The influence of new beta-adrenolytics nebivolol and carvedilol on intraocular pressure and iris blood flow in rabbits

Abstract

BackgroundThe aim of this study was to assess the influence of propranolol, nebivolol, and carvedilol on intraocular pressure and blood flow in vessels of rabbit’s (New Zealand White) eyeball.MethodsThe study was carried out on New Zealand white rabbits. Intraocular pressure was measured with the applanation tonometer Möller–Wedel and Icare; blood flow was measured with Doppler Laser Blood Flow Monitor MBD3.ResultsFollowing a single administration into a conjunctival sac, all drugs decreased intraocular pressure. Iris blood flow was decreased following administration of propranol, but increased by nebivolol and carvedilol. After single and repeated oral administration of nebivolol and carvedilol an IOP decrease was demonstrated, but with no effect of all applied doses on iris or retina/choroid blood flow.ConclusionStudies performed on an animal model indicate that it is possible to reduce the intraocular pressure and increase ocular blood flow in humans, following topical administration of carvedilol and nebivolol. Confirmation of those results in clinical trials may lead to development of a new anti-glaucoma treatment. Further clinical studies of long-term nebivolol and carvedilol are recommended. They are necessary for evaluation of usefulness of those drugs for selected groups of patients, for example those with glaucoma and arterial hypertension.

Quantitative study of the microvasculature and its endothelial cells in the porcine iris

“…Considering recent evidence from both clinical and experimental studies demonstrating the increased development of nuclear cataract as a consequence of disturbed ocular oxygen gradients caused by vitrectomy (Barbazetto et al, 2004;Holekamp et al, 2005), any iris vascular abnormality would probably affect the oxygen gradients in anterior chamber with pathological consequences. Moreover, there is added potential risk of corneal decompensation after traumatic procedures such as laser iridotomy (Szumny and Szelag, 2014;Wang et al, 2014;Youm et al, 2014).…”

Formulation and Characterization of Carvedilol Leciplex for Glaucoma Treatment: In-Vitro, Ex-Vivo and In-Vivo Study

“…Carvedilol is a beta-adrenergic blocking agent, indicated for the treatment of hypertension, angina pectoris, and heart failure [1]. Recent study suggests carvedilol as possible therapy for the increased intraocular pressure [2]. The intraocular pressure is controlled by the flow of aqueous humor in the eye where the excess fluid is drains through the trabecular meshwork.…”

The Effect of Timolol on the Iris Vascular Tone in Rats

“…Regarding the possibility of a catecholaminergic vasodilator tone in iris vessels, the results are contradictory. Propranolol administered conjunctivally, in vivo, causes iris vessels constriction in rabbits 5 , and timolol, in vitro, antagonized the possible vasodilator eff ect of isoprenaline, quantifi ed by the decrease of permeability to carbon particles, in rats' iris vessels 6 . Opposite to those mentioned above, timolol in conjunctival instillations produces, in vivo, dilation of iris vessels, in rhesus monkeys 7 .…”