Electrophysiological assessment of aphakic cystoid macular oedema. (49/91)

Focal electroretinograms (FERG), pattern electroretinograms (PERG), and visual evoked potentials (VEP) were studied in a group of 30 aphakic patients with cystoid macular oedema (ACME). When compared with a control group of age-matched aphakics, 35% of patients were found to have abnormal FERG responses and 53%--over half of whom had normal FERG responses--showed abnormal PERG amplitudes. Although most of the patients had associated optic disc leakage, VEP latencies were normal in 26 out of 30. These results may explain the more severe visual loss seen in some ACME patients where the ophthalmologically visible retinal changes do not seem sufficient to explain such reduction in vision.  (+info)

Refractive keratoplasty: keratophakia and keratomileusis. (50/91)

We have presented our early experience with the refractive keratoplasty techniques of Doctor Jose Barraquer--keratophakia and hypermetropic keratomileusis. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, his techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's corneaa and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be perfored by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.  (+info)

Basal iridectomy at 6 o'clock in the aphakic eye treated with silicone oil: prevention of keratopathy and secondary glaucoma. (51/91)

In the aphakic eye, with intact iris diaphragm, silicone oil has frequently caused a pupillary block. In this situation aqueous humour accumulates behind the iris and forces silicone oil through the pupil into the anterior chamber. An iridectomy at the 6 o'clock position can effectively prevent this pupillary block. The iridectomy allows free passage of aqueous to the anterior chamber which remains free of silicone oil. No permanent contact with silicone oil and the cornea is established, and development of keratopathy is prevented. The effect of this iridectomy in 62 eyes with intact iris diaphragm in patients in Rotterdam (35 cases) and Nagoya (27 cases) is demonstrated. Only in 6.5% of the cases was silicone oil present in the anterior chamber at the end of the follow-up period of 7 months.  (+info)

Aphakic cystoid macular edema and the operating microscope: is there a connection? (52/91)

The literature documenting the phototoxic effect of relatively low intensity light on the retina and the suggestions by several authors that this might influence the development of cystoid macular edema in the aphakic and pseudophakic patient is reviewed. In particular, the possibility that the operating microscope may be a factor has been emphasized. A study is presented, designed to investigate the possibility that the operating microscope is a factor important in the development of cystoid macular edema. No correlation was found. The need for further investigation into other phototoxic effects from the light of the operating microscope is stressed.  (+info)

Tear analysis in contact lens wearers. (53/91)

Tear analysis in contact lens wearers was compared with tear analysis in aphakics without contact lens wear and normal phakic patients. Subjects were divided into five groups: group 1, aphakic without contact lens; group 2, phakic with daily-wear hard contact lens; group 3, phakic with daily-wear soft contact lens; group 4, phakic with extended-wear soft contact lens; and group 5, aphakic with extended-wear soft contact lens. The experimental groups were compared with age- and sex-matched control groups for statistical analysis of tear variables by means of the Student's t-test. The variables measured were tear osmolarity, tear albumin, and lysozyme and lactoferrin concentrations in basal and reflex tears. Highly significant elevations of tear osmolarity were found in aphakic subjects without contact lenses. Less significant differences in tear osmolarity were found in phakic subjects with hard daily-wear lenses or with extended-wear soft lenses. Tear albumin, lysozyme, and lactoferrin in basal and reflex tears were not significantly different in the different groups of contact lens wearers or in the group of aphakic subjects without contact lenses compared with their control groups. Individual variations in tear albumin, lysozyme, and lactoferrin appeared to be responsible for the inability to demonstrate significant differences in tear composition in association with the wearing of different types of contact lenses. Older and aphakic patients demonstrated a tendency to have increased concentrations of proteins in the tears compared with younger, phakic contact lens wearers and normal controls without contact lenses.  (+info)

Indirect funduscopy in a gas filled eye: an observation. (54/91)

It has been observed that a vitrectomised, gas filled, phakic eye can produce a real, inverted, aerial image of the fundus anterior to the cornea. The optics of this phenomenon are discussed.  (+info)

Effects on perceptual development of visual deprivation during infancy. (55/91)

We measured three aspects of vision in children treated for unilateral congenital cataract: visual resolution, the symmetry of optokinetic nystagmus (OKN), and peripheral vision. Good visual resolution was achieved by children who had had the earliest treatment and who had had the normal eye patched close to 50% of the waking time throughout early childhood. All children treated for unilateral congenital cataract showed a marked asymmetry of OKN regardless of the age of treatment. One child with early treatment who could be tested with the Goldmann perimeter also showed especially poor sensitivity in the nasal visual field of her aphakic eye. We found no such deficits in the vision of children who had had normal visual experience during early infancy and then later developed cataracts in one or both eyes. The limitations observed in children treated for congenital cataract are similar to those reported in normal human infants, in normal kittens, and in cats which were visually deprived early in life.  (+info)

Critical evaluation of the NR-1000F Auto Refractometer. (56/91)

The manifest (dry) refractions of 165 eyes of 86 patients, aged 6 to 75 years, were studied on the Nikon Auto Refractometer NR-1000F. The results obtained were compared with the clinical refractive data, and they were analysed for degree of agreement of various refractive components in different types and grades of refractive errors in the separate age groups. On the NR-1000F the spherical and cylindrical components and spherical equivalents skewed towards more minus (or less plus), especially so in emmetropes, low hypermetropes, and low myopes. This error declined with increasing age over 40 years and was also significantly lower in aphakia and mixed astigmatism. Determination of cylinder axis was found to be reliable on the NR-1000F. In spite of the obvious utility of the device its inbuilt automatic fogging system does not seem adequately to neutralise the patient's accommodative efforts, as the fixation target probably induces instrument myopia.  (+info)