Obstacles to Fusion: Strabismus and Diplopia

Abstract

There are many potential obstacles to fusion for adult patients with diplopia. Monocular diplopia is the fi rst obstacle that should be ruled out in every adult patient before they are referred for a complete sensorimotor evaluation. Monocular diplopia is usually refractive in nature, but may also be the result of an ocular defect, or, in rare cases, the problem may be neurologic. Obstacles to motor fusion include: incomitant strabismus, insuffi cient fusional amplitudes, torsion, and nystagmus. Obstacles to sensory fusion include image disparity and sensory anomalies such as suppression, ARC, and eccentric fi xation. Sensory anomalies are the most diffi cult to treat and can result in intractable diplopia.