Visual function after photorefractive keratectomy.
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Contrast Sensitivity↗
Biomedical subjects
I Adamsons
Publications and source records attributed to I Adamsons.
The effect of early cataracts on glare and contrast sensitivity. A pilot study.
To establish the effect of cataracts on glare and contrast sensitivity, we graded type and amount of lens opacity in 110 subjects who underwent two glare tests (Brightness Acuity Tester and Berkeley glare test) and two contrast sensitivity tests (a sine-wave test and Pelli-Robson chart). Twenty-seven subjects (25%) had clear lenses (mean visual acuity of 20/20) and 83 subjects (75%) had early lens opacities (mean visual acuity of 20/40) in otherwise normal eyes. Multiple regression techniques were used to control for the effects of age and visual acuity. Glare test scores were significantly lower for nearly all patients with lens opacities than for patients with clear lenses and were the lowest for patients with lenses with posterior subcapsular opacity. Contrast sensitivity scores were lower for all patients with lens opacities than for patients with clear lenses at high frequencies only; all lens opacity groups scores similarly with each other. These results indicate reduced visual function among patients with cataracts whose visual acuity is only minimally impaired.
Cataract↗
A new method for documenting lens opacities.
We tested an anterior segment camera and digital analyzer on 32 eyes of 22 patients to determine whether its measurement of lens opacities correlated with measurements obtained by a standardized clinical grading system. The lenses were graded clinically for nuclear opacity, nuclear color, cortical opacity, and posterior subcapsular opacity. The lenses were then photographed and analyzed with this new device, and the results were compared. The camera system showed good reproducibility. Its results correlated well with the clinical gradings for nuclear capacity (P = .001) and cortical opacity (P = .001) but less well with posterior subcapsular opacity (P = .3), although there were only seven eyes with posterior subcapsular opacities. This camera system could help document and follow up lens opacity with more accuracy and reproducibility than has been previously possible.
Cataract↗
Prevalence of lens opacities in surgical and general populations.
The distribution and prevalence of lens opacities were examined and compared among three general population-based groups and a group that underwent cataract surgery. The population-based groups comprised subjects from the Framingham Eye Survey, the National Health and Nutrition Examination Survey, and the study of watermen in Maryland. Comparison among these groups revealed similar frequencies of lens opacities among age groups, with slightly higher rates for older individuals in the watermen study population. Comparison between the watermen and the surgical groups revealed that, of lenses with opacities, posterior subcapsular cataracts were present in a far greater percentage of surgery cases (60.6%) than in general population cases (5.3%). These findings confirm the generally held clinical belief that posterior subcapsular opacities are disproportionally represented in the surgical population and suggest that they cause more significant visual disability than do other types of cataracts.
Adult↗