Corneal staining characteristics after sequential instillations of fluorescein

Twenty-one healthy noncontact lens-wearing subjects were screened for the presence of corneal staining with fluorescein after sequential instillations of the vital stain (Phase I). These staining characteristics were further explored by monitoring the results of sequential instillations of fluorescein at 2-h intervals over a 12-h period (Phase II) and by patching 1 eye overnight and observing corneal staining after sequential instillations of fluorescein in the morning after patch removal (Phase III). In Phase II more eyes stained in the early morning. Throughout the day the most common staining areas were inferior and nasal. In Phase III, 9 of 12 patched eyes presented with fluorescein staining, as did 7 of the 12 unpatched eyes. Corneal staining after sequential instillations of fluorescein is more likely to be observed early in the day and is not reduced by overnight patching.