Autologous serum and plasma rich in growth factors

Autologous serum and plasma rich in growth factors are blood-derived eyedrops that are generally prepared from the patient's own blood. Therefore, they are autologous. 

However, if blood cannot be drawn from the patient, as may be the case with severe anaemia, or the patient is contraindicated for the use of their own blood, the blood of a compatible relative is used. In this case, the drop is allogenic.

Blood-derived drops contain proteins, growth factors and vitamin A as well as other substances that are present in the tear film and are important for the regeneration and the proliferation of the epithelial cells of the cornea and the conjunctiva. 

These qualities make the drops ideal for the treatment of eye surface pathologies when the cells are damaged. 

The use of these drops is indicated for dry eye disease, particularly in severe cases due to any cause: cornea ulcers because of lack of cornea sensibility, stem cell deficiency in the limbal area (region on the edge of the cornea), persistent corneal epithelial defect and recurring corneal epithelial erosions.

In the majority of cases, commercialised artificial tear treatment has not been effective. 

These drops have to be prepared in centres with the correct equipment and qualified staff. There are various types of blood-derived drops depending on the preparation. 

After drawing blood from the donor (from the patient themselves or a compatible donor), the next step is centrifugation so that the red blood cells are in the bottom portion and are separated from the yellow-coloured serum in the top of the centrifuge tube. 

If all this serum is used and is diluted in different percentages such as 20% or 50%, the "heterologous or autologous serum" will be obtained (depending on the donor). 

If the fine layer of serum that is most murky just above the portion of red blood cells is used, the "platelet-rich plasma" (PRP) would be obtained. This portion of serum contains a high concentration of platelets, proteins, vitamin A and growth factors, essential for the epithelial cells. In other words, we can say that PRP is a concentrated autologous/heterologous serum. 

If we can undertake a platelet elimination process with PRP, a "concentrated" serum would be left that only contains the desired substances without cells, named "plasma rich in growth factors" (PRGF).

Blood-derived eyedrop treatment is usually more or less effective depending on the severity of each patient's disease. Its efficacy may be detected both subjectively (the patient feels better, has less discomfort and better vision) and objectively (there are less damaged epithelial cells, the ulcer is smaller and the cornea is in a better condition).

Given that the eyedrops do not come from the patient themselves or a compatible relative, they do not get rejected. No cases reporting that the eyes have worsened or that there has been an inflammatory reaction causing a rejection to the blood-derived eyedrops have been published. 

The blood-derived eyedrops have to be kept cold all the time to preserve their qualities. If the cold chain is broken, the efficacy of the eyedrops is reduced. In addition, they have to be stored in a clean place and there must be a certain level of hygiene when they are instilled in the eyes as they do not contain preservatives and there is a risk of contamination from germs, although that risk is low.