Diabetic retinopathy is one of the leading causes of vision loss worldwide. Fluorescein angiogram still plays a primary role in its diagnosis but new non-invasive technologies as optical coherence tomography, fundus autofluorescence and microperimetry are gaining popularity in the last years. Anatomical changes found with these devices have been widely described but their correlation with visual function needs to be assessed and several features have been proposed as indicators of visual prognosis. The aim of this paper is to give a scope of the actual role of these techniques in the evaluation of retinal impairment secondary to diabetes.