Retinal Vascular Disease

Retinal vascular disease comprises disorders of the retina's arterial and venous circulation, principally retinal artery occlusion and retinal vein occlusion. These conditions cause vision loss through acute interruption of retinal blood flow or through venous obstruction with haemorrhage, oedema, and ischaemia, and they often signal underlying systemic vascular risk.

Definition

Retinal vascular disease is a group of disorders affecting the blood supply of the retina, dominated by retinal artery occlusion, in which arterial perfusion to part or all of the retina is interrupted, and retinal vein occlusion, in which obstruction of venous outflow causes retinal haemorrhage, oedema, and ischaemia.

Scope

This entry covers retinal arterial and venous occlusive disease as a topic within retinal and vitreous disease, including the central and branch forms of artery and vein occlusion, their ischaemic mechanisms, epidemiology, and systemic associations. The MeSH anchor descriptor is Retinal Artery Occlusion, but the entry is framed to encompass the broader category of retinal vascular occlusive disease. It is a reference entry and does not provide management protocols.

Core questions

• How do arterial and venous occlusions differ in mechanism and clinical presentation?
• Why is central retinal artery occlusion considered a form of acute ischaemia analogous to stroke?
• How does retinal vein occlusion lead to macular oedema and neovascular complications?
• What systemic vascular conditions are associated with retinal vascular occlusion?

Key concepts

• Central retinal artery occlusion
• Branch retinal artery occlusion
• Central retinal vein occlusion
• Branch retinal vein occlusion
• Retinal ischaemia and infarction
• Macular oedema
• Neovascularisation and neovascular glaucoma
• Systemic vascular risk factors

Mechanisms

In retinal artery occlusion, embolic or thrombotic blockage of the central retinal artery or a branch abruptly halts inner-retinal perfusion, producing ischaemic infarction; because retinal neurons tolerate ischaemia poorly, central retinal artery occlusion is regarded as an acute ischaemic event of the same family as cerebral stroke and is frequently associated with carotid and cardiac embolic sources. In retinal vein occlusion, obstruction of venous outflow, typically at an arteriovenous crossing in branch disease or at the lamina cribrosa in central disease, raises intraluminal pressure and causes haemorrhage, increased vascular permeability with macular oedema, and capillary non-perfusion; resulting ischaemia can drive vascular endothelial growth factor release and neovascularisation, with risk of vitreous haemorrhage and neovascular glaucoma (hayreh-2018; rogers-2010).

Clinical relevance

Retinal vascular occlusions are important both as causes of sudden or progressive vision loss and as markers of systemic vascular disease, including hypertension, atherosclerosis, and embolic sources, so they connect ophthalmology to cardiovascular and cerebrovascular medicine. This entry describes these relationships for reference and education and does not provide acute-management instructions for any individual.

Epidemiology

Pooled population data estimated that retinal vein occlusion affects on the order of 16 million adults worldwide, making it one of the more common retinal vascular disorders and a frequent cause of vision impairment, with prevalence rising with age. Retinal artery occlusion is less common but carries the urgency of an acute ischaemic event and shares risk factors with stroke and cardiovascular disease (rogers-2010; hayreh-2018).

Evidence & guidelines

Understanding of retinal vascular disease rests on epidemiological pooling, natural-history studies, and trials of treatments for the macular oedema and neovascular sequelae of vein occlusion, alongside reviews of the acute ischaemic management of artery occlusion. Specific clinical recommendations are set by professional bodies and stroke pathways; this entry summarises the evidence framework rather than reproducing them (rogers-2010; hayreh-2018).

History

Retinal vascular occlusions were recognised through ophthalmoscopy and later characterised by fluorescein angiography, which distinguished ischaemic from non-ischaemic patterns and clarified the role of capillary non-perfusion. Large multicentre vein-occlusion studies in the late twentieth century defined natural history and the consequences of ischaemia, and the subsequent identification of vascular endothelial growth factor in the oedematous and neovascular complications shaped modern pharmacological treatment (hayreh-2018; rogers-2010).

Seminal works

• rogers-2010
• hayreh-2018

Frequently asked questions

Why is central retinal artery occlusion compared to a stroke?

It is an acute interruption of arterial blood flow causing ischaemic injury to retinal neural tissue, mechanistically analogous to ischaemic stroke, and it shares embolic and atherosclerotic causes, which is why it prompts evaluation for systemic vascular sources.

What is the difference between retinal artery and retinal vein occlusion?

Artery occlusion blocks blood entering the retina and causes sudden ischaemic vision loss, whereas vein occlusion blocks blood leaving the retina and causes haemorrhage, macular oedema, and, if ischaemia develops, later neovascular complications.