Prevalence and causes of visual impairment in Asian and non-Hispanic white preschool children: Multi-ethnic Pediatric Eye Disease Study

Abstract

Purpose: To determine the prevalence and causes of decreased visual acuity (VA).

Design: Population-based cross-sectional study.

Participants: Multi-ethnic sample of children 30 to 72 months of age identified in Los Angeles.

Methods: All eligible children underwent a comprehensive ophthalmic evaluation including monocular VA testing, cover testing, cycloplegic autorefraction, fundus evaluation, and VA retesting with refractive correction. Decreased VA was defined as presenting or best-measured VA worse than 20/50 in children 30 to 47 months of age and worse than 20/40 for children 48 months of age and older. The prevalence and causes of decreased VA were determined, for both presenting and best-measured VA, in the better-seeing and the worse-seeing eyes.

Main outcome measures: Prevalence and causes of decreased vision.

Results: Presenting VA was assessed in 1840 children and best-measured VA was assessed in 1886 children. Presenting VA was decreased in the worse eye of 4.2% of Asian children and of 3.6% of non-Hispanic white (NHW) children. Close to one-fourth of these cases had no identifiable cause, and 81% of these resolved on retesting. Decreased presenting VA in the worse eye with an identifiable ophthalmic cause was present in 3.4% of Asian children and in 2.6% of NHW children. Decreased presenting VA attributable to simple refractive error (myopia ≥ 0.5 diopters [D]; hyperopia ≥ 3.0 D; astigmatism ≥ 2.0 D or ≥ 1.5 D for children older than 36 months) was present in the worse eye of 2.3% of Asian children and of 1.4% of NHW children and in the better eye of 0.5% of Asian children and of 0.3% of NHW children. Decreased best-measured VA attributable to a cause was present in the worse eye of 1.2% of both Asian children and NHW children and in the better eye of 0.2% of Asian and of 0.3% of NHW children. Amblyopia related to refractive error was the most common cause, and was 10 times as common as ocular disease. Severe visual impairment was rare.

Conclusions: Seventy percent of all decreased VA in Asian and NHW preschool children and more than 90% of decreased VA with an identifiable cause is related to refractive error--either uncorrected refractive error or amblyopia resulting from refractive error.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Figure 1

Visual acuity testing protocol. VA: visual acuity. IOD: inter-ocular difference in visual acuity. *Factoring in results of quality control retest, performed in a subset of children >=36 months under same conditions as presenting VA test (with child’s own glasses if worn): for the first exam of the day for each examiner, and for children with VA worse than 20/32 in either eye, if a second examiner was available. † IOD is defined as inter-ocular VA difference >=2 lines with 20/32 or worse in the worse eye. Decreased VA is defined as worse than 20/50 at any age, or worse than 20/40 if >=48 months of age. ‡ See Methods for definitions of amblyopia risk factors.