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Diabetes and Your Eyes
Most people with diabetes know that their diabetes can affect their eyes. Few with diabetes have a meaningful understanding of how serious diabetic eye disease can be and how important it is to get yearly eye exams.
Diabetes is the leading cause of blindness in working age Americans (20-65yo). The CDC estimates that between 12,000 and 24,00 people in the United States develop legal blindness due to diabetes each year. The number who have very poor vision is significantly higher.
In a perfect world, all blindness from diabetes would be preventable. If everyone who developed diabetes knew they had diabetes shortly after they developed it, and everyone could achieve normal blood sugar levels, then there would be no diabetic eye disease. Unfortunately, many don't know they have diabetes until they have been affected for several years. Furthermore, many don't work hard enough at controlling their sugars and others find it impractical to normalize their sugar levels.
Eventually many diabetics develop Background Retinopathy. This is the presence of small areas of bleeding, and leakage from blood vessels inside of the eye. If there is no macular edema, vision is usually good.
-At this stage closer monitoring is required and examinations may be scheduled more frequently than yearly.
A common instrument that we use in diabetics is Ocular Coherence Tomography (OCT for short.) This is a state of the art way of looking at the retina. With this test a scanning laser is used to get an incredibly detailed cross-sectional image of the retina. It is the most sensitive way to identify leakage that might lead to Macular Edema.
Retinopathy can cause the tiny blood vessels in the eye to leak. This results in tiny amounts of fluid in the retina. If the fluid leaks into the macula there is a gradual blurring of vision that even glasses or contact lenses can’t help.
If vision has already been affected: A series of injections will need to be done to the eye over several months. These aren't very painful, and are much better tolerated than you would imagine. Over time the injections become fewer, and eventually can be stopped.
If the central vision is not affected: -A special study (a Fluorescein angiogram) is performed to identify the leaky blood vessels. Laser is then gently applied to the sources of leakage” to cauterize them” allowing the fluid to gradually absorb.
Retina: This is the thin inner lining of the eye. This is responsible for turning the light one sees into signals the brain can understand.
Macula: This is the most important part of the retina. Although it is tiny (less than ¼ of and inch) it is responsible for all detailed vision (reading, recognizing faces etc.)
Crystalline lens: This is the lens inside of the eye that allows one to change focus between distant and near objects.
Vitreous humor: This is the clear gel that fills the large compartment in your eye.
Newly diagnosed Diabetes
Diabetic eye damage is sometimes present at the time of diagnosis. This is especially true if the symptoms of diabetes were present for some time before diagnosis.
-In the newly diagnosed Diabetic it is important to receive yearly examinations of the retina through a dilated pupil.
Refractive Error Shifts: Many diabetics notice changes in their vision either before diagnosis, or shortly after treatment is started. When the sugars are elevated above 200, the crystalline lens swells. This changes its power. Thus, vision that was previously good (either with or without glasses) will become blurry. Some people have had high sugars that went undetected for a while. These individuals may have had good vision before the diabetes was diagnosed, only to develop blurry vision when blood sugars become normal.
These changes in focusing can have a variety of effects. Typically, the shift makes you more nearsighted (things at near are clearer than things far away,) but it can be in the plus direction (distance and near both become blurrier.) Regardless of the direction of this change, once stabilized this can be improved with new glasses or contact lenses. This does not represent permanent damage to the eyes.
It takes time for the focusing state of the eye to stabilize enough to be evaluated for glasses. Ideally you should have two weeks of sugars consistently less than 200 prior to being checked for glasses or contact lenses.
The most important way that diabetes damages vision is through changes in the retina known as Diabetic Retinopathy. These are a few of the common terms used to describe Diabetic Retinopathy:
-Background Retinopathy (Nonproliferative Diabetic Retinopathy)
-Neovascularization (Proliferative Diabetic Retinopathy)
-Each of these has different consequences for the affected eye.
A small percentage of diabetics develop new vessels over their retina. These new vessels are known as “neovascularization.” These vessels are a serious finding, because they are fragile and tend to bleed. With time, they can even pull the retina off the eye wall, resulting in total blindness.
-At this point an intensive laser treatment known as Panretinal Photocoagulation is done. This treatment is often done in 2 or more sessions. This usually results in regression of the vessels. If there is blood in the eye caused by the blood vessels it is gradually absorbed by the body.
The neovascularization that forms often will bleed resulting in a Vitreous Hemorrhage, this is blood in the clear gel-like substance that fills the inside of the eye. If there is only a small amount of blood you will see dark floaters. Large bleeds can result in the temporary loss of useful vision in the affected eye.
Laser surgery and injections are used to shrink the abnormal blood vessels and reduce the risk of bleeding. The body will usually absorb blood but that can take months. If the blood does not clear in a reasonable time, or if a retinal detachment is detected you will be referred to a Vitreoretinal specialist to get a vitrectomy. A vitrectomy is a surgery to remove all of the blood-stained gel within your eye.
This occurs when the small blood vessels that nourish your macula close permanently. Vision blurs and blind spots form because the macula no longer receives sufficient blood supply to work properly. Unfortunately, there are no effective treatments for macular ischemia.
What can I do to prevent Diabetic Retinopathy?
Science has shown that good control of your blood sugars can delay the onset, and slow the progression of Diabetic Retinopathy. Follow your primary care doctor’s instructions carefully in regards to diet, medication and exercise.
-You should also be sure to come in yearly for dilated examinations.
-If you notice a change in your vision you should let us know as soon as possible.
Are their risks to the treatments for Diabetic Retinopathy?
Like all medical treatments the treatments for Diabetic Retinopathy has risks, and can even cause blindness. Numerous studies have been done on people just like you with Retinopathy. These studies show that the benefits of treatments far out way letting the Diabetes slowly blind you. The different treatments have different risks that will be discussed if you need them.Type your paragraph here.