Accommodation and pupillary response in early-onset myopia among schoolchildren.

Abstract

To investigate changes in accommodation and pupillary reaction in early-onset myopia among children. An objective infrared optometer and a pupillometer were used to evaluate simultaneously tonic accommodation, accommodative response, accommodative adaptation, and pupil diameter in 19 schoolchildren with early-onset myopia and 15 age-matched emmetropic controls. Tonic accommodation in the early-onset myopes (1.03 D) was significantly less than in the emmetropes (1.37 D) (p < 0.05), whereas accommodative response and accommodative adaptation showed no significant difference between the early-onset myopes and emmetropes. The average pupil diameter after 20 min of dark adaptation in the early-onset myopes was 4.52 mm, which was significantly smaller than that in the emmetropes (5.21 mm) (p < 0.05). During nearwork stimulation, the average pupil diameter further decreased to 3.83 mm in the early-onset myopes and 4.78 mm in the emmetropes (p = 0.003). These results suggest that low tonic accommodation and small pupil diameter may play important roles in the pathogenesis of early-onset myopia among schoolchildren.