TREATMENT OF KERATOCONJUNCTIVITIS SICCA IN RABBITS WITH 3-ISOBUTYL-1-METHYLXANTHINE

Objective: To examine the effects of topical 3-isobutyl-1-methylxanthi ne treatment on tear-film osmolarity, conjunctival goblet-cell densiti es, and corneal epithelial glycogen levels in a rabbit model for kerat oconjunctivitis sicca. Methods: Keratoconjunctivitis sicca was surgica lly induced in the right eyes of 16 rabbits. In a masked protocol, eig ht of these operated-on eyes underwent treatment for 12 weeks with a 3 .0-mmol solution of 3-isobutyl-1-methylxanthine. were left untreated a nd sewed as controls. Results: The 3-isobutyl-1-methylxanthine treatme nt resulted in a rapid and significant decrease in tear osmolarity and sodium (P<.5) and potassium levels (P<.05) and a significant increase in conjunctival goblet-cell densities and corneal epithelial glycogen levels compared with untreated and operated-on controls (P<.001). Con clusions: 3-Isobutyl-1-methylxanthine rapidly and significantly decrea sed tear-film osmolarity in this rabbit model for keratoconjunctivitis sicca and restored conjunctival goblet-cell densities and corneal gly cogen levels, thus reversing the disease process.