Intravitreal Avastin as a Treatment of Diffuse Diabetic Macular Edema

Abstract

Sideenah Badr MJ, Alfaitouri M Fathalla and Gumma Almusmari

Background: Macular edema, defined as retinal thickening within 2 disc diameters of the center of the macula, results from retinal microvascular changes that compromise the blood-retinal barrier, causing leakage of plasma constituents into the surrounding retina and, consequently, retinal edema. Focal edema is associated with hard exudate rings caused by leakage from micro aneurysms. Diffuse edema is caused by leakage from micro aneurysms, retinal capillaries, and arterioles. Avastin (Bevacizumab) is a recombinant humanized monoclonal IgG1 antibody that binds to and inhibits the biologic activity of human vascular endothelial growth factor (VEGF). It contains human framework regions and the complementaritydetermining regions of a murine antibody that binds to VEGF. Avastin produced in a Chinese Hamster Ovary mammalian cell expression system in a nutrient medium containing the antibiotic gentamicin and has a molecular weight of approximately 149 kilo Daltons.

Purpose: To assess the anatomic effect and visual acuity response after intravitreal (Avastin) in patients with diffuse diabetic macular edema.

Patients and Methods: This study included 15 eyes of15 Patients with stable diabetes mellitus with diffuse diabetic macular edema. All eyes had received some form of argon laser photocoagulation (pan retinal photocoagulation (PRP), Focal or Grid of duration not less than 6 months. Mean age of 59 years treated with two intravitreal injections of Avastin 1.25 mg in 0.05 ml six weeks apart. Patients were examined by experienced ophthalmologist visual acuity, evaluation of diabetic retinopathy, central macular thickness by optical coherence tomography each was evaluated at the begging of study (baseline) and follow-up visits.

Results: 15 eyes of 15 diabetic patients with persistent diffuse macular edema with no improvement in visual acuity. All the patients received two injections of A vastin six weeks apart. No complications were observed in any patient. The mean baseline visual acuity was (log Mar=1.338±0.455) and the mean visual acuity at three months following the second intravitreal injection was (log Mar=1.094±0.254), the mean central macular thickness at baseline was 492 µm decreased to 369 µm at the end of three months.

Conclusions: A vastin resulted in a significant decrease in macular thickness and improvement in visual acuity at three months after the second injection.

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