A Case of Superior Oblique Palsy without Brown Syndrome Induced by a Dog Bite.

BACKGROUND Pseudo-Brown syndrome is characterized by dysfunction of the superior oblique tendon-trochlear complex. Canine tooth syndrome, which involves superior oblique palsy with pseudo-Brown syndrome, results from damage to the trochlear and superior oblique tendon from dog bites around the eye. This report describes a variant of canine tooth syndrome without pseudo-Brown syndrome following a dog bite around the left upper eyelid. In this case, magnetic resonance imaging (MRI) facilitated early diagnosis and therapeutic intervention. CASE REPORT A 19-year-old man presented with torsional diplopia following a dog bite around the left upper eyelid and forehead. Five days after the injury, an alternate prism cover test revealed 6 prism diopters (Δ) exotropia and 5Δ left hypertropia. Ocular motility showed no significant limitation in elevation or depression during adduction. MRI performed on the same day showed a high-signal area extending from the superior oblique tendon to the trochlear region and the superior oblique muscle belly of the left eye. A diagnosis of canine tooth syndrome without pseudo-Brown syndrome was made and oral steroids were administered. Ocular alignment did not improve, so left inferior oblique myotomy was performed 7 months after the injury. The patient's cyclovertical diplopia resolved postoperatively. CONCLUSIONS Dog bites around the eye can result in abnormalities of the extraocular muscles. Early MRI may be useful for diagnosis and determining treatment strategies. This report has highlighted the importance of rapid assessment and management of patients with dog bites involving the eye.

Homozygous single nucleotide duplication of SLC38A8 in autosomal recessive foveal hypoplasia: The first Japanese case report.

PURPOSE: To characterize the clinical and genetic features of a Japanese male patient with foveal hypoplasia caused by a homozygous single nucleotide duplication in the SLC38A8 gene. METHODS: We performed a comprehensive ophthalmic examination including full-field electroretinography (FF-ERG) and pattern-reversal visual evoked potentials (PR-VEPs). Whole-exome sequencing (WES) was performed to identify the disease-causing variant; Sanger sequencing was used for confirmation. RESULTS: In the WES analysis, a homozygous single nucleotide duplication (c.995dupG; p.Trp333MetfsTer35) was identified in SLC38A8 of the patient. His unaffected mother carried the variant heterozygously. The patient exhibited hyperopia, congenital nystagmus, low visual acuity, and grade 4 foveal hypoplasia. Slit-lamp examination revealed mild posterior embryotoxon and goniodysgenesis. Fundus examination revealed the absence of foveal hyperpigmentation and foveal avascularity, but there were no retinal degenerative lesions. In the FF-ERG, the amplitudes of rod ERG, standard-flash, and bright-flash ERG were within the normal range; cone-mediated responses also showed nearly normal amplitudes. The PR-VEP findings revealed delayed P100 latencies and decreased amplitudes of the P100 components, but no chiasmal misrouting. CONCLUSIONS: This report is the first report on the clinical and genetic characteristics of SLC38A8-associated foveal hypoplasia in the Japanese population. This is also the first report of normal rod- and cone-mediated responses in a patient with this disorder.

Spontaneous Improvement of Visual Acuity in a 13-Year-Old Boy with Neuromyelitis Optica Spectrum Disorder.

Ophthalmic and MRI evaluations of a 13-year-old boy who reported loss of visual acuity in his right eye demonstrated the presence of unilateral optic neuritis. After serological tests showed positivity for anti-aquaporin 4 antibody, he was diagnosed with neuromyelitis optica spectrum disorder. Encephalopathy and myelitis were not observed. Since his unilateral optic neuritis was considered to reflect mild disease activity, only follow-up observations were performed. Visual acuity and central scotoma improved 1 week after the first examination. In the absence of any specific treatments, good visual acuity has remained for 20 months, with no relapse of optic neuritis.

[A Case of Renal Cell Carcinoma Choroidal Metastasis Diagnosed from Vision Disorders].

A 69-year-old male with the complaint of a cough was referred to our hospital from a clinic where he was found to have simultaneous metastases of the left kidney tumor. We performed left cytoreductive nephrectomy, and administered sunitinib after the surgery. The first line treatment was not effective. Then we changed the therapeutic agent to pazopanib as the second line treatment. Lung and lymph node metastases gradually shrunk, but he developed right vision disorders and was diagnosed with bilateral metastatic retinal tumors. First, irradiation to the right eye was performed while discontinuing pazopanib. Sudden treatment withdrawal caused his general condition to worsen temporally, but irradiation could be continued by resuming administration of pazopanib. As a consequence, the progression of the visual field disorder was suppressed by the additional ophthalmologic treatment. Renal cell carcinoma choroidal metastases are rare, but we need to consider them when the patient has vision disorders.