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Agents and preservatives both influence trabeculectomy outcome
SAN FRANCISCO — While preservatives used in topical agents contribute to exacerbating ocular surface disease that may affect the success of trabeculectomy, the agents themselves may also be contributors, according to a speaker here.
Preservatives do have desirable attributes, Douglas J. Rhee, MD, said at Glaucoma Day preceding the American Society of Cataract and Refractive Surgery meeting.
Douglas J. Rhee
"They provide an antimicrobial environment to allow the prolonged use of medications," he said. "And benzalkonium chloride in particular can assist with the intraocular penetration of drugs. Some drugs have a hard time getting through the cornea, particularly epithelium, if they don’t have something to disrupt the surface."
Furthermore, because they provide an antimicrobial environment, the preservatives allow for multi-dosing bottles.
Potential concerns regarding preservatives in topical medications are exacerbation of ocular surface disease, increased risk of failure of trabeculectomy and acceleration of the disease process.
Regarding failure of trabeculectomy, Rhee said to again consider the agents themselves.
"Chemically, we know that all of the different compounds we use — all of them — have the ability to shift the matrix metalloprotease and their inhibitors," he said. "Those are the enzymes that are mediating fibrosis; in other words, potential failure of trabeculectomy."
The conjunctival inflammation in these cases is reversible with preoperative use of topical steroids, he said.
Whether benzalkonium chloride contributes to the disease pathology in the trabecular meshwork is a matter for further study, he said.
Disclosure: Rhee is an ad hoc consultant for or receives research funding from Aerie, Alcon, Allergan, AqueSys, National Eye Institute, Merck and Santen.