The role of anisometropia in the development of accommodative esotropia

Purpose: To determine if anisometropia increases the risk for the development of accommodative esotropia in hypermetropia. Methods: Records of all new patients with a refractive error of ≥+2.00 (mean spherical equivalent [SE] of both eyes) over a 42-month period were reviewed. Three hundred forty-five (345) patients were thus analyzed to determine the effect of anisometropia (≥1 diopter [D]) on the relative risk of developing esodeviation and of requiring surgical correction once esodeviation was present (uncontrolled deviation). Results: Anisometropia (≥1 D) increased the relative risk of developing accommodative esodeviation to 1.68 (P<.05). Anisometropia (≥1 D) increased the relative risk for esodeviation to 7.8 (P<.05) in patients with a mean SE of <3 D and to 1.49 (P<.05) in patients with SE of ≥3 D. This difference was significant (P=.016). In patients with esotropia and anisometropia (≥1 D), the relative risk for an uncontrolled deviation was 1.72 (P<.05) compared with nonanisometropie esotropic patients. Uncontrolled esodeviation was present in 33% of anisometropic patients versus 0% of nonanisometropic patients with a mean hypermetropic SE of <3 D (P=.003); however, anisometropia did not increase the relative risk of uncontrolled esotropia in patients with SE of ≥3 D. Although amblyopia and anisometropia were closely associated, anisometropia increased the relative risk of esodeviation to 2.14 (P<.05) even in the absence of amblyopia. Conclusions: Anisometropia (>1 D) is a significant risk factor for the development of accommodative esodeviation, especially in patients with lower overall hypermetropia (<3 D). Anisometropia also increases the risk that an accommodative esodeviation will not be fully eliminated with hypermetropic correction.