Diabetes mellitus is one of the leading causes of blindness in developed countries in the world, including Singapore. It is responsible for a spectrum of eye complications, of which the most serious is diabetic retinopathy.
In this condition, the high blood sugar levels in diabetes cause changes in the retina, the light-sensitive layer of nerve cells at the back of the eye, thus leading to visual loss.
There are three stages in diabetic retinopathy:
This is the early stage in which the small blood vessels in the retina are blocked or damaged, causing swelling and leakage of blood and fluid into the vitreous body of the eye. There are usually no symptoms at this stage.
The macula is the pinhead-sized central area of the retina that lets us see details. When it swells up (edema) in the background stage, central vision is gradually lost, resulting in difficulty with tasks like reading and driving.
This is the advanced stage where new blood vessels form (proliferate) on the retina and optic nerve, as part of the body’s way of repairing the damage in the early stages. These new vessels are however, weak and tend to rupture, causing scarring which in turn, pulls on the retina, leading to retinal detachment ( see section on this condition ) and loss of vision.
The key to successful management of diabetic retinopathy lies in screening and early detection of the changes mentioned above to allow prompt treatment.
ALL diabetic patients should have their eyes checked at least once a year by an eye doctor, irregardless of the duration of their diabetes or whether they have any visual symptoms.
The examinations carried out are fundoscopy, fluorescein angiography and retinal photography.
It has been shown that good control of blood sugar levels and blood pressure can help to reduce the incidence of diabetic retinopathy. However, the progression of changes may still occur, despite the best of efforts.
There is no cure for diabetic retinopathy but surgical and medical treatments are available that help reduce visual loss. These are:
See relevant sections