Optometry and vision science : official publication of the American Academy of Optometry
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I hypothesize that the functional role of binocular correspondence, whether normal or anomalous, is that of detecting retinal disparity stimuli. Normal correspondence involves disparity stimulus detection that is quantitatively normal and stable, whereas anomalous correspondence involves disparity detection that is quantitatively abnormal and variable. Normal disparity stimuli typically produce motor fusion between normally corresponding biretinal areas. ⋯ The result is strabismus, usually coupled with anomalous single binocular vision (harmonious anomalous correspondence). Accordingly, corrective prism or muscle surgery only produces vergence movements that restore anomalous motor fusion, rather than eliminating the heterotropia. The inference is that anomalous correspondence involves a neurological disorder in the disparity detection mechanism, either on the convergent side (estropia with anomalous correspondence) or divergent side (exotropia with anomalous correspondence).
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Although Schiotz tonometry has been long ago replaced by Goldmann applanation tonometry measurement of intraocular pressure, it remains a viable clinical technique in nursing homes and other "out of office" settings. Because Schiotz tonometers come into contact with the cornea and tear film, they must be properly disinfected to prevent cross-infection with HIV and other infectious pathogens. The Centers for Disease Control and Prevention (CDC) recommends that all eye contact devices be disinfected by a 5- to 10-min soak in one of following disinfectants: 3% hydrogen peroxide, 1:10 sodium hypochlorite (household bleach), or 70% isopropyl alcohol. ⋯ The results of the study indicated that soaking in 1:10 sodium hypochlorite and 3% hydrogen peroxide damaged Schiotz tonometers and rendered them inoperable. Alcohol caused minor damage to the tonometer and was the safest of the CDC disinfectants. This study showed there is limited application of CDC infection control criteria to Schiotz tonometers due to the extensive corrosion and damage caused by hydrogen peroxide and bleach.
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Children often resist instillation of mydriatic drops for dilated fundus evaluation. As cycloplegic sprays have proven useful, this study's aim was to demonstrate efficacy of a mydriatic spray. ⋯ This study suggests that use of mydriatic sprays on closed eyelids is as efficacious as use of mydriatic drops in open eyes for children.
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The influence of pupil size, lens centration, and translation on multifocal contact lens performance suggests that these parameters should be accounted for in the optical design of presbyopic contact lenses. The purpose of the present article is to complete the existing experimental data with clinical measurements of pupil diameter and lens position relative to the pupil in a group of presbyopes, with controlled target luminance, stimulus distance, gaze angle, and convergence. The experiments involve an infrared video-pupillometer and ring-marked contact lenses. ⋯ The measured data on lens position confirm that soft contact lenses are generally decentered from the pupillary axis, usually in inferior temporal direction, and that their average translation between primary and downward gaze is very small. It is also found that the average relative position between lens and pupil centers is slightly modified by changes of luminance in far vision. All these results provide characteristic values which are helpful for the optical modelling of presbyopic contact lenses.
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Comparative Study
Factors affecting Staphylococcus epidermidis adhesion to contact lenses.
Staphylococcus epidermidis is a major causative agent of infectious keratitis associated with contact lens wear. Adhesion of this bacterium to contact lenses may contribute to the pathogenesis of infection and could be influenced by lens surface properties, packaging/storage solutions, and vary among different strains according to the level or type of adhesins expressed. ⋯ Properties of contact lens materials were not the sole determinant of viable S. epidermidis adhesion to lenses. Strain variability, including levels of exopolysaccharide expression, and the solution used for lens immersion also influenced adhesion.