Autologous serum (AS) drops are made from the patient’s own blood. The reason they are so good is because they more closely mimic the patient’s own natural tears. Natural tears contain elements that help to reduce inflammation and heal the surface of the eye. Unfortunately, artificial tears do not contain those healing elements but the plasma of blood does. In the 1970’s the potential for blood serum was recognised and in the last 15 years this has become a treatment option for severe dry eye.
To make the drops the patients blood is taken and then centrifuged to separate out the serum from the red blood cells. This serum is then mixed with preservative free artificial tears to dilute down the serum to a specified concentration, typically 20% to 50%. The vials are stored frozen and are thawed before use. The vials must be kept refrigerated while being used. So there is quite a complex process to manufacture the drops and it can be quite daunting for the patient to have to give blood to make them.
The production of drops is expensive and we would typically refer a patient to a hospital eye department which has the capacity to prescribe and manufacture the drops.
Many studies have shown the benefits of AS drops in severe dry eye and studies have also shown that they are safe for long-term use.
An alternative blood product to AS is albumin which is found in high concentrations in the blood. It is cheaper and easier to produce than AS and can be compounded into a 5% eye drop. It is not quite as effective as AS because it doesn’t contain the healing and regenerative factors. There has also been some work from the University of Missouri-St. Louis School of Optometry on platelet rich plasma which is another blood product which contains an abundance of growth factors which can help to heal the ocular surface.
Autologous serum eye drops are typically used as a last resort treatment for severe dry eye. They are also being used to help with neuropathic corneal pain because the nerve growth factors in the serum seem to help to normalise the functioning of corneal nerves.