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.
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.