The classification of amblyopia on the basis of visual and oculomotor performance.
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Biomedical subjects
Publications and source records attributed to S H Day.
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Monocular and binocular grating acuities were measured using a swept spatial frequency visual evoked potential (VEP) technique in a group of fifteen infants with esotropia and alternating fixation. Both monocular and binocular acuity measures fell significantly below the mean for age-matched normals. Infants with esotropia and alternating fixation did not have significant interocular acuity differences.
Refractive errors were determined photographically in a group of infants and children and were compared to conventional cycloplegic retinoscopy. The refractor consisted of a mirror telephoto lens and strobe flash designed to mimic the action of a retinoscope. Significant amblyogenic conditions such as anisometropia and high isoametropia were detectable. Strabismus and media opacities were also recordable. The technique provides a potential mass suited for infants.
Kaakinen (1979) presented a method of measuring refractive error and ocular alignment by simultaneous photography of corneal and fundus reflexes. As presented, the technique was unable to detect refractive errors of less than 2-3 diopters (Howland 1980; Kaakinen 1979). We demonstrate that the use of a catadioptric lens and a long working distance can improve sensitivity to less than 1.0 D. Refractions of a model eye, an accommodating eye and ametropic eyes indicate that refractive errors greater than 0.75 D are readily detectable. The improvement in sensitivity achieved by the present system is attributable to a reduction of the angle between the flash source and the entrance pupil of the photorefractor.
A 14-year-old native of Ethiopia with previously treated onchocerciasis moved to California where he was examined for evidence of persisting nematode infestation. Skin and conjunctival biopsy specimens initially disclosed no abnormalities. Subsequently, conjunctival nodules developed, and a biopsy specimen of one of these revealed microfilariae of Onchocerca volvulus lying adjacent to a necrotic eosinophilic granulomatous inflammatory nodule. To our knowledge, nodules of this type have not heretofore been reported to be a notable feature of ocular onchocerciasis. This type of inflammation has a relationship to degenerating microfilaria in onchocerciasis and in other nematode infestation.
INTRODUCTION: Covalent protein binding of metabolically reactive intermediates of drugs has been implicated in drug toxicity including the occurrence of idiosyncratic drug toxicity. Investigators therefore would prefer to avoid developing compounds that produce significant amounts of reactive metabolites. By incubating the radiolabeled drug of interest with liver microsomes it is possible to evaluate the propensity of a drug candidate to covalently bind to proteins. METHODS: Here we present a semi-automated method in which a Brandel cell harvester is used to collect and wash proteins that have been incubated with radiolabeled drug. This method utilizes glass fiber filter paper to capture precipitated protein, rather than the more traditional exhaustive extraction/centrifugation approach. Using model compounds (including [14C]diclofenac, [3H]imipramine, [14C]naphthalene, and [14C]L-746530) we compare the covalent binding results obtained using this method to results generated using the traditional method and we performed cross-laboratory testing of assay reproducibility. RESULTS: It was found that results from new method correlated highly with the traditional method (R2=0.89). The cross-laboratory testing of the method showed an average interlaboratory coefficient of variation of only 18.4%. DISCUSSION: This method provides comparable results to the more traditional centrifugation-based method with considerable time and labor savings.
The alternatives in the management of infantile glaucoma refractory to conventional treatment are quite limited and unrewarding. We did a retrospective study of 49 patients (53 eyes) under 12 years of age with advanced, uncontrolled glaucoma who each underwent implantation of a single-plate Molteno implant in one stage. Over the follow-up period ranging from 6 months to 3 years (mean 18 months), 36 of the 53 eyes (68%) had an intraocular pressure less than or equal to 21 mm Hg and were considered a success. Fourteen eyes (26%) required further glaucoma surgery, 2 eyes developed severe chronic hypotony, and 1 eye lost light perception following endophthalmitis. The number of anti-glaucoma medications was decreased from a mean of 2 (+/- 1) to 1 (+/- 1). The probability for success of the Molteno implant in controlling glaucoma increased with the age of the patient. Six eyes (11%) were late failures, most probably due to fibrous encapsulation of the bleb. Complications observed were: prolonged hypotony and flat anterior chamber, retinal detachment, migration of the tube, erosion of the tube through the conjunctiva, and an ingrowth of fibrous tissue in the anterior chamber. We consider the Molteno implant to be a reasonable option in the management of difficult cases of infantile glaucoma.
We have compared the performance of an off-axis (knife-edge) photorefractor with that of an on-axis (isotropic) system. Normal infants and children between the ages of 8 and 208 weeks were photographed with each camera both with and without cycloplegia. Refractive errors were estimated for each technique based on equations derived from ray-tracing. These refractions were compared to the results of retinoscopy under cycloplegia. Sensitivity and specificity of the two photorefraction systems were evaluated as a function of the magnitude of meridional hyperopia defined by retinoscopy. We also examined the effect of varying the photorefraction screening criterion. Thirteen percent of the infants in the screening sample presented with +3.50 diopters or more of meridional hyperopia. Using this level of ametropia as a referral criterion, the sensitivity and specificity of the off-axis system for infants without cycloplegia were 83% and 72%, respectively. For the on-axis system, sensitivity and specificity values were 85% and 53%. The use of cycloplegics did not significantly improve the performance of either system, but rather their use degraded the specificity of the on-axis system in the presence of moderate refractive errors. The results of the present study indicate that both on- and off-axis systems are effective in identifying highly ametropic infants, but that the off-axis system results in significantly fewer false positives. Moreover, the off-axis system has the advantages of an inherently greater dynamic range for a fixed camera design, and also more easily interpreted photographs.