||This 39-year-old woman's initial sign was painless, progressive, symmetric ptosis OU, without diurnal variation, that manifested when she was age 17 living in the Dominican Republic. At that time, she had no diplopia or systemic signs. She had no family history of ocular or muscle disease, and no other significant past history. She was first diagnosed in 1973 as myasthenic, but on what basis is unknown, and was started on Mestinon. The patient remembers her first Tensilon test and said it had no effect. From age 17 to 27, she was maintained on Mestinon (pyrodostigmine bromide), without effect. At age 27 she had ptosis without ophthalmoparesis and underwent two unsuccessful bilateral lid repairs. Reportedly, one of several acetylcholine receptor antibodies was positive. In 1982, she underwent ineffectual thymectomy; she then went on prednisone therapy for 8 years, also without any effect. From 1982 to 1989, she underwent two more ineffectual lid procedures OU. In early 1989, she was admitted for a brief episode of shortness of breath. Her workup included a vital capacity of 1.7, which was felt to be a moderate restrictive defect. A repeat Tensilon test was negative (2 mg every 30-45 seconds, total of 10 mg) and was EMG negative (eye muscles not performed). The only other neurologic finding at this time was terminal tremor. The patient was placed on thyroid replacement and was referred for neuro-ophthalmologic assessment on May 30, 1989, to determine whether concomitant Graves' disease caused her therapy to fail. At this time, she denied diplopia, and in fact, had not noted her ophthalmoparesis. She had no subjective appreciation of any vision change in light versus dark environments. Her medications at the time of the neuro-ophthalmologic examination were prednisone 20 mg qd, Mestinon (pyrodostigmine bromide) 60 qid, and levothyroxine 1.25 mg qd. the initial neuro-ophthalmologic examination in May 1989 showed best-corrected acuities 20/25- OU; Ishihara color plates 13/14 OD, 14/14 OS; pupils 4/4 RRL, no RAPD; lid fissures 3 mm OD, 4 mm OS, no change in upgaze, no Cogan's lid twitch sign, no fatigue; EOM 3+ underaction lateral recti OU, underaction medial recti OU, underaction up- and downgaze OU, minimal cyclotortion seen on attempted depression in adduction OU, forced ductions minimal restriction up and down OD, mild OS, restriction in downgaze, free everywhere else (? related to prior surgeries and symblepharon formation); slit-lamp showed mild superficial punctate keratopathy inferior to pupillary axis OU, symblepharon to upper lids OU; intraocular pressures were 16 mm Hg OD, 21 mm Hg OS; tangent field full to 3 mm/1000 white OU; media: clear; fundus: OU cup disc ration 0.3. normal pink color sharp, macula normal, perhaps temporal arterioles a trace narrowed, perivenous pigmentary clumping noted. The initial impression, because of the pigmentary changes, was that of the spectrum of chronic progressive external ophthalmoplegia plus Kearns-Sayre syndrome. The plan was to obtain a CT scan of the orbits because of her hypothyroidism and positive forced duction to rule out that the restrictive component was due to accompanying Graves' disease as well. An EKG with long rhythm strip and an ERG were obtained. The CT of the orbits showed markedly atrophic muscles (image 93_70). The ERG showed that all amplitudes (scotopic blue, red, white, and photopic white) were low to borderline. Muscle biopsy showed an increased fiber-sized variation, with many ragged red fibers and a few phagocytes. The ragged red fibers were stained at the periphery with NADH-TR, consistent with Kearns-Sayre disease. Electron microscopy showed subsarcolemmal accumulation of abnormal mitochondria, with crystalline stacks of filaments, also consistent with mitochondrial myopathy. The patient was tapered off of prednisone, and Mestinon without side effects or change in her examination.