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 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.