A 32-year-old male patient with retinitis pigmentosa complained of intermittent diplopia for the past few years, with recent progression. His corrected vision was 0.8 in both eyes. Fundus examination revealed retinal pigmentory changes, narrowing vessels, and relatively pale discs bilaterally, and VF examination showed that only the central island remained bilaterally []. Prism-cover testing revealed 30 PD left hypertropia (LH) and 4 PD XT. Ocular-motility testing demonstrated slight overaction of the inferior oblique muscle and slight underaction of the superior oblique muscle in the left eye. On prism-adaptation testing, the patient reported no diplopia with a 16 PD prism. However, he did not like prism glasses and asked for surgical correction. We performed an inferior oblique myectomy in the left eye. One month after surgery, cover testing revealed 18 PD LH and 4 PD XT at the primary position. The patient experienced occasional diplopia only with right-up gazing, but there was no diplopia at the primary position or with near work. At the last follow-up visit 3 months later, prism-cover testing measurements were unchanged. The patient was satisfied with being free of diplopia in daily life.
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.