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 29-year-old man presented with diplopia after a traumatic skull base and orbital bone fracture 4 years prior. He was an architect and the diplopia considerably hindered his work. Ocular examination revealed the BCVA to be 1.0 in both eyes. Fundus examination revealed bilateral optic atrophy, and VF examination showed bitemporal hemianopia []. The prism-cover testing revealed 18 PD XT and 6 PD RH at the primary position. Ocular-motility testing demonstrated normal eye movement bilaterally. The Bagolini striated glasses test demonstrated right-eye suppression. To eliminate the diplopia, we performed LRM recession of 9 mm and SRM recession of 2 mm in the right eye. One month after surgery, prism-cover testing revealed 10 PD XT and 5 PD RH. Three months later, synoptophore testing demonstrated an unstable subjective angle from 1 to 3 PD XT and from 3 to 6 PD RH. The patient still experienced diplopia and could not tolerate prism glasses.