Binocular diplopia following vision restoration in patients with keratoconus and sensory strabismus

To report the phenomenon of newly-noted binocular diplopia following vision improvement in patients with sensory strabismus secondary to keratoconus, and to document the effect of strabismus surgery on this diplopia.

Retrospective institutional case series [1982--2005] of records coded with keratoconus and strabismus. Keratoconus patients with visual acuity that could not be improved, childhood strabismus, known reason for acquired strabismus (other than decreased vision from kerataconus), decreased vision from other ocular disease, monocular diplopia, failure of strabismus surgery, and/or less than six months follow-up after strabismus surgery were excluded.

Although 103 medical records were identified, only seven met the strict inclusion criteria. All seven patients presented with gradual reduction in vision (not due to their strabismus), and none initially complained of diplopia. After intervention to improve visual acuity, six complained of constant binocular diplopia. This diplopia resolved after successful strabismus surgery. Postoperative Worth four-dot testing demonstrated suppression.

Binocular diplopia, noted after intervention to improve visual acuity in our patients with strabismus secondary to long-standing uncorrected keratoconus, resolved after successful surgical alignment. Our patients may have developed suppression from uncorrected keratoconus before their sensory strabismus occurred.