Stereoacuity in children with anisometropic amblyopia

Abstract

Purpose: To determine factors associated with pretreatment and posttreatment stereoacuity in subjects with moderate anisometropic amblyopia.

Methods: Data for subjects enrolled in seven studies conducted by the Pediatric Eye Disease Investigator Group were pooled. The sample included 633 subjects aged 3 to <18 years with anisometropic amblyopia, no heterotropia observed by cover test, and baseline amblyopic eye acuity of 20/100 or better. A subset included 248 subjects who were treated with patching or Bangerter filters and had stereoacuity testing at both the baseline and outcome examinations. Multivariate regression models identified factors associated with baseline stereoacuity and with outcome stereoacuity as measured by the Randot Preschool Stereoacuity test.

Results: Better baseline stereoacuity was associated with better baseline amblyopic eye acuity (P < 0.001), less anisometropia (P = 0.03), and anisometropia due to astigmatism alone (P < 0.001). Better outcome stereoacuity was associated with better baseline stereoacuity (P < 0.001) and better amblyopic eye acuity at outcome (P < 0.001). Among 48 subjects whose amblyopic eye visual acuity at outcome was 20/25 or better and within one line of the fellow eye, stereoacuity was worse than that of children with normal vision of the same age.

Conclusions: In children with anisometropic amblyopia of 20/40 to 20/100 inclusive, better posttreatment stereoacuity is associated with better baseline stereoacuity and better posttreatment amblyopic eye acuity. Even if their visual acuity deficit resolves, many children with anisometropic amblyopia have stereoacuity worse than that of nonamblyopic children of the same age.

Trial registration: ClinicalTrials.gov NCT00091923 NCT00094614 NCT00094692 NCT00315198 NCT00315302 NCT00315328 NCT00525174.

FIG 1

Relationship between baseline amblyopic eye visual acuity and mean baseline stereoacuity, adjusting for the effect of other covariates. Mean baseline stereoacuity (log arcsec) was computed for each level of baseline visual acuity, adjusting for age group, magnitude of anisometropia, anisometropia type, and protocol. Better stereoacuity was associated with better amblyopic eye visual acuity (P < 0.001).

FIG 2

Relationship between outcome amblyopic eye visual acuity and mean outcome stereoacuity after treatment, adjusting for the effect of other covariates. Mean stereoacuity at outcome after treatment (log arcsec) was computed for each level of amblyopic acuity eye visual at outcome, adjusting for age, baseline amblyopic eye acuity, baseline stereoacuity, and protocol. Better outcome stereoacuity was associated with better amblyopic eye visual acuity at outcome with treatment (P < 0.001).

FIG 3

Age group comparison of stereoacuity among subjects with amblyopic eye visual acuity of 20/25 or better and within one line of the fellow eye visual acuity compared to normal children. For each age group, the box on the left (gray) is the distribution of stereoacuity scores for the Amblyopia Treatment Study subjects and that on the right (white) represents the normal children. The top and bottom of each box represent the 25th and 75th percentiles of the data, the group medians are represented by a bolded line, and the group means are represented by a dot. For some of the box plots, the median also corresponds to the 25th and/or 75th percentile. The bars extending above and below each box represent 1.5 times the interquartile range (difference between the 25th and 75th percentiles). The open circles represent near statistical outliers, and the asterisks indicate far outliers. P values are from the age-matched comparison of stereoacuity among children with amblyopic eye visual acuity of 20/25 or better and within one line of the fellow eye visual acuity at outcome compared to that of normal children based on the Wilcoxon exact rank-sum test.