Average versus highest intraocular pressure analyses in glaucoma clinical trials.

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.