A Novel Avastin Injection Technique—“Sunalp Protocol”

Abstract

Purpose: The introduction of vascular endothelial growth factor (VEGF) inhibitors began a new era in the treatment of exudative age-related macular degeneration (ARMD). These drugs are effective at suppressing choroidal neovascularization (CNV) resulting in improvement or stabilization of visual acuity; however, the chronic nature of the disease require these drugs be administered periodically (usually monthly) for the life of the patient. Since intravitreal injections are administered through the sclera, there is the possibility of adverse events, such as vitreous hemorrhage, endophthalmitis, retinal tears, or retinal detachment. To avoid some of the adverse events associated with intravitreal delivery via the scleral route we have developed a technique to deliver bevacizumab (Avastin®) into the vitreous cavity in pseudophakic eyes via a corneal route.Methods: A 27-gauge, 5 mm angled cannula attached to a 1.0 ml syringe is fitted into an 11 o’clock limbal incision and advanced through the anterior and posterior chamber. The cannula is maneuvered through the zonules into the vitreous and 0.1 ml of Avastin is delivered behind the lens into the vitreous cavity. The procedure was performed in 50 eyes (Addendum 1: 499 injections 2014–2015), of five exudative ARMD patients, 21 diabetic macular edema (DME) patients, two cystoid macular edema (CME) patients, and one central retinal vein occlusion (CRVO) patient. Visual acuity (VA), edema, optical coherence tomography (OCT), and endothelial cell counts were performed 1 day following Avastin administration. VA was also determined in 16 eyes at 1 month after Avastin administration.Results: At 1 day post-Avastin administration, vision acuity and edema index improved or remained stable in all eyes, with the exception of one eye from an exudative ARMD patient whose vision deteriorated. At 1 month the average visual acuity in 16 eyes was also significantly improved. The improvement in edema was evident through retinal OCTs. No change in endothelial cell counts was observed.Conclusions: Administration of Avastin via an anterior chamber route in pseudophakic (Addendum 2: Phakic eyes were also treated with no cataract formation) patients is effective for the treatment of exudative ARMD, DME, CME and CRVO, minimizing the possible adverse events related to the administration by the traditional scleral route. In addition, anterior segment administration allows the ophthalmologist to directly observe the delivery of the drug with microscope precision. Pars plana injections are usually performed without magnification and no direct visualization.