Serum Application for the Treatment of Ocular Surface Disorders

Tears are the essential component to the maintenance of healthy ocular surface epithelium. When tears are depleted, various pathological reactions occur, such as squamous metaplasia or keratinization of the epithelium, inflammation, epithelial defects, and infection. Squamous metaplasia is the most common change in the ocular surface epithelium in the tear environment depletion called dry eye. What is the main function of tears? The knowledge accumulated in the last decade suggests the importance of components present in tears, such as epidermal growth factor (EGF) and vitamin A, for maintaining healthy proliferation, differentiation, and maturation of the ocular surface epithelium. When these components are depleted, the normal proliferation and maturation processes of the epithelium may be impaired. One example is the persistent epithelial defect in the cornea in severe dry eye. The corneal epithelium is unable to heal because of the lack of tears. Another example is Sjögren’s-type (SS) dry eye. In SS dry eye, tear components are not supplied at all, or at least not sufficiently, because of a lack of basic and reflex tears, resulting in greater alteration of the ocular surface epithelium, such as increased fluorescein permeability or rose-bengal staining. In non-SS dry eye, however, tear components can be supplied to the ocular surface through occasional reflex tears. Thus, the problems associated with complete depletion of essential tear components are not expected to be as severe as in non-SS dry eye, where only slight alteration of the ocular surface occurs as a result of the desiccation itself.