Retinal Vein Occlusion CRVO/BRVO

Question 1

What are the two types of retinal vein occlusions?

Answer 1

CRVO

BRVO

Question 2

How common is it?

Answer 2

RVO is the most common retinal vascular disease after diabetic retinopathy.

Question 3

What’s more common central or branch retinal vein occlusion?

Answer 3

Branch/BRVO

Question 4

What are the risk factors of BRVO?

Answer 4

Men over 60

HTN, high cholesterol, glaucoma, short axial length, inflammatory conditions (e.g. sarcoidosis, Lyme disease).

Question 5

What are the symptoms of BRVO?

Answer 5

Sudden painless loss of vision

May be asymptomatic if nasal branch but often superior temporal branch in most cases

May result in sector field defect or central field defect (if macular branch, -25% cases).

Question 6

What are the signs of acute BRVO?

Answer 6

Flame shaped hemorrhages. (respect the horizontal midline, confined to one quadrant)

Tortuous and dilated vein near occlusion
Retinal oedema-fluid leakage

CWS

Question 7

What are the signs of chronic BRVO?

Answer 7

• Hard exudates
• Vascular sheathing (appear white)
• Macular pigment
• Collateral vessel formation (small and tortuous, may cross horizontal raphe to drain into unaffected quadrant)
• Retinal ischaemia occurs downstream to occlusion  VEGF upregulation  increased vessel permeability  macular oedema.

Question 8

What happens if BRVO is left untreated?

Answer 8

Macular oedema often resolves within 12 months in 40% of cases

50% of eyes maintain VA of ≥6/12.

• 25% of eyes will be ≤ 6/60.
• BRVO occurs in fellow eye in 10% of cases.

Neovascular glaucoma is rare.

Retinal neovascularisation can occur (3 yr incidence
~10%2)

Question 9

How should you manage patient with BRVO?

Answer 9

Dilated fundus exam

Pupils, VA, visual field

Refer to GP cardiovascular investigation

Question 10

How does an ophthalmologist manage BRVO?

Answer 10

Fluorescein angiogram

Grid laser coagulation if macula oedema persistent

Prognosis good if untreated VA ≥6/12
But 25% will have VA <6/60

Question 11

What is CRVO caused by?

Answer 11

Caused by thrombus formation where central retinal artery and vein leave the optic nerve head, often at lamina cribrosa.

Question 12

What are the risk factors of CRVO?

Answer 12

HTN, DM, Open angle glaucoma, cardiovascular disease, systemic inflammatory conditions, oral contraceptive pill, raised IOPs over 30mmHg

Question 13

What are the signs of CRVO?

Answer 13

Blood and thunder fundus, retinal haems, dilated tortuous veins, CWS, macular oedema, optic disc swelling

Question 14

What are the 2 types of CRVO?

Answer 14

Ischaemic 20%

NON- ischaemic 80%

Question 15

How do you know if CRVO is ischaemic?

Answer 15

VA less than 6/60

RAPD

Extensive haems in all 4 quadrants, dilated tortuous veins, CWS, disc swelling

Question 16

How do you know if CRVO is NON- ischaemic?

Answer 16

VA better than 6/60

less haems and less CWS

Question 17

What are some complication arising from CRVO?

Answer 17

Neovascular glaucoma-red,painful eye, risk of rapif vision loss

New vessels at disc and elsewhere +vitreous haem

Perisstant macular oedema

Question 18

How do you manage BRVO and CRVO?

Answer 18

Refer all cases to GP for investigation- HTN

Normal IOP- refer urgent to opthalm

High IOP over 30- emergency referral

Question 19

How does ophthalmologist treat neovascularisation (retinal and iris/anterior eye)

Answer 19

Laser panretinal photocoagulation used to treat new vessels in iris / angle and retina.

Anti-VEGF therapy + photocoagulation has a positive effect.

Urgent referral for undiagnosed patients with new vessels.

Question 20

How does ophthalmologist treat Neovascular glaucoma

Answer 20

Caused by new vessels on iris or angle blocking drainage.

If established and eye is blind, aim is to keep eye pain free with topical steroids and atropine.

If vision remains, IOP controlled with drops and/or surgery.

Urgent referral.

Question 21

How does ophthalmologist treat Macular Oedema?

Answer 21

Most common cause of visual loss in patients with RVO.

Traditionally treated with laser photocoagulation.

Steroid injections / implants and anti-VEGF injections have been used more recently.

NICE guidelines currently recommend Ranibizumab (Lucentis) for treatment of visual loss due to macular oedema secondary to CRVO. Also secondary to BRVO when laser photocoagulation not suitable due to extent of macular haemorrhage.