A 10-year-old boy was referred to our clinic with the complaint of diplopia. He described a vertically displaced image that disappeared with chin-up posturing. He noted this vision change after cranial surgery for removing a craniopharyngioma 4 months prior. His preoperative ophthalmic examination was normal except for bilateral myopia. Cycloplegic refraction revealed − 2.50 diopters in the right eye and − 2.00 diopters in the left eye. Both eyes had a BCVA of 1.0. Prism-cover testing showed 11 PD XT at the primary position. Ocular motility testing revealed normal and symmetric eye movement bilaterally; however, the Hess chart demonstrated mild supraduction overaction in the right eye. Fundus examination revealed bilateral optic atrophy, and VF examination showed bitemporal hemianopia []. Since the patient could eliminate the diplopia with an adapted head posture, we proceeded with observation only. One year later, the patient noticed diplopia only with an upward gaze. The Worth four-dot test revealed left-eye suppression. The last follow-up was 6 years after the first visit, and the optic disc, VF defect, and XT remained stable. His BCVA was 1.0 bilaterally with a correction of − 4.75 diopters in the right eye and − 4.00 diopters in the left eye. The patient admitted that he seldom experienced diplopia and could simply ignore it when it occurred.
A 22-year-old male patient visited our clinic complaining of diplopia after a traffic accident 1 year prior. There was no abnormal eye position noted before his accident. The trauma caused encephalomalacia and fracture of the frontal bone and orbital bone. His best-corrected visual acuity (BCVA) was 1.0 in both eyes. Fundus examination revealed bilateral bow-tie shaped optic atrophy. His VF examination showed complete bitemporal hemianopia []. Traumatic optic chiasmopathy was then diagnosed. Ocular motility testing revealed no ophthalmoplegia, and the prism-cover test demonstrated 16 prism-diopter (PD) exotropia (XT) and 7 PD right hypertropia (RH). To eliminate this diplopia, we performed lateral rectus muscle (LRM) recession of 6.5 mm and superior rectus muscle (SRM) recession of 3 mm in the right eye. Three months after strabismus surgery, the prism-cover test revealed 0.5 PD XT and 4 PD RH at the primary position. Eye-alignment examination with the Hess chart also showed improvement over the preoperative findings. However, the patient complained that his diplopia persisted and failed to fuse with any prism.