Meta-analysis of 24-h intraocular pressure fluctuation studies and the efficacy of glaucoma medicines.

Purpose: To compare the change in 24-h fluctuation of the intraocular pressure (IOP) from various medical therapies in patients with ocular hypertension, primary open-angle (POAG), or exfoliative glaucoma (XFG).

Methods: A meta-analysis of published studies that were controlled, prospective, and comparative trials. Based on study requirements for an objective fluctuation analysis, only studies from the authors' work met the criteria for this analysis and contained: > or = 4-week treatment period, > or = 20 patients per treatment arm, and > or = 6 time points measured with Goldmann applanation over 24 h, not spaced >5 h apart. Fluctuations were defined by the mean of the difference between the highest and lowest measured IOP for each individual patient (Sigma[maximum - minimum IOP]/number of patients).

Results: Thirteen articles were included evaluating 28 treatment arms in 1,017 patients. Among all individual treatments, bimatoprost demonstrated the greatest reduction in fluctuation (P = 0.03, 3.4 mm Hg). In contrast, 2-drug therapy did not reduce fluctuations from monotherapy (P = 0.09). Among prostaglandin therapies, no statistical difference existed between evening and morning dosing (P = 0.20). In XFG, a greater reduction in fluctuations was observed progressing from 1 to 2 medicines (P = 0.01), but not increasing from 2 to 3 drug therapy (P = 0.14). In general, XFG patients demonstrated a greater decrease in fluctuations than POAG patients (P = 0.003).

Conclusions: In POAG differences exist in fluctuations among monotherapy treatments with bimatoprost showing the greatest effect. However, POAG patients generally demonstrate less decrease in fluctuations with treatment than compared with XFG.