Ophthalmic response to chlorhexidine digluconate in rabbits

Abstract

The reaction of ophthalmic tissues to repeated contact with chlorhexidine digluconate (CDG), an antimicrobial drug, was determined in rabbits. Subacute studies were conducted using (1) direct instillation of 0.1 ml of the drug into the cul-de-sac employing three separate regimens, and (2) lens wearing in which gel lenses were soaked 16 hr per day in preparations containing 0.005% CDG. During lens wearing studies the animals wore the lenses 7–8 hr per day for 21 test days. In the subacute direct instillation studies, a slight circumcorneal injection and conjunctivitis were observed in both experimental and control eyes. A concentration-dependent increase in the incidence of these reactions was noted as the CDG content increased from 0.005% to 0.05%. No deleterious ocular responses were observed throughout the gel lens wearing studies. These findings were confirmed by microscopic evaluation of opthalmic tissue. These studies, together with clinical results, suggest that CDG, formulated properly, has merit as a gel lens sterilizing agent.