Recent advances in corneal stromal dystrophies.

Newer biochemical, immunohistochemical, and cell culture techniques have been used to investigate metabolic abnormalities in corneal stromal dystrophies. Organ cultures of macular corneal dystrophy (MCD) have shown a defect in the synthesis of keratan sulphate proteoglycan. Alterations in corneal stromal glycoconjugates have also been detected using biotinylated lectins. An absence of normal keratan sulphate proteoglycan has been shown in the blood of patients with MCD. Granular corneal dystrophy (GCD) is associated with increased phospholipid, as shown by biochemical analysis and staining with Luxol-fast blue. Immunohistochemical stains revealed reactivity with antibodies against microfibrillar protein at the edges of the deposits. Clinically, recently described early features of lattice corneal dystrophy (LCD) include discrete ovoid subepithelial opacities, a diffuse central anterior stromal haze, and anterior stromal dots and filamentary lines. Early clinical recognition of these corneal genetic disorders, with appropriate studies to define their nature and possible pathogenetic mechanisms, are important in expanding our knowledge of this disease spectrum.