The Retina Flashcards
Name the 5 layers of the retina
- optic nerve fibre layer (inner)
- ganglion cell layer
- bipolar cell layer
- photoreceptor layer
- pigmented epithelium (RPE) (outer)
What imaging can be used to assess the layers of the retina & fovea
Optical Coherence Tomography
What are the types of diabetic eye disease
- non-proliferative retinopathy
- proliferative retinopathy
- maculopathy
Diabetic eye disease pathophysiology
→Loss of pericytes
→Protein glycosylation
→Blood vessel leakage
→Increased blood viscosity
→Reduced oxygen transport
→RETINAL ISCHAEMIA
Name the 4 signs of NPDR
- cotton wool spots
- microaneurysms/ dot haemorrhages
- blot haemorrhages
- venous changes (looping/beading)
Is NPDR typically asymptomatic or symptomatic
Asymptomatic
What are dot haemorrhages/ micro-aneurysms
Localised outpouchings of retinal capillaries where pericytes are lost. One of the earliest signs of NPDR
What are cotton wool spots
Ischaemic disruption of the axons in the nerve fibre layer
What are venous changes in NPDR
Generalised dilation and tortuosity plus areas of focal narrowing (beading)
What are blot haemorrhages in NPDR
Intraretinal haemorrhages and infarcts. The more visible, the more ischaemic the retina
What is the 4-2-1 rule
Classification of severe NPDR….
-Blot haemorrhages in 4 quadrants
-Venous beading in 2 quadrants
-IRMA in 1 quadrant
What are IRMA in NPDR
IntraRetinal Microvascular Abnormality - Represent shunts between the arterioles and venules, bypassing the retinal capillary bed. Act to supply areas of non-perfused retina
How is PDR classified
-NVD (disc)
-NVE (elsewhere in retina)
-NVI (iris)
How can PDR cause loss of vision
PDR treatment
Laser PRP (pan-retinal photocoagulation)
Where do you laser in PDR & why
Laser the ischeamic peripheral retina
This reduces VEGF production
This preserves vision
Laser in PDR consequence
Loss of peripheral vision
What are the two main signs of diabetic maculopathy
Exudates & microaneurysms in macula
When would you treat diabetic maculopathy
When it affects the fovea
What is exudates
Lipid deposits from leaking blood vessels
Diabetic maculopathy treatment
Anti-VEGF injections
What are the two types of retinal vein occlusion
Branch RVO (BRVO)
Central RVO (CRVO)
How does retinal vein occlusion present (symptoms)
- Painless vision loss
- RAPD (if significant)
Retinal vein occlusion pathophysiology
- Atherosclerotic plaque travels through artery
- Artery shares sheath with vein
- Artery occlusion causes venous & capillary pressure to rise
- Blood products extravasate veins
- Hypoxic drive occurs & VEGF is production/ released
