Is the Normal Periphery in Young Adults a Good Model for Reading in the Presence of Central Vision Loss?

Purpose: Reading is slow and difficult for many people with central vision loss. Numerous studies have used peripheral vision in normally sighted individuals without ocular disease as a model for reading with central vision loss. In this study, we tested the validity of this model. Methods: Oral reading speed was measured for a range of print sizes for 28 observers with bilateral central vision loss. Each set of reading speed versus print size data was fit with a bilinear function, from which the critical print size (CPS), the smallest print size that supports the maximum reading speed, and the maximum reading speed (MRS) were derived. The eccentricity of the preferred retinal locus (PRL) was determined for each observer. For comparison, values of CPS and MRS at PRL-matched eccentricities in normal peripheral vision of young adults were derived from Chung et al.22. Results: Compared with peripheral vision in young adults, observers with central vision loss exhibited a shallower change in reading speed with print sizes smaller than the CPS (mean ± 95% confidence intervals, 1.77 ± 0.47 vs. 2.32; P = 0.009). They also required larger CPS (mean, 2.24° ± 0.80° vs. 0.97° ± 0.19°; P < 0.0001) to reach their MRS, which was lower than that at PRL-matched eccentricity in normal peripheral vision (mean, 167.8 ± 28.1 words per minute vs. 396.9 ± 58.9 words per minute; P < 0.0001). Conclusions: Our findings suggest major differences in reading performance between the peripheral vision of young adults with normal vision and those with central vision loss, limiting the suitability of normal peripheral vision as a model for reading with central vision loss.