Diabetic Retinopathy Classification Flashcards

1
Q

What is diabetes?

A

Failure of insulin secretion, insulin action or both

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2
Q

What does insulin do?

A

It lowers blood glucose

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3
Q

What can chronic diabetes affect?

A

Eyes, kidneys, nerves, heart and blood vessels

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4
Q

What are the types of diabetes?

A

Primary: type 1 & 2
Secondary: happens because of something eg. gestational, drugs, pancreatic disease

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5
Q

What is type 1 diabetes?

A

Insulin dependant

loss of insulin production

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6
Q

What is type 2 diabetes?

A

Non-insulin dependant

Ineffective use of insulin (insulin resistance) or insufficient insulin production

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7
Q

Who requires insulin injections?

A

All type 1 and some type 2 diabetic

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8
Q

What are ocular complications of diabetes?

A
Retinopathy
Retinal detachment
CRVO/CRAO
Anterior ischaemic optic neuropathy (AION)
Maculopathy
Cataract
Rubeosis iridis 
(neovasc glaucoma)
Cranial nerve palsies
Corneal erosions, ulcers, persistent epithelial defects
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9
Q

Which cranial nerves can be affected in diabetic patients?

A

III, IV, VI, VII

Nerves to the extraocular muscles

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10
Q

What is diabetic retinopathy ?

A

It is a microvascular disease which means it affects the small blood vessels i.e capillaries

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11
Q

What is the earliest sign of DR?

A

Micro-aneurysms

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12
Q

What affects the risk of getting DR and progression of DR?

A
  • Duration person has had diabetes
  • Control of DM
  • Type (1 more common to get DR)
  • HTN, high cholesterol
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13
Q

What is the DES programme?

A

Diabetic eye screening offered by the NHS to 12+ type 1 and type 2 diabetics

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14
Q

What happens at the screening?

A

BCVA
Patient dilated
2 images taken for each eye, 1 centred on the macula and 1 centred on the optic disc. Both images merged together

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15
Q

What happens with the images taken

A

The images are graded. Optometrists or ophthalmologists grade the images. You can become a grader-need to be accredited

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16
Q

What does it mean if the image is not gradeable?

A

Patient may have cataract or asteroid hyalosis for example which does not give a clear image. these patients then need to be seen on slit lamp

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17
Q

Which two part of the retina does DR affect?

A

Periphery (R) or macula (M)

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18
Q

What 2 types of DR are there?

A

Non-Proliferative=no new blood vessels

Proliferative= new blood vessels

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19
Q

What are the retinopathy grades?

A
R0= No DR
R1= Background DR (no referral)
R2= Pre-proliferative (refer)
R3= Proliferative (urgent refer)
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20
Q

What are the features of R1?

A

Background DR

  • Micro-aneurysm
  • Retinal haemorrhage dot/blot
  • Exudates
  • Venous loops
  • Cotton wool spot in presence of other R1 features (meaning a single CWS and no other feature is R0)
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21
Q

What are the features of R2?

A

Pre-proliferative

  • Multiple blot haemorrhages
  • Venous beading
  • Venous reduplication
  • Intra-retinal microvascular abnormality (IRMA)
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22
Q

What are the features of R3?

A

Proliferative

  • NVD: New vessels at disc
  • NVE: New vessels elsewhere
  • Pre-retinal or vitreous haemorrhages
  • Pre-retinal fibrosis ± tractional retinal detachment
23
Q

What are micro-aneurysms caused by and what do they look like?

A

Vessels become weaker causing pouches to be formed in the vessel walls.
Rupture of vessels in the inner nuclear layer

Small dark red dots with sharp border, even 1 diagnoses DR

24
Q

What are dot haemorrhages and what do they look like?

A

Capillaries in the inner plexiform layer ruptured

They look exactly like micro-aneurysm.Smaller than blot haemorrhages but larger than micro-aneurysms.

25
Q

What are blot haemorrhages and what do they look like?

A

Deeper capillaries between IPL and INL. Sign of local ischaemia

Larger and darker than dot

26
Q

How do you know if it’s R1 or R2 when blot haemorrhages are present?

A

If only a few then R1

If multiple and in all 4 quadrants then R2

27
Q

What are flame shaped haemorrhages?

A

Occurs in the nerve fibre layer so feathery appearance as they follow pattern of nerve fibre axons

28
Q

What are conditions are flame shaped haemorrhages seen in?

A

HTN
Glaucoma
Vein occlusion

29
Q

What are exudates and what do they look like?

A

Lipid and lipoprotein deposits leaking from capillaries in the outer or inner plexiform layer (fat leaking out of blood vessels). Can reabsorb spontaneously or after treatment.

Bright yellow appearance

30
Q

How can you differentiate exudates from drusen?

A

Drusen are hazier in colour whereas exudates appear yellowish white

OCT: Drusen is under the RPE which you can differentiate from exudate which are in inner retinal layer

31
Q

What is oedema and what does it look like?

A

Accumulation of fluid within retina. Exudate and oedema shows the same thing – leakage from blood vessels, oedema is a leakage of fluid from blood vessels whereas exudate is leakage of fat, hard to see, best to see on OCT-black pockets of fluid in inner retinal layers

May see cysts and greying on fundus

32
Q

What are CWS and what do they look like?

A

Fluffy white lesions in RNFL Caused by focal or diffuse inner retinal ischaemia, disrupting RNFL axonal transport.

Basically arterial blood supply is reduced. They can reabsorb but can take 6+ months

They look fluffy white and obscure blood vessels underneath

33
Q

What are venous loops and what do they look like?

A

Abrupt curving away from normal path of vessel

34
Q

How can you remember R1 features?

A
H
O
M 
E
\+CWS and venous loops
35
Q

What is IRMA?

A

Intraretinal Microvascular Anomaly

  • IRMA are little capillaries that have dilates to bring extra blood in areas that have become hypoxia
  • Odd branching patterns
  • Doesn’t leak and doesn’t cross major vessels
  • Indicates ischameia
  • They look like new vessels but they are not
36
Q

How can you tell it’s IRMA and not new vessels?

A

They don’t cross major vessels, run from arteriole to venule and they don’t leak-when u do FA the flurocene doesn’t leak

37
Q

What venous changes can occur in R2?

A

Beading=looks like sausages

Occluded vessels, sign of severe ischaemia

38
Q

Why do new vessels grow in R3?

A

In response to growth factors (VEGF) due to ischaemia. Retina in under nourished so to compensate for this they eye grows new vessels

39
Q

What do the new vessels look like

A

Fragile, thin, leak and bleed, loop back on themselves

Crosses major vessels

Obscures underlying lesions therefore on top of retina

Eventually grows into vitreous

40
Q

Why does R3 require urgent referral?

A

High risk of vitreous haemorrhage.

Associated with fibrous traction on retina.

NVD= 50% risk blindness in 5y if untreated.

NVE=30% risk blindness in 5 years if left untreated

41
Q

How does Pre-retinal / vitreous haemorrhage occur?

A

When new vessels grow forward from the retina, cross pre retinal space and enter vitreous

42
Q

What are the symptoms of vitreous haemorrhage?

A

Sudden visual loss or sudden onset of dark floaters.

43
Q

What does vitreous haemorrhage look like?

A

Appears dark, may completely block view of the retina.

Flat top due to red blood cells settling down due to gravity (boat shape or D shape)

44
Q

Is a vitreous haemorrhage reversible?

A

It can reabsorb but takes months or years for the blood to reabsorb. If it doesn’t in 6 months then vitrectomy is done

45
Q

What is a Pre-Retinal Fibrous Traction?

A

Retinal detachment= retina is pulled off from the underlying choroid due to the fibrous tissue contracting

May have sudden loss of vision

46
Q

What does a Pre-Retinal Fibrous Traction look like?

A

Retina may appear wrinkled (traction lines), bumped and folded, or tears may be visible.

47
Q

What is Rubeosis Iridis?

A

Severe retinal hypoxia can cause new vessels to grow on the iris

48
Q

What can Rubeosis Iridis cause?

A

Neovascular glaucoma due to fibrovascular tissue blocking angle of drainage.

Very painful

49
Q

What is M0?

A

No maculopathy

Non-referable maculopathy (MAs or haems within 1DD of fovea but vision better than 0.3 LogMAR/ Snellen 6/12)

50
Q

What is M1?

A

Exudate within 1 disc diameter of the centre of the fovea

Circinate or group of exudates within the macula

Retinal thickening within 1 DD of the centre of the fovea (fluid pockets on OCT)

Any microaneurysm or haemorrhage within 1 DD of the centre of the fovea ONLY if associated with VA worse than Snellen 6/12 or 0.3 logMAR

Requires treatment: Clinically Significant Macular Oedema (CSMO)

51
Q

What is P0?

A

No photocoagulation (laser scars)

52
Q

What is P1?

A

Presence of photocoagulation scars:

  • Evidence of focal/ grid laser to macula
  • Evidence of peripheral scatter laser
53
Q

Why is laser treatment used for proliferative retinopathy?

A

Laser burns reduces the oxygen demands so less hypoxia

54
Q

What are the referral guidelines for DR?

A

R1=annual review

R2=Routine referral to HES

R3 new vessels=urgent referral to HES

R3 sudden loss of VA, ret detachment, vitreous haem, rubeosis iridis= emergency referral

M1= routine referral

P1=refer to HES if not recorded before