The retina is the nerve layer that lines the back of the eye. Its function is to sense light, capture all the images that we see, and send the information through the optic nerve to the brain. A retinal evaluation requires a thorough dilated examination of the eye and often requires obtaining images of the retina using multiple imaging modalities. The medical and surgical procedures performed by retina specialists are extremely delicate and range from in-office injections to highly technical surgeries conducted in the operating room.
Diabetic retinopathy is damage to the back of the eye (retina) caused by complications of diabetes, which can eventually lead to blindness. Diabetic retinopathy can develop in anyone who has type 1 diabetes or type 2 diabetes. The longer you have diabetes, and the less controlled your blood sugar is, the more likely you are to develop diabetic retinopathy.
As the condition progresses, diabetic retinopathy symptoms may include:
- Spots or dark strings floating in your vision (floaters)
- Blurred vision
- Fluctuating vision
- Dark or empty areas in your vision
- Vision loss
- Difficulty with color perception
Diabetic retinopathy usually affects both eyes.
Diabetic retinopathy may be classified as early or advanced, depending on your signs and symptoms.
Early diabetic retinopathy. This type of diabetic retinopathy is called nonproliferative diabetic retinopathy (NPDR). It’s called that because, at this point, new blood vessels aren’t growing (proliferating). NPDR can be described as mild, moderate or severe. When you have NPDR, the walls of the blood vessels in your retina weaken. Tiny bulges (called microaneurysms) protrude from the vessel walls, sometimes leaking or oozing fluid and blood into the retina. As the condition progresses, the smaller vessels may close, and the larger retinal vessels may begin to dilate and become irregular in diameter. Nerve fibers in the retina may start to swell. Sometimes the central part of the retina (macula) starts to grow, too. This is known as macular edema.
Advanced diabetic retinopathy. Proliferative diabetic retinopathy (PDR) is the most severe type of diabetic retinopathy. It’s called proliferative because, at this stage, new blood vessels begin to grow in the retina. These new blood vessels are abnormal. They may grow or leak into the clear, jelly-like substance that fills the center of your eye (vitreous). Eventually, scar tissue stimulated by the growth of new blood vessels may cause the retina to detach from the back of your eye. If the new blood vessels interfere with the proper flow of fluid out of the eye, pressure may build up in the eyeball, causing glaucoma. This can damage the nerve that carries images from your eye to your brain (optic nerve).
Complications can lead to serious vision problems including:
- Vitreous hemorrhage. The new blood vessels may bleed into the clear, jelly-like substance that fills the center of your eye. If the amount of bleeding is small, you might see only a few dark spots or floaters. In more-severe cases, blood can fill the vitreous cavity and completely block your vision. Vitreous hemorrhage by itself usually doesn’t cause permanent vision loss. The blood often clears from the eye within a few weeks or months. Unless your retina is damaged, your vision may return to its former clarity.
- Retinal detachment. The abnormal blood vessels associated with diabetic retinopathy stimulate the growth of scar tissue, which can pull the retina away from the back of the eye. This may cause spots floating in your vision, flashes of light or severe vision loss.
- Glaucoma. New blood vessels may grow in the front part of your eye and interfere with the normal flow of fluid out of the eye, causing pressure in the eye to build up (glaucoma). This pressure can damage the nerve that carries images from your eye to your brain (optic nerve).
- Blindness. Eventually, diabetic retinopathy, glaucoma or both can lead to complete vision loss.
Tests and Diagnosis
Diabetic retinopathy is best diagnosed with a dilated eye exam. For this exam, your eye doctor will place drops in your eyes that make your pupils open widely. This allows your doctor to get a better view inside your eye. The drops may cause your close vision to be blurry until they wear off several hours later.
During the exam, your eye doctor will look for:
- Presence or absence of a cataract
- Abnormal blood vessels
- Swelling, blood or fatty deposits in the retina
- Growth of new blood vessels and scar tissue
- Bleeding in the clear, jelly-like substance that fills the center of the eye (vitreous)
- Retinal detachment
- Abnormalities in your optic nerve
In addition, your eye doctor may:
- Test your vision
- Measure your eye pressure to test for glaucoma.
As part of the eye exam, your doctor may do a retinal photography test called fluorescein angiography. First, your doctor will dilate your pupils and take pictures of the inside of your eyes. Then your doctor will inject a special dye into your arm. More pictures will be taken as the dye circulates through your eyes. Your doctor can use the images to pinpoint blood vessels that are closed, broken down or leaking fluid.
Optical coherence tomography
Your eye doctor may request an optical coherence tomography (OCT) exam. This imaging test provides cross-sectional images of the retina that show the thickness of the retina, which will help determine whether fluid has leaked into retinal tissue. Later, OCT exams can be used to monitor how treatment is working.
Treatment and Drugs
Treatment depends largely on the type of diabetic retinopathy you have. Your treatment will also be affected by how severe your retinopathy is, and how it has responded to previous treatments.
Early diabetic retinopathy
If you have nonproliferative diabetic retinopathy (NPDR), you may not need treatment right away. However, your eye doctor will closely monitor your eyes to determine if you need treatment.
It may also be helpful to work with your diabetes doctor (endocrinologist) to find out if there are any additional steps you can take to improve your diabetes management. The good news is that when diabetic retinopathy is in the mild or moderate stage, good blood sugar control can usually slow the progression of diabetic retinopathy.
Advanced diabetic retinopathy
If you have proliferative diabetic retinopathy, you’ll need prompt surgical treatment. Sometimes surgery is also recommended for severe nonproliferative diabetic retinopathy. Depending on the specific problems with your retina, options may include:
- Focal laser treatment. This laser treatment, also known as photocoagulation, can stop or slow the leakage of blood and fluid in the eye. It’s done in your doctor’s office or eye clinic. During the procedure, leaks from abnormal blood vessels are treated with laser burns. Focal laser treatment is usually done in a single session. Your vision will be blurry for about a day after the procedure. Sometimes you will be aware of small spots in your visual field that are related to the laser treatment. These usually disappear within weeks. If you had blurred vision from swelling of the central macula before surgery, however, you may not recover completely normal vision. But, in some cases, vision does improve.
- Scatter laser treatment. This laser treatment, also known as panretinal photocoagulation, can shrink the abnormal blood vessels. It’s also done in your doctor’s office or eye clinic. During the procedure, the areas of the retina away from the macula are treated with scattered laser burns. The burns cause the abnormal new blood vessels to shrink and scar. Scatter laser treatment is usually done in two or more sessions. Your vision will be blurry for about a day after the procedure. Some loss of peripheral vision or night vision after the procedure is possible.
- Vitrectomy. This procedure can be used to remove blood from the middle of the eye (vitreous) as well as any scar tissue that’s tugging on the retina. It’s done in a surgery center or hospital using local or general anesthesia. During the procedure, the doctor makes a tiny incision in your eye. Scar tissue and blood in the eye are removed with delicate instruments and replaced with a salt solution, which helps maintain your eye’s normal shape. Sometimes a gas bubble must be placed in the cavity of the eye to help reattach the retina. If a gas bubble was placed in your eye, you may need to remain in a facedown position until the gas bubble dissipates — often several days. You’ll need to wear an eye patch and use medicated eyedrops for a few days or weeks. Vitrectomy may be followed or accompanied by laser treatment.
- Eye Injections. Injection of medication into the vitreous fluid in the eye may be effective in treating wet macular degeneration, diabetic retinopathy and broken blood vessels within the eye. For example, to treat wet macular degeneration, periodic injections of medications directly into your eye may help stop disease progression. In some cases, this treatment may help to partially recover vision.
Surgery often slows or stops the progression of diabetic retinopathy, but it’s not a cure. Because diabetes is a lifelong condition, future retinal damage and vision loss are possible. Even after treatment for diabetic retinopathy, you’ll need regular eye exams. At some point, additional treatment may be recommended.
Macular edema occurs when fluid and protein deposits collect on or under the macula of they eye (a yellow central are of the retina) and cause it to thicken and swell. The swelling may distort a person’s central vision, as the macula is near the center of the retina at the back of the eyeball. This area holds tightly packed cones that provide sharp, clear central vision to enable a person to see detail, form, and color that is directly in the direction of gaze.
Macular edema is often a complication of diabetic retinopathy and is the most common form of vision loss for people with diabetes particularly if it is left untreated.
Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye’s macula. The macula is a small area in the retina – the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly.
AMD is a common eye condition among people age 50 and older. It is a leading cause of vision loss in older adults. As people get older, the risk increases. Other risk factors include the following:
- Smoking. Research shows that smoking increases the risk of AMD two-fold.
- Race. Caucasians are much more likely to get AMD than people of African American descent.
- Family History. People with a family history of AMD are at a higher risk.
In some people, AMD advances so slowly that vision loss does not occur for a long time. In others, the disorder progresses faster and may lead to a loss of vision in one or both eyes. The vision loss makes it difficult to recognize faces, drive a car, read, print, or do close work, such as sewing or fixing things around the house.
Despite the limited vision, AMD does not cause complete blindness. You will be able to see using your side (peripheral) vision.
How is AMD detected?
The early and intermediate stages of AMD usually start without symptoms. Only a comprehensive dilated eye exam can detect AMD. The eye exam may include the following:
- Visual acuity test. This eye chart measures how well you see at distances.
- Dilated eye exam. Your eye care professional places drop in your eyes to widen or dilate the pupils. This gives him or her a better view of the back of your eye. Using a special magnifying lens, he or she then looks at your retina and optic nerve for signs of AMD and other eye problems.
- Amsler grid. Your eye care professional also may ask you to look at an Amsler grid. Changes in your central vision may cause the lines in the grid to disappear or appear wavy, a sign of AMD.
- Fluorescein angiogram. Your eye care professional may suggest you see an ophthalmologist to perform a fluorescein angiogram. With this test, your doctor injects a dye into your arm. Pictures are taken as the dye passes through the blood vessels in your eye. The test allows your doctor to identify leaking blood vessels and decide the best treatment.
Dry AMD is the most common form of AMD in its early or intermediate stages. It occurs in about 90 percent of the people with the condition.
Dry AMD happens when the light-sensitive cells in the macula slowly break down, gradually blurring central vision in the affected eye. As dry AMD progresses, you may see a blurred spot in the center of your vision. Your eye care professional may call this “geographic atrophy.”
Over time, central vision in the affected eye can be slowly lost as less of the macula works.
Symptoms of Dry AMD
Dry AMD has few symptoms in the early stages. It is important to have your eyes examined regularly before the disease progresses.
In the later stages, blurred vision is the most common symptom of dry AMD. Objects also may not appear to be as bright as they used to be.
As a result, you may have trouble recognizing faces. You may need more light for reading and doing other tasks. Both eyes can have dry AMD or one eye can be affected first.
Vision loss and Dry AMD
If you have vision loss from dry AMD in one eye only, you may not notice any changes in your overall vision. With the other eye seeing clearly, you still can drive, read, and see fine details.
You may notice changes in your vision if dry AMD affects both eyes or if you develop the wet form of the disease. In any case, see an eye care professional for a comprehensive dilated eye exam if blurring occurs in your vision.
Can the dry form turn into the wet form?
All people who have the wet form had the intermediate stage of the dry form first. The dry form also can suddenly turn into the wet form, even during early stage AMD. Eye care professionals have no way to tell if the dry form will turn into the more severe wet form.
Dry AMD can turn into wet AMD at any time. You should get an Amsler grid from your eye care professional to check your vision for signs of wet AMD.
Diet might help
Studies have shown that people who eat a diet rich in green, leafy vegetables and fish have a lower risk of developing AMD.
While there is no definitive proof that changing your diet will reduce your risk of developing AMD or having it progress, to maintain good health in general, there is no reason not to eat a healthy diet, exercise, avoid smoking, and see your healthcare professional regularly.
A note about early-stage dry AMD
Currently, no treatment exists for early-stage dry AMD, which in many people shows no symptoms or loss of vision. Your eye care professional may recommend that you get a comprehensive dilated eye exam at least once a year. The exam will help determine if your condition is advancing.
If your condition gets worse, your eye care professional may suggest that you take a specific high-dose supplement that contains antioxidants and zinc. Do not take these high-dose supplements unless your doctor recommends them. Research shows that high doses of specific vitamins and minerals may slow the condition’s progress.
What is wet AMD?
Wet AMD affects about 10 percent of all people with AMD. This type, however, is more severe than the early and intermediate stages of the dry form.
Wet AMD happens when abnormal blood vessels behind the retina start to grow under the macula. These new blood vessels can be fragile and leak blood and fluid. The blood and fluid cause the macula to swell and damage occur rapidly. The damage may also cause scarring of the retina.
Although the loss of central vision can happen quickly, eye care professionals can slow down or stop the progression of wet AMD if it is detected before severe vision loss occurs.
What are the symptoms?
During the early stages of wet AMD straight lines may appear wavy. People with wet AMD also may develop a blind spot, which results in the loss of central vision.
If you notice these or other changes to your vision, contact your eye care professional at once. Again, eye care professionals may be able to treat the condition before severe vision loss occurs.
Treatment options for wet AMD
With early diagnosis and proper treatment, you can delay the progression of AMD. The earlier it is detected, the better your chances of keeping your vision. Wet AMD typically results in severe vision loss. However, eye care professionals can try different therapies to stop further vision loss. You should remember that the therapies described below are not a cure. The condition may progress even with treatment.
- Injections. One option to slow the progression of wet AMD is to inject drugs into your eye. With wet AMD, abnormally high levels of vascular endothelial growth factor (VEGF) are secreted in your eyes. This substance promotes the growth of new abnormal blood vessels. The anti-VEGF injection therapy blocks its effects. If you get this treatment, you may need multiple injections. Your eye care professional may give them monthly. Before each injection, your eye care professional will numb your eye and clean it with antiseptics. To prevent the risk of infection, a doctor may prescribe antibiotic drops.
- Photodynamic therapy. This technique involves laser treatment of select areas of the retina. First, a drug called verteporfin will be injected into a vein in your arm. The drug travels through the blood vessels in your body, including any new, abnormal blood vessels in your eye. Your eye care professional then shines a laser beam into your eye to activate the drug in the blood vessels. Once activated, the drug destroys the new blood vessels and slows the rate of vision loss. This procedure takes about 20 minutes.
- Laser surgery. Eye care professionals sometimes treat certain cases of wet AMD with laser surgery, though this is less common than other treatments. This treatment is performed in a doctor’s office or eye clinic. It involves aiming an intense beam of light at the new blood vessels in your eyes to destroy them. However, laser treatment also may destroy some surrounding healthy tissue and cause more blurred vision.
What is advanced AMD?
Both the wet form and the advanced dry form are considered advanced AMD. It can occur in the same eye or an eye may have just one form or the other. In most cases, only advanced AMD can cause vision loss.
People who have advanced AMD in one eye are at especially high risk of developing advanced AMD in the other eye.
However, research has shown that high doses of vitamins and mineral supplements may slow the progression of intermediate AMD to the more advanced stage.
A note about the AREDS formulation
Researchers stress that the AREDS formulation is not a cure. It will not restore vision already lost from the condition. But it may delay the onset of advanced AMD. It also may help people who are at a high risk of developing advanced AMD keep their remaining vision.
Loss of Vision
Coping with AMD and vision loss can be a traumatic experience. This is especially true of those who have just begun to lose their vision or have low vision. Having low vision means that even with regular glasses, contact lenses, medicine, or surgery, people find everyday tasks difficult to do. Reading the mail, shopping, cooking, seeing the TV, and writing can all seem challenging.
However, help is available. You may not be able to restore your vision, but low vision services can help you make the most of what is remaining. You can continue enjoying friends, family, hobbies, and other interests just as you always have. The key is not delaying use of these services.
Cornea and Cataracts Specialty Center has a trained low vision optometrist that provides a low vision exam for those that are interested in using daily devices that can work best for you.