The effect of reading and near-work on the development of myopia in emmetropic boys: a prospective, controlled, three-year follow-up study

This study aimed to investigate the effect of reading and near work on myop ic development in emmetropic boys in school age. It involved totally 114 ch ildren in two groups. Right eyes of 67 randomly selected students (mean age = 12.93) with mean 6 h of reading and near work (Group 1) were compared wi th the right eyes of 47 apprentices (mean age = 12.96) working as skilled l aborers (Group 2). Cycloplegic refraction, keratometric readings and biomet ric measurements including anterior chamber depth (ACD), lens thickness (LT ), vitreous chamber depth (VCD) and axial length (AL) were performed for 3 years at 18 month intervals. Two analyses were conducted: (1) for subjects in both groups with baseline refractive error from + 0.50 to - 0.50 D: (2) for all subjects in both groups with baseline refractive error from + 1.00 to - 1.00 D. For subjects with baseline refractive error of + 0.50 D, myopi c shift was present in 20 of 41 (48.8%) in group I and in seven of 37 (18.9 %) in group 2 at the end of the study. The magnitude of the myopic shift wa s 0.56 and 0.07 D in group I and I respectively. For subjects with a baseli ne refractive error of +/- 1.00 D. myopic progression was present in 40 of 67 (59.7%) in group I and in 10 of 47 (21.3%) in group 2 at the last readin gs. In this larger refractive range, the magnitude of the myopic shift was 0.61 and 0.12 D in group I and 2. respectively. The mean ACID, VCD and AL w ere significantly higher in the last readings after 36 months than in the f irst readings (for each, P = 0.0001) in group 1. There was no statistically significant difference between two measurements of these parameters in gro up 2. The final keratometric dioptric readings were lower than the first va lues (for each, P = 0.0001) in both groups at the end of the study. This pr ospective and controlled study suggested that reading and near work., impor tant environmental factors, might cause refractive myopic shifts in emmetro pic students. The myopic shift was primarily related to significant increas es in ACID, VCD and AL in this young age group. (C) 2001 Elsevier Science L td. All rights reserved.