Treatment of heterophoria with botulinum toxin A — a case study

Background: Heterophoria (latent strabismus) is an imbalance in the tone of the oculomotor muscles. In a young child, this disorder usually does not affect the development of binocular vision. While looking, binocular vision (image fusion) keeps the eyeballs straight. With age, binocular vision may be impaired, for example, as a result of trauma, general disease, stress, or severe fatigue, and thus strabismus (heterotopia) may be revealed, which causes double vision. The patient, in our case, developed diplopia as a result of stress and fatigue. Case presentation: The patient underwent treatment with the use of botulinum toxin A. After each procedure, an ophthalmological examination was performed to measure the strabismus angle. Three courses of botulinum toxin A injection reduced the strabismus angle by 86%, the double vision passed. Conclusions: The case shows the possibility of curing an adult with Botulinum toxin A, in whom latent strabismus has turned into esotropia. Despite its transient kinetics, botulinum toxin A can have a lasting effect on eye alignment, favoring binocularity and reducing double vision, and can serve as a primary treatment. To obtain a permanent result, it is necessary to repeat the treatment