Adult flies fed a high-sugar diet (post-eclosion) develop hyperglycemia; they exhibit significantly decreased responsiveness to the light as a consequence of vision defects. Although the gross anatomical architecture of the external eye appears normal, progressive damage of photoreceptor cells is observed. Retinal cells of hyperglycemic animals exhibit molecular features of neurodegeneration such as apoptosis/autophagy dysregulation and oxidative stress.
[updated Mar. 2021 by FlyBase; FBrf0222196]
Diabetic retinopathy is a serious sight-threatening complication of diabetes; it is the leading cause of preventable blindness in working-aged people. The longer a person has diabetes, the more likely he or she is to develop diabetic retinopathy, particularly if the diabetes is poorly controlled. Over time, diabetes damages small blood vessels throughout the body, including the retina. Diabetic retinopathy occurs when these tiny blood vessels leak blood and other fluids. This causes the retinal tissue to swell, resulting in cloudy or blurred vision. [American Optometric Assn., https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/diabetic-retinopathy?sso=y]
Diabetic retinopathy (DR) was initially considered a pure microvascular disease. There is growing evidence that the degeneration of retinal neurons may occur before clinical signs of DR; metabolic pathways triggered by hyperglycemia lead to early abnormalities in the retina, such as death/dysfunction of neurons and tissue remodeling (FBrf0248489 and references cited therein).
