Diabetic eye diseases are the leading cause of blindness among working-age adults in the United States. One common condition known as diabetic retinopathy affects the retina, the inner lining at the very back of the eye that senses light and relays it to the brain. People with diabetes are also at higher risk for disorders such as glaucoma (damage to the optic nerve), cataracts (clouding of the lens inside the eye) and age-related macular degeneration (damage to a part of the retina called the macula).
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Screening is needed
Even though the need for eye exams is well documented in medical guidelines, the percentage of people who actually get them is low. A recent study published in the journal Diabetes Care found that among insured individuals with type 2 diabetes and no eye disease, almost half had no eye exam visits over the five years studied. Only 15.3% met current recommendations. The figures for type 1 diabetes were only slightly better, with a third having no visits and 26.3% meeting the recommendations.
“The surprising part is that among insured people, who presumably have access to health care, many are still not getting optimal diabetic eye disease screening,” said Stephen Benoit, MD, MPH, medical officer and surveillance lead, Division of Diabetes Translation, at the Centers for Disease Control and Prevention (CDC). “It is concerning, especially since early detection is key because there are very effective treatments.”
High blood glucose concerns
The main concern regarding the potential impact of diabetes on eye health is when blood glucose levels consistently run too high. Too much glucose can change fluid levels inside the eye or cause swelling of tissues. In the short term, this can lead to blurred vision. Longer term, poorly managed diabetes can damage the tiny blood vessels in the back of the eyes. The vessels may weaken, leading to leaking and swelling. When fluids leak into the middle part of the eye, scarring or dangerously high pressure can result in vision loss. “People with diabetes are more prone to retinopathy, a blinding disease that is preventable,” said Dustin D. French, PhD, associate professor of ophthalmology at Northwestern University’s Feinberg School of Medicine in Chicago. “The blood vessels in your eyes swell, bleed and cause permanent damage to the macula. This is the central visual receptor in your eyes.”
Serious eye diseases
The four most serious diabetes-related eye diseases are:
Diabetic retinopathy, or damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina).
Diabetic macular edema, which occurs when swelling leads to damage to the macula. This is the part of the retina you use to read, drive or see faces.
Glaucoma, a group of eye diseases that damage the bundle of nerves connecting the eye to the brain (also known as the optic nerve).
Cataracts, a condition in which the lenses in our eyes become cloudy. This often happens as we age, but cataracts tend to develop earlier in people with diabetes.
For the most part, there are no early symptoms for diabetic eye disease. However, you should call a doctor immediately for any sudden changes in your vision. These would include flashes of light, more spots or dark strings (floaters) than you usually see, or if it looks like a curtain has been pulled over your eyes. These are symptoms of a detached retina, which causes loss of vision very quickly.
Preventing eye problems
It is better for you to avoid eye problems when possible. The ways to do this are generally the methods you use to stop other complications of diabetes:
• Take medications as prescribed.
• Reach and maintain a healthy weight.
• Add physical activity to your daily routine.
Because retinopathy is so prevalent in diabetes and easily treatable if caught early, many professional organizations have issued guidelines calling for regularly scheduled eye examinations. Most suggest yearly dilated comprehensive eye examinations. For people with type 1 diabetes, these should start within the first five years of diagnosis. For those with type 2 diabetes, the exams should begin immediately after diagnosis. “Type 2 can be silent and not diagnosed for a long time,” says Benoit. “Without knowing how long a person has had diabetes, we can’t know if some problems might already be beginning.”
Comprehensive eye exams
Experts all agree that the exam should include dilation to see the back of the eye better. This should be done by an eye doctor who is knowledgeable and experienced in taking care of diabetes-related eye problems.
The first step of an eye exam will typically be the doctor checking your vision using a poster of random letters of different sizes called the Snellen chart. This is where you see the “Big E” during an examination.
The next step will be for the doctor to put medication drops in your eye, causing the pupils to dilate, or widen. This makes it easier to see structures in the back of your eyes. It is not unusual to feel stinging when the drops are placed, and you may have a metallic taste in your mouth. Your sight may also be blurry for a few hours until the pupils return to normal. None of these are cause for concern.
When the pupils are big enough, the doctor looks through a special magnifying glass to see the back of your eye. They will be looking at the blood vessels in the middle or front of your eyes and the area around the optic nerve.
They may also use a slit lamp to check on the clear surfaces of the cornea (the front surface of the eye). Your eye care provider additionally may numb your eyes and then touch them with a special device to measure the inside pressure.
They may take photos of the back of your eye, a process called a digital retinal exam or imaging. This can be completed without dilation. After the photos are complete, a doctor views them and decides if you need more tests or treatments.
Two kinds of eye doctors
There are two different types of eye doctors who can give you comprehensive eye exams. An ophthalmologist is a medical doctor trained to diagnose and treat eye problems. An optometrist holds a Doctor of Optometry (OD) degree instead of an MD degree. Depending on the rules of your state, an OD may or may not be able to treat eye diseases. They can refer you to an ophthalmologist after diagnosis.
There is a shortage of ophthalmologists, especially outside of urban areas. In many places, the optometrist may be your only viable option unless you want to travel long distances. However, one technology that may help with access issues is telemedicine.
“Telemedicine has been proven to be effective,” said Jinan B. Saaddine, MD, MPH, team lead, Vision Health Initiative, Division of Diabetes Translation, at the CDC. “Telemedicine can be done at the primary office by properly trained staff. Pictures of the eye are sent via the internet to a doctor, who can look them over and make a diagnosis.”
Although telemedicine is a promising technology, its rollout has been spotty. Some localities have aggressively placed the needed equipment in underserved areas. In others, though, the service may not yet be available.
When seeing either type of provider, make sure that the appointment is specifically for diabetes screening. Health insurance often will pay for vision services only if they are for a medical problem.
If you have no insurance or high deductibles, there may be options available to address care concerns. Ask your primary care doctor about free or low-cost clinics in your area. Your optometrist or ophthalmologist might be able to point you toward programs sponsored by their professional associations that cover the costs. Consumer organizations such as your area American Diabetes Association office or Prevent Blindness chapters might be able to guide you in the right direction.
Among the places to go for financial help are the following:
• EyeCare America is a public service program providing eye exams and care at no cost to eligible people 65 or older and those at increased risk for glaucoma.
• Lions Clubs International is a volunteer service organization with local clubs. A local Lions club in or near your community may sponsor a program that may help you buy eyeglasses or get eye care.
• InfantSEE® is a public health service program that provides eye and vision care for infants. Member optometrists provide a comprehensive eye assessment for infants between 6 and 12 months of age at no cost to the families.
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“Being an advocate for oneself and recognizing that diabetes-related eye diseases are preventable is an important part of getting the care needed,” said French. “It is time out of your life but time that could save your vision.”
Want to learn more about keeping your eyes healthy with diabetes? Read “Eating for Better Vision and Healthy Eyes” and “Keeping Your Eyes Healthy” and “Protect Your Eyes From Diabetes” and watch “Diabetes and Your Eyes.”