CONCENTRATION OF FLUORESCEIN IN TEAR FLUID AFTER INSTILLATION AS EYE-DROPS .1. ISOTONIC EYE-DROPS

Fluorescein was administered in isotonic aqueous and viscous solutions as eye-drops to volunteers in two age groups. The fluorescein concentration was measured in samples of tear fluid taken at regular intervals after administration. These concentrations were used for the estimation of the minimum permissible interval between applications of two different kinds of eye-drop in the same patient. The parameters for this interval were: (a) the time required for the fluorescein concentration to drop to 10%, and (b) the increase of the product of concentration and time up to 90% of the area under the curve. The recommended interval is 20 min for aqueous eye-drops and 30 min for viscous eye-drops. It seems probable that drug resorption is greater from viscous than from aqueous eye-drops and at higher age than at lower age. © 1979 S. Karger AG, Basel.