Average versus Highest Intraocular Pressure Analyses in Glaucoma Clinical Trials

Abstract

Purpose: To evaluate methods which account for both eyes as a single, independent variable in glaucoma clinical trials. Methods: A review of clinical trial articles published between January 1995 and April 2011 evaluating currently used topical glaucoma medications. Results: This analysis included 17 articles with 36 treatment arms of which 14 were prostaglandins, 13 β-blockers, 6 topical carbonic anhydrase inhibitors and 3 α-agonists. Twenty-four articles used average intraocular pressure (IOP) analysis, 12 used the highest IOP analysis and none utilized the randomized eye method. At untreated baseline, there was a difference in the IOP between average IOP and highest baseline IOP analyses at 8 a.m. (p = 0.001) and for the diurnal curve (p = 0.02) as well as specifically for β-blockers (p = 0.002) at 8 a.m. and β-blockers for the diurnal curve (p = 0.01). Conclusions: This study suggests that the highest IOP analysis method generally provides slightly higher IOPs at baseline than the average IOP analysis method.