The occlusion of a blood vessel caused by a clot can occur not only in the legs but also in the eye; this is known as a retinal venous occlusion. As a result, blood can no longer flow out of the retina and a backflow occurs. This causes blood and fluid to leak into the tissue and obscure or reduce vision.
Peripheral venous occlusions cause fewer symptoms than when the hemicentral or central vein is blocked.
In the case of non-ischemic venous occlusions, the prognosis is relatively good and vision can be medically rehabilitated if necessary. In the case of so-called ischemic venous occlusion (25%), the backflow of blood leads to an undersupply of oxygen to the retina, which not only causes permanent damage but also sequential damage.
0.77% of people worldwide are affected by venous occlusion over the course of their lives.
The exact cause of venous thrombosis in the eye has not been clarified, but there are certain risk factors that can promote venous thrombosis:
Venous thrombosis releases messenger substances in the eye, which cause fluid leakage in the area of the central retina, a so-called macular edema. This results in blurred and distorted vision. By intravitreal therapy If VEGF antibodies are injected into the eye, these messenger substances are bound and the macula becomes dry again.
Blood sampling from a family doctor is indicated in order not to miss systemic diseases as the cause of venous thrombosis.
3 months after the onset of thrombosis, retinal hemorrhages in the eye are usually resolved and fluorescence angiography is initiated to identify retinal areas with reduced blood flow.
Ischemic, i.e. areas of the retina with no blood flow, lead to the release of VEGF. This messenger causes the formation of macular edema and new vessels, which bleed frequently. The release of VEGF can be reduced by localized treatment of these areas with an argon laser.
The prognosis depends heavily on the affected retinal area and the type of occlusion. Non-ischemic venous occlusions treated with anti-VEGF usually have a good prognosis.
In most cases, only one session with the laser is necessary, after which the affected retina scars.
Intravireal anti-VEGF therapy is carried out monthly for three months. After this so-called saturation, the spray intervals can be extended as required. Injections are usually required over several months or even several years to keep the macula constantly dry before the treatment can be completely completed.
Checks and treatment are important to maintain eye vision.
Examinations by an ophthalmologist are also of great importance in cases of ischemic venous occlusion with blindness or partial blindness. Underserved or ischemic retinal areas can lead to the formation of new vessels in the eye, so-called neovascularizations. These vessels are of poor quality and can cause bleeding in the eye and painful increases in eye pressure or the development of a glaucoma lead.
