ABSORPTION OF FLUORESCEIN GIVEN UNDER THE UPPER LID

Background: The need for a more efficacious approach to administer top ical ocular medications prompted the authors to consider applying conv entional eye drops under the upper lid rather than beneath the lower l id. Preliminary observations on patients with glaucoma using a beta-bl ocker beneath the upper lid suggested a drop in intraocular pressure i nto the normal range in some previously refractory patients being trea ted with the same medications. To test this clinical observation, the authors observed if there were any physiologic differences in topical fluorescein absorption into the anterior chamber when given beneath th e upper lid versus the lower lid. Methods: A 5-mu l drop of fluorescei n solution was placed under the upper-lid fornix of one eye and under the lower-lid fornix of the other eye in human volunteers, and absorpt ion into the anterior chamber was measured at hourly intervals, for a total of 3 hours. Results: Hotelling T-2 multivariate analysis for all 3 hours demonstrates that upper-lid administration of fluorescein res ults in significantly higher absorption of fluorescein into the anteri or chamber than does lower-lid administration (P = 0.0088; for hours 2 and 3, the statistical difference is even more dramatic: P < 0.0044). Conclusion: Using conventional eye drops beneath the upper lid, the a uthors observed increased absorption of fluorescein into the anterior chamber when compared with lower-lid administration. Profuse tearing, especially by younger subjects, significantly and rapidly diminished a nterior chamber absorption of fluorescein. It is reasonable to conside r further clinical studies to test this new approach to drug delivery.