Retinal Vein Occlusion/Retinal artery occlusion/retinitis pigmentosa

Question 1

How does retinal vein occlusion occur?

Answer 1

Occurs when a blood clot (thrombus) forms in the retinal veins and blocks the drainage of blood from the retina.

The central retinal vein runs through the optic nerve and is responsible for draining blood from the retina.

Question 2

There are four retinal veins that make up the central retinal vein (when the central retinal vein is blocked it causes problems in the whole retina) what is the pathophysiology when one of the veins are blocked?

Answer 2

Blockage of a retinal vein causes pooling of blood in the retina, this results in leakage of fluid and blood causing macular oedema and retinal haemorrhages.

This results in damage to the tissue in the retina and loss of vision

It also leads to the release of VEGF, which stimulates the development of new blood vessels- neovascularisation

Question 3

What is the presentation of central retinal vein occlusion?

Answer 3

Blockage of one of the retinal veins causes sudden painless loss of vision.

Question 4

What are the risk factors for retinal vein occlusion?

Answer 4

Similae to those of MI
Hypertension
High cholesterol 
Diabetes
Smoking 
Glaucoma 
SLE

Question 5

What can be used to diagnose retinal vein occlusion and what would you see?

Answer 5

. Fundoscopy
. Flame and blot haemorrhages
. Optic disc oedema
. Macula oedema

Question 6

Other than doing fundoscopy, what other tests would you consider in a patient with retinal vein occlusion?

Answer 6

FBC for leukaemia
ESR for inflammatory disorders
Blood pressure for hypertension
Serum glucose for diabetes

Question 7

What is the management of retinal vein occlusion?

Answer 7

Should be referred immediately to an opthalmologist for assesment and management

The aim of the treatment is to treat macular oedema and prevent neovascularisation

The options are…

• laser photocoagulation
• intravitreal steroids ie: dexamethasone
• anti VEGF therapies

Question 8

Give an example of an anti VEGF med…

Answer 8

Ranibizumab

Question 9

What is the centrak retinal arteyr occlusion?

Answer 9

This is where something blocks the flow of blood through the central retinal artery, the central retinal artery supplies the blood to the retina which is a branch of the ophthalmic artery which is a branch of the internal carotid artery.

Question 10

What are the risk factors for central retinal artery occlusion?

Answer 10

Older age
Family history 
Smoking 
Alcohol consumption 
Hypertension 
Diabetes
Poor diet 
Inactivity 
Obesity

Question 11

What is the presentation of central retinal artery occlusion?

Answer 11

Sudden painless loss of vision
There will also be a relative afferent pupillary defect (where the pupil in the affected eye constricts more than the other eye.

It occurs because the input is not being sensed by the ischaemic retina when testing the direct light reflex but is being sensed by the normal retina during the consensual light reflex.

Question 12

What will fundoscopy show for someone with central retinal artery occlusion?

Answer 12

Pale retina with a cherry red spot
The retina is pale due to the lack of perfusion with blood, the cherry red spot is the macula which shows the choroid below.

Question 13

What should older patients be tested for and ultimately treated for if they have suspected central retinal artery occlusion?

Answer 13

Giant cell arteritis
This is an important potentially reversible cause
Testing involves ESR and temporal artery biopsy

Question 14

How is Giant cell arteritis treated if suspected?

Answer 14

High dose steroids- prednisolone 60mg

Question 15

What is the management of central retinal artery occlusion?

Answer 15

Ocular massage
Removing fluid from the anterior chamber to reduce intraocular pressure
Inhaling carbogen (a mixture of 5% CO2 and 95% oxygen) to dilate the artery
Sublingual isosorbide dinitrate to dilate the artery

Long term involves treating reversible risk factors and secondary prevention of cardiovascular disease.

Question 16

What is retinitis pigmentosa?

Answer 16

This is a congenital inherited condition where there is degeneration of rods and cones in the retina. There are many different causes and some are systsemic whilst others are isolated cases of retinitis pigmentosa.

Question 17

Do rods or cones degenerate more in genetic causes of retinitis pigmentosa?

Answer 17

In most genetic causes, the rods degenerate more than the cones which leads to night blindness
They get decreased central and peripheral vision.

Question 18

What is the presentation of retinitis pigmentosa?

Answer 18

Night blindness is often the first symptom

Peripheral vision is lost before the central vision

Question 19

What will fundoscopy show if someone has retinitis pigmentosa?

Answer 19

Pigmentation, this is described as ‘bone spicule’ pigmentation

There may be associated narrowing of the arterioles and a waxy or pale appearance to the optic disc

Question 20

Give one example of an associated systemic disease of retinitis pigementosa and what it leads to…

Answer 20

Ushers syndrome- this causes hearing loss + retinitis pigmentosa

Question 21

What is the management of retinitis pigmentosa?

Answer 21

Referral to an opthalmologist for assesment and diagnosis
Genetic counselling
Vision aids
Sunglasses to protect the retina from accelerated damage
Driving limitations and informing the DVLA
Regular follow up to assess vision and check for any reversible conditions that may worsen the vision ie: cataracts

Some options that may be considered to slow the disease process...
Vitamin and antioxidant supplements
Oral acetazolamide 
Topical dorzolamide 
Steroid injections 
Anti VEGF 

Gene therapy in the future