[Progression of Bietti's crystalline dystrophy].

Bietti's crystalline dystrophy is a rare form of tapetoretinal degeneration associated with numerous glittering deposits on the retina of the posterior pole and in the limbic part of the cornea. The case of a patient with Bietti's crystalline dystrophy followed-up for more than 5 years is described together with the changes seen during progression of the dystrophy. The patient was examined for the first time at the age of 27. At the last visit, marked impairment of night vision had developed, while there was no change in visual acuity. Ophthalmoscopic examination revealed that retinal crystals at the posterior pole were reduced in number, pigmented atrophy was more profound and that wide areas of choriocapillary atrophy had developed. There was a reduction in amplitude of the electroretinogram and the development of incomplete annular paracentral scotomas in the visual field. This case confirms that the symptoms of Bietti's dystrophy develop late and that progression of the dystrophy involves atrophy of the choriocapillary lamina and the choroid. At advanced stages, the disease may resemble a severe form of retinitis pigmentosa.