We examined the plasma membrane glycoconjugates of cultured corneal stromal cells derived from patients with keratoconus and healthy subjects. Using radiolabeled lectins as probes, we found that a majority of our keratoconus strains contained more binding sites for concanavalin A, Ricinus communis agglutinin I, and soybean agglutinin than did the controls. The number of binding sites in cultured keratoconus cells for radioactive peanut agglutinin, wheat germ agglutinin, and Griffonia simplicifolia agglutinin I, however, was similar to that found in normal controls. Using a second method with biotin-labeled lectins as probes, we confirmed that increased amounts of glycoconjugates would bind to concanavalin A and R communis agglutinin I in stromal cells of patients with keratoconus compared with those of the control subjects. This study suggests that plasma membranes of cells derived from some patients with keratoconus may contain elevated amounts of glycoconjugates with glucose and/or mannose, terminal galactose, and N-acetylgalactosamine residues.