Central crystalline corneal dystrophy.

The purpose of this paper is to report the first family from Great Britain with central crystalline corneal dystrophy and to discuss the pathogenesis of this condition, a welldocumented entity (Waardenburg, Franceschetti, and Klein, I96I), the genetical basis of which was first demonstrated in a family of eight by van Went and Wibaut (1924), and confirmed by Schnyder (1927, I929, 1939). The condition is often known as the crystalline corneal dystrophy of Schnyder.. It is transmitted as an autosomal dominant trait, usually with I00 per cent. penetrance (Franceschetti and Forni, I952). The clinical descriptions of reported cases are fairly uniform. The essential feature is the presence of many tiny needle-like crystals in the anterior stroma of the central cornea as seen with the slit lamp. These crystals shine and reflect many different colours. Macroscopically the corneal dystrophy is greyish or brownish in colour, central in position, and usually disciform in shape. The opacity is present in the first few years of life and progresses very slowly, rarely causing significant impairment of vision. There is no vascularization, no irritative phenomena, and no impairment of corneal sensation. Because of the infrequent necessity for corneal grafting only three studies of the composition of the crystals have been reported. The crystals have shown them to be fatty in nature. Bonnet, Paufique, and Bonamour (I934) thought that they were cholesterol crystals because they were doubly refractile in polarized light and were soluble in ether. Sedan and Valles (I946) found cholesterol and oxalic acid by chemical analysis, and Malbr'an, Paunessa, and Vidal (1953) thought that the crystals consisted of neutral fat as they stained with Sudan IV. The presence of arcus juvenilis or senilis in association with central crystalline dystrophy was noted by Sysi (I950), MalbrAn and others (I953) and other workers. Bonnet and others (I934) were the first to consider blood fat levels and in a single case the blood cholesterol was found to be i6o mg. per cent., a normal result. Similar normal values were found in the isolated cases reported by Cavara (I940) and Pandolfi (I941) and also in the nine cases reported by Fry and Pickett (I950). Raised levels of blood fat were found by PWrez Llorca (I949) in two isolated cases, Sysi (1950) in four familial cases, and by Malbran and others (I953) in the one case he studied out of a family with six affected members. Luxenberg (i967), in an isolated case, found mild elevation of serum cholesterol and phospholipids, but these were not significantly above the normal range.