Effect of illumination on reading performance in Japanese patients with age-related macular degeneration

Purpose: Several studies of Western patients with age-related macular degeneration (AMD) have investigated reading performance that improved at high levels of illumination; however, the relation between reading performance and macular function has not been evaluated in detail in Japan. The goals of this study were to evaluate the effect of different levels of illumination on reading performance in Japanese patients with AMD and determine the factors, such as macular function, that affect these results.

Study design: Cross-sectional study.

Methods: We prospectively included 39 patients with bilateral AMD or maculopathy. We evaluated reading performance; reading acuity (RA), critical print size (CPS), and maximal reading speed (MRS) using charts with Japanese sentences based on the MNREAD-J in 500-7500 lx. Patients were classified into two groups based on the presence of a central scotoma (CS) or no CS (NCS) diagnosed by microperimetry.

Results: The RA improved significantly in 500-7500 lx in both groups (NCS, p = 0.001; CS, p = 0.046). The RA improvement differed significantly (2000 lx, p = 0.021; 5,000 lx; p = 0.021; 7500 lx, p = 0.047) between 500 lx and other illumination levels only in the NCS group and then plateaued over 2000 lx. The CPS and MRS did not improve significantly at any illumination level.

Conclusions: These results suggest that the difference in macular function was related to improvement in the RA with increased illumination in Japanese patients with AMD.