Contrast Sensitivity–A useful adjunct in the assessment Retinitis Pigmentosa.

Abstract

Abstract: : Purpose: The assessment of visual function for those with Retinitis Pigmentosa routinely includes: electroretinography, visual acuity, ocular examination and Goldman visual field testing. Many patients with retinitis pigmentosa complain of changes in visual function that are not detected by these eye tests. In the current study we want to compare tests of visual function separately and in combination to identify the best predictors of changes in central perceived visual function in patients with Retinitis Pigmentosa Methods: Subjects with progressive Retinitis Pigmentosa, males and females, 10–65 years of age, with vision better then 1 logMAR and normal anterior segments were recruited from the Ocular Genetics Program at The Hospital for Sick Children and the eye clinic at Mount Sinai Hospital, Toronto. Subjects were tested four times over a period of one year. Visit 0 was a learning visit and visit 1 was the first data collection visit. At each visit all subjects underwent the following tests– 1) Central Visual Acuity (logMAR crowded test charts Vetch Consultants, Dayton, Ohio). 2) Contrast Sensitivity (Pelli–Robson Contrast Sensitivity chart,Harlow, Essex). 3) Central Visual Field Test (Humphrey 10–2, Zeiss Humphrey systems). 4) Color Vision (Mollon–Reffin ‘Minimalist’ test, Cambridge, U.K). 5) Modified Visual Function Questionnaire (Szylk, Ophthalmology, 2001,108, 65–75) for central perceived visual functions. The Rasch analysis was used to estimate the "perceived visual ability" for each person. Results: We present the interim results (n=103) from visit 0 and 1, using Rasch analysis for the questionnaire. Mean age: 42 years, 45 males: 58 females. Repeat test correlation was high (ICC>0.9) for all parameters between visit 0 and 1. The best single predictor of Central Perceived Visual Function (visit 1) was Contrast Sensitivity (R square =0.30, p<0.0001) followed by visual acuity (R square =0.26, p<0.0001). The best combined predictor of Central Perceived Visual Function was visual acuity and central visual field (R square=0.36, p<0.0001) closely followed by contrast sensitivity and visual acuity (R square=0.33, p<0.0001). Discussion: The addition of Contrast Sensitivity testing to routine visual assessment may improve the quality of visual function assessment in those with retinitis pigmentosa.

Keywords: contrast sensitivity • retinal degenerations: hereditary