Vision Health Part 2: Diabetic Retinopathy
"The fact that it's irreversible, doesn't mean that it's not manageable or preventable."
Dr. Keller Wortham, MD, is back for part two of his four-part series on vision health and things that can cause vision loss. In part one, we discussed the components of the eye and how it works.
Today, we'll be talking about some of the ways that vision can go wrong, starting with Diabetic Retinopathy — the number one cause of irreversible blindness worldwide. We'll learn how to recognize it, what we can do to treat it, and most important of all, steps we can take to prevent it. Stay tuned for this important information!
- 01:39: Diabetic Retinopathy
- 03:29: What Causes Retinal Disease
- 04:49: Getting a Look at the Retina
- 06:17: How to Know if You’re Suffering from Diabetic Retinopathy
- 07:44: Why Does Diabetes Lead to Retinopathy?
- 11:42: Risk Factors for Diabetic Retinopathy
- 14:10: Treating Diabetic Retinopathy
- 16:11: Preventing Diabetic Retinopathy
- 17:35: Wrap-Up
As we discussed in part one, the eye is an amazing contraption; it’s extremely complex, which means there are many elements that can go wrong. Over the next three parts of the series, we’ll take a closer look at several of those, starting with:
As the first word indicates, this condition involves diabetes. So if you have diabetes or you know some with diabetes, this information is especially important. The good news is, the fact that it's irreversible, doesn't mean that it's not manageable or preventable.
So what is diabetic retinopathy? Retinopathy refers back to a word that we talked about in part one: the retina. The retina, as we discussed, is a very important tissue layer at the back of the eye. You can think of it as the film in the back of a camera, or the screen onto which light from a projector is projected. Its function is to basically take the light that's coming into the eye, and then translate it through a very sophisticated group of cells and nerves and blood vessels, into an image that can be projected back to your brain. So, the retina in the back of the eye is a very crucial part of our vision. And retinopathy is just the scientific word to describe a disease of the retina.
What Causes Retinal Disease
So, what is basically the cause for disease of the retina? The retina contains very specialized cells, called rods and cones, which take the light that comes in through our eyes and sends it back to the brain. It needs a very specialized system of tiny blood vessels at the back of the eye to give nutrients to all these important nerves and cells. And this microvascular and neural complex, this thin tissue in the back of the eye, is very delicate. This makes it very susceptible to disease.
Getting a Look at the Retina
The retina is at the back of the eye and although it's so important for us to see, it's actually very difficult for the doctor to see it. If you go to the doctor, they’ll usually look at your retina, especially if you’re diabetic or have a history of retinal disease. But to see the retina in the back of your eye, they have to shine a light in your eye. You may remember in part one we discussed that there's a pupil in the front of your eye, which constricts when light is shined into it. So, it makes it a very delicate process to shine light into the eye with a special magnifying lens to see the back of the eye where the retina exists without making the pupil close and block the view.
That’s why doctors will often send patients to an ophthalmologist — a doctor specializing in eye health. The opthamologist can use a special technique of dilating the eyes, which causes the iris to open up, making the pupil very large, allowing them a larger area through which to see the retina when they shine the light into the back of your eye. They can get a very good look with a magnifying lens.
How to Know if You’re Suffering from Diabetic Retinopathy
Your first step in diagnosing this condition is to go to an ophthalmologist and get screened, especially if you have diabetes. The opthamologist can observe changes at the back of the eye that might indicate a problem. This is important to do because the symptoms of diabetic retinopathy are often extremely subtle until the condition is more advanced. And when it advances, you lose vision that is very hard to recuperate. So, you'll want to make sure that you're checking frequently to stop the progression before you experience irreversible vision loss.
Some of the symptoms that you can get eventually, as the condition progresses, include blurred vision, or double vision in a particular eye, as well as floaters — small spots that float across your field of vision. You might start to see shadows, and experience difficulty reading. But these symptoms come along after the disease has begun advancing, so you want to catch it early.
Why Does Diabetes Lead to Retinopathy?
Keep in mind that diabetes is an issue with blood sugar, and high levels of blood sugar are very damaging to all sorts of areas of the body, especially tiny blood vessels. As we discussed above, you have very tiny blood vessels on the retina which bring nutrients to that very specialized tissue. If there’s too much sugar coursing through those blood vessels, they can start to get damaged and may even become clogged. If the blood vessels that provide nourishment to the retina become damaged or clogged, they start to leak, leading to fluid retention in the retina. This condition is called diabetic macular edema.
Diabetic Macular Edema
There's a very important central area in the back of the retina called the macula, which enables us to see faces and bright colors, and brings things into their sharpest focus. There are a lot of blood vessels there as well, because we need a lot of nutrients for those specialized cells.
As sugar starts to damage the blood vessels in a certain area and those blood vessels leak, swelling edema occurs, and that swelling is really damaging to the retina. It releases certain growth factors that start to cause blood vessels to first break and then to grow abnormally. Now you've got abnormal blood vessels growing in an area where what you need is tiny, fine vessels, but these are larger and more prone to bleeding. When this happens, it’s called proliferative diabetic retinopathy. Proliferative means “growing”.
So essentially, you have high blood sugar, which has damaged the little blood vessels. The blood vessels then start to release chemicals which cause swelling and larger damaging blood vessels to grow, and it creates a vicious cycle. If that continues, you can start to really damage that very important macula in the back of your eye.
When you start to lose the function of the macula, your vision really suffers. In fact, you may have heard the term “macular degeneration”. That is a really dangerous and progressive form of blindness, which you want to avoid at all costs.
As the macula gets swollen and the blood vessels break, they can scar. If you have ever gotten a scar anywhere, you know that scar tissue is tougher than healthy tissue, it contracts, and sometimes you can see it pulling against the rest of your skin. The same thing happens in the retina of your eye — so that scar tissue can start to pull on the retina. If it pulls too hard, it can actually start to lift the retina off of that vascular tissue underneath; this is called retinal detachment. It can happen very quickly and is extremely serious, because you're taking that screen off of the blood supply underneath. When retinal detachment occurs, you will often feel a very sudden blackening of a visual field, almost like somebody is drawing a curtain across your eye. If this happens, get your doctor immediately because you will need to be treated to help reverse that detachment, or you'll be left with permanent blindness in that particular area.
Risk Factors for Diabetic Retinopathy
Of course diabetes is the main risk, but it gets a little more specific than that. There are a couple of factors that come into play:
- How long have you had diabetes? The longer you've had diabetes, whether type 1 or type 2, the more cumulative damage to the blood vessels has occurred, and the higher your risk of developing diabetic retinopathy is.
- How well controlled are your blood sugars? If you have really good control of your blood sugar, that’s great. But if your blood sugars are out of control and going high, then that sugar damage is happening to those blood vessels in the back of your eye and your risk is substantially elevated.
High Blood Pressure
Again, we’re talking about tiny, delicate blood vessels, which should not have a lot of blood pressure coursing through them.
High cholesterol is inflammatory to the blood vessels. When there’s a lot of inflammation and a lot of pressure going through the system, that could damage those tiny blood vessels that your retina needs.
If you go to an ophthalmologist and they do a dilated eye exam and come to the conclusion that you're at risk or showing signs of diabetic retinopathy, then there are a few things you will want to do.
The first one is to do a more extensive evaluation to determine exactly where your risk is. There are a couple of ways to do this:
One is called Optical Coherence Tomography, and involves looking at the layers of the eye and more specifically at how much damage of the retina they can actually visualize. Another is called a Fluorescein Angiography. For this, they use a very special dye and course it through the tiny arteries of the retina in order to map out how those arteries look, and whether they are damaged, nicked, or bleeding.
These are a few techniques to determine how healthy the retina looks, how the macula looks, and how damaged the blood vessels look. Once they've assessed the damage, then it's time to act.
Treating Diabetic Retinopathy
Keep in mind that the best thing to do is always to control the underlying conditions, like high blood sugar, blood pressure, and cholesterol. If you’re keeping these things in check, you're going to really reduce the effect that diabetes could have on your eyes.
Additionally, you’ll want to talk to your doctor about other techniques you might want to implement. One option that’s available is an intravenous injection. This would involve injecting something that blocks the activity of a certain growth factor that the broken veins produce — vascular endothelial growth factor — into the vitreous humor of the eye. Those injections to your eye can block the proliferative aspect of the chemical being produced by damaged blood vessels.
Laser therapy is another option to help restore or reduce the progress of this blindness. They can use lasers not only to try to control the size of some of those larger blood vessels that you don't want there, but also maybe to weld the retina to the back of the tissue in order to prevent detachment. So if there has been a lot of damage, or many tiny little tears, they could use a laser to essentially cauterize or weld that retina to the framework underneath it.
If your disease is fairly progressed, or if you have already experienced retinal detachment, sometimes they do have to do a more involved surgery.
Again, talk with your doctor once they've assessed the damage and go over what steps are best for you.
Preventing Diabetic Retinopathy
Prevention is always the best treatment. If you have diabetes, take steps to keep it controlled. If you’re prediabetic, or you're just trying to keep your retina healthy in general, then make sure you practice lifestyle measures that can help prevent diabetes from developing.
Stay Active. Exercise is really great at lowering blood pressure, lowering cholesterol, and lowering blood sugar.
Eat a healthy diet. Make sure you're getting lots of antioxidants. Healthy antioxidants are great for reducing inflammation, and reducing vascular disease. If you don't think you get enough healthy fruits and vegetables in your diet, take a multivitamin, like Smarter Nutrition’s Smarter Multi. It's chock-full of very, very essential vitamins and minerals that you need to help keep your body healthy. So make sure you're getting it from your diet or supplementing with a multivitamin.
- Stop smoking. Smoking is absolutely terrible for your retina. It’s very inflammatory for the tiny blood vessels in your body, including those tiny blood vessels in your eyes.
We hope this has been helpful. If you do have diabetes or you know someone who does, please take this information seriously. Get screened or talk to your loved one about getting screened for diabetic retinopathy, and take these crucial steps to prevent the progress of this irreversible kind of blindness.
Once the vision is gone, it's really hard to get it back. But just because it's irreversible, that doesn't mean that you can't manage it, and it doesn't mean that you can't prevent the progress. However, there ARE some reversible types of vision problems, which we’ll discuss in part three.