METHODS: 35 OAG patients (35 eyes), 31 women (88.6%) age 63.3 (8.9) years were evaluated in a 3 month randomized, cross-over, single-masked study. During the experiments BP, heart rate, IOP and
OPP were assessed 4 times per day (8-12-16-20 h). RBF was measured twice per day (8-20 h) using Color Doppler imaging in the ophthalmic (OA), central
retinal (CRA), nasal (nSPCA) and temporal (tSPCA) posterior ciliary arteries. In each vessel, peak systolic velocity (PSV) and end-diastolic velocity (EDV) were assessed and vascular resistance (RI) calculated.
RESULTS: Both add-on
therapies lowered IOP in a statistically significant manner from 15.7 ± 2.4 mmHg at
latanoprost baseline to 14.9 ± 2.2 mmHg using
dorzolamide (p < 0.001) and 14.2 ± 1.9 mmHg using
timolol (p < 0.001). The IOP lowering effect was statistically significant at 20 h, favoring
timolol as compared to
dorzolamide (1.4 ± 2.4 vs. 0.2 ± 2.1 mmHg), (p < 0.05).
Dorzolamide add-on
therapy showed smaller IOP (2.0 ± 1.4), SPP (13.3 ± 7.9), systolic BP (13.5 ± 8.7) and diastolic BP (8.4 ± 5.4) fluctuations as compared to both
latanoprost baseline or
timolol add-on
therapies. Higher difference between morning and evening BP was correlated to decreased evening CRA EDV in the
timolol group (c = -0.41; p = 0.01). With increased MAP in the morning or evening hours, we found increased evening OA RI in
timolol add-on group (c = 0.400, p = 0.02; c = 0.513, p = 0.002 accordingly). Higher MAP fluctuations were related to impaired RBF parameters during evening hours-decreased CRA EDV (c = -0.408; p = 0.01), increased CRA RI (c = 0.576; p < 0.001) and tSPCA RI (c = 0.356; p = 0.04) in the
dorzolamide group and increased nSPCA RI (c = 0.351; p = 0.04) in the
timolol add-on group.
OPP fluctuations correlated with increased nSPCA RI (c = 0.453; p = 0.006) in the
timolol group.
OPP fluctuations were not related to IOP fluctuations in both add-on
therapies (p < 0.05).
CONCLUSIONS: Both
dorzolamide and
timolol add-on
therapies lowered IOP in a statistically significant fashion
dorzolamide add-on
therapy showed lower fluctuations in IOP, SPP and BP. Higher variability of daytime
OPP led to impaired RBF parameters in the evening.