Near reading speed changes after panretinal photocoagulation in diabetic retinopathy patients: a prospective study using an iPad application for the measurement of reading speed

Purpose To investigate the changes in the near reading speed after panretinal photocoagulation (PRP) in diabetic retinopathy patients. Methods This non-randomized, prospective, clinical study enrolled diabetic retinopathy patients who underwent PRP from January 2016 to June 2017. The near reading speed was measured before and 1 week, 1 month, and 4 months after PRP by using an iPad application for the assessment of reading speed; near best-corrected visual acuity (BCVA) and subfoveal choroidal thickness (SFCT) were also analyzed. The reading speed of age-matched healthy individuals was compared with that of diabetic retinopathy patients. Results Forty-seven patients were enrolled in this study. The baseline near reading speed of diabetic retinopathy patients was significantly slower than that of age-matched healthy controls. The near reading speed was reduced at 1 week after PRP, but recovered at 1 and 4 months after PRP. Near BCVA showed a similar pattern after PRP. SFCT increased at 1 week after PRP and significantly decreased at both 1 and 4 months after PRP. Conclusion The near reading speed of diabetic patients was significantly slower than that of age-matched healthy controls. The speed was temporarily reduced at 1 week after PRP, potentially due to short-term impairment of parasympathetic nerve innervation.