Autologous serum-eye-drops for ocular surface disorders. A literature review and recommendations for their application

The natural tear film has mechanical, optical, antimicrobial and nutritional properties. Tear film components, such as EGF, fibronectin and vitamin A, play a vital role in the proliferation, migration and differentiation of the corneal and conjunctival epithelium. In ocular surface disease, such as severe dry eye, the epithelia may be depleted of these nutritional factors. Replacing the aqueous component of tears alone, by using pharmaceutical tear substitutes, often has little effect on the ocular surface. Eye-drops prepared from autologous serum are a new treatment option for severe ocular surface disease. They can be produced according to the regulations on drug use as an unpreserved blood preparation. Autologous serum eye-drops are non-allergenic and their biomechanical and biochemical properties are similar to normal tears. In cell culture experiments, serum was found to be superior to preserved or unpreserved pharmaceutical products in the maintenance of human keratinocyte morphology and function. It supports the migration of corneal epithelial cells and the differentiation of conjunctival epithelial cells. The first clinical cohort studies report its successful use for severe dry eyes and persistent epithelial defects. In these studies, however, varying methods for the preparation and different concentrations of autologous serum eye-drops were used. These methodological variations determine the biochemical properties and thus the epitheliotrophic effect of serum eye-drops. In this review we summarise the currently available clinical evidence, discuss relevant legislatory restrictions and describe a standard operating protocol for the use of serum eye drops. This has to be evaluated and optimised in more detail before any meaningful, randomised, controlled trial can attempt to establish the role of serum eye-drops in the management of severe ocular surface disease.