Disturbance of binocular vision following macular heterotopia

Background Tractive translocation of the macula (secondary macular heteroto pia) may result in disturbance of binocular vision. The report of a case sh all discuss the sensorial problems of these patients. History and signs We report of a 40-years old male who had decreased visual acuity and loss of binocular vision for several years due to episodes of u veitis with intravitreous hemorrhage and cataract formation. After bilatera l vitrectomy and cataract extraction a good visual acuity was restored in b oth eyes. Postoperatively, the patient monocularly complained about disturb ed egocentric localization (tilting of the visual environment, "past-pointi ng") and metamorphopsia. Binocularly he was confused by doubled vision with tilted images. Both maculae showed a tractive translocation of 15 degrees downward. Measurements of binocular alignment with the tangent screen showe d an excyclotropia of 8 degrees and an exotropia of 7 degrees in all direct ions of gaze. Haploscopic examination with fusion images demonstrated that sensorial fusion was not possible even with perfect ocular alignment due to disturbed relative retinal localization (obligate fixation disparity). Therapy and outcome Initially, full time occlusion of the left eye was requ ired. After improvement of symptoms occlusion therapy was slowly tapered. W ithin one year the patient had learned to suppress the image of his left ey e and reported only minor residual visual disturbances even without occlusi on of his left eye. Conclusions Secondary translocation of the macula monocularly results in a disturbance of egocentric localization and in metamorphopsia. Binocularly d oubled vision with tilted images and a loss of sensorial fusion are seen. W ith monocular vision, perceptual adapting to the aberration in egocentric l ocalisation is possible within weeks by reallocation of the retinal meridia ns in the central nervous system. Binocular improvement of symptoms is limi ted to the learning of suppression. Improvement of binocular symptoms by ad aptation of retinal correspondence does not occur.