Estimation of strabismic amblyopia by small-sized concentric gratings in preverbal children

Abstract

Evaluate the ability to assess strabismic amblyopia of small-sized Concentric Gratings in comparison with classic linear gratings preferential looking test. Thirty-three preverbal children (age 6-30 months) with esotropia were tested for monocular visual acuity, using small-sized Concentric Gratings (target size 1.6, in 1/3 octave steps) and the Teller Acuity Cards. A fixation preference testing score was also obtained. In 17 of these children, 1-3 years later, after treatment of amblyopia and strabismus, fixation preference testing score, and visual acuity with Teller Acuity Cards, Concentric Gratings, and Glasgow Acuity Cards were measured. In 24 additional verbal untreated strabismic children (age 39-48 months), the same procedures were used. Correlations between interocular acuity difference of each preferential looking test and the Glasgow Acuity Cards were compared. Correlations between interocular acuity difference of each preferential looking procedure and fixation preference testing score were also compared. Concentric Gratings procedure was correlated significantly better than Teller Acuity Cards with fixation preference testing score (0.7 and 0.49, respectively), in the preverbal group (P=0.04). In treated verbal children, correlation of Concentric Gratings and Glasgow Acuity Cards (0.90) was stronger (P=0.06) than correlation of Teller Acuity Cards and Glasgow Acuity Cards (0.64). In untreated verbal children, correlation of Concentric Gratings and Glasgow Acuity Cards (0.89) was stronger (P=0.045) than correlation of Teller Acuity Cards and Glasgow Acuity Cards (0.67). The small-sized Concentric Gratings procedure improves detection and estimation of amblyopia depth in strabismus when compared with classic linear gratings.