Absorption of fluorescein given under the upper lid

Area of Science:

• Ophthalmology
• Pharmacology
• Drug Delivery Systems

Background:

• Conventional topical ocular drug administration via lower lid instillation may be suboptimal.
• Preliminary glaucoma patient observations suggested improved intraocular pressure control with upper lid medication application.
• Physiological differences in anterior chamber drug absorption between upper and lower lid administration needed investigation.

Purpose of the Study:

• To compare the absorption of topical fluorescein into the anterior chamber when administered under the upper lid versus the lower lid.
• To evaluate the potential for enhanced ocular drug delivery through upper lid application.

Main Methods:

• Human volunteers received a 5-microliter fluorescein drop under the upper-lid fornix in one eye and lower-lid fornix in the contralateral eye.
• Anterior chamber fluorescein absorption was measured hourly for 3 hours post-instillation.

Main Results:

• Upper lid administration resulted in significantly higher fluorescein absorption into the anterior chamber compared to lower lid administration (P = 0.0088).
• Statistical significance increased at hours 2 and 3 (P < 0.0044).
• Profuse tearing, particularly in younger subjects, rapidly reduced fluorescein absorption.

Conclusions:

• Topical ocular drug delivery beneath the upper lid enhances anterior chamber absorption compared to the lower lid.
• This method holds promise for improving the efficacy of topical ocular medications.
• Further clinical studies are warranted to validate this drug delivery approach.