Hyperopic blur due to temporary myopic shift after sustained near activity due to near induced transient myopia act as a cue for myopia progression. The study aimed at comparing near induced transient myopia parameters after reading with smartphone and print material among children.
Children (8-13years) with only refractive error were enrolled into the study. All subjects underwent initial comprehensive eye examination. Pre-task refractive error was measured using Grand Seiko WAM 5500 following a 5-minutes dark adaptation. The subjects were then asked to read a text equivalent to N8 text size at 20 cm on mobile phone for 5 minutes. Immediately after reading, the subject’s post-task distance refractive error was measured for 2 minutes. The procedure was repeated with print reading material.
Total of 13 myopes and 13 emmetropes were enrolled. The average NITM magnitude after mobile and print reading for myopes was 0.16 D and 0.20 D respectively. Emmetropes showed a hyperopic shift of 0.11 D and 0.05 D after mobile and print reading respectively. Analysis of variance revealed a statistically significant difference in NITM magnitude between myopes and emmetropes with mobile (F(1)=99.660;p<0.001) and print (F(1)=102.206;p<0.001) usage. Decay time was less after reading with print material when compared to reading with mobile which was statistically significant (Z=-3.18;p=0.01).
Longer dissipation time was noted after reading with mobile when compared to reading a print text. Given the additive nature of NITM, long hours of near work with mobile phone could pose a greater risk of myopia progression.