What you need to know about diabetic eye disease

How’s your vision? If you have diabetes, you may want to be extra vigilant about the health of your eyes.

Diabetic eye disease is a leading cause of blindness, according to the National Eye Institute (NEI). Among the various types of diabetic eye disease, which include glaucoma, cataracts, and diabetic macular edema, diabetic retinopathy is the most common cause of vision loss among people with diabetes. 

“People think of diabetes as affecting their blood sugar levels, but they don’t always think of it affecting their eyes,” notes ophthalmologist Rahul Khurana, MD, a clinical spokesperson for the American Academy of Ophthalmology (AAO). But it’s important that they do as early detection and timely treatment can greatly reduce the risk of severe vision loss.

November is National Diabetes Month and National Diabetic Eye Disease Awareness Month. So, this time of year marks a great opportunity for you to learn more about how diabetes can affect your eye health. You can learn more about conditions like diabetic retinopathy and how you may be able to prevent vision problems or severe vision loss from developing.

What is diabetic retinopathy?

Diabetic retinopathy is a condition that develops as a result of damage to the tiny blood vessels of the retina, which is the thin layer of tissue at the back of the eye near the optic nerve.

According to the Centers for Disease Control and Prevention (CDC), diabetic retinopathy is the “most common cause of vision impairment and blindness among working-age adults in the United States.” Nearly 8 million adults have diabetic retinopathy, and that number is expected to grow. The World Health Organization also reports that diabetes retinopathy causes nearly 3% of vision loss worldwide.

 In a healthy eye, the retina receives light from the lens of the eye, converts that light into signals and sends those signals to the brain. That’s how you see.

 But if you have diabetes and your blood glucose levels tend to be too high, your eyes may pay the price. When blood sugar levels remain elevated over time, they can damage your blood vessels—that includes the tiny blood vessels in your eyes. As a result, those blood vessels may begin to swell or rupture. Some begin to leak fluid into your retina. Your body may respond by trying to grow new blood vessels, but that can cause new problems to develop. Eventually, you may lose the ability to see.

 There are two main types of diabetic retinopathy: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).  

Nonproliferative diabetic retinopathy

Nonproliferative diabetic retinopathy is the early stage of this disease. You might not even notice any symptoms during this stage, although some people report some blurriness.  

Some experts further divide nonproliferative retinopathy into three stages. Here’s what happens during those stages:

• Mild nonproliferative retinopathy: During this stage, capillary walls begin to weaken, causing microaneurysms to develop.
• Moderate nonproliferative retinopathy: The microaneurysms begin to rupture, causing tiny hemorrhages in the retina. The weakened blood vessels also leak or weep fluid into the retina. The leakage can make part of the retina swell. Some of the blood vessels become blocked, reducing the blood supply to the retina.
• Severe nonproliferative retinopathy: More ruptures occur, and more blood vessels become blocked, further cutting off the blood supply to the retina.

Proliferative diabetic retinopathy

Proliferative diabetic retinopathy is the more advanced form of diabetic retinopathy.

When you develop this form, your retina begins growing new blood vessels, a process known as neovascularization, according to the AAO. Those new blood vessels tend to be very fragile, so they often break open and bleed into the vitreous, the gel-like substance in the middle of your eye. When this happens, you might notice some small specks or lines floating across your field of vision. These floaters can cloud or block your vision.

However, that’s not all that can happen if you have PDR. Scar tissue can form on those new blood vessels, which can lead to detachment of the retina. The retina is pulled out of its normal position at the back of your eye, so your retinal cells don’t get their usual supply of oxygen from the blood vessels. The longer it’s left untreated, the more likely that this retinal detachment can lead to permanent vision loss.

How can you tell if diabetes is affecting your eyes?

In the early stages of diabetic retinopathy, you might be blissfully unaware that anything is wrong. Your vision might seem totally normal.

But, you could be in the early stages of diabetic retinopathy without realizing it. That’s why regular comprehensive eye exams are so critical: The only way you would know is for your eye doctor to detect the signs of damage during a dilated eye exam. 

“Just because you think you’re fine, don’t risk losing your vision and developing blindness,” warns Amir Moarefi, MD, MS, an ophthalmologist in Long Beach, California.

The symptoms of diabetic retinopathy typically start with blurred vision. According to the AAO, other symptoms, as the disease progresses, can include:

• Floaters or spots in your vision
• A dark area in your central vision
• Trouble seeing at night
• Colors look faded or washed out
• Vision changes from blurry to clear

If left untreated, diabetic retinopathy can also lead to other eye conditions, such as a form of glaucoma known as neovascular glaucoma. 

Plus, about half of all people with diabetic retinopathy go on to develop a condition diabetic macular edema (DME). With this condition, part of your retina called the macula begins to swell as a result of all the fluid leaking from blood vessels. This can cause blurry vision. 

RELATED: 10 early signs of diabetes and when to see a healthcare provider

Who develops diabetic retinopathy? 

Anyone with diabetes can develop diabetic retinopathy. It doesn’t matter if you have Type 1 diabetes or Type 2 diabetes. But you also must consider how long you’ve had diabetes. 

“The longer you have diabetes, the higher risk you have of developing diabetic retinopathy over time,” Dr. Khurana says.

That’s because over time, high blood sugar levels can cause damage to those tiny blood vessels in your eye. The risk is greater if you’ve had trouble managing your blood sugar levels and keeping them within your target range.

There are also other risk factors for diabetic retinopathy, including:

• Race: African American and Hispanic people seem to have a higher risk for developing diabetic retinopathy.
• Family history: Research suggests that a family history of diabetic retinopathy may increase your odds of developing it, too.
• Pregnancy: If you develop gestational diabetes when you are pregnant, your chances of developing diabetes later in life increase—and so do your chances of developing diabetic retinopathy.
• Other medical conditions: If you have high cholesterol or high blood pressure, you’re at increased risk for developing diabetic retinopathy.

Can diabetic eye damage be reversed?

Especially in the early stages, diabetic retinopathy is treatable.

“Even if you are losing vision from diabetic retinopathy, we now have a whole new set of options to manage it,” explains Dr. Khurana. “So, it’s even more important to see your ophthalmologist when you have diabetes.”

The diabetic retinopathy treatment options include:

• Tighter blood sugar control: Prevent the damage from occurring to the blood vessels in your eye, and you may not need additional treatment. You can talk to your endocrinologist if you need help with this task.
• Medication: Your eye doctor may suggest medication in the form of steroids or anti-VGEF treatments. Anti-VGEF treatments are injections of medicine designed to inhibit a protein that your cells produce called vascular endothelial growth factor, which promotes blood vessel growth. The injections can slow or stop abnormal blood vessel growth that may be affecting or reducing your vision. The three main anti-VGEF medications are Avastin, Lucentis, and Eylea.
• Laser surgery: If you have more advanced, or proliferative, diabetic retinopathy, you may be a candidate for a type of laser treatment called scatter laser surgery, also known as panretinal photocoagulation. Essentially, it removes the peripheral edges of the retina, eliminating some of those blood vessels that are causing vision loss.
• Vitrectomy: According to the AAO, this type of surgery may be appropriate for a person with an advanced form of diabetic retinopathy. It involves removing some of the vitreous gel and leaking blood vessels in the back of the eye (and sometimes scar tissue). Removing those substances allows light to once again properly focus on the retina so you can see.

As with any kind of treatment, there are upsides and downsides of the various treatment options for diabetic retinopathy.
For example, panretinal photocoagulation can be very effective, Dr. Moarefi says, but you are basically sacrificing your peripheral vision in order to preserve your central vision. And that can affect your ability to carry out some of your activities of daily living, including walking and driving.

At a certain point, if the diabetic retinopathy has reached an advanced stage, it may not be possible to reverse the damage, Dr. Khurana says. At that point, your eye doctor will emphasize preserving the vision that you still have—and halting any further damage from occurring.

How can people with diabetes prevent eye problems?

“The only way to prevent the damage is to really take it seriously and be proactive with your screening,” Dr. Moarefi explains.

That means that anyone with diabetes should schedule a comprehensive dilated eye exam every year, so your eye doctor can assess the health of your retina and look for signs of impending damage. Your doctor will administer eye drops that make your pupils dilate, or widen, to give a better view of the retina.

If your eye doctor suspects you have severe diabetic retinopathy, a diagnostic test called a fluorescein angiogram may also be warranted. Fluorescein angiography (FA) involves injecting a colored dye into your veins, then using a camera to take pictures of those blood vessels in the retina when the dye passes through them.

Don’t blow off your eye examination, even if you haven’t noticed any symptoms.

“Dedicate that one hour of your year in the beginning to make sure you don’t suffer a lifetime of blindness or visual and physical impairment,” Dr. Moarefi says.

You can also work to prevent diabetic retinopathy from developing by keeping your blood sugar under good control. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), if you focus on managing your blood sugar levels, you may be able to avoid having chronically elevated levels that can damage those blood vessels in your eyes.  

But there are a couple of other health conditions that you should also pay close attention to managing: your blood pressure and your cholesterol levels. Managing these three conditions, which the NIDDK calls “the diabetes ABCs” can help you stay healthy and keep your eyes healthy, too.

Even if you get an annual dilated eye exam and are vigilant about keeping your blood sugar levels within your target range, watch out for any changes to your vision. If you start to notice some unusual symptoms, don’t ignore them.

For example, if you notice a burst of new floaters or flashes of light, this could be a sign of retinal detachment, which can occur in very advanced cases of diabetic retinopathy. It’s a very serious condition that can lead to permanent vision loss if not addressed quickly.