To the Editor.
—Fluorescein has been proposed as an aid in vitreous surgery. This agent can be injected intravenously prior to operation1 or introduced directly into the eye.2 Intravenous injection carries the risk of serious systemic reaction and is also of little use in unplanned procedures, since the dye has to be injected at least 18 hours preoperatively if uniform staining of the vitreous is to be achieved. Direct introduction of a known dilution of fluorescein in a balanced salt solution (BSS) seems to be a more useful technique. However, to my knowledge there are no studies confirming the safety of fluorescein when used in this context.The pH of BSS varies slightly but is usually in the region of 7.5. A single minim drop of 2% fluorescein in 2 mL of BSS increases the pH by about 0.2. The osmolality (308 mOsm) remains about the same as
M. F. P. Griffiths. The Use of Fluorescein in Vitrectomy. Arch Ophthalmol. 1987;105(7):889. doi:10.1001/archopht.1987.01060070025009