Reducing Your Fear of Diabetic RetinopathyApr 18, 2022
Hi, it's Paul Coker here.
If you are anything like me then retinopathy (Diabetic eye disease) is one of the scariest complications to think about and talk about. Perhaps that is because it is so common? Perhaps it is because there is a culture of blame around it that if only you had managed your diabetes better this would not be happening to you? Perhapos it is because it always seems so comnplicated? It is also likely that is because losing the ability to see is a scary, scary thought.
There is so much confusion about what Retinopathy is, what if means and even how we might me putting ourselves at more risk of developing it. So, I invited Dr Becky Thomas to talk to us about the topic.
Becky is a senior research officer at Swansea University School of Medicine and she was one of my tutors when I did an MSc in Diabetes Practice. Becky’s specialty is Diabetic eye disease, and this blog accompanies the fabulous webinar that she did explaining Diabetic eye disease and Retinopathy. She will cover how it develops and a little bit about the screening processes, there will be a little discussion on how Retinopathy, muculopathy and Diabetic eye disease can be treated but Becky is not an ophthalmologist and she is the first person to tell us that treatment of eye diseases is not her strength. The main purpose of this bloig is to reduce any fear that you might have about your diabetes and how it might affect your eyes.
Over to You Becky
I first became interested in Diabetic Retinopathy began way back in 2003 when I was a retinal grader at the Welsh screening service. So I've got quite a lot of background in, in grading the images that we take of your eyes, what those scary letters that the screening send you mean, and how the screening and process works, especially in Wales.
If we are going to talk about Retinopathy, first we need to think about the retina
The retina goes across the whole of the back of the eye and it contains millions of light-sensitive cells (rods and cones) and other nerve cells that receive and organize visual information. Your retina sends this information to your brain through your optic nerve, enabling you to see.
When we examine your retina, the orange part in the diagram above . We really look at images on a tiny part of the retina and this is because these are the areas where if anything happens in these areas, then it, it becomes more immediately sight threatening.
Another important area to talk about is the optic disc here. This is also known as a blind spot and this is where all of the nerves, all of the blood vessels come from the brain into the eye. There's no vision here as, as it is, but it is an structure.
You get all of your central vision and fine focus from an area called the fova, which you can see in the picture. The area surrounding your fovea is called the macular. So that is one optic disc diameter all the way around.
I know this is all a bit technical but is a really important area when we start talking about maculopathy. So that's why I'm pointing that out and we will be coming back to it in a moment.
We all love to hate the eyedrops, so let’s talk about them.
The eyedrops are quite important for screening, because they they dilate the pupil, they they make it bigger, allowins more light inside it and that allows us to take multiple images of your eyes.
You could get the same effect by sitting in a dark room for 10 to 20 minutes, but that method would only allow us to take one image because your pupils does not stay dilated (bit) when the camera flash goes off. That means we would not be able to get a decent second image or take your other eye.
Retinopathy Technical Terms
Background Retinopathy (R1) & Microaneurysms
Background Retinopathy (sometimes called R1) describes the first changes that we can see in your eyes as a result of your Diabetes. This happens when tiny bulges, sometimes called microaneurysms, develop in the blood vessels, which may bleed slightly but do not usually affect your vision. It's a really wide category. You can have anything from a single microaneurysm, which is a small red blood spot all the way up to several hemorrhages.
Cotton Wool Spots
Cotton wool spots can develop as a result of Diabetic Retinopathy these are white patches which are ischemic, and that means that they are lacking in oxygen because the blood is leaking out, instead of being supplied all around the eye. Sometimes these are also called exudates and they are caused by fatty deposit lipids that are leaking out the blood vessels as well.
If You Get A Letter Saying You Have Background Retinopathy…
If you get a letter saying you have background Retinopathy the good news is that you know that it is not sight threatening at this stage. However you don’t know if you have one microaneurysm, several, or some minor bleeds and some exudates.
If we see this in you, because it is not sight threatening, we would only re-screen you in 12 months time. We would recommend really trying to concentrate on looking after your blood glucose levels, yes we know this is hard to do, your blood pressure and your lipids, because this really, can really make a big difference in delaying any of this Retinopathy from getting any worse
Pre-Proliferative Retinopathy (R2)
Pre-proliferative Retinopathy (sometimes called R2) happens when you have gone from those multiple hemorrhages (microaneurysms) and now there's a lot more hemorrhaging and cotton wool spots going on in this stage. So if you remember, those are the ischemic patches, meaning that they are not being supplied with oxygen, often because the blood is not getting through these small blocked vessels in the eye. We can sometimes see a characteristic pattern in the blood vessels that looks like a string of sausages; think of it as areas where all the meat is as the fat sections of the vein fat, and then where you twisted all the skin together, so the vein becomes thin and then it gets fat.
At this stage you might be referred to a specialist ophthalmology clinic for closer monitoring, but with current technologies you probably would not have any treatment. Again we would normally recommend really trying to concentrate on looking after your blood glucose levels, your blood pressure and your lipids, because this really, can really make a big difference in delaying any of this Retinopathy from getting any worse
Proliferative Retinopathy (R3)
Your eye needs lots of oxygen all of the time. So when the vessels in your eye become blocked as a result of your diabetes sometimes they will try to create a new blood vessel to bypass the blockage. This sounds like a great thing, but these vessels can cause problems because they are weak and leaky; meaning they can leak blood into the jelly like fluid inside of your eyes (the vitreous humour).
If these new vessels are seen close to the optic nerve (within a 1 optic disc diameter) then your are typically diagnosed with Proliferative Retinopathy (R3).
New Blood Vessels Forming & Their Treatment
Your ophthalmologist will normally look for new blood vessels forming in your eye (neovascularisation) and if necessary treat these new ‘leaky’ vessels by sealing them shut with a laser before they cause a significant bleed.
The laser therapy, sometimes called photo coagulation, can be used to seal leaking blood vessels closed. However careful judgement needs to be made on the best time to use the laser.
Ideally, we want to be using a laser to seal these leaking vessels just as they are starting to grow because less laser therapy is needed then. The laser itself is a destructive process, it's actually killing the parts of the retina that it touches. The aim is to stop that part of your eye from needing so much oxygen supply and that reduces the need to grow new, leaky vessels and that in turn reduces your risk of a significant bleed into your eye. However, we try to minimize the use of the laser as far as possible so that your vision is affected as little as possible.
If you do get a bleed into the eye then your ophthalmologist has to wait for the blood to be reabsorbed so that they can see what is happening in your eye and then they can work out the best way we can treat it. Treatment is often with a laser to seal the leaking vessels closed.
Maculopathy is graded separately from Retinopathy it can occur when you've just got background Retinopathy or when you've got pre proliferative or proliferative Retinopathy.
Maculopathy describes lesions that appear within that macular area of the eye, so that is a one disc diameter circle around you the optic nerve, any lesions occurring within this region would be thought of as maculopathy. We are really protective in screening when there is any suggestion of maculopathy because any issues in this area can be sight threatening.
Ophthalmologists can sometimes use a laser to make some holes in the retina in this region to help fluid drain away and reduce the swelling and sometimes they can use a special injection into the eye called anti-VEGF (Vascular Endothelial Growth Factor) is used or a combination of both. Your ophthalmologist will work out the best course of treatment for you if this becomes necessary.
Anti-VEGF therapy has great success and it actually helps to regress the new vessels as well. So that might mean that you need less laser therapy, but it is not for everybody and your ophthalmologist will work out if this is the best treatment for you.
Does a Referral to Ophthalmology Mean I Need Treatment?
Being being referred for Retinopathy doesn't necessarily mean you're going to laser therapy of anti-VEGF injections. It is just for those extra further tests that the ophthalmologist can do that we can't do in screening, because they have more expertise and some different equipment.
Sometimes you will be given the all clear and referred back to the normal eye screening service; this might even been done without you seeing the ophthalmologist and thisis because sometimes they can make an expert opinion based oupon the images they screening service supplies them with.
Optical Coherence Tomography (OCT)
In ophthalmology they sometimes use a special machine called an and Optical Coherence Tomography (OCT) camera, and that measures the thickness of the retina and it is used to see if there's any swelling, any fluid buildup within the retina, which would suggest that you might have maculopathy.
The results of this are used to determines whether or not there is any, need for treatment for maculopathy depending on how thick the swelling of the retina is.
The main message is if you are referred from screening into ophthalmology, it's to get extra tests rather than you need treatment we just being extra cautious
Risk of progression of Retinopathy
If you've got no Retinopathy in your eye, your chances of developing referable eye disease within the next 3 years is 1 in 15. That is quite a low risk that within the next three years that you're going develop a serious problem.
If you've got background Retinopathy in one eye, this risk increases to a 1 in 5 chance within the next 3 years.
If you've got background Retinopathy in both eyes then this reduces to a 1 in 4 chance that within the next three years that you might develop a referable level of Retinopathy.
So, once you've got background Retinopathy, your risk of progression is that much higher and what we want do is try and delay it from developing, for as long as possible.
Risk Factors For Diabetic Retinopathy
There are a lot of risk factors, but there are things that you can do to reduce your risks.
If you've got high blood glucose, high blood pressure or high cholesterol, then lowering these, can reduce your risk of developing Retinopathy. But, it doesn't reduce the risk to zero. There's still a chance that you could develop Retinopathy and that is why screening remains important.
Unfortunately you can't do anything about how long you've had your diabetes for, and some ethnic groups including individuals people from south Asian or Africa appear to have a genetic pre-disposition to developing Retinopathy.
You are at higher risk of developing Retinopathy when you become pregnant, this could be from the pregnancy hormone(s) and it could be from rapidly and aggressively reducing glucose levels to protect and maintain your pregnancy
There is some evidence to suggest that puberty might play a part, but it’s a bit ‘sketchy’ at the moment. I think it's probably something to do with the hormones around at that time and your genes.
Your genes do play a big part in your risk of developing Retinopathy because even if you have been managing your blood glucose forever, and you've never had a high HbA1c results you could still develop Retinopathy. On the other hand, we have seen some cases where individuals have had really high HbA1c’s all the way through, their journey with Diabetes and they have never, develop Diabetic Retinopathy.
It really seems like is something going on in the genes that we really don't know about and there needs to be more research into that. Sadly we don’t know which genes are involved so you best chance at reducing your risks are to maintain the best blood glcuseo management that you can.
Back to the Risks
So this tends to get a bit scary; after 20 to 25 years of having Type 1 Diabetes, 80 to 90% of people develop some form of Retinopathy, most of those cases are going to be background Retinopathy (R1), but around 20 to 30% of people with Type 1 Diabetes develop referable Retinopathy after 20 to 25 years.
Reducing Your Risks
Lower HbA1c is linked with lower risk of developing Retinopathy. Ideal target appears to be less than 7% (in old money, I think that is around 48mmol/mol in the new measurement system)
Managing your blood pressure so that it is less than 140/90 mm/Hg reduces your risk considerably too.
Reducing cholesterol levels appears to have a significant role in reducing the risks of developing and progression of maculopathy.
Research published in 2022 suggested that insulin sensitivity may be a more reliable risk factor in predicting the development of complications of Diabetes, including Retinopathy, than HbA1c. The best risk mitigations appeared to come from low HbA1c and high insulin sensitivity.
Early Worsening of Diabetic Retinopathy
Are you are aware of the early worsening of Retinopathy phenomenon?
Several studies have shown that if you have Retinopathy present and then a large and rapid reduction HBa1C you are likely to experience a worsening of your Diabetic Retinopathy and it appears progress more quickly than it normally would.
This has been shown in studies of initiation of insulin therapy in Type 2 Diabetes and it's also been shown in, in intensification studies, so that the big one was the Diabetes Control and Complications Trial (DCCT).
We've also seen this phenomenon in pregnancy, and also following bariatric surgery.
The latest one was in the initiation of GLP-1 therapies (semaglutide).
What is a Large & Rapid Improvement in Diabetes Management?
What we say is 2% reduction in a two to three months, period, would be a risk if the Retinopathy was already present. If there isn't any Retinopathy, then there is no risk of it actually developing.
However, reducing your HbA1c gradually appears to be safe and protects from other forms of diabetes complications too.
There is another treatment for Retinopathy. it's been shown in two studies; the FIELD study, which took place in Australia and the ACCORD study, which was a European trial. They used a medication from the 1970’s for lowering triglycerides called Fenofibrate and it seemed to work on the Retinopathy, even when it didn't lower cholesterol levels.
We are not really sure what the mechanism of action is for Fenofibrates but it has been shown to reduce a progression of Retinopathy. but it's only had its license changed in Australia and India, but it's not in the UK or any other country as far as I'm aware.
If Fenofibrates are mentioned by your ophthalmologist, then there would need to be a discussion between primary care and secondary care to determine your individual benefits and the consequences.
Treatment for Retinopathy is Available
If you do develop sight threatening Retinopathy, there is treatment. It doesn't automatically mean that you're going to lose your sight.
Laser therapy has been around since the 1950’s and it works by sealing the leaking vessels. It reduces the regrowth of the new vessels and regresses them as well.
The newest therapy we've had developed is the anti-VEGF, vascular endothelial growth factor, injections. It blocks these chemicals and slows vessel leakage and reduces the growth of new vessels as well.
Then there are intravitreal steroid injections. These reduce the oxidates and the inflammation in the eye.
Finally, there is the option of a vitrectomy, this is removal of that vitreous humour, the jelly like fluid in the eye and can have a number of benefits.
Other Eye Conditions
If you have Diabetes, unfortunately you are at higher risk of other eye conditions. You are more likely to have a refractive error, e.g. you're more likely need glasses; it can cause diplopia, which is double vision and you are also at higher risk of developing cataracts. If you develop cataracts it typically occurs at a younger age in people with Diabetes than people without. You are also at risk of developing glaucoma.
In addition to attending Diabetic Retinopathy screening, you should really attend appointments with your opticians as well, because they're the ones who check your overall eye health and screening does not check for these things.
Take Home Messages”
Sight loss due to Diabetes is not inevitable, just because you have Diabetes doesn't mean that you will go blind, or you will develop a sight threatening form of Retinopathy.
If Retinopathy does develop, progression can be slowed or delayed, especially if you make conservative changes to your blood glucose and blood pressure. It really does make a huge difference in delaying the progression of Retinopathy
If you develop Retinopathy and it does progress treatment is available, the earlier that treatment is used, the better for your visual outcome.
Remember that even if you have a great HbA1c, great cholesterol and great blood pressure the risk of developing Diabetic Retinopathy is not reduce to zero, you can still develop and it’s not your fault. Unfortunately, it is just a part of Diabetes but the hard work that you are putting in will reduce your risks and attending your eye screening appointments will help to identify if you need some additional help early and that leads to the best outcomes.
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