AIM: To report clinical experience and the comparative value of axial and instantaneous topography data in fitting Rose-K design contact lenses in moderate and severe keratoconus. MATERIALS AND METHODS: Thirty-eight eyes (of 23 patients) with keratoconus were fitted with Rose-K design contact lenses and followed up for at least six months or more. Visual acuity with habitual vision correction available was measured. Axial and instantaneous topography maps for each eye were recorded. Contact lens wear comfort was graded on a ten point rating scale every three months. RESULTS: Fourteen (100%) moderate keratoconus eyes (average Sim K 48.61 +/- 1.24D) and 23 of 24 (96%) of severe keratoconus eyes (average Sim K 60.88 +/- 5.31D) were successfully fitted with the Rose-K lenses. Final fit contact lenses in severe keratoconus had statistically significant steeper base curves compared to average axial corneal curvature than in moderate keratoconus eyes. Average simulated corneal curvature on axial maps predicted final fit contact lens base curves significantly better than on instantaneous maps. Thirty-three of the 37 eyes fitted with contact lenses maintained wear comfort over average follow up period of 13 +/- 3.5 months. CONCLUSIONS: Rose-K design rigid contact lenses are successful in visually rehabilitating 100% of moderate and 96% of severe keratoconus eyes. Most patients (90%) maintained contact lens wear comfort. Corneal curvature on axial maps is a better predictive of base curve of final fit contact lens. (+info)
Reduced epithelial adhesion after extended contact lens wear correlates with reduced hemidesmosome density in cat cornea.
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Reduced epithelial adhesion in cat corneas after continuous wear of thick hydrogel contact lenses has been reported previously. To investigate the mechanism(s) underlying this observed loss of epithelial adhesion further, the corneas of both eyes of cats that had worn low-oxygen-transmissible thick parallel-design hydrogel contact lenses only in one eye for 8-121 days were examined using both light and transmission electron microscopy (TEM). Contact lens wear induced many changes in the epithelium, including a decrease in the number of cell layers and appearance of cuboidal rather than columnar basal cell shapes. In addition, TEM revealed that the number of hemidesmosomes (HDs) per micrometer of basement membrane was reduced significantly after contact lens wear. Anchoring fibrils in lens-wearing corneas appeared normal, and the reduction in epithelial adhesion occurred without obvious epithelial edema. Decreased epithelial adhesion after contact lens wear appears to be directly related to the reduced numbers of HDs. Possible reasons for decreased HD density, such as loss of basal cell shape and chronic epithelial hypoxia after contact lens wear, are discussed. (+info)
Measurement of corneal swelling variations without removal of the contact lens during extended wear.
(19/53)
PURPOSE: To validate the use of noncontact scanning slit pachymetry and OCT pachymetry measurements without contact lens (CL) removal, to determine corneal swelling variations during extended wear (EW). METHODS: Central corneal thickness (CCT) was measured with ultrasonic (US) pachymetry, noncontact scanning slit pachymetry (Orbscan II; Bausch & Lomb, Tampa, FL), and optical coherence tomography (OCT) 1 week before the wearing of CLs and during 1 week of EW. High-Dk (lotrafilcon A) and low-Dk (etafilcon A) soft CLs were randomly fitted for EW in the right and left eyes of 20 subjects with normal ocular health. Orbscan and OCT were also performed without CL removal after 3 and 7 days of wear. RESULTS: CCT measured with Orbscan and OCT showed a high correlation with US pachymetry. There were corneas with edema and without edema. Bland-Altman analysis showed a high level of agreement between Orbscan and OCT, with and without CL removal and with US pachymetry. High repeatability of Orbscan (r(2) = 0.000) and OCT (r(2) = 0.001) measurements without CL removal was also found. Etafilcon A lenses induced significantly higher corneal swelling than did lotrafilcon A lenses measured with Orbscan and OCT. CONCLUSIONS: Orbscan and OCT are accurate, noninvasive, and reproducible techniques for evaluation of CCT without CL removal. OCT has more accuracy and repeatability than does Orbscan. Both techniques allowed for measurement throughout the study period of the CCT differences induced by CL wear. (+info)
Sustainability of orthokeratology as demonstrated by corneal topography.
(20/53)
PURPOSE: To determine the sustaining effects of orthokeratology. METHODS: This study enrolled 58 eyes with moderate myopia. LK-DM lenses (Lucid Korea Dream Lens) were fitted daily for at least eight hours on an overnight regimen. The effects of orthokeratology and it's sustainability throughout the day were recorded twice; immediately after removal in the morning and eight hours later. Sustainability was measured by comparing the changes from morning to afternoon for best uncorrected visual acuity, apical corneal power, keratometric values, spherical equivalent and induced astigmatism. RESULTS: UCVA demonstrated improved values at all follow up periods. Fluctuations during the day stabilized after 4 weeks of lens wear. K values averaged a mean of 42.4 mm at baseline, and reduced to 40.9 mm by week 12. Unaided logMAR visual acuity changed from 0.94+/-0.14 at baseline to -0.11+/-0.17 by week 12. The sustainability of orthokeratology, defined as the difference between morning and afternoon values of unaided logMAR visual acuity, increased from -0.82 on day 1 to -0.11 on week 12. CONCLUSIONS: UCVA and spherical refractive error did not change to a significant degree after 4 weeks. Although statistically insignificant minute fluctuations during the day were observed up to week 12, these fluctuations decreased to a statistically significant level after week 4. (+info)
Use of fluid-ventilated, gas-permeable scleral lens for management of severe keratoconjunctivitis sicca secondary to chronic graft-versus-host disease.
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Keratoconjunctivitis sicca (KCS) occurs in 40%-60% of patients with chronic graft-versus-host-disease (cGVHD) after allogeneic hematopoietic cell transplantation. Although immunosuppressive therapy is the primary treatment of chronic GVHD, ocular symptoms require measures to improve ocular lubrication, decrease inflammation, and maintain mucosal integrity. The liquid corneal bandage provided by a fluid-ventilated, gas-permeable scleral lens (SL) has been effective in mitigating symptoms and resurfacing corneal erosions in patients with KCS related to causes other than cGVHD. We report outcomes in 9 consecutive patients referred for SL fitting for cGVHD-related severe KCS that was refractory to standard treatments. All patients reported improvement of ocular symptoms and reduced the use of topical lubricants after SL fitting resulting from decreased evaporation. No serious adverse events or infections attributable to the SL occurred. The median Ocular Surface Disease Index improved from 81 (75-100) to 21 (6-52) within 2 weeks after SL fitting, and was 12 (2-53) at the time of last contact, 1-23 months (median, 8.0) after SL fitting. Disability related to KCS resolved in 7 patients after SL fitting. The use of SL appears to be safe and effective in patients with severe cGVHD-related KCS refractory to conventional therapies. (+info)
The effect of nonpreserved care solutions on 12 months of daily and extended silicone hydrogel contact lens wear.
(22/53)
Proteomic analysis of protein deposits on worn daily wear silicone hydrogel contact lenses.
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PURPOSE: Previous studies have demonstrated deposition of tear proteins onto worn contact lenses. In this study, we used proteomic techniques to analyze the protein deposits extracted from worn daily wear silicone hydrogel contact lenses in combination with different lens care solutions. METHODS: Worn lenses were collected and protein deposits extracted using urea and surfactant. Protein extracts were desalted, concentrated, and then separated using one-dimensional gel electrophoresis. Individual protein components in extracts were identified using liquid chromatography combined with tandem mass spectrometry (LC-MS-MS) after trypsin digestion. RESULTS: One-dimensional gel electrophoresis revealed that lysozyme and other small proteins (around 20 kDa) were the most abundant proteins in the extracts. LC-MS-MS revealed a wide array of proteins in lens extracts with lysozyme and lipocalin 1 being the most commonly identified in deposit extracts. CONCLUSIONS: Worn contact lenses deposit a wide array of proteins from tear film and other sources. Protein deposit profiles varied and were specific for each contact lens material. (+info)
Myopia progression during three years of soft contact lens wear.
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