Diabetic retinopathy is the leading cause of blindness in adults, occurring in 29.1 million individuals. It can occur in one or both of the eyes, and if not treated can result in permanent vision loss. Diabetes symptoms can vary from normal vision to complete vision loss. Often there are no symptoms in the early stages of the disease, nor is there any pain. Blurred vision may occur as the disease progresses. The earlier you receive treatment, the more likely treatment will be effective and vision can be maintained.
Type one diabetic patients are classified as being insulin dependent. Classically these patients are of regular weight and usually younger in age. These patients will likely not show signs or symptoms of vision issues until after puberty (around 10 years of age) or not until after about 5 years from when they are diagnosed. It has been noted that 97% of patients with type one will have some form of retinopathy after 15 yrs from original diagnosis.
Type two diabetic patients account for 90-95% of all cases. Around 20% of type two patients will have retinopathy immediately when they are diagnosed. Of the patients who are asymptomatic at initial diagnosis, 10% have changes at 10 years, 40% after 15 years, and 60% after 20 years with diabetes. This type is associated with older age, obesity, physical inactivity, and occurring more in populations of African, Hispanic, Native, and Asian American decent.
During pregnancy, diabetes may also worsen or become diagnosed. Around 4% of pregnant women having diabetic issues before pregnancy will progress to the more severe stages. Of the patients who develop diabetes because of the pregnancy, 5-10% of patients become diabetic long term. Those who do not become diabetic at that time have a 20-50% chance of developing diabetes in a 5-10 year period. To protect vision, every pregnant woman with diabetes should have a comprehensive dilated eye exam as soon as possible.
Diabetic eye issues are detected during a dilated comprehensive eye exam. Drops are used to open the pupil (the round dark area in the center of your eye). This acts like a window for your doctor to observe the retina (the very back part of your eye) for changes. After the exam, your close-up vision may remain blurred for several hours. The purpose of the dilation in diabetic patients is to check for the following:
- Bleeding from leaking blood vessels.
- Deposits on the retina--signs of leaking blood vessels.
- Swelling of the macula (where you get your central vision)—signs of leaking of blood vessels.
- Areas of vessel re-growth from lack of blood flow. ( may occur in the back or front part of the eye)
- To note: Cataracts will usually present earlier in patients with diabetes as well
Stages of Diabetes
Diabetes will cause decreased circulation, vessel wall damage, blood vessel blockage, and poorly formed vessel growth. This sequence results in damage to important structures, and possible permanent vision loss. Diabetic retinopathy has four stages:
- Mild Non-proliferative Retinopathy. Excess sugar in the blood gets turned into alcohol, which damages the smaller blood vessels in the eyes and weakens the walls. Microaneurysms, the earliest signs of retinopathy, are an out pouching of the weak vessel walls. The walls then break, leading to hemorrhages, leakage of fluid or deposits causing obstructed vision.
- Moderate Retinopathy. As the disease progresses, more blood, fluid and deposits leak onto the retina. As this worsens, closure of the vessels occurs, decreasing oxygen and blood to important areas of the eye. This appears as subtle cotton balls in the retina. Changes in the appearance of the vessels may also occur.
- Severe Retinopathy. Even a greater amount of bleeding and leakage occurs. More blood vessels become blocked, depriving several areas of the retina from their blood supply. The retina sends signals to the body to grow new blood vessels for nourishment.
- Proliferative Retinopathy. The signals sent by the retina trigger the growth of blood vessels. The new vessels are thin, abnormally fragile, and poorly made. When interacted with, can break cause darkening to vision (or a vitreous hemorrhage), glaucoma, retinal detachments or even Pain can occur at this stage.
- Vitreous Hemorrhage: This is when the new faulty vessels interact with the gel inside of the eye, the vitreous, and break. These hemorrhages may take weeks to months to clear depending on the severity and location. The dense darkening of vision is a dramatic bleeding of the fragile vessels that have broken.
- Macular edema is the leading cause of visual impairment in patients presenting with diabetes. It is caused by fluid leakage or swelling into the macula, where we get our central vision. It can occur at any stage of diabetes and can be treated with laser.
To prevent progression of diabetic retinopathy, people with diabetes should control their levels of blood sugar, blood pressure, and blood cholesterol. Studies have shown that better control of blood sugar levels slows the progression of retinopathy and the need for surgery with the eyes. Other studies have also shown that controlling blood pressure and cholesterol can reduce the risk of vision loss.
Depending on the level of retinopathy you have will dictate when you need to be seen:
- Mild Retinopathy: usually yearly exams.
- Moderate Retinopathy: every 6 months
- Severe Retinopathy: every 3-4 months
- Proliferative indicates the need to see a retinal specialist. Severe and Proliferative patients will need some type of surgery and should be seen by a retinal specialist as directed
Proliferative retinopathy is treated with laser surgery and/or injections into the eye. The laser procedure is called Pan Retinal Photocoagulation. The laser treatment helps to decrease the flow to the faulty vessels and focus attention on the more important ones. Your doctor places 1,000 to 2,000 laser burns in the areas of the retina away from the macula, causing the abnormal blood vessels to shrink. Although you may notice some loss of your side vision, the treatment is meant to preserve as much central vision as possible.
Injections can be used to stop the fragile blood vessel growth and swelling inside your eyes. They can be used prior to the laser surgery to keep the vessels from leaking to prevent swelling, depending on the severity. Injections can also be used to decrease the swelling inside of the eyes.
In a vitrectomy, blood is removed from the center of your eye. If you have a lot of blood in the vitreous, you may need a vitrectomy to restore your sight prior to other procedurs being done. If you need vitrectomy in both eyes, they are usually done weeks apart.
Macular edema is treated with laser surgery as well. This procedure is called focal laser. Your doctor places up to several hundred small laser burns in the areas of retinal leakage. These burns slow the leakage of fluid or deposits.
Laser surgery and appropriate follow-up care can reduce the risk of blindness by 90 percent. However, laser surgery often cannot restore vision that has already been lost; it can only attempt to prevent the vision from getting worse. That is why finding diabetic retinopathy early is the best way to prevent vision loss.