Diabetes: caring for your eyes

Diabetes can wreak havoc on the body in surprising ways. A person with diabetes may see changes to their energy levels, their weight, or their skin. One change they may not see coming is the way diabetes can affect their vision.

People with diabetes often develop cataracts at a younger age. They experience glaucoma more than others, and 40% to 45% of people with diabetes will face diabetic retinopathy (damage to the tissue at the back of the eye called the retina). It is the most common cause of blindness in people under the age of 65.

The retina senses light as it enters the eye, and it is a vital component of good vision. In diabetic retinopathy, elevated blood glucose levels can damage the vessels that feed and nourish the retina. People with diabetes who also have high blood pressure are at a much higher risk for diabetic retinopathy because high blood pressure can also damage the retina.

The early stage of retina damage is called nonproliferative retinopathy. Weakened vessel walls can leak blood into the retina. Bulges in the vessels may develop. The leaking vessels often lead to swelling in the retina and cause a decrease in vision. A person with eye damage at this point may have normal vision or slightly blurred vision.

Over time, the damaged vessels can no longer provide enough oxygen to the retina, causing parts of the retina to die. At advanced stages of retinopathy, called proliferative retinopathy, the body may trigger the production of new blood vessels to supply the retina. But these new blood vessels are often weak, leading to even more bleeding into the retina. This, in turn, can block light from reaching the back of the eye, obscuring vision with floating spots along with decreased vision. Eventually, the damaged vessels may form scar tissue and tear away from the eye. An untreated detached retina can lead to vision loss or full blindness.

The loss of vision may be due to macular edema (swelling of the macula). The macula is the part of the eye where the most detailed and clear vision occurs. When fluid leaks into the centre of the macula, the swelling causes blurred vision. Macular edema can occur at any time, but it is more likely to happen as the retinopathy progresses.

Some patients with type 2 diabetes may have retinopathy at the time of diagnosis, as many of these patients have had undiagnosed high blood sugars for many years. Eye surgery may be necessary to remove blood from the eye to improve vision. Laser surgery may also be an option to help shrink the abnormal new blood vessels forming in the retina.

Tips for preventing eye damage and vision loss:

• Monitor and control blood glucose levels.
• Monitor and control blood pressure.
• Monitor and control blood cholesterol.
• Don't smoke. Smoking causes more blood vessel damage.
• Have a thorough eye examination every year, more often if necessary or if advised by your physician or primary health care provider. The exam should include pupil dilation, which will allow an eye specialist or other qualified health care provider to check for signs of retinal damage, cataracts, and glaucoma.

If you notice changes in your vision, visit your physician or primary health care provider as soon as possible.

If vision loss occurs, talk to your eye specialist or health care provider about low vision services or devices that could help you optimize the vision you still have. You can still continue to do most, if not all, of your daily activities, including caring for your diabetes. Many adaptive vision tools are available. You don't have to let poor eyesight affect your diabetes management. Here are some tips to help you with low vision:

Diabetes care tips:

• Use home blood glucose monitors with a large result display.
• Label your medication vials using large print written on larger paper or stock cards and tape it to the vials.
• Use felt-tip pens to record your blood glucose readings.
• Take advantage of blood glucose monitors that have memory and allow you to view and print your results on the computer. When it comes time to look and print the results, use a larger font size.
• Use vision aids that make taking insulin easier, such as devices that help align the insulin bottle and syringe for correct needle insertion, or tactile measuring devices.
• Try a tape or digital recorder to record your blood glucose results and other information.
• See a vision specialist and seek out resources or agencies in your community to find out more about adaptations for day-to-day tasks to make life with vision loss easier.