Abstract
Purpose :
Peripheral refraction is often measured by rotating the eye to gaze at a range of target positions. Contact lenses decentration on the eye during eye rotations may alter refraction measurements. We investigated the influence of contact lens decentration on peripheral refraction in the horizontal field.
Methods :
Right eyes of 6 participants (2 emmetropes, 4 myopes) underwent cycloplegic peripheral refraction, using a Grand-Seiko WAM-5500 Autorefractor, along the horizontal visual field to ±35° eccentricities. Targets at a range of positions were fixated using either eye rotation only or head rotation only. Refraction was obtained without correction, with Proclear single vision lenses (CooperVision), with Proclear multifocal centre-distance aspheric lenses with +2.50D add (CooperVision), and with NaturalVue aspheric lenses (Visioneering Tech.). Photographs of eyes during lens wear were taken at each eye rotation; positive values indicated on-eye lens decentration nasally or superiorly. Peripheral refraction was compared between eye and head rotations for each eccentricity/lens combination using Student’s t-test, and repeated measures ANOVAs evaluated effects of eye/head rotation, lens condition (excluding without-correction) and eccentricity on peripheral refraction.
Results :
Horizontal ranges across the 70° visual field were ≈1.3±0.3mm for Proclear single vision and multifocal lenses, but were significantly smaller at 0.6±0.3mm for NaturalVue lenses (Fig. 1). The lenses produced different changes in peripheral refraction patterns (Fig. 2), but there were no significant differences in refraction between eye and head rotation at any eccentricity/lens combination. ANOVAs also showed no significant differences between eye and head rotation, but results for the single vision lens were significantly different from those for other lenses (p≤0.002).
Conclusions :
Upon eye rotation the contact lenses decentered on the eye, but not enough to have significant effects upon peripheral refraction. For the lens types assessed, it is valid to use eye rotations to investigate peripheral refraction, at least for the horizontal visual field.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.