A thrombosis is a blood clot that forms in a blood vessel and may partially or completely occlude it. This blood clot is also called a thrombus. Thromboses often occur in the veins because the blood flow rate is lower than in arterial vessels and the walls of the veins are thinner.
In most cases, thromboses occur preferentially in vessels far from the heart, such as in the leg or pelvic veins. But thrombosis in the eye is also possible. In this case, the blood clot forms in a vein that supplies the retina and therefore leads to impaired vision. Rapid treatment is therefore of great importance in order to reverse the damage caused as far as possible.
Causes
In addition to the generally applicable factors that cause thrombosis, a number of diseases in particular are associated with a particularly high risk of thrombosis in the eye. These include permanently elevated intraocular pressure, diabetes mellitus and arterial hypertension. The blood clot in the retinal vein means that the oxygen-poor blood can no longer be transported sufficiently away from the retina.
In the acute phase, bleeding into the retina therefore occurs. In the long term, there is a lack of oxygen for the retinal cells, which in turn causes permanent visual impairment. In addition, in the chronic phase of the disease there are often vascular proliferations in the retina, which can lead to further visual impairment.
Symptoms
A thrombosis in the eye is usually not painful for those affected and is only accompanied by a deterioration in vision. Depending on which vein is affected by the occlusion, the location of the visual deterioration may also vary. For example, the upper or lower field of vision may be affected earlier, but a more lateral or central loss of vision is also conceivable.
It is particularly impressive for affected persons if the center of the retina is affected either directly (by the occlusion of the vein itself) or indirectly (by water retention in the center of the retina). If the latter is the case, affected persons often report about it, especially in the morning about a visual deterioration in the form of veil vision. This is due to the fact that the removal of water from the retina is lower, especially at night, and thus water can preferentially accumulate there until the morning hours. It is important, however, to clearly and early distinguish a thrombosis in the eye from a stroke, since the latter is often accompanied by similar symptoms.
