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22 || AWSAR Awarded Popular Science Stories - 2019
II diabetes are affected by retinopathy during the first two decades of diabetes. The risk factors associated with the progression of DR include hyperglycemia (high levels of blood glucose), dyslipidemia (unhealthy levels of fat or lipids in the blood), hypertension (high blood pressure), and the duration of diabetes in the patient.
I will first give a brief
outline of the physiological
changes that take place in the
diabetic retina. The initial stage
of DR is usually characterized
by mild abnormalities in the
retina, including irregularities in
blood vessels and tiny bulges
in the walls of capillaries
(capillaries are very tiny blood
vessels), which lead to small
focal hemorrhages (bleeding).
These injured capillaries cause
leakage of fluid and blood into
the retina, leading to blurry vision. In the late stage of DR, one can observe the growth of new, fragile blood vessels in the retinal tissue, attempting to compensate for the lack of blood flow. These atypical new capillaries are very fragile, and exude fluid easily, causing edema. These may even spread out into the vitreous body, which is a clear gel present between the lens and the retina. This further leads to
vitreous hemorrhage and is manifested as the presence of “floaters” in the visual field (Fig. 1). This may eventually lead to the formation of scar tissue on the retina, which may contract along with the vitreous, leading to retinal detachment or tear, even resulting in blindness unless surgically repaired.
Since the most noticeable clinical characteristic of DR are abnormalities in these tiny retinal blood vessels, therapeutic interventions in the last decade have often attempted to reduce the injury to capillaries by targeting chronic retinal inflammation or reducing the leakiness of damaged capillaries. Apart from blood vessels, the retina consists of distinct classes of neurons
Fig. 2. Structure of the eye.
Fig. 1. What is it like to have diabetic retinopathy?
Today, India houses the second largest number of people with type 1 diabetes (caused by insulin deficiency), type 2 diabetes (caused by insulin resistance and impaired insulin secretion by the pancreas), and undiagnosed diabetes.