure the number and size of cells on the inside of the cornea (corneal endothelium), which have the function of pumping water out of the cornea. (augenklinik-bern.ch)

By measuring the distance between these rings at various points, the unit creates a color-coded map that illustrates the contour of the corneal surface. (medscape.com)
The computerized corneal topography measures this important surface giving us a color coded display containing detailed information about the shape of your cornea. (eyefreedom.com)
These high accuracy CNN models can aid ophthalmologists in keratoconus screening with color-coded corneal topography maps. (arvojournals.org)

Microbiological findings and predisposing risk factors in corneal ulcers. (nih.gov)

Anterior and posterior corneal elevation data were decomposed into a set of Zernike polynomials up to the 8th order within a 4.0 mm diameter region. (biomedsearch.com)

Central corneal regularization (CCR) is a novel, customized, topography-guided, transepithelial PRK treatment specifically developed for combined use with CXL (iVIS™ platform, Ligi Tecnologie Medicali S.r.l. (biomedcentral.com)

To develop and compare deep learning (DL) algorithms to detect keratoconus on the basis of corneal topography and validate with visualization methods. (arvojournals.org)
METHODS: Orthotopic corneal allografts (C57BL/6 strain donor) and syngeneic grafts were performed in A/J mice. (biomedsearch.com)

Corneal transplant surgery -- also called keratoplasty -- preserves or restores vision impaired by advanced corneal disease or when the cornea has been damaged by scarring, trauma, or infection. (dukehealth.org)
Effect of anterior and posterior corneal surface irregularity on vision after Descemet-stripping endothelial keratoplasty. (biomedsearch.com)

The usual measurements are corneal, white to white,and axial length. (rockymountaineye.com)

Several types of topography are noted (see the image below). (medscape.com)
Different types of topography maps can help you better evaluate the eye's anterior surface and fit contact lenses. (clspectrum.com)

We can actually evaluate thousands of corneal data points on a single map. (optometricoffice.com)

Anatomy2

Diseases8

Analytical, Diagnostic and Therapeutic Techniques and Equipment13

Psychiatry and Psychology1

Phenomena and Processes3

Information Science1

Zernike representation of corneal topography height data after nonmechanical penetrating keratoplasty. (1/329)

Changes in corneal wavefront aberrations with aging. (2/329)

Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system. (3/329)

Proposed classification for topographic patterns seen after penetrating keratoplasty. (4/329)

Reassessment of the corneal endothelial cell organisation in children. (5/329)

Pterygium-induced corneal astigmatism. (6/329)

Effect of disagreement between refractive, keratometric, and topographic determination of astigmatic axis on suture removal after penetrating keratoplasty. (7/329)

Corneal topography by keratometry. (8/329)

Corneal Topography

Keratoconus

Cornea

Lasers, Excimer

Refraction, Ocular

Astigmatism

Photorefractive Keratectomy

Keratomileusis, Laser In Situ

Myopia

Corneal Diseases

Refractive Surgical Procedures

Keratoplasty, Penetrating

Aberrometry

Visual Acuity

Refractive Errors

Image Processing, Computer-Assisted

Disease Progression

Quantitative Structure-Activity Relationship

Contact Lenses

Prosthesis Fitting

Keratectomy, Subepithelial, Laser-Assisted

Hyperopia

Strabismus

Oculomotor Muscles

Contact Lenses, Extended-Wear

Zernike representation of corneal topography height data after nonmechanical penetrating keratoplasty. (1/329)

Changes in corneal wavefront aberrations with aging. (2/329)

Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system. (3/329)

Proposed classification for topographic patterns seen after penetrating keratoplasty. (4/329)

Reassessment of the corneal endothelial cell organisation in children. (5/329)

Pterygium-induced corneal astigmatism. (6/329)

Effect of disagreement between refractive, keratometric, and topographic determination of astigmatic axis on suture removal after penetrating keratoplasty. (7/329)

Corneal topography by keratometry. (8/329)

Corneal topography changes following strabismus surgery

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ESCRS | European Society of Cataract & Refractive Surgeons

3D Corneal Topography

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OSA | Contribution of the cornea and internal surfaces to the change of ocular aberrations with age

Corneal topography

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Patente US7582081 - Systems and methods for corneal surface ablation to correct hyperopia - Google Patentes

Patent WO2003020167A2 - Ophthalmic instruments capable of measuring aberrations - Google Patents

Visual acuity and corneal surface regularity after blinking [3] (multiple letters)<...

100. Jahrestagung der DOG, 26.-29.9.2002: Case Report: IOL Calculation after PRK

Patent US8118752 - Apparatus and methods for mapping retinal function - Google Patents

Assessing Soft Multifocal Contact Lens Alignment with Corneal Topography

The PAR Technology Corneal Topography System

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Complex eye conditions

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Evaluation of Corneal Thickness using two different non-contact devices in adult eyes. - Clínica Rementería

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$ESCRS | European Society of Cataract & Refractive Surgeons$ ESCRS | European Society of Cataract & Refractive Surgeons

$Essilor AKR Cornea 500 Automatic refractometer$ Essilor AKR Cornea 500 Automatic refractometer

$Photorefractive keratectomy$ Photorefractive keratectomy

$Photorefractive keratectomy$ Photorefractive keratectomy

$Refractive surgery$ Refractive surgery

$Corneal Tomography and Topography for the Cataract and Refractive Surgeon | ASCRS$ Corneal Tomography and Topography for the Cataract and Refractive Surgeon | ASCRS

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$Refractive improvements and safety with topography-guided corneal crosslinking for keratoconus: 1-year results | British...$ Refractive improvements and safety with topography-guided corneal crosslinking for keratoconus: 1-year results | British...