Reversal of Central Fusional Disruption Associated with Severe Convergence Insufficiency
Laura C. Huang, MD; Charlotte A. Houston, CO; Douglas R. Fredrick, MD; Scott R. Lambert, MD
Byers Eye Institute, Stanford University
Palo Alto, California
Introduction: To demonstrate a treatment paradigm for loss of sensory and motor fusion associated with severe convergence insufficiency.
Methods: Retrospective case series of 2 patients with history of convergence insufficiency producing constant diplopia of at least 2 years duration. There was no history of intracranial pathology including traumatic head injury in either patient. Neither patient had visual acuity worse than 20/20 in either eye. On initial visit, the patients showed inability to obtain or maintain sensory fusion even after correction of their deviation with prisms.
Results: Both patients had severely reduced convergence and fusional reserves with inability to obtain binocular single vision. Treatment consisted of Fresnel prism glasses and convergence exercises. Both patients achieved binocular single vision within 6 weeks and were able to fuse without Fresnel glasses. Follow-up time was 5 and 10 months.
Discussion: We report, for the first time, central fusional disruption in association with severe convergence insufficiency and the successful reversal of fusional disruption with conservative management.
Conclusion: Fusional disruption is known to occur in association with midbrain damage(1), sensory deprivation to the visual cortex(2, 3), and in the setting of an acquired strabismus(1, 3), but has not been reported previously without these risk factors. Recognition of loss of fusion in association with severe convergence insufficiency is paramount to counsel these patients and initiate appropriate treatment to reverse disruption of binocularity.
References: 1. Pratt-Johnson JA, Tillson G. Acquired central disruption of fusional amplitude. Ophthalmology. 1979;86(12):2140-2.
2. Leefkens-van den Broek MM, Wenniger-Prick LJ. Fusion loss as a result of long-standing unilateral traumatic cataract or uncorrected aphakia. Strabismus. 1995;3(2):79-84.
3. Digout LG, Awad AH. Restoration of binocular single vision after long-term fusion disruption. J AAPOS. 2003;7(3):185-9.