Pigment changes of the retina in chronic progressive external ophthalmoplegia (CPEO)

A study was made of the retinal functions in 4 patients with chronic progressive external ophthalmoplegia, general myopathy, EEG anomalies and pigment changes of the fundus oculi (ophthalmoplegia-plus). Three of them exhibited typical, granular pigmentations in a linear or reticular arrangement at the periphery. All four showed slight to moderate pigment epithelial defects in the maculae, mostly only discernible with fluorescence angiography. In all 4 cases, a slight decrease of the visual acuity, a mildly abnormal ERG, mild concentric restriction of the field of vision and, in two cases, an abnormal dark-adaptation curve led to the conclusion of a mild diffuse, widely disseminated receptor affection of the retina (both rods and cones). The EOG appeared normal in 3, and at the lower limit of normal in 1 case. On the basis of a detailed study of the literature we can conclude that the retinal lesions in chronic progressive external ophthalmoplegia may vary from benign pigmentations without functional impairment to genuine 'retinitis pigmentosa' with all gradations of rod-cone or cone-rod dystrophy. Emphasis is laid on the possibility of a correlation between the mitochondrial abnormalities encountered in ocular myopathy and ophthalmoplegia-plus on the one hand, and the retinal abnormalities on the other, with special reference to a possible disorder of the utilization of pyruvate in the citric-acid cycle and a loose coupling of the oxidative phosphorylation.