Baseline findings in Early Glasses Study and erratic change of refraction between 14 and 23 months

Abstract

Purpose : “Amblyopia risk factors” have not yet been objectified in terms of relative contribution of risk. The Early Glasses Study (EGS) determines the relation between refraction at age 1 and visual equity at age 4, and the effect of glasses for high refractive errors in preventing amblyopia and accommodative esotropia.

Methods : Children aged 12-18 months were recruited through screening health care offices and examined by orthoptists with retinoscopy in cycloplegia. Those exceeding >+3.5D, >1.5D cyl, >1.0D cyl (10°-80°), >1.5D aniso were randomized into glasses or not, and are followed up 2-3x annually to age 4. Excluded were ophthalmic, congenital, neurologic disease, prematurity, and children exceeding double thresholds of refraction. Glasses wearing is monitored electronically during 1 week at age 2. Preliteracy is measured in randomized children with the TOPEL-test at age 4. Both in randomized children and in those below threshold, visual equity is measured with logarithmic Tumbling E’s at age 4.

Results : Until now 525 children (age 14.4 SD1.64 months) of 858 recruited were examined. Excluded were 1 child (0.2%) with amblyopia, 7 (1.3%) with strabismus (4 exo, 3 eso) and 5 (1.0%) exceeding the double threshold. Mean spherical equivalent (SE) of 1050 eyes was 1.87D SD1.23 for the most and 1.65D SD1.13 for the least hyperopic eye (top figure). Until now 47 children (9.0%) were randomized, mean SE of 94 eyes was 3.12D SD1.69 for the most and 2.52D SD1.52 for the least hyperopic eye. Of randomized children, 21 had follow-up examinations after 8.9 SD3.78 months, some had an increase of 0.75D or decrease of 2.25D. Their SE decreased 0.01D SD0.02 per week, with a wide variation (bottom figure).

Conclusions : Sufficient children have been included in this this prospective, longitudinal study of a representative cohort to determine the relative contribution of risk of amblyopia risk factors at age 4. In consideration of the erratic change of refraction and its previously found correlation with amblyopia, prescription of glasses based on a single measurement of refraction is unfounded at age 1.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.