About 60 per cent of patients who have had diabetes for 15 years or more will have some blood vessel damage in their eyes, says the SNEC.

As the disorder gets more advanced, abnormal blood vessels may grow in the retina. These new vessels tend to break and may bleed into the vitreous - the clear jelly-like substance that fills the center of the eye.

Scar tissue can form and when it contracts , the scars may pull on and detach the retina, causing loss of vision. The new blood vessels may also grow on the iris and cause a form of glaucoma.

Symptoms:
Dark spots or clouds floating in your vision
Vision loss or blurred vision
A dark or empty spot in the center of your vision

Treatment of diabetic retinopathy involves the use of laser to seal up leaking vessels or cause them to shrink and eventually disappear. In some cases, like when the bleeding is heavy or when scar tissue is pulling the retina away from the wall of the eye, a procedure known as vitrectomy may be performed. In vitrectomy, the vitreous is removed with the blood and scar.

Age-related macular degeneration
Macular degeneration is a chronic disease of the eyes caused by the deterioration of the central portion of the retina, called the macula. The macula is responsible for clear central vision in the eye and is thereforeimportant for reading, watching television, etc. The disease affects central vision but not peripheral vision.

Distorted vision of a child whose eyes are suffering from the age-related macular degeneration.

Age-related macular degeneration (AMD), which is associated with ageing, is the leading cause of blindness among the elderly in the developed world. AMD occurs in two forms: dry and wet

Dry AMD occurs when the light-sensitive cells in the macula slowly break down, gradually blurring central vision in the affected eye.

Wet AMD is the condition in its advanced stage and occurs when abnormal blood vessels behind the retina start to grow under the macula. These vessels are fragile and often leak blood and fluid, lifting the macula from its normal place at the back of the eye. Damage to the macula happens very fast.

Symptoms:
Straight lines appearing wavy
Letters in newspapers, books and magazine appearing blurry
Dark, empty spaces in the centre of vision

Treatment for wet AMD involves the use of laser to seal off or destroy the abnormal blood vessels. While treatment will not bring back any of the vision you have lost, it may halt the loss of your vision or at least slow down the rate of vision loss.

New treatments for wet AMD involve the injection of drugs into the eye to stop new abnormal blood vessels from forming.

As for dry AMD, no treatment is available to reverse it. However, as the condition usually progresses slowly, most people with this form of AMD are able to lead relatively normal lives.