Diabetic Retinopathy Flashcards
What type of disease is diabetes?
A microvascular disease (it affects small blood vessels).
In diabetic retinopathy where do the earliest changes occur and what happens?
In the capillaries- We get capillary closure and pericyte loss as well as capillary drop out.
What are the earliest signs of diabetic retinopathy that we can actually see when we look at the fundus?
Microaneurysms - these appear as dots and blots.
What do complication of diabetic retinopathy arise through?
Ischaemia
What is diabetic retinopathy graded in regards to?
Where exactly changes are seen at the back of the eye and their severity.
so the M refers to the location and the R grade refers to severity.
What grade is diabetic maculopathy given?
M1
What are the features of diabetic maculopathy?
- Any microaneurysm or haemorrhage within 1 disk Diameter of centre of fovea BUT only if associated with VA ≤ 6/12
- Exudate within 1DD of fovea
-Circinate or group of exudates within macula
•Retinal thickening within 1DD of centre of fovea
[M0 = absence of any M1 features]
What does an exudate in the macula look like and how could you double check for the presence of an exudate?
A yellow flicker in the macula region.
To double check if you did an OCT you would see a hyper-reflective spot (basically a white spot) siting in the retina.
What is happening in this picture and what has caused this?
Macula thickening/oedema.
This has been caused by capillary closure (ischaemia) which leads to the accumulation of:
- extracellular oedema: fluid from damaged outer blood-retina barrier
- intracellular oedema: fluid accumulating within individual retinal cells as a result of hypoxia (the cells not getting enough oxygen because capillary closure has occured).
What is the result of macula oedema on VA?
VA will obviously decrease.
How would this be graded?
Possibly M1 as there is a group of circinates at macula BUT only if associated with VA ≤ 6/12
How would we record that there is no Diabetic retinopathy?
Using the grade ‘R0’
What are features of R1?
This is background Diabetic retinopathy i.e. none present on the macula or within one disk diameter of it.
In R1 you can expect to see Micro-aneurysms and small retinal haemorrhages.
[Refer to photo - the small red dots]
How do we manage R0 or R1?
Routine Diabetes Mellitus care
Annual screening
How do you diffrentiate between a ‘Dot and blot’ haemorrhage and a flame Haemorrhage?
Dot and blot haemorrhages tend to be small and round in shape. Thye are intra-retinal (in the retina).
Flame Haemorrhages occur in the nerve fibre layer and take on the shape of a flame as they follow the nerve fibre layer.
Thus you can diffrentiate by either shape or location.
What is the R2 stage known as?
The pre-proliferative stage.
What are features of R2 diabetic retinopathy?
•Venous looping, beading or reduplication of the blood vessels.
(So blood vessel either loops around or lookis like its got beads on it)
- Intra Retinal Microvascular Abnormality (IRMA)
- Multiple deep, round/blot haemorrhages
- Cotton Wool Spots (CWS)
What is the management of R2 diabetic retinopathy?
- Management of diabetes
- Opthalmogical monitoring
What feature can be seen in the photo and why does this occur?
Venous looping-Venous looping may represent foci of venous endothelial cell proliferation that have failed to develop into new vessels
What feature can be seen in the image below and where does this occur?
Venous beading - venous beading occurs in areas of extensive capillary closure
What is IRMA caused by?
[IRMA- Intra Retinal Microvascular Abnormality]
•Extensive closure of capillaries between an arteriole and venule – this leads to dilated capillary remnants.
What is being shown by the two different arrows?
Black arrow shows IRMA. Appear as spiky tortuous micro-vascular abnormalities in the areas of capillary occlusion.
Blue arrow shows beading.
What are cotton wool spots?
Swollen ends of interrupted axons, where build-up of axoplasmic flow occurs at the edge of the infarct
Where are Cotton Wool Spots most frequent?
Most frequently where the nerve fibre is densest such as the nasal side of the optic nerve
Are cotton wool spots a symptom exclusive to diabetic retinopathy?
No
What is the R3 stage of Diabetic retinopathy also called?
The proliferative phase
What are features of R3 diabetic retinopathy?
- Ischaemia which result is Vascular Endothelial Growth Factor being released - this prompts:
- New blood vessels (neovascularisation)
•New vessels may occur at the disc these are refered to as NVD - they tend to have a thin spindly look to them - these are the ones which can be seen in the image.
- New blood vessels may also occur elsewhere in which case they are referred to as NVE.
- Pre-retinal or vitreous haemorrhage
- Pre-retinal fibrosis ± tractional retinal detachment
What is the feature being shown in the picture?
Neovascularisation - specifically NVE
How is pre-retinal or vitreous haemorrhaging caused?
Typically when new vessels (from neovascularisation) break - basically there is a bleed into the pre-retinal space or into the vitreous itself. This type of haemorrhaging sits infront of the retina and so is seen as follows via fundus photography.
[Because of gravity blood often settles with a flat top and a curved bottom - thus is often caused a boat shape haemorrhage]
Are boat shaped haemorrhages exclusive to Diabetic Retinopathy?
No
What is pre-retinal fibrosis?
This is a condition in which an extremely thin membrane of scar-like tissue covers the surface of the retina.
What can pre-retinal fibrosis cause?
It can cause traction (basically a pulling effect) which causes retinal detachment.
What are diabetic retinopathy complications?
•Rubeosis Irides - which is where we have new blood vessels forming in the anterior chambre angle. This causes a really painful red eye and high IOP.
Why does the NHS bother with the Diabetic Eye Screening (DES) program?
There is Evidence that early identification and treatment of DED can ⬇ sight loss
Who is diabetic eye screening offered to?
Type one and type 2 diabetics above 12 years old unless px is already under opthalmogical care.
Pregnant women with diabetes are offered additional tests.
What is the aim of Diabetic Eye Screening ?
To identify Pxs at risk of Diabetic Retinopathy
[Note it is not there to diagnose thus you will have false positive and negatives]
How does the DES scheme work?
- It is a Digital screening
- Only approved software is used
- Tests occur every 6months to ensure quality
•
- There is a Uniform grading structure
- Images are graded within 1 week of being taken
- All graders grade at least 1000 image sets per year (optometrists/ophthalmologists: 500)
- 2 photos of each eye are seen which are combined together.
What happens if image is ungradable in the DES scheme?
Px should be seen within 6 weeks for SL-BIO
What is deemed as an ungradeable image in the DES scheme?
If vessels not clearly visible within 1 disk diameter of the centre of the fovea or you see small vessels at disk.
Examples of this are attached as well as the reasons for being ungradable.
What are the management for the different stages of Diabetic Retinopathy?
What does a grading of P mean?
That the diabetic retinopathy has been treated with Photocoagulation
What is the RSA stage also known as?
Active proliferation
What happens when a Px goes to the Hospital eye service (HES) following a diabetic retinopathy screening/request?
An ophthalmogical examination takes place:
- SL-BIO Dilated Fundus Examination
- May also be offered Fluorescein angiography
- OCT
What is the opthalmogical managment for Diabetic retinopathy?
- Pan-retinal photocoagulation - Heat from a laser seals or destroys abnormal leaking Blood vessels in retina (the laser is targetted at new vessels)
- Focal photocoagulation - same thing but except in this case its just in a local area.
[Both of these obviously happen away from the macula]
What does an eye that has had photocoagulation to treat diabetic retinopathy look like?
A- before photocoagulation
B- after photocoagulation (pale white spots are where each laser burn is present)
What is the ophthalmogical managment for maculopathy?
- Anti-VEGF intravitreal injection (so literally the injection into your eye)
- Corticosteroids
- E.g. Dexamethasone implant
