Diabetic Eye Disease

Question 1

5 RFs for progression of diabetic retinopathy

Answer 1

Lack of exercise
Not getting annual eye exam
Poor BP control
Poor glycaemic control
Pregnancy

Question 2

What is the most common cause of blindness in adults aged 35-65?

Answer 2

Diabetic retinopathy

Question 3

Describe pathophysiology of diabetic retinopathy

Answer 3

Hyperglycaemia increases retinal blood flow
Causes blood vessels to weaken/ rupture→ micro aneurysms + small haemorrhages

Endothelial dysfunction
→ increased vascular permeability
→ hard exudates on fundoscopy.

As blood flow increasingly compromised, hypoxia stimulates release of VEGF promoting neovasculization

Question 4

What are the broad stages of diabetic retinopathy?

Answer 4

Background (Mild NPDR)

Pre-proliferative

Proliferative

Diabetic maculopathy

Question 5

What is diabetic retinopathy?

Answer 5

Vascular disease of retina
Asymptomatic initially, progresses to visual impairment + blindness

Question 6

What are the classes of diabetic retinopathy?

Answer 6

Non-proliferative diabetic retinopathy (NPDR)
Proliferative diabetic retinopathy (PDR)

Question 7

What constitutes mild NPDR? (background retinopathy)

Answer 7

> ,1 microaneurysm

Question 8

What constitutes moderate NPDR? (pre-proliferative)

Answer 8

Microaneurysms
Blot haemorrhages
Hard exudates
Cotton wool spots
Venous beading/ looping
Intraretinal microvascular abnormalities (IRMA)

Question 9

What are cotton wool spots?

Answer 9

‘Soft exudates’
Areas of retinal infarction

Question 10

What constitutes severe NPDR? (pre-proliferative)

Answer 10

4:2:1 rule
>20 blot haemorrhages in 4 quadrants
Venous beading in >, 2 quadrants
IRMA in >,1 quadrant

Question 11

What is the hallmark feature of PDR?

Answer 11

Neovascularisation due to widespread retinal ischaemia

Question 12

What are complications of PDR and why do these arise?

Answer 12

New vessels are fragile + prone to leaking
Complications: vitreous haemorrhage + tractional retinal detachment

Question 13

In which patients is PDR more common?

Answer 13

T1DM

Question 14

What is the prognosis of PDR?

Answer 14

If untreated, 50% blind in 2y

Question 15

Describe early PDR

Answer 15

New vessels less than 1/3 of the disc area, no vitreous haemorrhage, and no tractional retinal detachment.

Question 16

What characterises high-risk PDR?

Answer 16

Any of:
Neovascularization of the disc (NVD) >,1/3 of the disc area

NVD a/w vitreous or preretinal haemorrhage,

Neovascularization elsewhere (NVE) >,1/2 disc area with vitreous or preretinal haemorrhage.

Question 17

What is diabetic macular oedema (DME)?

Answer 17

Complication of diabetic retinopathy + can occur at any stage
Most common cause of vision loss in those with diabetic retinopathy

Question 18

How does DME arise?

Answer 18

Fluid + protein deposits collect on/ under the macula, causing it to thicken + swell (oedema)

Question 19

How is DME classified?

Answer 19

Focal DME: foci of vascular abnormalities, primarily microaneurysms.

Diffuse DME: dilated capillaries in the retina.

Question 20

When can diabetic macula oedema be detected? What is the GS Ix?

Answer 20

NOT on a 2D photo unless there are exudates in the macula
Exudates suggest there is/ has been fluid
GS: OCT

Question 21

In which patients is diabetic maculopathy more common?

Answer 21

T2DM

Question 22

What is optical coherence tomography?

Answer 22

OCT provides cross-sectional view of retina
Often used when examining DME

Question 23

What investigations should be performed in diabetic eye disease?

Answer 23

HbA1c
Comprehensive dilated eye exam
Fundus photography
OCT
Fluorescein angiography

Question 24

What is the gold-standard technique for visualising the vasculature of the retina?

Answer 24

Fluorescein angiography

Question 25

Describe medical management of diabetic retinopathy

Answer 25

Glycemic control BP control Diet, exercise + smoking cessation

Question 26

What is the primary intervention in management of PDR and severe NPDR?

Answer 26

Photocoagulation Using laser to create numerous burns in the retina, destroying photoreceptors Reduced O2 demand Delays progression

Question 27

What are the 2 methods of photocoagulation?

Answer 27

Focal photocoagulation Pan-retinal photocoagulation

Question 28

What occurs in focal photocoagulation?

Answer 28

Specific point of leakage identified + targeted with the laser.

Question 29

What occurs in pan-retinal photocoagulation?

Answer 29

Periphery of retina targeted with aim of achieving a global reduction in O2 demand

Question 30

Tx for proliferative diabetic retinopathy

Answer 30

Pan retinal laser photocoagulation (PRP) Induces regression of new vessels before they bleed/ re-bleed causing vitreous haemorrhage

Question 31

Following pan retinal photocoagulation for PDR, what do ~50% of patients develop?

Answer 31

Reduction in their visual fields due to scarring of peripheral retinal tissue

Question 32

List 3 complications of panretinal photocoagulation other than reduction in visual fields

Answer 32

Decrease in night vision (majority of rods (responsible for low light conditions) are on periphery) Decrease in visual acuity Macular oedema

Question 33

What intravitreal injections can be used in management of PDR?

Answer 33

Anti-VEGF: minimises neovascularisation Corticosteroids: improve visual acuity + reduce maculopathy

Question 34

Name 2 anti-VEGF injections used in PDR

Answer 34

Aflibercept (Eylea) Ranibizumab (Lucentis)

Question 35

Tx for diabetic macular oedema

Answer 35

Anti-VEGF Intravitreal injections Macular laser (rarely) if allergy to drugs

Question 36

When may a vitrectomy be performed in management of PDR?

Answer 36

Persistent haemorrhage Central, sight-threatening tractional retinal detachment

Question 37

List 3 complications of diabetic retinopathy

Answer 37

Neovascular glaucoma Retinal detachment Vitreous haemorrhage

Question 38

What is diabetic maculopathy?

Answer 38

Any structural abnormality due to diabetes affecting macula Often preceded by diabetic retinopathy

Question 39

Ix for diabetic macular ischaemia

Answer 39

No fundal signs Suspected in diabetic with unexplained poor vision (in absence of diabetic macular oedema)

Question 40

How should diabetic maculopathy be managed?

Answer 40

If change in visual acuity: intravitreal VEGF inhibitors

Question 41

How should NPDR be managed?

Answer 41

Regular observation If severe: consider pan retinal photocoagulation