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 40-year-old man complained of diplopia 4 days after trabeculectomy of the right eye 4 months before visiting our clinic. His corrected vision was 0.5 with − 5.50-diopter correction in the right eye and 1.0 with − 3.50-diopter correction in the left eye. Fundus examination revealed enlarged disc cupping in the right eye and a normal left eye. His VF examination showed an extremely constricted VF in the right eye, with only 7.5° × 5° remaining in the central island []. Prism-cover testing revealed 20 PD XT at the primary position. Ocular motility testing demonstrated no ophthalmoplegia. To eliminate the diplopia, we performed a right LRM recession of 7.0 mm. One month postoperatively, prism-cover testing revealed 3 PD right hypotropia. The patient described alleviation in diplopia, although it did occur sometimes. He also reported improved stereoacuity.