Different Reading Ability but Same Distance Acuity of Patients with Drusen Maculopathy and CNV-scars

Abstract

Abstract: : Purpose: To compare the reading performance of patients with drusen maculopathy to patients with CNV-scars with respect to reading acuity, maximal reading speed, reading speed based on print size and critical print size. Methods: 111 patients (60 patients with drusen, 51 with CNV-scars) were studied. Patients were assigned to 4 groups based on their best-corrected LogMAR distance acuity (EDTRS-Charts) and ocular diagnosis: Patients with LogMAR 0.2-0.4 into D1(=Drusen 1) and S1(=Scars1), patients with LogMAR > 0.4-0.7 into D2 and S2. Reading acuity was determined in LogRAD (=reading equivalent of LogMAR). Reading acuity and reading speed were tested monocularly with the standardized Radner Reading charts. The patients read with best distance correction and an addition of +4 diopters at 25 cm. Results: The patients’ mean best-corrected distance visual acuity was comparable between the corresponding groups S1 and D1 and between S2 and D2.The reading acuity of patients in the D1- group was LogRAD 0.32 ±0.1 (=93.6% of LogMAR) and significantly lower in the D2- group with LogRAD 0.56 ±0.24 (=87.0% of LogMAR). Between the corresponding groups D1 and S1 [S1: LogRAD 0.35 ±0.07 (=94.9% of LogMAR)] no significant difference in reading acuity was found. In contrast, S2 patients [S2: LogRAD 0.7 ±0.18 (=70.6% of LogMAR)] showed a statistically lower reading acuity when compared to D2 patients (p=0.03). The mean maximal reading speeds were: 166.2 ±25.7wpm (D1), 142.6 ±30.2wpm (D2), 125.5 ±22.5wpm (S1) and 114.6 ±26.0wpm (S2). Both groups of patients with scars, S1 and S2, read significantly slower than the corresponding groups D1 and D2 (p<0.001). Additionally, the mean reading speed at every print size and the critical print size (CPS) for the groups S1 and S2 were significantly worse than those for the corresponding groups D1 and D2 (p-values ranging from 0.0005 to 0.02). Conclusions: Despite comparable distance visual acuity of drusen and CNV-scar patients, the patients with CNV-scars showed a significantly more severe impairment of reading ability in all parameters. This indicates that distance visual acuity alone clearly underestimates the real functional impairment of CNV patients.

Keywords: age-related macular degeneration • reading • visual acuity