Fluorescein stain is used in the eye to stain

Biomicroscopic examination after staining of corneal ulcer with 2 percent freshly prepared aqueous solution of fluorescein dye or sterilized fluorescein impregnated filter paper strip to note site, size, shape, depth, margin, floor, and vascularization of corneal ulcer. On biomicroscopy also note the presence of keratic precipitates at the back of the cornea, depth and contents of the anterior chamber, color and pattern of iris and condition of the crystalline lens. Image : Fluorescein-stained anterior segment images obtained at baseline show a large corneal ulcer. A striking complete healing was observed in the corneal ulcer only 2 weeks after the adjuvant treatment with CoQ10 eye drops. Reference : A K KHURANA Comprehensive Ophthalmology edition 4, page-98