1. RVO- Retinal Vein Occlusion (RVO) Flashcards
Difference between veins and artery?
Veins take (drain) deoxygenated blood away.
Role of vein?
Transport
All the veins in the eye join to?
Central retinal vein then joins the cavernous sinus.
2 common causes of vein occlusion?
- Compression of vein walls (Atherosclerosis vessel)
- High intra- arterial pressure
What are the 3 causes of increased blood viscosity?
- Diabetes
- Vasculitis (inflammatory condition)
- Phrombophilic disorders (clotting factor)
What happens when veins are occluded?
An overflow–> Blood vessels blocked, causes veins to block, creating blockage (stagnation). This then causes hypoxia (healthy blood can’t get in) causing lack of oxygen. Leading to swelling (oedema) and hemorrhage. This leads to increased extravascular pressure (pressure around the veins) which then causes further stagnation, and the cycle continues.
3 types of vein occlusions?
- Central Retinal Vein Occlusion (CRVO)
- Branch Retinal Vein Occlusion (BRVO)
- Hemi- Retinal Vein Occlusion (HRVO)
Cause of CRVO?
Due to thrombosis of central retinal vein at the lamina cibrosa. Caused by inflammation of central optic nerve. Also, happens at the central retinal vein, happens at the lamina cibrosa or behind (This could be compression on the nerve behind or aneurysm).
How does CRVO look?
ALL 4 QUDRANTS INVOLVED, Blot and flame hemorrhages, Optic disc oedema, cotton wool spots, swollen disc secondary to vein occlusion, dilated and tortuous veins.
Cause of cotton wool spots?
When veins became hypoxic or ischemic
What is the location of BROV?
Anywhere on the retina. Most commonly seen where artery-venous are crossing at high pressure.
most common location is super- temporal
Always seen more peripheral
BRVO- does it cause disc swelling?
Disc swelling uncommon with BRVO unless very close to the disc.
What is seen on the fundus with BRVO?
Hemorrhages along 1 arcade. May have CWS and localized oedema
How does HRVO look?
Hemorrhage in one half of the fundus- either superior or inferior only.
May have disc swelling
4 signs of ischemic occlusion?
- VA commonly less than 6/60
- RAPD present
- Severe disc/ macular oedema
- Neovascular changes (disc or iris)
Differential diagnosis of vein occlusions?
1.Ocular ischemic syndrome
2.Asymmetrical diabetic retinopathy -Unusual
3.Hypertensive retinopathy -Bilateral
4.Microaneurysm –“Bubbles in the vessel in the retina- which can burst”
5.Peripheral choroidal neovascularization –“AMD in the periphery”
Optometric Investigation of vein occlusions?
1.Best corrected VA
2.Colour fundus photography
3.Gonioscopy (if available and if ischemic CRVO is suspected)
4.OCT
5.IOP check – high IOP is the cause of central vein occlusion.
Is RVO linked to the risk of px likely to get a stroke?
NO
RVO in pxs <50, commonly associated with what 4 causes?
Hypertension, Dyslipidemia, Diabetes, Possible role for dehydration
Ophthalmology investigation for RVO
*OCT
*OCTA - common
*Fundus photography
*Fluorescein angiography (less common)
What is looked for on OCT in px with RVO?
Macular oedema
Macular oedema treated with?
Anti- VEGF injections or steroids
How does OCTA work?
Need to have active flow to be picked up- it works by bouncing light off from moving red blood cells.
What is seen in pxs with RVO on FA (fluorescein angiography)
Leaky patches - that indicate new blood vessels
Treatment is offered to what 2 conditions only?
Macular oedema or neovascular changes
Describe the treatment route for RVO?
Anti-VEGF - unblock vessels
If it doesn’t work,
Steroid:
Ozurdex/ illuvin for 6 months
Ozurdex/ illuvin side effects?
Risk of cataract or increased IOP
Neovascular changes occurs in which RVO?
In ischemic RVO
BRVO or CRVO- which one has a better prognosis?
BRVO
If drop in vision is caused by macular oedema, is it likely that px will recover vision?
Unlikely
Why is disc collaterals a positive sign?
It is a reassuring sign that the px will not become ischemic.
Patients with significant retinal ischemia are at risk of?
Neovascular changes
