Diabetic Retinopathy

Question 1

Define Diabetic Retinopathy

Answer 1

Diabetic retinopathy is a global term for vision loss secondary to macular oedema (retinal thickening and oedema involving the macula), haemorrhage from new vessels, retinal detachment or neovascular glaucoma.

Question 2

Epidemiology of Diabetic Retinopathy

Answer 2

15.3% of people with diabetes (type 1 and type 2) have diabetic retinopathy

Question 3

Classification of Diabetic Retinopathy

Answer 3

Termed non-proliferative or proliferative (presence of abnormal new blood vessels emanating from the retina)

Question 4

Diabetic Retinopathy Pathogenesis

Answer 4

Advanced DR causes vision loss and blindness via two distinct mechanisms

• Diabetic macular oedema (most common)
• Proliferative diabetic retinopathy

Question 5

Symptoms of Diabetic Retinopathy

Answer 5

Early stages there is no change for the patient. As the DR develops the patient may experience

• floaters
• blurred vision
• distortion
• progressive visual acuity loss.

Question 6

Signs of Diabetic Retinopathy

Answer 6

• Microaneurysms
  
  • Dot and blot haemorrhages
  • Flame-shaped haemorrhages
  • Retinal oedema and hard exudates
  • Cotton-wool spots
  • Venous loops and venous beading
  • Intraretinal microvascular abnormalities
  • Macular oedema

Question 7

Define Microaneurysms

Answer 7

The earliest clinical sign of diabetic retinopathy; these occur secondary to capillary wall outpouching due to pericyte loss; they appear as small, red dots in the superficial retinal layers

Question 8

Define Dot and blot haemorrhages

Answer 8

Appear similar to microaneurysms if they are small; they occur as microaneurysms rupture in the deeper layers of the retina, such as the inner nuclear and outer plexiform layers

Question 9

Define Flame-shaped haemorrhages

Answer 9

Splinter hemorrhages that occur in the more superficial nerve fiber layer

Question 10

Define Retinal oedema and hard exudates

Answer 10

Caused by the breakdown of the blood-retina barrier, allowing leakage of serum proteins, lipids, and protein from the vessels

Question 11

Define Cotton-wool spots

Answer 11

Nerve fiber layer infarctions from occlusion of precapillary arterioles; they are frequently bordered by microaneurysms and vascular hyper permeability

Question 12

Define Venous loops and venous beading

Answer 12

Frequently occur adjacent to areas of nonperfusion; they reflect increasing retinal ischemia, and their occurrence is the most significant predictor of progression to proliferative diabetic retinopathy (PDR).

Question 13

Define Intraretinal microvascular abnormalities

Answer 13

Remodelled capillary beds without proliferative changes; can usually be found on the borders of the nonperfused retina

Question 14

Define Macular oedema

Answer 14

Leading cause of visual impairment in patients with diabetes

Question 15

Define neovascularisation

Answer 15

Neovascularisation occurs in response to ischaemia. This results in bleeding of new and abnormal vessels. Visual loss is associated with virtual haemorrhage or retinal detachment.

Question 16

Non-proliferative vs Proliferative Diabetic Retinopathy

Answer 16

• Non-proliferative - has variable nerve-fibre layer infarcts (cotton wool spots), intraretinal haemorrhages and hard exudates
  
  • Proliferative - has neovascularisation arising from the disc and/or retinal vessels.

Question 17

Diabetic Retinopathy Prevention

Answer 17

Good control of blood glucose and blood pressure