Treatment with intravitreal injections
Intravitreal injections are a modern treatment for the exudative (wet) age-related macular degeneration (AMD), diabetic macular oedema, retinal vein occlusion, myopic maculopathy and other less common ocular conditions.
What does treatment with intravitreal injections involve?
An intravitreal injection is an injection into the eyeball. Various drugs are administered into the vitreous chamber of the eye using a very thin needle. The vitreous body, on the other hand, is a gelatinous substance that fills the posterior segment of the eyeball.
Treatment with injections improves vision in many cases and also protects against serious complications such as macular haemorrhage. The injection itself takes a very short time in a treatment room under sterile conditions and under eye drop anaesthesia – it doesn’t hurt! Once the medication has been administered, the patient goes home.
After injection, a feeling of gritty eyes, discomfort and displacement of dark spots are possible. The above symptoms subside hour by hour. Monitoring of the effectiveness of the treatment takes place during subsequent visits to the ophthalmologist, along with OCT evaluation.
We have all intravitreal preparations registered in the European Union. The choice of drug and the regimen of administration is decided by the doctor during the qualification visit.
The SPEKTRUM Clinical Ophthalmology Centre was one of the first centres in Poland to introduce intravitreal anti-VEGF preparations for the treatment of exudative age-related macular degeneration in 2005.
What is the macula lutea and why does it degenerate with age?
The mechanism of action of the human eye can be compared to the mechanism of action of a camera. The image is captured on film, which in this case is the light-sensitive tissue of the eye – the retina. Its central, most valuable part is the macula lutea. This is what makes us see sharply.
In a healthy macula lutea, there are several million cone cells – light-sensitive cells – in which, under the influence of visual stimuli, chemical changes take place and then electrical impulses are emitted, which reach the brain via the optic nerve. This is why macular lesions are very dangerous and can lead to permanent loss of vision.
Indications for intravitreal injections:
nAMD – exudative form of neovascular age-related macular degeneration – the so-called exudative or wet form. It is caused by an abnormal proliferation of defective blood vessels in the macula lutea, which can allow fluid to pass through, which results in swelling, and bleeding can occur.
Retinal vein occlusion (RVO) – more common in older age due to atherosclerotic changes in the retinal vessels and circulatory disorders. This also occurs in younger patients and may be related to the special structure of the retinal vessels, systemic and inflammatory diseases, increased ocular pressure and the use of certain medications.
Myopic maculopathy – is a particular form of macular disorder associated with myopia. It involves the proliferation of pathological vessels in the macula lutea, thin retina of myopic eyes (myopia results from axial elongation of the eyeball, which causes, among other things, thinning of the retina) and this can lead to oedema, haemorrhage into the macula and subsequent fibrosis and atrophic changes.
DMO – Diabetic macular oedema – is a major cause of visual impairment/loss in the working population! Diabetes mellitus damages the blood vessels of the eyeball. They become leaky, often compared to a ‘rusting pipe’, and fluid leaks through them along with various blood elements to the outside. Oedema develops. If it affects the central part of the retina – the macula lutea – we are dealing with diabetic macular oedema.
This requires intensive and systematic treatment.
Forms of age-related macular degeneration
There are two forms of age-related macular degeneration:
- dry form
- exudative (wet) form
Dry macular degeneration
This accounts for the majority of AMD cases.
With age, macular drusen develops, i.e., an accumulation of material from the metabolism of retinal cells, which is systematically removed at a younger age. Above them, the retina is damaged. It may disappear over time, and this process lasts until the end of life and is irreversible. It is usually quite slow, but causes problems with everyday activities, i.e., reading – initially single letters are missing, then whole words. One of the typical symptoms is a gradual loss of facial and road sign recognition.
Peripheral vision is preserved.
It is worth noting that the vision of one eye is compensated by the other eye. It is necessary to examine each eye separately. There is currently no treatment for this form of AMD.
Exudative form of age-related macular degeneration – wet form
In about 10 % of cases, there is proliferation of pathological vessels under the retina. This is the defence response of the retina to hypoxia. Many factors circulating in the blood, the so-called cytokines, of which the best known are vascular growth factors – VEGF (Vascular Endothelial Growth Factor) and angiopoietin participate in the process of carcinogenesis.
During the first period of the disease, there may be less characteristic symptoms such as a general deterioration of vision. One of the typical symptoms of exudative AMD is wavy straight lines and a dark spot in the central visual field. The course of the exudative form of age-related macular degeneration can be very rapid.
In this case, a quick diagnosis and prompt treatment can save sight.
Although most people with advanced AMD do not experience complete loss of vision, its deterioration negatively affects quality of life, and in 1/3 of patients, it leads to clinically overt depression, even if the disease affects only one eye. If advanced macular degeneration develops in one eye, the likelihood that it will also affect the other eye within five years is up to 40%. The risk of bilateral blindness in a person with unilateral visual impairment, due to the exudative form of AMD, can be approximately 12% over 5 years.
How do drugs (anti-VEGF) administered by intravitreal injections work?
Such drugs:
- inhibit the growth of abnormal, pathological blood vessels
- seal pathological vessels
- sometimes cause atrophy of pathological vessels
- reduce retinal oedema
Key factors in the development of AMD:
- Age
The most important risk factor for AMD – the risk of the disease increases after the age of 50 - Sex
Women are at greater risk of developing the condition. - Genetic factors
– relatives of people with AMD have a 20-fold higher risk of developing the disease
– iris colour – people with blue irises are significantly more likely to develop AMD
– white race - Diet and lifestyle, inter alia:
– insufficient intake of vitamins and antioxidants
– excessive alcohol consumption
– frequent consumption of foods rich in saturated fatty acids and cholesterol - Smoking cigarettes increases the risk of developing AMD by up to six times!
- Cardiovascular diseases
– Ischaemia of the ocular tissues promotes the development of AMD - Obesity
In severely overweight people, a reduced content of free radical neutralising substances is found in the macula. - Lack of physical activity
- Frequent and excessive exposure to intense UV radiation
Self-monitoring with the Amsler test
The test allows the assessment of macular function. The examination is carried out for each eye separately. The patient should cover one eye and place the Amsler test in front of the other eye at a distance of about 30-40 cm – if he or she is using reading glasses, they need to be put on beforehand. It is important to look at the central point. If the lines around remain straight, the squares even, and no spots or darkening appear, this means that the test is negative, i.e., the macula lutea is healthy.
If you experience the symptoms mentioned above, you should visit your ophthalmologist immediately and have an OCT evaluation!
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