Ranibizumab (rhuFab V2) and Scatter Laser Photocoagulation in Treatment of Patients With Clinically-significant Diabetic Macular Edema With Peripheral Retinal Nonperfusion (RaScaL)

Detailed Summary

To investigate the role of ranibizumab and angiographically-directed peripheral scatter laser therapy in patients with clinically-significant diabetic macular edema (CSME) and peripheral nonperfusion. We propose a novel treatment of CSME in a subgroup of patients defined by a combination of ultrawide-field angiography (UWFA) and optical coherence tomography (OCT). Within this classification scheme, patients with CSME are subdivided by the presence of: 1) focal macular leakage, 2) vitreomacular interface traction, and/or 3) peripheral nonperfusion. The successful treatment of diabetic macular edema would be dictated by pathophysiology-directed therapy based on this classification. The subgroup of interest for this clinical trial is characterized by diabetic macular edema, peripheral nonperfusion on UWFA, and the absence of macular traction on OCT. This group of patients has previously not been well recognized or characterized due to limitations in previous, standard angiographic evaluation of the retinal periphery. We postulate that this subcategory represents one with a high rate of failure of accepted therapies given persistence of the basic pathophysiologic mechanism for CSME, namely ischemia-induced production of Vascular Endothelial Growth Factor (VEGF) from the retinal periphery. This also represents a population of patients with likely recurrence of CSME despite treatment with anti-VEGF therapy alone for the same reason.

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