Retinal venous occlusions suddenly strike in adulthood. It happens to individuals suffering from hypertension, heart disease or diabetes. Also, in the cases of high cholesterolemia or arterial sclerosis. Until a few years ago, surgery was limited to laser treatments only. However, now there have been more effective treatments for circumstances that do not respond to classical therapy. Some of them are intravitreal injections of cortisone or antiangiogenic.
The typical symptomatology generally involves a 50-year-old hypertensive who observes a decline of vision in one eye. The vision is generally low, 1/10 or 2/10 with correction. Examination of the fundus shows venous congestion in the retina, hemorrhages, rare cottony nodules and hyperemic papilla.
Retinal venous occlusions represent the second most common vascular disease affecting the retina after diabetic retinopathy. It is good to be aware of the factors that increase the risk of meeting this condition, and how it can be prevented.
For various reasons, when partial or total obstruction of the retinal veins occur, we speak of venous occlusion (or thrombosis). The discontinuation or slowdown of blood flow causes the retina to be deoxygenated and malnourished. This can lead to ischemia and even to the infarct of the innermost portion of the retina itself. Moreover, the smaller and more peripheral the vessel involved; the less problem is found in the retinal area. On the contrary, the larger and more central the vessel concerned; the more serious are the consequences involved.
In general, retinal vein occlusion is distinguished into:
· Bundle Branch Obstructions (BBO: involving only the venous branches of the retina. The obstruction is caused by a thrombus that occurs in areas where the arteries and veins cross
· Occlusion of The Central Vein of The Retina (OVCR): involving the entire central retinal vein
There are also two main forms, such as:
· Exudative (Edematous) Forms. They represent 60% of the forms. The occlusion starts relatively slow and reaches its complete state within 2-10 days. The retinal veins and capillaries dilate, resulting in bleeding and edema
· Ischemic forms. They represent 15% of the forms. This is relatively abrupt and fast in nature. Ischemia associated with vascular pathology can cause the formation of neovascular membranes, which can cause some significant vitreous bleeding. This type of occlusion can also lead to a severe form of glaucoma (neovascular glaucoma)
Risk Factors Of Retinal Vein Occlusions
It is not always possible to trace the occlusive back to a known cause. However, there are several factors that can increase the chances of retinal vascular disease. The more these risk factors coexist, the higher the probability of the disease.
These factors include:
· Age over 50 years
· Diabetes mellitus
· Nicotine addiction
· Autoimmune diseases and hematological diseases
Generally, retinal vein occlusions are not associated with pain and occur only in one eye. The decrease in vision associated with the disease varies depending on the retinal area involved.
In the case of central venous occlusion, there is a loss or decrease in vision which is sudden and also quite severe. In the case of venous branch occlusion, the visual decline does not affect the full vision, but the retinal area in which it is located. For example, if the area of the macula (i.e. the central part of the retina) is involved, the central vision will be lost.
In order to diagnose retinal venous occlusions, it is necessary to undergo a complete ophthalmological examination.
Examination Of The Ocular Fundus
Fluorangiography, which allows to accurately highlight the occluded vessel and identify any retinal ischemia.
Optical Coherence Tomography. If the macular area is involved, it is preferred to carry out the OCT. This examination makes it possible to follow the macular fluid (edema) without the use of contrast medium, according to the treatments established.
As we have said retinal venous occlusions represent a vascular pathology. For this reason, it is possible to prevent them by implementing some preventive measures:
· Keep your blood pressure under control
· Check the values of cholesterol and blood sugar
· No smoking
· Maintain normal weight
· Avoid sedentariness and practice moderate but regular physical activity