Ultrawide Field Imaging in Diabetic Retinopathy: Exploring the Role of Quantitative Metrics

Abstract

Ultrawide field imaging (UWF) has allowed the visualization of a significantly greater area of the retina than previous standard approaches. In diabetic retinopathy (DR), significantly more lesions are seen on UWF imaging compared to the seven-standard ETDRS fields. In addition, some eyes have lesions that are located predominantly in the peripheral retina that are associated with an increased risk of DR progression. The current DR severity scales are still largely based on clinically visible retinal microvascular lesions and do not incorporate retinal periphery, neuroretinal, or pathophysiologic changes. Thus, current scales are not well suited for documenting progression or regression in eyes with very early or advanced DR, nor in the setting of vascular endothelial growth factor inhibitors (antiVEGF). In addition, the categorical system is highly subjective, and grading is variable between different graders based on experience level and training background. Recently, there have been efforts to quantify DR lesions on UWF imaging in an attempt to generate objective metrics for classification, disease prognostication and prediction of treatment response. The purpose of this review is to examine current quantitative metrics derived from UWF fluorescein angiograms and UWF color imaging to determine their feasibility in any potential future DR classification.

Keywords: diabetic retinopathy; ultrawide field imaging.

Figure 1

Early treatment diabetic retinopathy study (ETDRS) seven-standard fields compared to ultrawide fields (UWF). (A) Color UWF image showing an overlay of the seven scheme fields. (B) A green-filtered image of the same eye showing enhanced visibility of the choroidal vessels and locations of the vortex veins (white asterisk).