The Syndrome of Antimetropia and Switched Fixation in Strabismus

Abstract

The onset of diplopia in adolescence in a patient with longstanding strabismus may be due to a switch in fixation from a preferred eye that has just evolved into myopia to a previously suppressed still hyperopic fellow eye. This paper describes the syndrome of mixed anisometropia and switched fixation in strabismus. Diplopia is the most frequent symptom in this group of patients with small residual deviations because of the inability to suppress the image from the eye with incipient myopia even though it is no longer the fixing eye. Other symptoms include asthenopia and difficulty with concentration in reading. Signs of the syndrome include a mixed anisometropia of at least two diopters difference between the two eyes, a residual small deviation on cover test and evidence of poor sensory fusion. The treatment of such patients is to restore fixation preference to the eye with incipient myopia by prescription of the appropriate glasses.

• anisometropia
• antimetropia
• switched fixation
• fixation preference
• myopia