[2] Retinal Arterial Occlusion Flashcards
What is central retinal artery occlusion?
A disease of the eye where the flow of blood through the central retinal artery is occluded
How important is retinal artery occlusion?
Its an ophthalmic emergency
What retinal artery occlusion be divided into?
- Central retinal artery occlusion
- Branch retinal artery occlusion
What is central retinal artery occlusion?
When the CRA occludes before any of its branches
What is branch retinal artery occlusion?
Where one or more of the branches of the CRA are blocked
What are the two sources of blood supply to the retina?
- Central retinal artery
- Ciliary artery
Where does the central retinal artery come from?
It is the first branch of the ophthalmic artery
Where does the ophthalmic artery come from?
It is the first branch of the internal carotid artery
What part of the retina is first supplied by the central retinal artery?
Surface of the optic disc
After supplying the optic disc, what happens to the central retinal artery?
It divides into a superior and inferior branch and then temporal and nasal branches
What do the superior and inferior nasal and temporal branches of the central retinal artery supply?
The 4 quadrants of the retina
What part of the retina does the ciliary artery supply?
The outer retina
How does the ciliary artery supply the retina?
Via the choriocapillaries of the chorid
What anatomical variation is relevant to retinal artery occlusion?
The cilioretinal artery
What percentage of the population are thought to have a cilioretinal artery?
15-30%
What does the cilioretinal artery do?
Supplies the macular retina to varying degrees
What is the importance of the cilioretinal artery to retinal artery occlusion?
It may preserve some central vision in CRA occlusion
How does the cilioretinal artery appear on fundoscopy?
A single vessel emerging from the edge of the optic disc towards macula
What variation does variation in location of occlusion create in retinal artery occlusion?
- Different layers
- Different quadrants
Where in the central retinal artery will an occlusion have the most devastating effect?
More proximal
Why does a more proximal retinal artery occlusion cause a more devastating effect?
It will affect more layers and more areas of the retina
What will occlusion of a distal end branch of the retinal artery affect?
The inner neural layer of the part of the retina supplied
What will a distal retinal end artery occlusion spare?
The photoreceptors (so limits visual loss)
What is central retinal artery occlusion the ocular equivalent of?
Cerebral stroke - it is a process of end organ ischaemia