[A case of chronic progressive external ophthalmoplegia with Oguchi's disease]

A 52-year-old case of chronic external ophthalmoplegia accompanied by Oguchi's disease was reported. The patient noticed night blindness and deafness since childhood. Later he developed ocular movement limitation to all directions by the age of 40. He had 20/20 corrected visual acuity and normal anterior segment, as well as normal color vision. Goldmann's perimetry showed generalized constriction of the peripheral field. Golden tapetal reflex without dark adaptation disappeared after 4 hours of dark adaptation, i.e. Mizuo-Nakamura's phenomenon was recognized. Recovery of diminished a and b wave electroretinogram to the subnormal range was also observed after 4 hours of dark adaptation. Rod-cone interaction test revealed a monophasic adaptation, and no suppression to the cones from the rods was observed. This finding was also compatible with Oguchi's disease. ECG revealed incomplete atrio-ventricular as well as right bundle branch blocks. Neurological examination findings were entirely normal other than slight enhancement of deep tendon reflexes in the lower extremities and mixed typed difficulty of hearing. Muscle biopsy of the right medial rectus muscle revealed ragged-red fiber, suggesting mitochondrial abnormalities. Never the less the quadriceps femoris muscle biopsy specimen showed normal histological findings. This is the first case report of progressive external ophthalmoplegia associated with Oguchi's disease. Mitochondrial abnormality was confirmed only in the external ocular muscle. This case may be a variant of Kearns-Sayre syndrome.