Diabetes, during its course, can cause a long series of chronic complications.
Diabetic Retinopathy is one of the most serious. This, if not properly followed, can lead to a severe reduction in visual acuity that can result, in the most severe cases, in blindness. In fact, Diabetic Retinopathy and Age-Related Macular Degeneration share the sad record of the leading causes of acquired blindness among adults in Western countries.
The duration of diabetes and poor glycaemic control are determinants of both the ‘onset of diabetic retinopathy and the rapidity of its evolution, from which it follows that glycaemic control is critical to delaying the onset of retinopathy or slowing its worsening.
It is then essential to check the ocular fundus periodically so that any initial retinal damage can be detected early.
Diabetic retinopathy is classified into two forms:
- Nonproliferative, earlier and less severe, in mild, moderate, or advanced variants
- Proliferating
Nonproliferating if not promptly diagnosed and treated as per protocols, can evolve into the proliferating form which is severely disabling.
In diabetes, the retina is damaged because hyperglycaemia alters the structure of retinal vessels, inducing the formation of microaneurysms and microhaemorrhages, as well as causing alterations in retinal vascular calibre.
All these phenomena can lead to two main consequences:
- The passage some blood components, through damaged vessel walls with oedematous and exudative phenomena
- The reduced perfusion of retinal tissue to the point of complete ischemia
The formation of ischemic retinal areas provides the stimulus for the formation of retinal neovases, which characterize the proliferating form. These new blood vessels have a less robust structure than normal ones and can rupture easily, resulting in pre-retinal and endovitreal haemorrhages and secondary retinal detachments.