[Conjunctival calcification in patients in chronic hemodialysis. Morphologic, clinical and epidemiologic study].

The authors compared the presence of conjunctival calcifications in a group of 37 patients undergoing chronic hemodialysis with laboratory findings and radiologic examinations. These calcifications appear to develop in patients suffering from hypercalcemia, particularly when the mathematical product of inorganic calcium and phosphorus (Ca x PO4) exceeds the value of 3.8-4.0. Ocular calcifications are usually asymptomatic although conjunctival inflammation due to crystal deposition, better known as "red eyes", has been reported in uremic patients. This has been noted to improve after the Ca x PO4 product is reduced. Such a conjunctival inflammation has not been reported in patients undergoing chronic hemodialysis and we do not report any case of disturbance due to the presence of conjunctival lesions. These lesions usually occur in the paralimbal conjunctiva, in the limbal area exposed by the interpalpebral fissure. This is thought to be due to the relatively high alkalinity, resulting from the diffusion of CO2 from the exposed surface of the eye, which promotes the deposition of calcium salts. However, the frequent presence of pinguecula, or histologic elastosis, in the eyes of uremic patients with calcifications, suggests a pathogenic role of local degenerative changes as well. Among these 37 patients, 6 underwent a biopsy of the conjunctival lesions, allowing a pathological examination. This permitted the authors to confirm the presence of calcium deposits in the basal lamina of the conjunctival epithelium and also in the sub-epithelial tissue. In every case, a significant degeneration of the elastic tissue of the conjunctiva was found, confirming that this lesion can precede calcium deposition in these particular patients.(ABSTRACT TRUNCATED AT 250 WORDS)