Morphologic examinations of biopsy specimens of the conjunctiva from 28 patients with keratoconus (56 biopsy specimens) revealed two types of pathologic processes: (1) acute and chronic immune inflammations of cell-mediated and mixed type (in 9 patients) and (2) fibrosis and acellular sclerosis as the result of the inflammation with the reduction of the microcirculatory bed and ischemia (19 patients). These data indicate the necessity of a differentiated approach to pre- and postoperative drug therapy of patients with keratoconus, exposed to perforating keratoplasty. The clinical picture does not permit a differentiation between types and phases of the inflammation for objective individualized prescription of drug therapy before and after perforating keratoplasty, therefore conjunctival biopsy is advisable in such cases as a diagnostic test. Histologic analysis gives data on the migration and proliferation of inflammatory cells, on the production of the intercellular substance, on the microcirculatory status. The results of this study helped the authors suggest a schematic approach to conservative therapy of patients suffering from keratoconus, aimed at inhibition of the inflammation.