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How can diabetes affect my vision?

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Diabetes can damage the light-sensitive area on the back of your eyes, called the retina.

Light goes in through the front of our eyes and onto the retina at the back. The retina acts like a camera film, capturing the images we see.

The macula is the central part of the retina. It is the most sensitive part, and it allows us to see the fine detail that we need to read, recognise faces and to drive. It also lets us see colour.

The rest of the retina lets us see less defined images. It gives us our peripheral vision, or side vision, helps us sense movement, and helps us see at night.

Diabetic retinopathy

Diabetic retinopathy is the name for any damage to the retina caused by diabetes. Anyone with diabetes – type 1 or 2, or gestational – needs to have a check for diabetic retinopathy, as it can happen at any time.

Over time, high blood sugar levels damage the blood vessels in the retina, at the back of your eye, which can then bleed.

The picture below shows what eye specialists see when they look through your pupil to the retina at the back. At the top is a normal, healthy eye. Below it is an eye with diabetic retinopathy. You can see some burst blood vessels.

Types of diabetic retinopathy

The top image shows a normal retina and macula, while in the bottom mage you can see leaking blood vessels. This is diabetic retinopathyThe first stage of diabetic retinopathy is called nonproliferative (non-pro-lif-er-a-tive) diabetic retinopathy. In the early stages, blood vessels in the back of your eyes leak a little, and the walls of the blood vessels bulge.

In some people this develops into vision-threatening retinopathy. Fluid can leak out of the damaged blood vessels at the back of your eye and cause swelling (called oedema). When this happens in the macular part of your retina, which is important for detailed vision, it can cause major vision problems. This type of diabetic retinopathy with macular swelling (oedema) is called maculopathy. It is the most common cause of vision loss in diabetes.

The next stage is called proliferative retinopathy. This is when fragile, abnormal new blood vessels grow on your retina. They can also grow forward into the gel-like fluid in your eyeball (called vitreous fluid).

These new blood vessels cause bleeding in your retina and vitreous fluid. This is called a vitreous haemorrhage. This bleeding can affect your vision, as it stops the light from getting onto the retina. It can also cause scarring. When the scars shrink, they can pull your retina out of place. This is called retinal detachment. You need your retina to be in place to see, so around half of people with untreated retinal detachment will suffer serious vision loss or total blindness.

Most people with diabetes will get some retinopathy. If it's mild it won't affect your vision, but it can get worse if it's not treated. How mild or severe it becomes depends on how well-controlled your diabetes is and whether you have regular diabetic eye screening tests.

Other eye problems with diabetes

People with diabetes are more likely to suffer from glaucoma than people without diabetes. The longer someone has had diabetes, the more likely they are to get glaucoma. Glaucoma is an increase in pressure inside your eye that can make you lose your vision. Your risk of glaucoma increases with age. You can get your eyes checked for signs of glaucoma when you have your diabetes eye check.

People with diabetes are also more likely to get cataracts, and to get them at a younger age than people without diabetes. Their cataracts are also likely to get worse much more quickly. A cataract is when the eye's clear lens gets cloudy, blocking light.

  HealthInfo recommends the following pages

On the next page: Diabetes eye checks

Written by Canterbury optometrists. Adapted by HealthInfo clinical advisers. Endorsed by clinical director, Ophthalmology, Canterbury DHB. Page created April 2015.


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Review key: HIDYE-139181