Using diurnal intraocular pressure fluctuation to assess the efficacy of fixed-combination latanoprost/timolol versus latanoprost or timolol monotherapy.

AIM To evaluate differences in diurnal intraocular pressure (IOP) fluctuation in glaucoma/ocular hypertension patients treated with once-daily fixed-combination latanoprost/timolol, once-daily latanoprost or twice-daily timolol. METHODS In two 6-month, double-masked, parallel-group studies, patients received run-in timolol (2-4 weeks) and randomised (1:1:1) to therapy. IOP was measured three times/day at baseline and weeks 2, 13 and 26. In posthoc analyses, diurnal IOP fluctuation = highest daily IOP-lowest daily IOP at baseline and week 26. Fluctuation also was dichotomised: high (>6 mm Hg), low (< or =6 mm Hg). RESULTS 854 patients were randomised (fixed combination = 278; latanoprost = 287; timolol = 289). Diurnal fluctuation was significantly reduced from baseline to week 26 with the fixed combination (p = 0.002) but not with latanoprost or timolol monotherapy (p = 0.601; p = 0.097). Relative to baseline, the percentage with high diurnal IOP fluctuation at week 26 was reduced by 48% with fixed combination but increased 13% with latanoprost and 48% with timolol. Changes in IOP fluctuation and in mean IOP were significantly correlated for the monotherapies but not the fixed combination. CONCLUSIONS Fixed-combination latanoprost/timolol results in lower diurnal IOP fluctuation and significantly fewer patients with a high fluctuation than treatment with latanoprost or timolol monotherapy. The fixed combination may have an independent effect on reducing IOP fluctuation in addition to lowering IOP.