The retina is the light-sensitive tissue at the back of the eye that is covered with cones and rods for good vision. To function properly, the retina needs blood that contains nutrition and oxygen. The blood also removes waste products from the retina. The blood reaches the retina via the arteries and leaves the retina via veins. With a retinal occlusion, which is possible when both veins and arteries are blocked, blood vessels leak so that blood, fluid and proteins end up in the retina and cause damage. The hardening of the arteries is the main cause of this eye disease that suddenly causes a decrease in vision. The doctor treats the eye disease using laser therapy and medication, although the prospects are not always good. This especially applies to patients in whom complications have occurred.
- Types of retinal occlusion
- Causes: Hardening of arteries
- Risk factors: blockage of the blood vessels of the retina
- Symptoms: Sudden vision loss
- Diagnosis and examinations
- Treatment via laser therapy and medication
- Prognosis is variable
- Complications of eye disease
- Prevention of eye disease
Types of retinal occlusion
Retinal arterial occlusion
When a blood vessel supplying blood is occluded, this is called a retinal arterial occlusion. Due to the lack of nutrition and oxygen, part of the retina may die. Retinal arterial occlusions are less common than venous occlusions.
Retinal vein occlusion
An occlusion of a blood vessel is known as a retinal vein occlusion. This retinal disease often occurs in patients over the age of fifty with a history of cardiovascular disease.
Causes: Hardening of arteries
A blockage of a blood vessel may be due to various factors. Arterial occlusion often causes a blood clot to occur due to hardening of the arteries (medical term: arteriosclerosis). Cholesterol and other fats accumulate in the wall of the blood vessel, causing it to thicken. When this thickening tears open, blood clots enter the bloodstream. The blood clots continue through the bloodstream but become stuck in a narrower blood vessel, resulting in a blockage of the narrow blood vessel.Smoking is a risk factor for the blockage of the retinal blood vessels / Source: Geralt, Pixabay
Risk factors: blockage of the blood vessels of the retina
With these conditions or due to these factors, patients are more likely to have problems with the blood vessels of the eyes. This causes arteriosclerosis to occur more quickly, including in the retina of the eye.
- Diabetes mellitus (diabetes)
- A vitreous hemorrhage (sudden loss of vision)
- A heart and vascular disease (cardiovascular disease) such as an irregular heart rhythm (arrhythmia) or heart valve disease
- High blood pressure (hypertension)
- High cholesterol (hyperlipidemia)
- Glaucoma: increased intraocular pressure that causes damage to the optic nerve
- Intravenous drug use
- Age: above sixty years
- Macular edema: swelling, fluid retention and thickening of the central part of the retina (= yellow spot)
- Overweight (obesity)
- Smoking
- Rare blood diseases
Symptoms: Sudden vision loss
The severity of symptoms varies and depends on the location of the blockage. Usually a sudden (within a few seconds) reduction in vision occurs. In severe cases, even transient sudden blindness occurs, known as amaurosis fugax (stroke in the eye). The patient otherwise has a normal -looking eye. The temporary loss of vision is also painless.
Diagnosis and examinations
Ophthalmological examination
The ophthalmologist performs a thorough eye examination. Visual acuity is reduced to less than counting fingers. He also measures eye pressure using tonometry. He also dilates the pupils using special eye drops, known as mydriatics, to obtain an image of the retina. In addition, the doctor tests the patient’s pupillary response. Through an ophthalmoscopy, an examination of the back of the eye, the doctor obtains a typical image of the retinal occlusion.Electrocardiography (ECG) / Source: CardioNetworks, Wikimedia Commons (CC BY-SA-3.0)Diagnostic examination The ophthalmologist carries out several examinations, such as a visual field examination, an OCT scan (retinal scan) and a fluorescent angiography to visualize the blood vessels of the retina. Other general tests that a doctor orders are a blood test, an echocardiography, an electrocardiography (ECG: measurement of the electrical activity of the heart) and a heart monitor to check the heart rhythm. In this way the doctor gets an idea of the patient’s vascular system.
Treatment via laser therapy and medication
Retinal arterial occlusion
The ophthalmologist prescribes blood thinners (blood thinners) for retinal arterial occlusion. When proliferation of new blood vessels (neovascularization) occurs, the ophthalmologist treats this with laser therapy.
Retinal vein occlusion
The ophthalmologist treats the resulting leaks using laser therapy. Anti-VEGF medications also slow down the proliferation of new blood vessels. VEGF stands for vascular endothelial growth factor, a growth factor that ensures the production of new blood vessels. Anti is the medical term for against. In other words, the medicines stop the new formations. When the blood vessels are blocked, macular edema occurs, a swelling of the macula (the central part of the retina). The ophthalmologist treats this eye problem with corticosteroids, a strong medicine with an anti-inflammatory effect. The ophthalmologist injects this medication (Dexamethasone (Ozurdex)) through an implant rod that is placed in the eye.
Prognosis is variable
The visual outlook in retinal arterial occlusion is very different. Some patients regain a small or large part of their vision. In other patients, the vision in the affected eye is and remains limited or the patient is even completely blind. The ophthalmologist monitors the patient closely after a retinal occlusion because complications sometimes only occur months later. When complications occur, the visual prognosis is generally (very) poor.
Complications of eye disease
Macular edema, neovascularization (new formation of blood vessels in the eye), neovascular glaucoma and retinal detachment are possible complications of retinal occlusion.
Prevention of eye disease
Arteriosclerosis is the main cause of retinal occlusion. It is therefore best for the patient to ensure that he maintains a healthy lifestyle, which is accompanied by a healthy low-fat diet, a healthy weight, good blood pressure, sufficient exercise and no to moderate smoking and alcohol consumption. If necessary, the doctor prescribes medication to lower blood pressure. The patient may also receive a doctor’s prescription for statins. These are medications that lower high cholesterol levels.
read more
- Ocular infarction: Closure of blood vessels in the retina
- Temporary vision loss (sudden vision loss)
- Amaurosis fugax: Temporary blindness due to stroke in eye
- Suddenly blind in one eye or both eyes due to conditions
- Retina: Conditions and problems with the retina in the eye