Effects of the timolol-dorzolamide fixed combination and latanoprost on circadian diastolic ocular perfusion pressure in glaucoma.

PURPOSE. To evaluate the effect of the timolol-dorzolamide
fixed combination (TDFC) and latanoprost 0.005% on 24-hour
intraocular pressure (IOP), systolic (SBP) and diastolic (DBP)
blood pressure, and diastolic ocular perfusion pressure (DOPP)
in patients with primary open-angle glaucoma (POAG).
METHODS. This was an institutional, randomized clinical trial.
After a 24-hour assessment without treatment, 27 previously
untreated patients with POAG were randomized to 6 weeks’
treatment with twice-daily TDFC (8 AM and 8 PM) followed by
once-daily latanoprost 0.005% (8 PM), or vice versa. One eye
was analyzed per patient. The mean values of IOP, DBP, SBP,
and DOPP (difference between DBP and IOP) were recorded at
each time point, and the 24-hour data are the mean values of
each patient’s measurements over the 24-hour period. The
differences between the values of the first treatment period
and the baseline and the second treatment period and washout
were calculated and analyzed by means of an analysis of variance
model that tested the effects of sequence and treatment.
RESULTS. Both treatments significantly reduced 24-hour IOP
(P <0.0001), but TDFC led to lower 24-hour pressure
(mean ±SD: 15.4 ±1.9 vs. 16.7± 1.7 mm Hg; P=0.004).
Latanoprost did not lead to any significant reduction in mean
24-hour SBP and DBP (SBP: P =0.952; DBP: P=0.831), but
TDFC did (SBP and DBP: P < 0.0001). Both treatments significantly
increased 24-hour DOPP (P < 0.0001), with no difference
between the two medications (P=0.09).
CONCLUSIONS. In previously untreated patients with POAG, TDFC,
and latanoprost equally enhanced 24-hour DOPP: the former by
counteracting the decrease in DBP with a substantial reduction in
IOP and the latter by not affecting DBP and significantly reducing
IOP