The association between nonstrabismic anisometropia, amblyopia, and subnormal binocularity.

Area of Science:

• Ophthalmology
• Pediatric Optometry
• Vision Science

Background:

• Anisometropia, a refractive error causing unequal vision between eyes, is a known risk factor for amblyopia and subnormal binocularity.
• Existing guidelines recommend treatment or observation based on the degree of anisometropia, but specific thresholds for visual development impacts require further characterization.

Purpose of the Study:

• To identify critical thresholds of anisometropia associated with the development of amblyopia and subnormal binocularity.
• To compare these identified thresholds with current clinical guidelines for anisometropia management.

Main Methods:

• Retrospective review of 361 untreated patients with anisometropia and 50 controls over 42 months.
• Assessment of uncorrected visual acuity, monofixation response, and stereopsis.
• Cycloplegic refraction and spectacle correction used to determine refractive error and visual acuity.

Main Results:

• Spherical myopic anisometropia >2D and spherical hyperopic anisometropia >1D significantly increase amblyopia and decrease binocular function.
• Cylindrical myopic or hyperopic anisometropia >1.5D also significantly increases amblyopia and reduces binocular function.
• Higher degrees of anisometropia correlate with increased incidence and severity of amblyopia.

Conclusions:

• Established thresholds for spherical and cylindrical anisometropia correlate with increased risk of amblyopia and subnormal binocularity.
• The study findings support and refine existing clinical guidelines for the treatment and observation of anisometropia.