Effect of latanoprost 0.005% and brimonidine tartrate 0.2% on pulsatile ocular blood flow in normal tension glaucoma

Abstract

Aim: To determine the effect of brimonidine tartrate 0.2% and latanoprost 0.005% on pulsatile ocular blood flow (POBF) in patients with normal tension glaucoma (NTG). Method: NTG patients with progressive optic neuropathy, new disc haemorrhage, or field defects that threatened fixation were enrolled into a randomised, investigator masked, crossover study. Group I patients received 4 weeks each of latanoprost, lubricant, and brimonidine, while group II patients received 4 weeks each of brimonidine, lubricant, and latanoprost. Diurnal POBF was measured at baseline and after each 4 week treatment. Results: 25 patients completed the study and had reliable POBF measurement at each visit. There was no significant diurnal change in baseline POBF (p = 0.768). Latanoprost increased POBF by 213 (SD 257) µl/min (22.8%, p <0.001) while brimonidine increased it by 97 (183) µl/min (10.4%, p = 0.014). POBF increased at 8 am (p = 0.004), 12 noon (p = 0.002), and 4 pm (p <0.001) with latanoprost, while it increased only at 8 am (p = 0.016) with brimonidine. After adjusting for the factor of IOP, neither latanoprost nor brimonidine increased POBF significantly. Conclusions: Latanoprost increases the mean POBF that is related to its IOP lowering effect. The increase in POBF noted after brimonidine is within the range of long term variation and may not be attributable to the drug effect.

First-line therapy with latanoprost 0.005% results in improved ocular circulation in newly diagnosed primary open-angle glaucoma patients: a prospective, 6-month, open-label study

“…Because blood flow to an organ depends directly on the perfusion pressure, an increase in MOPP could have a beneficial effect on blood flow to the ONH; this effect, however, is regulated by changes in local vascular resistance and occurs only in healthy vascular beds. 54,55 Indeed, in the presence of local vascular dysregulation this beneficial effect could be less evident. 7 Therefore, the clinical significance of MOPP improvement on glaucoma' prognosis requires further clarification.…”

Prostanoids in the Therapy of Glaucoma

“…In glaucoma patients,1 week to 3 months of topical latanoprost treatment did not affect retinal vessel blood flow, as measured by color Doppler imaging or by fluorescein angiography (as a measure of arterial-venous passage time) (21,23). In contrast, choroidal blood flow in glaucoma patients was increased by up to 20% over the baseline value by topical latanoprost (18,31). Bimatoprost and travoprost have also been evaluated for their effects on ocular blood flow in glaucoma patients, and both positive and negative results have been obtained (1,66).…”

Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

“…Latanoprost significantly increased pulsatile OBF in healthy volunteers, 48,49 and OAG 50,51 and NTG [52][53][54] subjects, although not consistently found. 55 A randomized double-masked crossover study 56 found a more favorable effect on ocular perfusion pressures (OPP) (which are directly related to OBF) with latanoprost than timolol.…”

“…Head-to-head trials post-dated the study hence studies comparing the medication in question and timolol 71-73, 81,116,119,147,148 or betaxolol 149 were included. In contrast, head-to-head trials, 43,52,53,59,70,76,77,83,[150][151][152][153][154][155][156][157] only were analyzed for the second meta-analysis. 146 The pooled summary estimate significantly favored latanoprost (weighted mean difference (WMD) = 1.10, 95% CI 0.57 to 1.63) over brimonidine.…”