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.