Abstract
Purpose: :
To investigate the visual function of patients with retinitis pigmentosa (RP) by measuring the visual acuity of different contrast levels.
Methods: :
Thirty nine eyes of 39 RP patients (38.0 ± 12.5 years [±SD]) and 38 eyes of 38 normal volunteers (NV) (35.0 ± 9.8 years [±SD]) were participated in this study. All the eyes had corrected visual acuity of 20/20 or better and no other ophthalmic complication. The contrast visual acuity was measured with three different contrast levels, 100%, 25% and 10%, for day vision, day vision with glare, evening vision, and evening vision with glare. Repeated measure ANOVA was used to determine if changes in contrast visual acuity were significantly different between all four conditions.
Results: :
The contrast visual acuity was decreased approximately linearly as contrast level decreased in all four conditions in both RP patients and NV. The contrast visual acuity of LogMAR in RP patients and NV, respectively, were: day vision, 0.09 ± 0.1 and -0.08 ± 0.05, 0.2 ± 0.2 and -0.01 ± 0.1, and0.4 ± 0.2 and 0.1 ± 0.1; day vision with glare, 0.09 ± 0.1 and -0.06 ± 0.05, 0.2 ± 0.1 and -0.003 ± 0.08, and 0.4 ± 0.2 and 0.1 ± 0.1; evening vision, 0.2 ± 0.1 and 0.005 ± 0.08, 0.4 ± 0.2 and 0.2 ± 0.1, and 0.6 ± 0.2 and 0.4 ± 0.2; evening vision with glare, 0.2 ± 0.2 and -0.003 ± 0.08, 0.5 ± 0.2 and 0.2 ± 0.1, and 0.8 ± 0.2 and 0.5 ± 0.2: 100%, 25%, and 10%. There was a significant difference in changes in contrast visual acuity between day vision and evening vision (P < 0.001) and between evening vision and evening vision with glare (P < 0.001) in both RP patients and NV. As compared to NV, the degree of the decrease in contrast visual acuity for day vision was significantly larger in RP patients (P < 0.05). Although the contrast visual acuity of NV was not declined in contrast level of 25%, that of RP patients was significantly decreased under 20/20 (P < 0.001).
Conclusions: :
The measurement of contrast visual acuity would be useful to understand visual function in patients with RP.
Keywords: contrast sensitivity • retina • visual acuity