Ipoh Echo’s EYE HEALTH series continues with Consultant Eye Surgeon Dr S.S. GILL talking to us about Ocular Strokes.
An interruption to the blood flow of the eye results in what is referred to as an eye stroke. Eye strokes are acute and vision-threatening. The eyesight effects range from mild blurring vision to severe irreversible blindness depending on the type and extent of stroke. Several underlying factors are frequently associated with strokes in the eye. One of the main culprits is hypertension, also called high blood pressure which afflicts almost 40% of people above the age of 25 years by the World Health Organisations (WHO) estimates.
Hypertension damages blood vessels in the eyes. Both, duration and also the severity of hypertension play a role in determining the extent of damage to blood vessels in the eyes. Other common illnesses that play a part in accelerating the damage are diabetes mellitus, hypercholesterolemia (increased cholesterol levels), cardiovascular disease and smoking.
The effect on the eyes can be broadly divided into 3 types:
Retinal Artery Occlusion – blockage of the arteries to the eye (retina).
Retinal Vein Occlusion – blockage of the veins draining the blood from the retina.
Ischaemic Optic Neuropathy – poor blood flow to the eye causing optic nerve damage.
When the above occurs, it means that it has reached a complicated stage of hypertension.
RETINAL ARTERY OCCLUSION
Serious because it results in sudden profound loss of vision in the affected eye. It is an eye emergency and any delay in treating this results in permanent loss of vision in the affected eye. Quick treatment improves the chances of recovery but even this is only by about 20 to 25%. Should this happen to an individual, a thorough cardiovascular assessment will need to be done as this condition is an ominous sign of potential vascular complications to the organs. If the artery involved is the main artery (Central Retinal Artery Occlusion), the vision loss is profound. If it is the branch that is involved (Branch Retinal Artery Occlusion as shown in the picture – lower half is pale), the vision loss is less profound.
RETINAL VEIN OCCLUSION
The occlusion may affect either the main retinal vein (Central Retinal Vein Occlusion – adjacent pic) or one of its branches (Branch Retinal Vein Occlusion). If it is the main vessel, the visual effects are more serious than if a branch is affected.
A vein occlusion is still the lesser of the two evils if it is compared to retinal artery occlusion described above.