Reduced stereoacuity often persists after resolution of anisometropic amblyopia

This study's authors analyzed pooled data from seven studies conducted by the Pediatric Eye Disease Investigator Group to determine factors associated with pre- and post-treatment stereoacuity in patients with moderate anisometropic amblyopia. The results indicate that better post-treatment stereoacuity is associated with better baseline stereoacuity and better post-treatment amblyopic eye acuity. The authors found that many children with anisometropic amblyopia whose visual acuity deficit resolved still had stereoacuity worse than that of nonamblyopic children of the same age.

The study included 633 subjects aged 3 to 17 years with anisometropic amblyopia, no heterotropia and baseline amblyopic eye acuity of 20/100 or better. Of this group, a subset of 248 subjects was treated with patching or Bangerter filters and underwent stereoacuity testing at both the baseline and outcome examinations.

The authors found that better baseline stereoacuity was associated with better baseline amblyopic eye visual acuity (P < 0.001), less anisometropia (P = 0.03) and anisometropia due to astigmatism alone (P < 0.001).

Only 48 of the 248 patients in the subgroup (19 percent) had post-treatment amblyopic eye visual acuity of 20/25 or better and within one line of the fellow eye. Despite this marked improvement, stereoacuity among these 48 patients remained worse than that of children with normal vision of the same age. The authors say this finding supports the premise that anisometropic amblyopia is associated with subnormal binocular development.

They conclude that although visual acuity in the amblyopic eye can improve to normal or near-normal levels with treatment, a significant deficit in binocular function, as implied by reduced stereoacuity, persists in many children.