14 Nov Eye Retinopathy
Retinopathy means damage to the retina, the light-sensitive part of the back of the eyeball which receives light and transmits it to the brain to turn into visual images.
Retinopathy can be caused by a disease of the cells in the retina, or by disease of the arteries of the retina, which in turn reduces the supply of blood to the retinal cells so they become damaged and lose their function. People with retinopathy experience gradual or (less often) sudden loss of vision.
Doctors diagnose retinopathy by visualising the back of the eye with an ophthalmoscope which shines a light through the eye pupil onto the retina. Other imagine tests such as x rays and scans can show doctors where and where the damage has occurred.
The most common forms of retinopathy are:
People with diabetes, especially if they have had it for many years, are prone to damage of the retina (known as diabetic retinopathy) caused by the disease of the arteries that occurs in diabetes.
There are three main types. In non-proliferative retinopathy, retinal blood vessels leak fluid or bleed, causing slow but gradual vision loss. There is also macular oedema, i.e. swelling of the macula, caused by the leakage of fluid from retinal blood vessels, causing loss of central vision. Proliferative retinopathy happens when normal blood vessels are replaced by new fragile vessels that bleed easily and can cause a sudden loss of vision.
Diabetic retinopathy can be prevented or delayed by good control of blood sugar levels and blood pressure and cholesterol. It is important to for people with diabetes to have regular eye tests. People with the macular oedema and proliferative retinopathy forms can be treated with laser treatment. A tiny laser beam helps seals leaking blood vessels and reduces growth of new fragile vessels, helping prevent vision loss. In severe cases, surgery performed on the blood vessels may also help.
In hypertension (ongoing high blood pressure) the walls of the retina’s blood vessels may thicken and narrow, preventing normal blood supply to the retina, causing vision problems.
People with hypertensive retinopathy have usually had high blood pressure for many years (though they may not be aware of it) and they will often also have other conditions such as heart disease, atherosclerosis (general disease of the arteries), diabetes, or have a high cholesterol. They may be smokers, be overweight and have an unhealthy diet. Effective treatment for hypertensive retinopathy involves controlling and lowering high blood pressure with a combination of medications and lifestyle changes.
Age-related macular degeneration (AMD)
Macular degeneration is the leading cause of blindness in older Australians. One in seven people over the age of 50 are affected by it, and it gets more common with age.
At the back of the eye is a small light-sensitive part of the retina called the macula which is responsible for central vision and colour perception. In AMD, the macula degenerates, causing loss of central vision.
There are two types of AMD; ‘wet’ and ‘dry’. In ‘wet’ AMD there is blood vessel growth and blood leakage over the macula. In the more common ‘dry’ type, the macula thins and degenerates.
People with a family history of the condition, people over the age of 75 and smokers are most at risk of developing AMD. It progresses gradually and significant damage may occur to the eye before a person notices the effects. Those effects are the loss of central vision and colour vision, although peripheral vision is preserved. People with AMD have difficulty reading, recognising faces and doing close up work.
There is no cure for AMD, but here are treatments that can slow down its progression, such as laser treatment, radiotherapy, surgical removal of scar tissue, and treatments in which drugs are injected directly into the eye to stop blood vessel growth.
Eye Health – Diabetes Australia
Vision Initiative – Victorian Government