Refsum's disease. Eye manifestations in a patient treated with low phytol low phytanic acid diet

The cardinal eye symptoms of Refsum's disease are night blindness, retinal pigmentary degeneration and constriction of the visual fields. Similarities with or differences from retinitis pigmentosa are discussed. A 39-year-old male has had manifestations of Refsum's disease from the age of 7 years and has been on a low phytol low phytanic acid diet for the last 13 years. Peripheral ring scotomas were present. Some reduction of the visual fields has been recorded, but only in the far periphery. The central field has not been significantly constricted during a 7-year period. Very good visual functions were found within this area. All cone mechanisms were functioning at a normal level. A moderately reduced sensitivity level of the rod mechanism could be explained in a great measure by poor pupillary dilation in the dark. In this patient minimal or no progression of the visual findings was apparent. Probably an effect of treatment, there is little resemblance with ordinary retinitis pigmentosa. ERG showed moderate abnormality. Normal conducting time was found by VER. With fluorescein angiography a central area of normal appearance was sharply outlined in contrast to marked degenerations in paracentral regions.