Autologous is a term that refers to the use of one body tissue to help another part of the body. Serum is the medical term for a liquid component of blood that does not contain any clotting substances, but which contains a variety of biological molecules. Autologous serum can be medicinal for some people with eye conditions, as the substances present in the serum can help soothe and heal eye problems.
Blood contains many different components, ranging from cells to antibodies. In addition to carrying oxygen and glucose around the body to those cells that need it, blood is also a transport medium for immune system factors and molecules involved in growth and cell repair. It is these potentially beneficial substances that provide medicinal benefits to diseased or damaged eyes.
Eye conditions that affect the surface of the eye are those that benefit best from autologous serum treatment. Commonly the treatment is used to alleviate severe cases of dryness and reduction in tear production, as well as cases where the epithelial layer of the eye does not maintain itself normally. Without treatment, these conditions produce pain, irritation and can potentially lead to blindness.
Apart from the substances present in the blood that can help improve eye conditions, a significantly useful characteristic of autologous serum is that it is derived from the patient, and so the patient can tolerate the workings of the components easily. Serum is also a complex mixture of lots of different components, which would be very complicated to replicate for each individual person.
For a prospective patient to receive autologous serum as an eye drop, the serum must first be removed. This involves extracting a blood sample, from which the clotting proteins and various cells are removed in a laboratory. Each sample is also tested for infectious diseases such as hepatitis or human immunodeficiency virus (HIV.) The remaining liquid is then diluted down with saline, which is a sterile mixture of water and salt. Once packaged into eye drop bottles, the autologous serum is ready for use.
As the serum is not sterile and breaks down over time, each bottle has to be frozen to prevent spoilage. Typically, then, a patient removes a new frozen bottle daily to replace an open bottle which has been thawed. The application of the liquid into the eye is the same as other eye drop medications, which simply involves dropping a set amount of liquid into the eye daily.