Alterações conjuntivais induzidas por drogas utilizadas no tratamento do glaucoma

Abstract

Glaucoma is a disease whose major risk factor is the increase of intraocular pressure (IOP), that leads to a progressive loss of retinal ganglion cells, causing a progressive reduction in visual field and, finally, blindness. Glaucoma's therapy is focused on reducing the IOP, using drugs or surgical techniques. Timolo! is a drug already wellestablished for this purpose, reducing the aqueous humor production. In the 90's, the prostaglandin (PG) analogues appeared (latanoprost, travoprost and bimatoprost), which are hypotensive drugs that increase the aqueous humor outflow through uveoscleral way. More recently commercial combination of PG analogues and timolol were released, adding reduction of aqueous humor production with increase in its outflow. However, chronic instillation of eye drops incites inflammatory reaction in the conjunctiva, which can contribute to surgery failure, such as trabeculectomy. Chronic topic therapy can also induce a reduction in the number of goblet cells, responsible for producing the mucous part of lachrymal film, what reduces the quantity and quality of tears and contribute to ocular discomfort. This research tested three PG analogues and timolol combinations (Ganforte® - bimatoprost+timolol, Duo-Travatan® - travoprost + timolol and Xalacom® - latanoprost+timol), by histomorphometric and imunohistochemical evaluations. All tested combinations caused some degree of conjunctival inflammatory response.The intensity of change caused by each one of the evaluated parameters (inlammatory infiltrate, epithelial thickness and number of goblet cells) varied with each drug. The less deleterious combinatiowas the bimatoprost+timolol, that caused an intermediary inflammatory infiltrate when compared to other drugs, and also provoked a greater increase in number of goblet cells. Another part of this research was the investigation of cyclosporine and prednisolone use in post-operatory of trabeculectomy, showing that the association of these drugs has a synergic effect inhibiting post-surgical fibrosis and inflammatory reaction. Therefore, the combined use of cyclosporine and prednisolone can possibly reduce surgical flap adherence, keeping this way the trabeculectomy for longer time.