Novel biomarkers for early diagnosis and treatment strategies of diabetic retinopathy: A comprehensive review.

Diabetic retinopathy (DR) is one of the most frequent microvascular complications of diabetes mellitus, and one of the most frequent causes of avoidable blindness in working-age adults. Although it is common, early detection of DR in asymptomatic patients is a difficult task because it does not have any dependable biomarkers. Nowadays, DR is normally diagnosed at very late stages when characteristic morphological lesions can be observed through the fundoscope. The chronic hyperglycemia results in specific changes in the retinal vessel calibre, blood flow, oxygen saturation, and capillary network structure, which precede the development of apparent DR lesions. The available evidence indicates that neurodegenerative alterations in the retina start at an early stage of diabetes, and the disintegration of the retinal neurovascular unit precedes the onset of microvascular damage. This review explains the major biomarkers used in the early diagnosis of DR, their possible role in the detection of persons at high risk of development. The validation of these biomarkers would probably contribute significantly to early diagnosis and enable the creation of personal treatment plans, which would positively affect clinical outcomes and prevent the loss of vision.