[Duration of fluorescein diacetate in corneal endothelium]

Fluorescein diacetate (FDA) is a suitable substance for vital staining of corneal endothelium. Uptake and metabolism is an active process. This means that a fluorescing cell must be functionally intact. The duration of endothelial fluorescence is limited and should be tested in an experimental study. Cultured endothelial cells (calf aorta endothelial cells) were stained by FDA and the loss of fluorescence time registered. We tested corneal buttons in the same way. The cultured endothelial cells showed no fluorescence after 2 h and the corneal buttons after 40-50 min. The fluorescence of FDA-stained endothelial cells decreases both in cultured cells and in whole corneal buttons, but this is not a sign of loss of endothelial viability. This fact must be taken into consideration when interpreting the results of FDA staining.