At 3 individual time points , travoprost provided a lower IOP than tafluprost : at 4 PM ( 13.82.7 vs. 14.82.6 mmHg , P = 0.041 ) , at 6 PM ( 13.52.5 vs. 14.42.5 mmHg , P = 0.006 ) , and at 8 PM ( 13.32.5 vs. 14.52.4 mmHg , P = 0.029 ) .