Abstract
BackgroundReduced choroidal perfusion is hypothesized to play a role in the pathogenesis of normal tension glaucoma. Thus the impact of antiglaucomatous eye drops on ocular perfusion has been the focus of recent research and the subject of intensive investigations. The present study investigates whether topically applied latanoprost or bimatoprost influence ocular perfusion in patients with normal tension glaucoma and compares these effects with that changes detected after the treatment with dorzolamide.MethodsOcular hemodynamics were assessed by color Doppler imaging (CDI) shortly before and after a one-month treatment with either latanoprost, bimatoprost or dorzolamide. Primary end-points of the study were peak systolic and end-diastolic blood flow velocities in the short posterior ciliary artery (SPCA) under the new therapy. Intraocular pressure (IOP) and additional perfusion parameters in the SPCA and other retrobulbar vessels were tracked as observational parameters. n = 42 patients with normal tension glaucoma were enrolled in the study.ResultsSystolic and diastolic blood flow velocities in the SPCA showed no significant alteration after the treatment with latanoprost or bimatoprost. Dorzolamide lead to increase of peak systolic velocity. IOP was reduced by all three agents in a range reported in the literature.ConclusionTopically applied latanoprost and bimatoprost act in a hemodynamically neutral manner and have the capability to lower IOP even in patients with normal tension glaucoma and low initial IOP level. Dorzolamide accelerates blood flow in systole. None of the tested compounds has a negative impact on hemodynamics in the short posterior ciliary arteries.
Highlights
Reduced choroidal perfusion is hypothesized to play a role in the pathogenesis of normal tension glaucoma
BMC Ophthalmology 2005, 5:6 http://www.biomedcentral.com/1471-2415/5/6 who develop the major features of glaucoma, meaning progressive visual field loss and atrophy of the optic nerve head, the Intraocular pressure (IOP) is in the normal range below 21 mmHg in these individuals. [2,3,4,5,6] This variant of primary open angle glaucoma has been termed as normal tension glaucoma and the glaucomatous changes have been – at least in part – attributed to reduced perfusion of the optic nerve head by different authors. [6,7,8] patients with normal tension glaucoma constitute a interesting group for investigating pharmacological effects on ocular perfusion
The hemodynamic effects of locally applied antiglaucomatous drugs are subject to intensive investigations within the last years: [13,14,15,16] Dorzolamide, an inhibitor of the carbonic anhydrase has shown the most promising effects on ocular hemodynamics. [17,18,19] In contrast, brinzolamide did not to alter ocular perfusion.[20] ß-receptor antagonists influence parameters of ocular hemodynamics differently depending on the compound used: betaxolol and carteolol lower vascular resistance while timolol seems to lead to an increased vascular tone.[15]
Summary
Reduced choroidal perfusion is hypothesized to play a role in the pathogenesis of normal tension glaucoma. [17,18,19] In contrast, brinzolamide did not to alter ocular perfusion.[20] ß-receptor antagonists influence parameters of ocular hemodynamics differently depending on the compound used: betaxolol and carteolol lower vascular resistance while timolol seems to lead to an increased vascular tone.[15] The α2-receptor agonist brimonidine did not affect ocular perfusion in primary open angle glaucoma patients.[21] Derivatives of prostaglandins have become more and more popular for the treatment of glaucoma patients since they are very effective in lowering IOP and have to be applied only once a day.[22] Up to now there are predominantly four substances in clinical use: latanoprost, bimatoprost, travoprost and unoprostone. Few studies have addressed the influence of prostaglandin analogues on ocular perfusion so far
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