In vivo corneal and conjunctival epithelial nuclear stain

Epithelium plays a very important structural and functional role in the cornea and conjunctiva. Evaluation of the epithelium is the first step in diagnosing many pathologic states. We have developed a new technique for the in vivo staining of nuclei of corneal and conjunctival epithelium in rabbits and guinea pigs. Several drops of 0.01%, 0.1%, 0.25%, 0.5%, or 1.0% toluidine blue or 1.0% methylene blue were applied to the conjunctival sac to stain epithelial cells. The cells picked up the vital dye within 5 minutes and could be photographed at 30X with the Keeler-Konan wide-field specular microscope. Cells and nuclei were clearly observable. Photographs could be further enlarged to enhance details. Wash out time was rapid and no toxic effects were observed. This technique adds a new dimension to the study of epithelium in normal and pathologic states in experimental animals. This technique may also be applicable to human eyes for discerning such diseases as carcinoma, herpes simplex, or superior limbic keratoconjunctivitis.