LAUSR

Dear Editor, Congenital cranial dysinnervation disorders (CCDDs) represent a group of neurodevelopmental diseases of the brainstem and cranial nerves [1]. Congenital superior oblique palsy (SOP) is one of the most representative CCDD because 73% of patients show an absent trochlear nerve and superior oblique hypoplasia [2]. CCDD is not limited to a single nerve and sometimes affects two or more nerves [3–7]. Coexistence of SOP with other CCDDs such as Duane’s retraction syndrome has been reported [2]. However, combined superior rectus hypoplasia and superior oblique palsy without a trochlear nerve has never been reported. A 35-year-old man presented with persistent diplopia for the past 5 years and an abnormal head posture consisting of a face turn to the right, head tilt to the left, and chin up position. He had noticeable asymmetry of the face. He had previously undergone strabismus surgery twice of a right superior rectus resection followed by left superior rectus recession 1 year apart in another university hospital. Diplopia had improved immediately after surgery, but recurred a few weeks later. His past medical history was unremarkable. He denied any previous event of head trauma. On examination, his best-corrected visual acuities were 20/ 20 OU. He showed right hypotropia (RHoT) of 18 prism diopters (Δ) at distance and RHoT 12Δ at near on alternate prism and cover test in the primary position. He showed RHoT 25Δ in the right gaze, RHoT 18Δ in the left gaze, RHoT 6Δ on right head tilt, and RHoT 16Δ on left head tilt. The right eye showed limited elevation (− 2) and depression on adduction (− 1) (Fig. 1). He showed pseudoptosis in the right eye. The Lancaster red-green test revealed RHoT and extorsion (Fig. 2). Ocular versions and the Lancaster redgreen test results before the first surgery in an outside university hospital were similar. The thyroid function tests, antiacetylcholine receptor-antibody test, and repetitive nerve stimulation test were all negative. T2-weighted coronal imaging was obtained with 1-mm slice thickness for the orbit to evaluate extraocular muscles.