Intravitreal injections for the treatment of ocular pathologies

Intravitreal injections consist of the introduction of millimeter needles into the vitreous humor. The main pathology treated is the exudative form of age-related macular degeneration (AMD). Correct monitoring and administration of the injections reduces the probability of blindness to practically zero.

Intravitreal injection: what it consists of

The intravitreal injection technique consists of the careful introduction of very small needles into the interior of the eye (in the vitreous humor), through the sclera (white part of the eye). The treatment is performed under local anesthesia using a combination of anesthetics in drops, so that the pain is bearable, and has an extremely short duration, equivalent to injections to draw blood in the arm.

Pathologies treatable with intravitreal injections

Currently, the main pathology treated with intravitreal injection is the exudative form of age-related macular degeneration (AMD). Biological treatments are used that inhibit vascular endothelial growth factor (VEGF), the main factor responsible for this disease, as well as for diabetic retinopathy and diabetic macular edema, macular degeneration associated with myopia, and macular edema caused by retinal thrombosis. Alternatively, intravitreal corticosteroid injections can also be used in specific contexts.
Much less frequent is the use of intraocular chemotherapy to treat intraocular tumors, lymphomas or intraocular inflammation. Antibiotics and antivirals are also used for certain intraocular infections. Or intravitreal injections of air or gases which may be useful for some forms of retinal detachment.

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Contraindications to intravitreal injection

In general there is no contraindication to receive intravitreal injections. The only special precaution to be taken is that there is no ocular infection (conjunctivitis, sties…) at the time of injection, because of the risk of developing serious complications such as intraocular infections.
The efficacy of the treatment is greater the earlier it is started from the onset of the disease, and the greater the frequency of check-ups and injections in the initial months of the disease. For example, in the exudative form of age-related macular degeneration (AMD), the periods between follow-up visits should generally not exceed 6 to 8 weeks.

Results of intravitreal injection

The results with intravitreal injection are favorable in the vast majority of cases. But what is really important is the treatment regimen and the time between intravitreal injections.
There is no maximum limit to the number of injections an eye can receive. And injections are usually repeated as needed every 4 weeks.

Treatment before or after intravitreal injections

No pre- or post-treatment is required for patients receiving intravitreal injections. Pre- and/or post-injection antibiotics have been shown to be dangerous and do not prevent the risk of infection, but rather increase it. In the moments before the intravitreal injection, diluted povidone-iodine drops are applied to asepticize the injection site. This is sufficient and accepted by international clinical practice guidelines.
Patients should be alert to possible loss of vision and pain in the days following the injection. In such a case, they should immediately consult their ophthalmology and retina specialist to rule out an infection secondary to the injection, which occurs very rarely in approximately 1 out of every 1000 injections.
In conclusion, it could be stated that, if as a patient you are correctly followed up and the injections are correctly placed at the correct times, the possibility of going blind is minimal.