Accommodative Response to Proximity and Defocus in Myopes and Emmetropes

Abstract

Abstract: : Purpose: Myopic children tend to have larger accommodative lags than emmetropes if accommodation is stimulated by negative lenses or proximity (Gwiazda J, et al. IOVS 1993; 34). The purpose of this study was to measure the accommodative response in adult myopes and emmetropes to combined variations of proximity and defocus (minus or plus lenses). Methods: Accommodative response of 21 adults (10 myopes and 11 emmetropes) wearing their far vision correction was measured with a Shin–Nippon SRW–5000 autorefractor. Measures were made while subjects viewed binocularly a target of constant angular size for proximities ranged between 0 and 5 D and lenses between +2.00 and –2.00 D. Results: Accommodative lag increases with proximity and minus lenses and decreases with positive lenses for all subjects. Myopes showed larger accommodative lags than emmetropes for optical proximities (proximity of the target + dioptric power of the lens) greater than 3 D. Conclusions: If myopia is driven by retinal blur, a +2.00 addition in association with a working distance greater than 33 cm should decrease myopia progression.

Keywords: myopia • adaptation: blur