Anin vitroanalysis of glycoprotein produced by nine human ocular isolates of HSV-1 is reported. The source of the isolates was; three patients with recurrent dendritic keratitis, three with chronic stromal disease and three with primary keratoconjunctivitis. Virus strains were labelled with the radioactive precursors (35s) methionine and (14c) glucosamine. Radiolabelled viral glycoproteins were subsequently analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), followed by autoradiography. Viral glycoproteins were further characterised by immuno-precipitation with polyclonal and monoclonal antibodies to HSV. The stromal isolates excrete larger amounts of 'soluble' precursor glycoprotein D than those in the other two disease categories. It is possible that the immune response to glycoprotein D is in part responsible for the severity of stromal disease.