Variance between near, distance visual acuity in amblyopia may be due to test repeatability

J Pediatr Ophthalmol Strabismus. 2011;15(4):342-344.

In children with moderate amblyopia from anisometropia or strabismus, no systematic differences were found between distance and near visual acuity, according to a study.

"Individual differences between distance and near visual acuity are likely due to test-retest variability," the study authors said.

Data were culled from a randomized trial of atropine regimens for treatment of moderate amblyopia in children conducted by the Pediatric Eye Disease Investigator Group. Investigators compared daily atropine therapy with weekend therapy after 4 months of treatment in children with moderate amblyopia, defined as distance visual acuity of 20/40 to 20/80.

The study included 168 patients between the ages of 2 years and 6 years. Mean patient age was 5.3 years. Four patients with amblyopia of undetermined cause and 35 patients enrolled before near visual acuity testing was added to the study protocol were excluded from the study, leaving 129 eligible subjects.

A vision tester used electronic HOTV optotypes to gauge distance visual acuity ranging from 20/800 to 20/16 at 3 m.

Flip cards with single-surrounded HOTV optotypes were used to measure near visual acuity ranging from 20/400 to 20/20 in 0.1 logMAR intervals at 40 cm.

Study results showed mean logMAR distance visual acuity of 0.45 and mean near visual acuity of 0.45 in the amblyopic eye. Eighty-six subjects tested within one logMAR line at both near and distance, 19 subjects tested more than one logMAR line better at distance, and 24 eyes tested more than one logMAR line better at near.

Mean differences in acuity did not vary according to cause of amblyopia, age or spherical equivalent refractive error, the authors said.