Distribution of Nonperfusion Area on Ultra-widefield Fluorescein Angiography in Eyes With Diabetic Macular Edema: DAVE Study

Purpose To explore the distribution of nonperfusion area (NPA) in eyes with diabetic macular edema (DME) and its relationship with the severity of DME. Design Prospective, observational case series. Methods Forty eyes of 29 patients with treatment-naïve DME who participated in the DAVE study (NCT01552408) were included. Ultra-widefield fluorescein angiography images were sent to the Doheny Image Reading Center, where they were montaged and corrected using stereographic projection to adjust for peripheral distortion. Two experienced, independent/masked certified graders manually segmented the NPA and the total visible retinal area (TRA), and computed the NPA and TRA in square millimeters (mm²). The ischemic index (ISI) was calculated. The distributions of NPA and ISI within different retinal zones were correlated with the severity of DME. Results In 40 eyes with treatment-naïve DME (mean age, 55.8 years) visual acuity (VA) (mean 59.6 EDTRS letters) was correlated with central macular thickness (CMT) (mean 536.9 μm, R = −0.418, P =.008) and macular volume (MV) (mean 11.9 mm³, R = −0.449, P =.004). The NPA and ISI among the different retinal zones were significantly different (NPA: P <.001; ISI: P =.005). The NPA and ISI in the midperiphery were negatively associated with CMT (NPA: P =.04; ISI: P =.02). However, the global NPA and ISI for the entire retina were not associated with CMT or MV (P >.05). Conclusion In eyes with DME, the ISI increases with increasing distance from the fovea. The severity of DME does not appear to correlate with global NPA and ISI.