Intravitreal triamcinolone has been effective for central macular thickness reduction and concomitant visual acuity improvement in patients with diabetic macular edema (DME). VEGF is a very effective inducer of permeability, being 50.000 times more potent than histamine, and may exert its effect on retinal vascular permeability by altering tight-junctions proteins, such as occluding and VE-cadherin. Based on these principles, there is a rationale for anti-VEGF agents treatment of increased retinal capillary permeability conditions, such as diabetic macular edema. Therefore, we conducted a randomized, prospective study to compare the efficacy and safety of intravitreal triamcinolone acetonide and intravitreal bevacizumab injection for refractory diffuse DME.

Inclusion Criteria:

• Refractory diffuse DME (defined herein as clinically significant DME [by biomicroscopic evaluation] unresponsive to focal laser photocoagulation [performed at least 3 months before evaluation] and generalized breakdown of the inner blood-retina barrier with diffuse fluorescein leakage involving the foveal center and most of the macular area on fluorescein angiography),
• Snellen logarithm of minimum angle of resolution (LogMAR) BCVA equivalent of 20/40 or worse, and 3) central macular thickness (CMT) greater than 300µm on optical coherence tomography (OCT)

Exclusion Criteria:

• Aphakic or pseudophakic eyes,
• Glycosylated hemoglobin (Hb A1C) rate above 10%,
• History of glaucoma or ocular hypertension,
• Loss of vision as a result of other causes,
• Systemic corticoid therapy,.
• History of thromboembolic event (including myocardial infarction or cerebral vascular accident);
• Major surgery within the prior 6 months or planned within the next 28 days;
• Uncontrolled hypertension (according to guidelines of the seventh report of the joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure [JNC-7]);16
• Known coagulation abnormalities or current use of anticoagulative medication other than aspirin;
• Severe systemic disease; or
• Any condition affecting follow-up or documentation