Brimonidine Tartrate for Pterygium Surgery

Overview

Pterygium excision and conjunctival autograft surgery is commonly done to treat pterygiums. Excessive bleeding during the procedure creates a challenging operating field, prolongs surgery time, and prolongs healing. Brimonidine tartrate has a vasoconstrictive effect, which helps to reduce the amount of blood flow and hyperemia to the eye. Preoperative use of brimonidine has been shown to decrease subconjunctival hemorrhage during procedures such as cataract surgery, laser assisted in situ keratomileusis, strabismus surgery, and intravitreal injections. The focus of this study is to assess the effect of preoperative application of brimonidine tartrate 0.15% (Alphagan) and 0.025% (Lumify) on reducing hemorrhage during pterygium excision and conjunctival autograft surgery.

During pterygium excision and conjunctival autograft surgery, incision into the conjunctiva of the operated eye causes a significant amount of subconjunctival hemorrhage. Brimonidine-tartrate is a selective alpha-2-adrenergic agonist. The 0.15% concentration (Alphagan) is commonly used to treat glaucoma, while the 0.025% (Lumify) is an over-the-counter drop used for its vasoconstrictive anti-hyperemia effect. Brimonidine 0.15% has been evaluated in other studies to reduce bleeding in LASIK, cataract surgery, strabismus surgery, as well as intravitreal injections. In these mentioned clinical trials, brimonidine was found to safely reduce subconjunctival hemorrhage intraoperatively and hyperemia postoperatively. Interestingly, prophylactic topical brimonidine was found to increase risk of early flap slippage in LASIK due to molecular interference with flap stabilization. Because creation of a flap is not a component of pterygium surgery, preoperative brimonidine does not interfere with healing. A recent study by Ucar et al. has validated the use of preoperative brimonidine 0.15% for conjunctival whitening prior to pterygium surgery, allowing for minimized hyperemia and reduced surgical duration (Ucar, 2020). However, the long-term clinical outcomes, and efficacy of brimonidine 0.025% has yet to be examined. This study aims to further examine the comparative efficacy of preoperative brimonidine at different concentrations to reduce subconjunctival hemorrhage during pterygium surgery. Potential side effects of topical application of brimonidine eye drop may include blurred or loss of vision, burning, dry, or itching eyes, discharge or excessive tearing, disturbed color perception, double vision, halos around lights, headache, itching of the eye, night blindness, photophobia, redness of the eye or inner lining of the eyelid, swelling of the eyelid, tearing of the eye, tunnel vision. Side effects of this medication are self-limited, and reversible after the medication is stopped. The risk of this study to the subject is negligible as the standard surgical procedure will be followed. This trial will be conducted in compliance with the protocol, GCP, and the applicable regulatory requirement as set by William Osler Health System Ethics Review Board.