Ophthalmology

While strokes typically occur in the brain, they can also affect the eyes. An eye stroke occurs when the blood supply to the retina or optic nerve is interrupted, leading to sudden and painless loss of vision. 

There are different types of eye stroke, depending on the structures affected: 

Ischaemic Optic Neuropathy
Ischaemic Optic Neuropathy (ION) occurs due to a reduced blood supply to the optic nerve. This condition can be transient, affecting vision for a few seconds or minutes before returning to normal. ION has two forms: arteritic and non-arteritic. The arteritic form, often caused by giant cell arteritis, is more severe. The nonarteritic form is more common, and often linked with conditions like hypertension, diabetes and smoking.

Retinal Artery Occlusion
When the blood flow through the central retinal artery is interrupted, the oxygen supply to the entire retina is disrupted. This condition, known as Central Retinal Artery Occlusion (CRAO), typically results in a sudden loss of vision across all visual fields. The vision loss can be transient, lasting from seconds to hours before complete occlusion occurs. Since visual loss may indicate an impending cerebral stroke, patients require urgent referral to neurology or acute stroke management services. When a branch of the central retinal artery is blocked, causing partial visual loss as only a part of the retina is affected, the condition is known as Branch Retinal Artery Occlusion (BRAO).

Retinal Vein Occlusion
If the blockage occurs in the retinal veins draining out of the eye, blood and other fluids may build in the retina and cause ischaemia and macular oedema. Lack of oxygen in the retina may also occur and abnormal growth of new blood cells may develop in the eye. Central Retinal Vein Occlusion (CRVO) is caused by the obstruction of the main vein while Branch Retinal Vein Occlusion (BRVO) is due to the obstruction of a small branch of retinal veins. The severity of vision loss in BRVO is generally lesser than that of CRVO. 

Our ophthalmologist will explain the condition and advice on which treatment is most appropriate for the patient.

Depending on the diagnosis, treatment may include:

• Hyperbaric oxygen (CRAO)
• Eyeball massage (CRAO)
• Lowering the eye pressure(CRAO)
• Retinal endovascular cannulation surgery to displace or lyse the embolus or thrombus (CRAO)
• Intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agent or steroids to treat macular edema (CRVO)
• Retinal laser therapy (Pan Retinal Photocoagulation) and intravitreal injection of anti-VEGF agent to treat abnormal growth of new blood vessels (CRVO)
• Steroid treatment (giant cell arteritis)
• Modification of risk factors
• Referral to neurology or cardiology for further workup and treatment for underlying cerebrovascular and cardiovascular conditions