Cellular and Molecular Interactions between Corneal Epithelium and Fluorescein Sodium

Sodium fluorescein (‘fluorescein’) in corneal epithelium staining is widely utilized for the evaluation of ocular surface integrity. Clinically observed ocular surface fluorescence is affected by various factors including concentration of fluorescein, thickness of the fluorescein layer, the wavelength of the exciting light source, tear acidity and etc. Despite the widespread application of fluorescein to assess the ocular surface, clinical understanding and interpretation of corneal surface fluorescence and the basic causative mechanisms of this phenomenon has not been considered completely. Additionally, for better understanding of corneal fluorescein staining and its clinical manifestations, we need to know the basic and molecular physicochemical properties of fluorescein dye and its relationships with molecular and cellular microanatomy and physiology of the cornea. In this review, we have attempted to provide a critical evaluation of the articles published in PubMed database between 1970 and 2015 based on the inclusion and exclusion criteria relating to the basic interactions between the corneal surface cells and fluorescein molecules.