Diabetic retinopathy

Question 1

How is diabetic retinopathy classified?

Answer 1

1. Non-proliferative diabetic retinopathy
2. Proliferative diabetic retinopathy
3. Macular oedema

Question 2

What are microaneurysms?

Answer 2

‘Out-pouching’ of vessels resulting from weakened capillary walls

• earliest visible clinical sign of diabetic retinopathy

Question 3

What are dot and blot haemorrhages?

Answer 3

Damaged vessels that have ruptured and leak blood

Question 4

What are hard exudates?

Answer 4

Deposits of lipids that have leaked onto the retina through damaged vessels

Question 5

What are cotton wool spots?

Answer 5

Microinfarction of the retinal nerve fibre layer due to chronic ischaemia

Question 6

What is venous beading?

Answer 6

Venous changes which are a reliable indicator of generalised ischaemia

Question 7

What are intraretinal microvascular abnormalities (IRMA)?

Answer 7

Irregular formations of dilated capillary beds

Question 8

What are the features of mild NPDR?

Answer 8

1+ microaneurysm

Question 9

What are the features of moderate NPDR?

Answer 9

• Microaneurysms
• Blot haemorrhages
• Hard exudates
• Cotton wool spots
• Venous beading
• IRMA

Question 10

What are the features of severe NPDR?

Answer 10

(AKA severe pre-proliferative diabetic retinopathy)

• Blot haemorrhages and microaneurysms in 4 quadrants
• Venous beading in at least 2 quadrants
• IRMA in at least 1 quadrant

Question 11

What features/signs are associated with proliferative diabetic retinopathy?

Answer 11

1. Neovascularisation
2. Vitreous haemorrhage
3. Retinal detachment

Can present as neovascular glaucoma and pre-retinal fibrosis

Question 12

What are diabetic macular oedema, and how does it usually present?

Answer 12

• Oedematous changes in or around the macula
• As the macula is responsible for central vision, affected patients tend to present with blurred vision when reading or difficulty recognising faces
• Commonest cause of vision loss in patients with diabetes

Question 13

What are the subcategories of diabetic macular oedema?

Answer 13

• Focal/diffuse macular oedema
• Ischaemic maculopathy
• Clinically significant macular oedema

Question 14

Describe focal/diffuse macular oedema.

Answer 14

Fluid escapes from damaged vessels and can either be well-circumscribed (focal) or widespread and poorly demarcated (diffuse)

Question 15

Describe ischaemic maculopathy.

Answer 15

Patients will be symptomatic with defects in visual acuity due to ischaemia at the site of the macula (best visualised using fluorescein angiography)

Question 16

Describe clinically significant macular oedema.

Answer 16

Condition that describes significant changes associated with retinopathy, such as hard exudates and retinal thickening, found within a certain distance to the fovea or greater than a certain size

Question 17

What investigations should be done for diabetic retinopathy?

Answer 17

1. Bloods - HbA1c
2. Optical coherence tomography (OCT)
3. Fluorescein angiography

Question 18

What is optical coherence tomography (OCT)?

Answer 18

• Imaging that provides a cross-sectional view of the retina
• More typically used when examining diabetic macular oedema as it helps to quantify the levels of oedema and retinal thickness in and around the macula

Question 19

What is fluorescein angiography? Why is it used in the investigation of diabetic retinopathy?

Answer 19

**GOLD STANDARD technique for visualising the vasculature of the retina

• Fluorescein is injected intravenously to highlight retinal vessels, which are then photographed
• Used in DR for clearer identification of signs such as retinal ischaemia and identifying microvasculature
• Can also visualise microaneurysms and dot/blot haemorrhages

Question 20

What is the medical management of diabetic retinopathy?

Answer 20

• Good glycaemia control (aim for HbA1c of 48-58 mmol/mol)
• BP control (<140/80, ideally systolic <130)
• Diet, exercise, and smoking cessation

Question 21

What is the typical management of NPDR?

Answer 21

• Optimisation of medical management
• Regular observation
• Photocoagulation for severe NPDR

Question 22

What is the management of proliferative DR?

Answer 22

1st: Photocoagulation
2nd: Intravitreal anti-VEGF
3rd: Vitrectomy

Question 23

What are the different types of photocoagulation?

Answer 23

• Focal/grid photocoagulation

- Pan-retinal photocoagulation

Question 24

Describe focal/grid photocoagulation.

Answer 24

Focal photocoagulation:
- specific point of leakage is identified and targeted with laser

Grid photocoagulation:
- Targets more diffuse retinal thickening and oedema with no obvious point of leakage

Question 25

What are the complications of focal/grid photocoagulation?

Answer 25

• Decreased quality of central vision
• ± formation of a paracentral scotoma
• if diabetic macular oedema is present it may worsen

Question 26

Describe pan-retinal photocoagulation.

Answer 26

Periphery of the retina is targeted with the aim of achieving a global reduction in oxygen demand

• more commonly used than FP, ~1200-1500 burns can be made to the retina using this technique

Question 27

What are the complications of pan-retinal photocoagulation?

Answer 27

• Restricted peripheral vision
• Reduced quality of night vision
• Ocular pain
• Worsening of macular oedema

Question 28

What are the most commonly used anti-VEGF agents used in treating DR?

Answer 28

• Aflibercept (Eylea)
• Ranibizumab (Lucentis)

*anti-VEGF - minimise neovascularisation

Question 29

What are the complications of anti-VEGF injections?

Answer 29

• Cataract formation

- Increased IOP

Question 30

What are the contraindications to anti-VEGF?

Answer 30

Stroke or MI in the last 3 months

Question 31

What are the indications for vitrectomy?

Answer 31

• Persistent haemorrhage

- Central, sight-threatening tractional retinal detachment

Question 32

What is a vitrectomy?

Answer 32

Removal of the vitreous and surgical repair of any scarring/detachment of the retina