Autologous Serum Eye Drops - An Overview

Introduction

The tear film is the superficial layer of the eye and an important component in the visual pathway. Tears are necessary to maintain the stability of the ocular surface due to their lubricant, antimicrobial, and mechanical properties. Dry eye disease (DED) is a chronic ocular condition characterized by insufficient tear production or poor tear quality; it requires multiple treatment modalities. There has been a recent exponential increase in this condition due to the use of electronic devices, and the number of people affected is also expected to increase in the future. There is no complete cure for this disorder, but various treatment methods are available that help reduce the symptoms and provide significant relief. Collagen tear duct plugs, eyelid hygiene regimens, laser treatment, artificial tears, and ointments help boost natural tear production. However, they may not be effective in some instances, during which autologous serum eye drops can be considered as an alternative treatment option.

What Are Autologous Serum Eye Drops?

Tears contain certain major components, such as growth factors, vitamins, and fibronectin, that help maintain ocular health. A lack of these factors can cause ocular surface disorders such as dry eye disease, neurotrophic keratopathy (a rare eye disorder affecting cornea), persistent corneal epithelial defects (non-healing eye defects), etc. Recently, autologous serum eye drops (ASEDs) have been reported as an effective treatment for these eye disorders. The term autologous means from one's own body, and hence, autologous serum eye drops are eye drops made from the patient’s blood and are known to be well-tolerated and highly effective. Autologous serum tears were first described by Ralph in 1975 to treat tear deficiency in a group of patients with varying ocular surface disorders. It was found to be successful, and patients also expressed unanimous satisfaction. Since then, autologous serum eye drops have been used in various conditions.

What Are the Indications of Autologous Serum Eye Drops?

For several years, studies have demonstrated that autologous eye drops have effectively treated moderate to severe dry eye disease or dry eye syndrome. These are also used in neurotrophic keratopathy, neuropathic ocular pain, and non-healing corneal defects. They were first used in the treatment of chemical burns of the eye. ASEDs are recommended by organizations such as the American Society of Cataract and Refractive Surgery, the International Taskforce on Dry Eye, and the Tear Film and Ocular Surface Society. ASEDs are also known to be used in the management of dry eyes due to medical conditions such as Sjogren’s syndrome (autoimmune disease causing less secretions), rheumatoid arthritis (joint disease), keratoconjunctivitis sicca (dryness of the cornea and conjunctiva), and temporary dry eye symptoms after laser surgery. Eye specialists also recommend autologous serum eye drops, such as anti-glaucoma medicines, eye lubricants, and topical medications, for some patients with drug or preservative toxicity.

How Are Autologous Serum Eye Drops Made?

• Autologous serum eye drops are prepared in an eye bank, blood bank, or laboratory with a suitable sterile work area and appropriate equipment. Approximately 10 ml (milliliter) of blood is collected without an anticoagulant in plain vacutainer tubes, and the blood is allowed to clot at room temperature for 30 to 60 minutes.

• The vacutainer tubes are centrifuged at 2500 to 3000 rpm (revolutions per minute). Then, under aseptic conditions, the amber-colored supernatant serum is collected in a tube using a pipette to avoid the aspiration of red blood cells.

• Slightly hemolyzed blood may cause a light reddish color to the serum, which is usually harmless, but heavily hemolyzed blood cannot be used.

• The serum is then diluted with sterile normal saline by maintaining the final concentration at 20 percent and distributed in small vials (eye dropper bottles) in a laminar flow hood under aseptic conditions.

• Any culture mediums, such as thioglycollate broth, blood agar, brain heart infusion broth, etc., are used for sterility checks of the diluted serum.

• The vials contain the patient’s name, identity number, and manufacturing date.

• The final quality check is done by placing the last two to three drops of diluted serum on chocolate agar and incubating for 48 hours at 37 degrees Celsius. No growth determines the sterility of the product.

• Autologous serum eye drops are dispensed in a frozen gel pack and must be refrigerated before and after use. It must be used completely for two to three weeks; storing beyond three weeks is not generally safe as it increases the chance of contamination.

How Do Autologous Serum Eye Drops Work?

Autologous serum eye drops are ready after 48 hours of sample collection. The recommended dose is usually one drop every two hours for three months or as the doctor prescribes. ASEDs help lubricate the ocular surface, promote epithelial healing, and are the mainstay in treating dry eye disease. Natural tears have growth factors and proteins necessary for maintaining eye health. These lack artificial tears and are known to have limited benefits. However, autologous serum eye drops are similar to natural tears in pH, composition, and biochemical properties, thus highly effective in managing ocular surface disorders. Significant symptom improvement is observed after about two weeks of regular use, and maximum benefit can be seen after six to eight weeks of treatment.

What Are the Drawbacks of Autologous Serum Eye Drops?

• The preparation of autologous serum eye drops requires certain facilities for maintaining the temperature and sterility and specialized equipment for storage and transportation.

• Centers where autologous serum drops are prepared and dispensed, may not be available in all places, thus affecting the accessibility for many patients. These conditions can limit the use of this treatment modality.

• This treatment requires frequent blood extractions and can be a prolonged treatment that may not be comfortable for most patients. It can also be expensive and may only be affordable for some people.

• Autologous serum eye drops are not preferred as the first line of treatment for dry eye disease by many doctors due to the logistics challenges and, therefore, they can be used only in severe conditions.

• The risk of contamination of autologous serum eye drops is higher, which can lead to the development of eye infections.

Conclusion

Tears possess antimicrobial, optical, mechanical, and nourishing properties vital to the visual pathway. Conditions such as dry eye syndrome, neurotrophic keratitis, Sjogren’s syndrome, or other chronic eye pathologies can affect tear quality and production. Autologous serum eye drops are made from the patient’s blood and closely resemble natural tears. This treatment modality is associated with certain drawbacks, and the effectiveness depends on the usage and severity of the condition. However, ASEDs lubricate the eyes, reduce inflammation, promote healing, and provide significant comfort to the patients.