Abstract
Purpose: :
To describe the effect of intravitreal bevacizumab on clinically significant macular edema (CSME). Vascular Endothelial Growth Factor (VEGF) is a potent mediator of retinal vascular leakage in patients with diabetic retinopathy. Bevacizumab (Avastin, Genentech) is a recombinant humanized, full length, anti–VEGF monoclonal antibody that binds to all isoforms of VEGF–A.
Methods: :
This is a retrospective interventional case series of 5 patients with CSME who were treated with intravitreal bevacizumab (1.0 mg). Patients were considered for treatment on the basis of severity of CSME involving the foveal center and/or a failure to respond to previous treatment. Patients were between the ages 43–62 years. Pre–treatment best corrected visual acuity (VA) ranged from 20/20 to 2/200. Blood pressure, medical history, and fluorescein angiogram (FA) were obtained. Pre–treatment FA showed leakage into the fovea and no significant foveal capillary drop–out in all patients. An expanded informed consent with an off–label use waiver and explanation letter was reviewed with all patients. Ocular coherence tomography (OCT, Zeiss) was obtained pre and post treatment in 2 patients. The treatment eye was prepped using topical anesthetic and fluoroquinolone antibiotic drop followed by 5% betadine. A trans–pars plana intravitreal injection of 1.0 mg (0.04 ml of 25 mg/ml) bevacizumab was performed followed by antibiotic drops QID for one week. Follow up was planned at one and six weeks following the injection.
Results: :
One week follow up was obtained in 3/5 patients with improved VA of 1 Snellen line seen in one case and no change in the remainder. One patient returned at 3 weeks without improvement in VA. Of these, two patients had OCT measurements performed which showed reduction in maximum retinal thickness by 35% (447 to 289 microns) and 37% (607 to 382 microns) without an associated improvement in visual acuity (20/40 and 2/200 respectively). Six week follow up was obtained in one patient at the time of abstract submission. VA improved by 2 Snellen lines in this patient with an associated large reduction in FA leakage. All patients (5/5) had clear reduction of CSME following treatment. There were no adverse events including vitritis or systemic effects.
Conclusions: :
Treatment with intravitreal bevacizumab results in a rapid reduction in CSME. This treatment may result in a dramatic decrease in foveal edema without an associated improvement in visual acuity, probably due to pre–existing cystic neural degeneration of the retina. More follow up is needed to demonstrate that this is an effective and safe method for treatment of CSME.
Keywords: diabetic retinopathy • macula/fovea • retina