Before brimonidine treatment (t1), IOP was within normal limits in all eyes (10–21 mm Hg). There was no significant difference comparing control and interventional eyes before treatment for mean IOP (t1;
P > 0.34), mean ocular pulse amplitude (OPA;
P = 1), mean OPP (
P > 0.26), mean arterial RBFV (
P > 0.54), mean venous RBFV (
P > 0.66), or mean overall RBFV (
P > 0.57). Mean arterial BP and mean heart rate were 88.9 (±11.59) mm Hg and 69.4 (±7.14) beats per minute, respectively. Following treatment (t2), mean IOP decreased (−5.1 mm Hg, −36.17%,
P < 0.05) and mean OPP increased distinctly and significantly (
P < 0.05) in interventional eyes, whereas remaining stable in control eyes (mean IOP =
P > 0.24; mean OPP =
P > 0.06). In both groups, mean overall RBFV increased (interventional eyes: +0.209 mm/s, +5.98%,
P > 0.18, 95% confidence interval [CI] = −0.123 to –0.543 mm/s; control eyes: +0.461 mm/s, +13.61%,
P > 0.01, CI 0.106–0.816 mm/s), without demonstrating significant differences between the two groups (
P > 0.47). The changes in mean arterial RBFV and mean venous RBFV in each group were relatively similar. Mean arterial BP was 95.1 (±5.55) mm Hg and mean heart rate was 63.4 (±8.19) beats per minute. No correlation was found among mean RBFV and mean arterial BP, mean heart rate, mean IOP, or mean OPP post-treatment (all
P > 0.25). Ophthalmic parameters before and after brimonidine treatment are shown in
Table 2 and
Figure 2.