Beta blokatori razlicito djeluju na promjene u vidnom polju kod glaukoma

U nedavno objavljenom clanku (vidi dole), autori ukazuju da lijekovi protiv glaukoma ( koji se koriste u kapima), koji smanjuju ocni tlak (IOP), pored toga sto smanjuju ocni tlak, treba i da zaustave  smanjivanje opadanja vidnog polja. U tome su autori vidjeli razliku kod dva lijeka, betaxolola i timolola, odnosno da betaxolol daje bolju prognozu u pogledu negativnih promjena u vidnom polju. Buduca istrazivanja treba da se pored uticaja na IOP usmjere i na uticaj lijekova na gubitak vidnog polja.

Is the medication used to achieve the target intraocular pressure in glaucoma therapy of relevance? – An exemplary analysis on the basis of two beta-blockers.

Grieshaber MC, Flammer J.

Department of Ophthalmology, University Hospital of Basel, Basel, Switzerland.

Glaucoma, the most common optic neuropathy (GON) is characterised by the loss of retinal ganglion cells and their axons, as well as tissue remodelling of both the retina and the optic nerve head with corresponding visual field defects. Elevated intraocular pressure (IOP) is generally regarded as the major risk factor for glaucoma and its reduction is the most common target for therapy of GON. There are indications that the greater the IOP reduction, the better is the visual field prognosis. This article investigates, on the basis of two beta-blockers, betaxolol and timolol, whether the amount of IOP reduction is truly a good surrogate for successful glaucoma therapy with respect to visual field outcome. Contrary to what is generally expected, our analysis of the literature exemplifies that despite a smaller IOP reduction, patients treated with betaxolol had a smaller rate of visual field deterioration than patients treated with timolol. Based on the dissociation of IOP reduction and visual field prognosis, we postulate that for successful treatment in glaucoma not only the amount of IOP reduction is relevant but also the drug by which the reduction is achieved. This seeming paradox phenomenon highlights that ocular hypotensive drugs have relevant effects on GON other than IOP-related. Some of these effects on retinal ganglion cells (neuroprotection) or on ocular blood flow are mediated by calcium- and sodium channels. Future studies on glaucoma treatment should focus on their effect on visual field function, and not just on IOP. This should particularly be considered when comparing drugs from different classes.

PMID: 19733652 [PubMed – as supplied by publisher]