SCHNYDER'S CRYSTALLINE CORNEAL DYSTROPHY: A CASE REPORT.

Schnyder's crystalline dystrophy is a rare hereditary corneal disease, the clinical forms can be varied.

It is classically characterized by the presence of central corneal opacities, disc or ring, with or without crystals, and sometimes associated with a peripheral corneal arch or the limbic belt of Vogt.

The pathogenesis is linked to an abnormality of lipid metabolism with accumulation of lipids at the corneal level.

The purpose of our observation is to recall the clinical and biological characteristics of Schnyder’s corneal dystrophy, and to underline the risk of the occurrence of diffuse vascular damage favoring cardiovascular accidents.

We report the case of a 30-year-old patient that was referred to us for a gradual decline in visual acuity. 

The patient has reported the appearance of white spots in her eyes, gradually increasing in size over the past 15 years.

The corrected visual acuity was 3/10 in the right and 2/10 in the left eye, and the intraocular pressure was 14 mmHg in the right and 16 mmHg in the left eye.

Biomicroscopic examination revealed bilateral and symmetrical involvement with central corneal opacities, in disc form following an accumulation of iridescent crystals in the central portion of the stroma, a peripheral lipid arc with a haze in the middle periphery.

The patient had an anterior segment optical coherence tomography (OCT): areas of hyper-reflectivity corresponding to the location of the lesions were visible in the stroma, reaching its full depth.

Schnyder's crystalline dystrophy is a rare hereditary corneal disease, the clinical forms can be varied.

It is transmitted in an autosomal dominant manner, the responsible gene being located on the short arm of chromosome 1.

The signs found in this dystrophy result from the accumulation of cholesterol and phospholipids in the corneal stroma associated with a degeneration of collagen fibrils.

Schnyder's crystalline dystrophy is typically characterized by the presence of fine crystals forming a central round or oval, annular or disc opacity in the anterior stroma, and it is now well established that crystals are present in about 50% of cases, as is the case in our patient.

In patients with this pathology, hypercholesterolemia should be sought in order to be treated if necessary. Other classic associations should also be sought, such as: genu valgum, chondrodystrophy or atherosclerosis with diffuse vascular suffering.

No treatment is available to stop the progression of this disease. However, several surgical techniques can be proposed, the choice of which depends on the depth of the damage to the stroma.

The clinical case reported here, very suggestive of Schnyder's dystrophy, underlines the value of clinical examination for diagnosis.

Ophthalmologists should be aware of the ocular and general signs of this disease in order to preserve the functional visual and cardiovascular prognosis.