Peripheral Ischemia in Diabetic Retinopathy and Retinal Vein Occlusion: New Insights with Ultra-Wide-Angle Fundus Imaging and Wide-Angle Fluorescein Angiography

Abstract

In several diseases such as diabetic retinopathy and retinal vein occlusion, relevant pathophysiological changes take place in the retinal periphery. These changes may determine the prognosis and outcomes of therapy. Recent ultra-wide-angle camera systems promise improved and simplified visualisation of the outer periphery of the retina. This could potentially lead to novel clinical applications of these methods, with potential impact on therapy decisions. Literature and database research on ultra-wide imaging for diabetic retinopathy and retinal vein occlusion. With ultra-wide-angle angiography, it is possible to visualise up to 3.2-fold more retinal surface than conventional 7SF images (7SF: 7 standard field). Initial studies imply that diabetic changes can be found outside of the boundaries of the 7SF images. Patients with central vein occlusion have more extended and severe macular oedema and poorer visual acuity if ischemia of the periphery is more pronounced (measured by the ischemic index [ISI]). The amount of ischemia influences the size of the macular oedema, its resolution under therapy and the number of anti-VEGF injections needed to treat it. Ultra-wide-angle camera systems allow visualisation of the peripheral retina outside the boundaries of standard methods. Initial studies have detected potentially relevant changes in the outer periphery, which would have been missed by 7SF. Nevertheless, there have been no systematic studies on the relevance of these changes with regards to prognosis and therapeutic decisions.