If a retinal artery of the eye is occluded, the retina is no longer supplied with enough oxygen. The cause is a flush in blood clot (embolism), which usually originates from a cervical artery or occurs as part of a heart rhythm disorder in the atrium of the heart. If the blood clot remains stuck in the central artery of the eye, the entire retina of the eye is no longer supplied with blood. This is known as a central artery occlusion and the affected eye sees black. Smaller clots only get stuck in thinner peripheral arteries, which results in an arterial branch occlusion, and therefore only the upper or lower visual field or a smaller part of the peripheral visual field goes blind. After just 60 to 90 minutes, the first permanent damage to the underserved retina occurs and the examination reveals that the affected retinal area is turning pale.
By reducing intraocular pressure with medication, hyperventilation, oxygen administration and massaging the eyeball, emboli can reach further peripherally and the resulting retinal damage can theoretically be reduced.
In approximately 25% of people, in addition to the central artery, there is a so-called cilioretinal artery, which supplies the center of the retinal tissue. In this case, those affected may retain central vision and not become completely blind due to the central artery occlusion.
If blindness only lasts a short period of time and regresses completely, it is referred to as amaurosis fugax or TIA (transient ischemic attack), the clot has resolved by itself. This is a sign that there is an underblood flow in the eye and brain, i.e. a harbinger of a possible stroke. Detailed medical diagnosis can prevent impending strokes and arterial occlusions.
Immediate presentation at a tertiary hospital (stroke unit, eye clinic at university or cantonal hospital). Within the first four to six hours, there is a chance that medication can dissolve the blood clot and thus save vision.
Patients aged 60 to 70 are usually affected, men more often than women. Only 1-2% have the shutter affects both eyes
Arterial occlusion is often a harbinger of a stroke; precise clarifications can help to find the cause of it. Targeted treatment of these causes can prevent impending strokes and further arterial occlusions in the other eye with the risk of complete blindness.
If the clot cannot be dissolved in the first few hours, the prognosis is very poor. The underserved retina is remodeled and can no longer function.
Unfortunately, there are no such treatments available at the present time.
Even if blindness or partial blindness has occurred, regular examinations by an ophthalmologist are still important, because the underserved retinal areas can lead to the formation of new vessels in the eye. These vessels are of poor quality and can cause bleeding in the eye, increased eye pressure and pain.
