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 37-year-old woman developed diplopia after a second brain surgery 2 months prior, with left occipital craniotomy for recurrent tentorial meningioma removal. She had good vision and no strabismus before the first surgery for removing her brain tumor, 18 months previously. Diplopia and esotropia (ET) developed after her first brain surgery, although 10 PD prism glasses eliminated the diplopia in daily life. However, after her second surgery, she experienced diplopia even with the prism glasses. Ocular examination revealed a BCVA of 0.8 in the right eye with − 1.75-diopter correction and 1.0 in the left eye with − 1.75-diopter correction. Fundus examination revealed no optic atrophy, and VF examination showed new-onset right homonymous hemianopia []. Prism-cover testing revealed 25 PD ET at the primary position, with both near and distant fixation. Her eye movement was free and the range of eye movement was normal bilaterally. To eliminate the diplopia, we performed MRM recession of 7 mm in the left eye. One month after surgery, prism-cover testing revealed 8 PD ET. The patient was satisfied with new prism glasses.