Diabetic retinopathy

Question 1

Two principle ways in which patients go blind from diabetes?

Answer 1

End stage proliferative disease leading to gross haemorrhage/scarring/retinal detachment due to traction;
End stage maculopathy

Question 2

Rule of thumb for the grading of retinopathy vs maculopathy?

Answer 2

Retinopathy grading depends on the magnitude of the change;

Maculopathy grading depends on the proximity of the change to the fovea

Question 3

Changes in the retina as a result of diabetes? (5) [excluding proliferative]

Answer 3

Microaneurysm formation
Dot and blot haemorrhages
Cotton wool patches
Abnormalities of venous calibre
Hard exudates

Question 4

What are cotton wool patches?

Answer 4

Swollen nerve axons which appear fluffy and white against the red background

Question 5

What are hard exudates?

Answer 5

Distinct yellow deposits resulting from plasma leakage from capillaries

Question 6

Examples of abnormalities of venous calibre? (3)

Answer 6

Beading
Dilatation
Small sections of reduplication

Question 7

Grading categories of diabetic retinopathy?

Answer 7

No retinopathy
Non proliferative retinopathy (mild, moderate, severe)
Proliferative retinopathy

Question 8

What is the underylying stimulus of the observed changes in diabetic retinopathy?

Answer 8

Microvascular disorder causing tissue hypoxia

Question 9

Key mediator of proliferative retinopathy?

Answer 9

VEGF

Question 10

Why are the blood vessels formed in proliferative retinopathy maladaptive?

Answer 10

Lack the integrity of normal retinal vessels; form on the posterior face of the vitreous where they do not address the issue of hypoxia and are subject to traction

Question 11

What defines the severity of non-proliferative retinopathy?

Answer 11

Large amounts of haemorrhage and microaneurysm formation; venous beading

(cotton wool patches and hard exudates are irrelevant to the grading system)

Question 12

Presence of micro-aneurysms ONLY indicates….

Answer 12

Mild non-proliferative retinopathy

Question 13

Treatment of

a) proliferative retinopathy
b) maculopathy

Answer 13

a) retinal laser photocoagulation; between 1000-5000 laser burns scattered across the fundus excluding the macula
b) more gentle laser therapy applied discretely around the fovea

Question 14

Potential adverse effects of laser treatment?

Answer 14

Loss of peripheral vision

Direct foveal burns –> sudden and immediate visual loss