What is Diabetic Eye Disease?

Diabetic Eye Disease describes a number of changes that can occur within the eyes as a result of diabetes. These can occur in any type of diabetes (Type 1, Type 2, gestational, etc). Diabetes is one of the largest causes of eye problems in the US. It’s also one of the biggest culprits of blindness in young adults. Since diabetes is a vascular disease, it makes sense that it affects those organs with delicate, highly vascularized tissues. Examples include kidneys and eyes as well as fingers and toes.

What your doctor sees: This is an example of diabetic changes in the eye. The red arrow points to blots of blood (from poorly functioning vessels; these little spots behave like bruises and heal over time). The gray arrow points to exudates (residue left behind after blots of blood heal; it is the lipids in your blood and show your doctor where damage was in the past.)

Diabetic retinopathy

Diabetic retinopathy describes damage to the blood vessels inside of the eyes, specifically to the retina. (Retinopathy translates to disease of the retina.) It is broken down into two main categories, non-proliferative (more mild) and proliferative (usually very severe). In many cases, patients do not experience any symptoms of this disease. Without annual eye exams they may not know they are having any problems.

Non-proliferative diabetic retinopathy (NPDR): In early stages of damage, the blood vessels in the back of the eye become leaky as a result of high blood sugar. This allows small amounts of blood and protein to escape from the vessels and sit on top of or between the layers of the retina. Later stages allow significant leakage and changes to the structure of the blood vessels. If the underlying condition is not addressed and blood sugars are allowed to remain too high, the disease will progress to the proliferative stage.

Proliferative diabetic retinopathy (PDR): In the proliferative form of the disease, the cumulative blood leakage and retinal damage caused by earlier disease encourages the formation of new blood vessels inside the eye. These new vessels can develop between layers of the retina, on top of the retina, or even on the iris (colored structure) located toward the front of the eye. These new blood vessels are very fragile, which makes them a big source of concern inside the eyes. These vessels can leak very large amounts of blood inside the eyes, and can also lead to retinal detachment, retinal cell death, or even a very rapid form of glaucoma. All of these situations can lead to permanent and total blindness.

Macular edema: This describes swelling that can occur in a patient’s central vision, and can be seen in combination with either NPDR or PDR. This can be sight threatening and will often require treatment.

Diabetic cataract

While everyone slowly develops age-related cataracts (if they live long enough), diabetes causes their rapid onset even in young people! This often requires surgical treatment to restore vision. Cataract surgery in the 40s is not unheard of for a diabetic patient with poor blood sugar control.

Other issues caused by diabetes:

Delayed healing. If you develop an injury or infection in your eye, it can take significantly longer to heal than for someone without diabetes. This will require more careful monitoring by one of our doctors.
Refractive shifts that change your prescription. If blood sugars are allowed to fluctuate significantly (i.e. when diabetes is undiagnosed or not well controlled) it is possible for your vision to shift dramatically day to day or even hour to hour. This occurs as a result of sugar levels causing the crystalline lens inside your eye (the structure that helps with focusing) to swell or shrink.
Problems with eye movement or double vision. Diabetes can sometimes cause nerve palsies; these are usually temporary paralyses of the muscles that control eye movement and eye position. This can cause you to appear as though you have a lazy eye when you never have before, and can cause you to see double. This needs to be evaluated and managed by your optometrist to ensure other, more serious issues, are the cause.
Loss of corneal sensation. just like diabetes can cause peripheral neuropathy (e.g. loss of sensation in the feet and toes), it can cause a loss of sensation in the clear front tissue of your eye. This means you may not even notice, or not notice as quickly, an injury or infection in your eye.

Do you think you have diabetic eye disease?

People with diabetic eye disease can experience:

Large fluctuations in vision (one hour your vision is fine, and later that day, everything is very blurry)
Blurry spots in your vision
A sudden large dark cloud in your vision
Areas of vision that are suddenly missing
A new eye turn or new double vision

If you are experiencing any of these, even if you have not been diagnosed with diabetes, we recommend you schedule an exam. Often a diagnosis of diabetes is first made after an eye doctor finds signs of diabetic eye disease.

If you have any form of diabetes, we recommend that you have your eyes checked annually. If any type of diabetic eye disease is found, we will often recommend more frequent visits.

Moderate stage of diabetic retinopathy: the grey arrow points to cotton wool spots (area of swelling), the red arrow points toward more blot hemorrhages.

Notice the look of the blood vessels. Compare it to the picture at the top of this article. These are much more bent and make lots of sharp turns; these are called tortuous blood vessels. This shows there is stress on the blood vessels making them take on a longer path and become more winding; it’s very common with diabetes or hypertension.

What causes it?

High blood sugar levels can impact the cells that make up your blood vessel walls, causing them to separate slightly. This allows blood or protein from the bloodstream to leak out of the vessel and sit inside the eye. This leakage of blood can interfere with the normal process of nutrient transfer and delivery to cells in the eye. These cells become “starved” and send out signal molecules indicating they need nutrients. In response, the body can develop whole new blood vessels, usually in areas where blood vessels are not normally found.

These new blood vessels are very fragile and can break easily, leading to even larger amounts of blood being released into the eye, or can lead to retinal detachments. If new blood vessels grow from the iris into the anterior chamber, a very rapid form of glaucoma can develop. (This area is referred to as “the angle”; it is an area where the iris and cornea meet, and fluid drains to maintain a consistent eye pressure)

What to expect at the doctor’s visit/how it’s diagnosed?

At our office, your doctor will perform a thorough evaluation of your vision, prescription, eye movements, and more. They will dilate your eyes, allowing them to see out to the edges of your retina, looking for signs of diabetic retinopathy, retinal detachments, and more. Frequently they will take retinal photos to document the level and extent of damage present (if any). Some changes can be very subtle, so our doctors strongly recommend screening photos even if no damage is uncovered as a benchmark to compare you to at your next visit. They may also perform an OCT or a detailed light scan of the retina, especially if macula edema is suspected.

How is it treated?

One of the best ways to treat diabetic eye disease in many stages (especially early on) is to establish good, (or tight) control over the underlying problem – the diabetes! We will work with you and your primary care doctor and/or endocrinologist to ensure that your daily blood sugar levels and A1C are at optimal levels. We communicate with your other providers after each visit you have in our office, and we can help counsel you on achieving healthy daily habits. Obtaining and maintaining good blood sugar control can minimize daily prescription changes and can reverse more mild levels of retinopathy!

As diabetic retinopathy becomes more advanced or as macular edema develops, treatment by an ophthalmologist may become necessary. These treatments may involve lasers, injected medications, or a combination of those. The goal of these treatments is to try to preserve the healthy retinal tissue that you have left, and vision improvement may not be guaranteed. In the most severe forms of diabetic retinopathy, invasive surgeries may be required to repair retinal detachments, lower eye pressure (to minimize damage from glaucoma), and more.

Diabetic cataracts can cause severe vision impairment, at which point they need to be removed surgically. This surgery is the same one that is performed for normal age-related cataracts. However, you will need to be more closely monitored due to the slower wound healing that occurs in diabetes. If you are young and develop a cataract that must be removed, you may end up needing bifocal glasses after the procedure, as you will no longer have the natural ability to shift your focus from far away to up close.

We’re here to help!

Diabetic eye issues can be scary and cause life altering changes to your vision. Early detection is key to maintaining healthy vision and functioning to your fullest potential. If you have diabetes, but haven’t been to an eye doctor in a while, we encourage you to make an appointment. Knowing where you are right now, helps you to understand what is happening, and allows you to adapt to what might happen next. We want to be there to help you understand where you are no matter what’s happening in your eyes.