Losing vision in one eye, even without pain, is never trivial. It may even be the main sign of an emergency called an eye stroke in which you can lose your sight for good. We must therefore react quickly! Explanation with Dr. Gérald Kierzek, emergency physician and medical director of True Medical.
An eye can also have a stroke
Eye stroke, also called retinal arterial or vein occlusion, corresponds to a sudden interruption of blood circulation in the vessels of the retina. The cause: a blood clot (thrombosis) or vascular compression (ischemia).
“As with a cerebral stroke, every minute counts, because the retina is a tissue very sensitive to lack of oxygen” announces Dr. Kierzek.
There are several forms, with more or less severe consequences.
The most feared is central retinal artery occlusion (CRAO). “It is the equivalent of an eye infarction. The main artery, which supplies blood to the retina, suddenly becomes blocked, causing a sudden, painless and almost complete loss of vision in one eye”. Vision becomes black or extremely blurry. Without rapid restoration of circulation, the lesions become irreversible within a few hours.
The most common: central retinal vein occlusion (CRVO). “Here, it is the blood drainage system that is blocked. The loss of vision can be sudden or progressive, often less severe than in CRAO. However, it is not benign: it can be accompanied hemorrhages and retinal edemasometimes leading to permanent after-effects.
Finally, certain occlusions only affect an arterial or venous branch, thus affecting only part of the retina. This causes a scotoma, a blind area in the visual field.
One symptom, many causes
Whatever the nature of a sudden loss of vision, it is essential to consider it as an emergency. The causes of these occlusions are multiple, but almost always relate to a poor vascular health. Atherosclerosis (plaque deposits in the arteries), embolism (clot coming from the heart or carotids), hypertension, diabetes, glaucoma, coagulation disorders or inflammation of the vessels (vasculitis) are all risk factors.
Dr. Kierzek insists: “An eye stroke never happens by chance. It can be the first sign of a more general cardiovascular problem. A complete assessment is therefore necessary, with an electrocardiogram, carotid ultrasound, blood test, etc.
Limited but essential treatments
What treatment if this happens to you? In the case of CRAO, treatment in the acute phase remains controversial. “No strategy has demonstrated obvious effectiveness in restoring vision beyond 4 to 6 hours, it is often catastrophic. We can try to lower the intraocular pressure, or even administer anticoagulant treatments or thrombolysis, but Le prognosis remains poor”.
On the other hand, for CRVO, targeted treatments exist. Anti-VEGF drugs can be injected into the eye to reduce edema, laser or corticosteroids can be used in cases of severe ischemia. Visual improvement is possible, but often partial, and complications may persist, such as macular edema or neovascularization.
The right reflex: consult urgently
“A sudden loss of vision should be considered an absolute emergency” insists our expert. If you experience symptoms, you should immediately consult an ophthalmologist or go to the emergency room.
“The quicker the intervention, the greater the chances of saving vision – and preventing other strokes, particularly cerebral ones – are. An eye stroke is an alarm signal that must be recognized and taken seriously. Not only to preserve vision, but also to avoid much more serious cardiovascular events.”