According to the most recent data from the public Health Agency of Canada, about 3.0 million Canadians (8.1%) were living with diagnosed diabetes in 2013–2014, representing 1 in 300 children and youth (1–19 years), and 1 in 10 adults (20 years and older). It is important to know that diabetes can affect and cause eye damage.
Fortunately, there are ways to prevent or reduce eye damage caused by diabetes. That is why it is important that people who suffer from it should have a complete oculo-visual examination as soon as the disease is diagnosed and then at least once a year.
Regular eye exams are particularly necessary for people who have been suffering from diabetes for at least 5 years or more, for those who have difficulty controlling their blood sugar levels, and for pregnant and diabetic women.
Diabetic retinopathy is potentially a serious eye disease caused by diabetes. It affects the retina - the nervous tissue in the back of the eye that transmits visual messages to the brain. Lesions in this delicate tissue can cause significant damage or even blindness.
Diabetic retinopathy begins with a slight deterioration of the small blood vessels of the retina. Portions of these vessels swell and a fluid escapes into the retinal tissue around it.
Generally, these changes in the retina do not cause any symptoms. On the other hand, they can be detected by a trained professional to see the subtle changes of this retinal disease.
In many people with diabetic retinopathy, the disease will never cause significant visual problems. But in some individuals, the vessels can continue to flow and thus cause macular edema. Edema is an accumulation of fluid at the macula - the portion in the center of the retina responsible for clear and precise vision. When the macula becomes swollen because of excess fluid, the vision decreases so much that it becomes difficult or even impossible.
Other people develop an even more severe condition called proliferative retinopathy. This condition can develop with or without macular edema. During proliferative retinopathy, new abnormal vessels will be created on the surface of the retina. These new vessels are very fragile and break easily: haemorrhages appear and can block vision. Scicators are also formed near the retina and there is danger of detachment of the retina. Severe loss or blindness can result. But this only happens in a small minority of people with diabetes.
Nearly 40% of all diabetics will have at least slight signs of diabetic retinopathy. Nearly 3% will suffer from severe visual loss due to this disease.
In general, the longer diabetes has existed, the more likely it is to develop diabetic retinopathy.
As previously indicated, diabetic retinopathy will be one of the main symptoms. But proliferative retinopathy can progress long before symptoms appear. That's why people with diabetes should have a complete oculo-visual examination so that eye problems are detected and treated if necessary.
Recently, researchers have shown that laser treatment can prevent visual loss in many people with macular edema. This treatment, called photocoagulation, consists of focusing the laser light on the vessels that let the fluid pass through the macula. The purpose of the treatment is to seal the vessels to prevent the passage of fluid. In many patients, this treatment may stop visual impairment or even improve vision.
Research has also shown that laser photocoagulation can significantly reduce the risk of blindness in people with proliferative retinopathy. For these patients, the laser is used in a different way: it is not focused on the macula, but on hundreds of points located in the other parts of the retina. The goal of this treatment is to destroy the affected tissues and to prevent retinopathy from spreading. In fact, treatment can reduce the risk of severe visual loss by 60%.
Usually, the ophthalmologist plans a laser treatment when the diabetic person has proliferative retinopathy or retinal signs that predict its development. Also, people who have edema of the macula may also benefit from treatment.
The decision to recommend a laser treatment to someone will depend on both potential benefits and side effects: prevention or slowing of vision loss - versus the risk of unwanted side effects like loss of central or peripheral vision.
Unfortunately, laser treatment can not restore vision to those who have already suffered retinal damage because of diabetic retinopathy. Also, the laser can not be used if an internal haemorrhage of the eye makes it difficult or impossible to see the regions of the retina that are to be treated.
Some patients with retinopathy - including those who have had photocoagulation - may become blind because of intensive bleeding in the eye. Currently, ophthalmologists can remove blood and scar tissue out of the eye. This technique is called vitrectomy.
Following a vitrectomy, patients can often see well enough to move around by themselves. Occasionally, the vision of the operated eye is sufficient to resume everyday activities such as reading or driving.