Transfusion medicine handbook

9. Other Services Provided by NZBS

9.5 Serum Eye Drops

• Autologous serum eye drops (SED), a blood component prepared by NZBS, is used for treating dry eyes and corneal epithelial defects. It is not normally first-line treatment due to the cost and requirement that patients donate blood. However, in selected patients, SED have proven a successful treatment modality.
• Conditions for which SED can be used include severe Sjögren’s syndrome, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, some causes of epithelial limbal stem cell deficiency such as chemical or thermal ocular surface burns and other severe ocular surface disorders that do not respond to conventional therapies. SED may also be useful in acute management of severe sight threatening ocular surface chemical or thermal burns.
• Although not fully defined, it is believed that epidermal growth factor, vitamin A, platelet-derived growth factor and fibronectin are important serum constituents that promote healing of the ocular surface.
• SED is prepared from a single blood donation and contains no added preservatives or antimicrobial agents. It has the potential to transmit infectious diseases or become contaminated with microorganisms. Accordingly, blood collected for SED must meet standard safety requirements. This includes a donor health assessment and screening of the blood donation to exclude evidence of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. Following the manufacture of SED, a proportion of the eye drop bottles are cultured for 14 days to confirm bacterial sterility.
• To access the service, ophthalmologists complete a specific request form that is forwarded to NZBS. This constitutes a prescription and is valid for three months only, as per the Medicines Act (1981), although blood is only collected every six months. Due to the time required for manufacturing and sterility testing, 18 working days are normally required from donation to issuing of SED. In exceptional circumstances and with the patient’s consent, the ophthalmologist may request that SED are issued prior to completion of the sterility testing.
• Appropriate storage of SED vials is essential to minimise the risk of bacterial contamination. Vials are stored frozen in a NZBS facility or hospital blood bank and are dispensed in quantities necessary to cover a 4-week period. The dispensed vials should be kept frozen until needed, usually in the patient’s domestic freezer. Each vial usually lasts one week and should be stored in a refrigerator once thawed. Any adverse events should be reported to NZBS for investigation.
• For patients who cannot safely donate autologous blood or where allogeneic SED are the preferred product, for example in ligneous conjunctivitis, NZBS can, on a named patient basis, prepare SED from an allogeneic donation. NZBS does not hold this as a stock item.