Glaucoma, a progressive optic disc neuropathy causing visual field reduction, is the second leading cause of world blindness. The treatment of glaucoma is mainly based in reducing intraocular pressure (IOP) with topical medications. Many patients required two or more medications to achieve a target IOP. Combinations of B-blockers and prostaglandin analogs (PGA) are frequently used in clinical practice because their additive effect in lowering IOP levels. The aim of this study was to investigate the effects of fixed combinations of timolol maleate and PGA on the blood-aqueous barrier and evaluate the measurement of foveal thickness in pseudophakic patients with primary open-angle glaucoma (POAG).

Most studies found a lower incidence of systemic and ocular adverse events with fixed combinations than with the unfixed combinations. Fixed combinations are better tolerated than their respective prostaglandin analogue. However, among the most serious side effects induced by PGA are the breaking down of the blood-aqueous barrier (BAB) and the development of cystoids macular edema (CME). Also, timolol maleate drops increase protein concentration in the human and benzalkonium chloride, eye drops preservative induces anterior chamber inflammation. This randomized, masked-observer, prospective clinical trial was approved by the Ethics Committee of the University of Campinas, and it adhered to the tenets of the Declaration Of Helsinki. Written informed consent was obtained from each patient.

Inclusion Criteria:

• Patients were eligible for participation if they met the following inclusion criteria: age older than 18 years, pseudophakia and diagnosis of primary open angle glaucoma (an untreated IOP levels of more then 21 mmHg, specific changes in the optic disc or specific visual fields changes. Optic disc changes were focal notching, optic disc haemorrhage, retinal nerve fiber layer (RNFL)defects, overpass-blood vessel crossing over an area of neuroretinal rim loss.Visual fields changes were the glaucoma hemifield test outside normal limits or a cluster of three or more non-edge points in a typical location of glaucoma or a corrected pattern standard deviation that occurs in less than 5% of normal visual fields

Exclusion Criteria:

• Exclusion criteria included history of uveitis or CME, substantial ocular irritation at baseline, or a history of intraocular surgery or a laser procedure within 6 months of baseline, the presence of systemic disorders that could be associated with uveitis or CME (ie, diabetes mellitus and rheumatologic diseases), presence of age-related macular degeneration and other macular diseases, pregnancy, breastfeeding, and inadequate contraception (in females), treatment with systemic beta-blocker, history of bronchial asthma, chronic obstructive pulmonary disease , sinus bradycardia, second and third degree atrioventricular block , sinoatrial block and functionally significant visual field loss