Ocular abnormality in myotonic dystrophy.

A 61-year-old white woman with terminal myotonic dystrophy exhibited advanced peripheral and central retinopathy. Retinal lesions were characterized by hyperpigmentation, common, though nonspecific, in myotonic dystrophy. They resemble both heredo (tapetoretinal) and idiopathic involutional degenerations but rarely cause severe visual impairment. Neither the type nor degree of retinopathy appears to correlate with other ocular features or with the stage of the underlying disease. Our histologic observations confirm and extend those previously described. Electron microscopy suggests a primary disorder of mitochondria which may also affect smooth muscle and the myocardium.