Gold standard medical therapy for glaucoma: defining the criteria identifying measures for an evidence-based analysis.

Background: Over the past decade, several new medical therapies have become available for the treatment of primary open-angle glaucoma (POAG). A systematic evidence-based approach for identifying an optimal therapeutic agent is lacking.

Objectives: The aims of this review were to critically evaluate published treatment recommendations for POAG and, based on a systematic review of the literature, to develop criteria that would define a "gold standard" medical therapy that reflects new treatment advances and established therapeutic goals.

Methods: A MEDLINE search spanning the years 1966 to 2002 and using the search terms gold standard, drug of choice, agent of choice, benchmark, ophthalmology, eye, and glaucoma was conducted and the results reviewed by a panel of 15 experts in the field of glaucoma. Published treatment recommendations for POAG were discussed. Criteria, anchored to medical evidence, for distinguishing a standard of medical therapy for POAG were defined.

Results: The terms connoting a gold standard therapy were found in only 258 of approximately 368,000 ophthalmology-related citations and 53 of almost 23,000 glaucoma citations, validating the need to define therapeutic standards. The lack of recommendations for the use of new classes of ocular hypotensive agents was acknowledged. Criteria identified to evaluate intraocular pressure (IOP)-lowering agents as gold standards included the following: efficacy in reducing IOP consistently over a 24-hour period to a level that will preserve the visual field and protect the optic nerve without inducing tachyphylaxis and tolerance, paucity of local and systemic adverse effects, promotion of patient compliance, and applicability in diverse patient populations.

Conclusions: These criteria should be employed as measures for evidence-based analyses to evaluate available and future IOP-lowering medical therapies for POAG. The conceptual framework presented may be applicable to other therapeutic areas.