Absorption of Fluorescein Given under the Upper Lid

Background: The need for a more efficacious approach to administer topical ocular medications prompted the authors to consider applying conventional eye drops under the upper lid rather than beneath the lower lid. Preliminary observations on patients with glaucoma using a beta-blocker beneath the upper lid suggested a drop in intraocular pressure into the normal range in some previously refractory patients being treated 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 the upper lid versus the lower lid. Methods: A 5-μl drop of fluorescein 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 absorption 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 upperlid administration of fluorescein results in significantly higher absorption of fluorescein into the anterior chamber than does lower-lid administration ( P = 0.0088; for hours 2 and 3, the statistical difference is even more dramatic: P Conclusion: Using conventional eye drops beneath the upper lid, the authors 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 anterior chamber absorption of fluorescein. It is reasonable to consider further clinical studies to test this new approach to drug delivery.