• Fluorescein sodium can be administered safely by mouth. The resulting fluorograms are useful in demonstrating many retinal conditions characterized by bright late leakage, such as cystoid macular edema. Oral administration of fluorescein may be preferred in studies of children, patients with difficult veins, and in some surveys of large patient populations.
Kelley JS, Kincaid M. Retinal Fluorography Using Oral Fluorescein. Arch Ophthalmol. 1979;97(12):2331-2332. doi:10.1001/archopht.1979.01020020547007