Autologous Serum Tears (ASTs) are a highly specialized treatment option used by eye care professionals for patients suffering from severe and chronic dry eye disease or certain corneal conditions.
What Are Autologous Serum Tears?
Autologous Serum Tears are eye drops made from a patient's own blood serum. "Autologous" means that the substance comes from the patient's own body, ensuring compatibility and minimizing the risk of allergic reaction. Serum is the component of blood that remains after the red blood cells and clotting factors have been removed. This serum contains essential growth factors, vitamins, immunoglobulins, and other proteins that are naturally present in healthy tears.
What Are Autologous Serum Tears Used to Treat?
ASTs are typically reserved for patients who have not found adequate relief from conventional dry eye treatments, such as commercially prepared artificial tears and prescription anti-inflammatory drops. Conditions commonly treated with ASTs include:
- Severe Dry Eye Syndrome (Keratoconjunctivitis Sicca): Especially cases caused by conditions like Sjögren's Syndrome, chronic graft-versus-host disease (GVHD), or post-LASIK complications.
- Persistent Epithelial Defects (PEDs): Non-healing wounds on the surface of the cornea.
- Recurrent Corneal Erosions: A condition where the outermost layer of the cornea repeatedly peels off.
- Neurotrophic Keratopathy: A degenerative disease of the cornea resulting from impaired nerve function.
How Do Autologous Serum Tears Work?
The strength of ASTs lies in their biological composition, which closely mimics the natural tear film. When applied to the eye, the components within the serum provide numerous therapeutic benefits:
- Promoting Healing: Growth factors (like Epithelial Growth Factor and Transforming Growth Factor-Beta) and Vitamin A help stimulate the regeneration and health of the corneal and conjunctival surface cells.
- Fighting Inflammation: Immunoglobulins and other anti-inflammatory agents help reduce the chronic inflammation often associated with severe dry eye.
- Providing Nutrition: Essential nutrients help maintain the health and function of the ocular surface.
- Lubrication: They offer superior lubrication and comfort compared to standard artificial tears, which often lack the necessary biological factors.
How Are Autologous Serum Tears Prepared?
The preparation of Autologous Serum Tears is a precise, multi-step process performed in a specialized compounding pharmacy or laboratory.
The general steps for preparing a batch of ASTs are:
- Blood Draw: A blood sample is drawn from the patient, similar to a standard blood test.
- Clotting: The blood is left to clot for a period (e.g., 2 hours) to allow the serum to separate.
- Centrifugation: The sample is spun in a centrifuge to separate the blood components, isolating the clear, yellowish serum (containing growth factors, vitamins, antibodies) from the red blood cells and clotting factors.
- Filtration: The serum is often filtered to remove any remaining fibrin strands, which can reduce effectiveness.
- Dilution: The collected serum is then diluted with a sterile, preservative-free saline solution to achieve the prescribed concentration (commonly 20% serum).
- Compounding & Packaging: A compounding pharmacist under strict aseptic conditions (in a cleanroom/hood) mixes the solution and dispenses it into sterile, unit-dose dropper bottles, ready for use.
A typical blood draw is often sufficient to produce enough individual bottles of AST to last from 3 to 6 months. Patients are instructed to store the majority of their AST vials in a freezer and keep a single vial in the refrigerator for current use, to ensure the stability and potency of the biological components.
To discuss treatment options for your eyes such as autologous serum tears and other options, make an appointment at Eye Associates at (210) 340-1212.
More Information:
Autologous and Allogenic Serum Tears - EyeWiki
Autologous serum eye drops in dry eye disease: Preferred practice pattern guidelines; IJO