The embolism in the eye

What is an embolism in the eye?

An embolism is a pathological event that leads to a blockage of vessels. The cause is usually a small blood clot (Latin: thrombus). But air and fat embolisms can also occur in the eye - fortunately, they are very rare.

The clogging of the blood vessel leads to an insufficient supply of the tissue with oxygen and other nutrients transported via the blood. As a result, the tissue dies. An embolism usually occurs in the small blood vessels that supply the retina. The damaged retina can no longer properly perceive the incident light stimuli. A loss of vision results.

The cause

The causes of an embolism in the eye are diverse and mostly systemic in nature. For example, increased coagulability of the blood can lead to increased formation of blood clots. These trigger small embolisms in many parts of the body.Such an embolism quickly becomes noticeable in the eye, since the eye is a very small structure. Even very small clots can cause blockages.

The blood vessels can be blocked by very small clots and the retina will quickly fail. In addition, diseases of the heart also play an important role in the formation of blood clots. Cardiac arrhythmias result in small clots that are carried to other organs by the bloodstream.

Other causes of embolism in the eye can also be inflammatory processes - especially if the inflammation affects vessels near the eye, such as temporal arteritis (inflammation of the temporal artery). The reason for this is the body's immune reaction, which favors the formation of blood clots. But diseases of the eye itself, such as glaucoma (increased intraocular pressure) can cause embolisms. The pressure in the eye changes the blood flow, it flows more slowly and can therefore clot in the blood vessel.

Find out all about the topic here: The blood clot.

The accompanying symptoms

Embolism in the eye most often affects the retina of the eye. This does not have sensors that can perceive pain stimuli, which is why you usually cannot feel an embolism in the eye. As a rule, the embolism is only noticeable when parts of the retina that are needed for vision are affected.

There are many receptors in the retina that transmit signals to the brain when light falls on them. If the defect in the retina is too large due to the embolism, the brain notices that light signals can no longer be received at a certain point in the eye. Affected people notice this through a loss of a small area of ​​the field of vision. For example, objects and movements can no longer be perceived at a certain point. In the case of small defects, the brain is able to think up the missing image (usually only one eye is affected by an embolism and the brain receives information about the invisible area from the other eye). Often there are only severe restrictions in the case of major circulatory disorders in the eye. These can, for example, lead to half or even the entire field of view being lost in one eye.

Since the embolism in the eye is often a sudden process, one should definitely think about an embolism in the event of an acute loss of vision and have this clarified by a doctor.

This article might also interest you: The visual field examination.

The diagnosis

Diagnosing embolism in the eye consists of several steps. First of all, the person concerned is asked about their complaints, mostly about the impairment of vision.

This is followed by an examination of the eye, during which the doctor looks into the eye with a special lamp (slit lamp). To ensure a better view of the back of the eye, the pupil is often "dripped wide". Eye drops are used to dilate the pupil. With this slit lamp examination, the retina and its vessels can be assessed; an embolism of the retinal vessels can usually be seen there.

The treatment

Treatment of the embolism of the eye ideally takes place before the disease occurs. In this case one speaks of prevention. Various risk factors that favor blood clotting can be treated with medication. Blood clots are prevented by means of blood thinning. The treatment of excessively high blood lipid levels and the treatment of blood sugar disease (diabetes mellitus) can also reduce the risk of an embolism in the eye.

If an embolism actually does occur, blood thinning is also the therapy of choice. One tries to dissolve the blood clot as quickly as possible so that the affected retinal sections are supplied with blood again as quickly as possible. If this does not succeed, new blood vessels are often formed in the eye within the next few months to replace the old, blocked vessel. However, this so-called neovascularization can increase intraocular pressure or cause the retina to detach. Therefore one tries to prevent these vessel formation by means of laser treatment. In addition, growth-inhibiting substances are used, which are injected into the eye using a syringe. These should also reduce the formation of new vessels.

Find out more about the topic here: The anticoagulants.

The duration

An embolism in the eye is a blood clot that initially remains in the blood vessel if the clot is not dissolved with medication. After a few days, the body can dissolve the embolism on its own. In most cases, however, secondary damage occurs due to the long phase in which the affected parts of the retina were not supplied with blood.

These consequential damages are treatable to a limited extent and often cause problems again and again. After an embolism in the eye, the risk of another embolic event in the eye (or in other organs) is also increased. Therefore, a long-term to permanent treatment of the risk factors should be considered.