Neuro-ophthalmic manifestations of mitochondrial disorders and their management.

The visual system has high metabolic requirements and is therefore particularly vulnerable to mitochondrial dysfunction. The most commonly affected tissues include the extraocular muscles, photoreceptors, retinal pigment epithelium, optic nerve and visual cortex. Hence, the most common manifestations of mitochondrial disorders are progressive external ophthalmoplegia, macular pattern dystrophy, pigmentary retinopathy, optic neuropathy and retrochiasmal visual field loss. With the exception of Leber hereditary optic neuropathy and stroke-like episodes seen in mitochondrial encephalopathy, lactic acidosis and stroke-like episodes, the majority of neuro-ophthalmic manifestations have an insidious onset. As such, some patients may not recognize subtle progressive visual symptoms. When mitochondrial disorders are highly suspected, meticulous examination performed by an ophthalmologist with targeted ancillary testing can help confirm the diagnosis. Similarly, neuro-ophthalmic symptoms and signs may be the first indication of mitochondrial disease and should prompt systemic investigations for potentially life-threatening associations, such as cardiac conduction defects. Finally, the ophthalmologist can offer symptomatic treatments for some of the most disabling manifestations of these disorders.

Feasibility of a Nonmydriatic Ocular Fundus Camera in an Outpatient Neurology Clinic.

OBJECTIVE: To determine the feasibility of nonmydriatic fundus photography in the neurology outpatient setting and to record frequency of clinically relevant fundus findings. METHODS: Over 5 weeks, fundus photographs were obtained using a nonmydriatic fundus camera in both eyes of adult patients attending our general neurology and headache clinics. A neurologist, who had received 15 minutes of training on the use of the camera, took the photographs. Quality of photographs was graded. Photographs were reviewed by 2 neuro-ophthalmologists. Treating neurologists completed a survey on the use of this technology in the neurology clinic. Feasibility parameters including ease, comfort, speed, quality, and clinical relevance of nonmydriatic fundus photography was assessed. RESULTS: We obtained 505 fundus photographs of 206 patients. Median time to completion of photographs per patient was 2.12 minutes. Mean rating for ease, comfort, and speed was 9.7 out of 10. Among these, 160 had normal and 44 had abnormal findings. In 114 of 206 patients, neurologists relied on photographs for ocular fundus assessment. In the remaining 92 patients, 18 patients had abnormal photographs, of which neurologists missed the abnormality in 14 (78%). All neurologists preferred nonmydriatic fundus photography over direct ophthalmoscopy. CONCLUSIONS: Using nonmydriatic fundus photography in an outpatient neurology clinic is feasible without disrupting patient flow or causing patient discomfort. Findings of optic nerve pallor, optic nerve swelling, or normal optic nerves were particularly relevant to these patients seen for headaches or demyelinating disease and helped inform immediate diagnosis and management.