In the course of a study of retinal atrophy in dogs, it became necessary to obtain colored photographs of the fundus. A Bausch & Lomb fundus camera was used for this purpose, with a carbon arc as its light source.
The disadvantages of the carbon arc in human fundus photography are numerous and are too familiar to ophthalmologists to require enumeration here (Hansell and Beeson,1 1953). An additional difficulty arises during protracted observations on experimental animals, when the lids are held open by a speculum or by sutures. Under these conditions, with the lids immobilized, the cornea tends to dry out; this tendency is greatly increased by the heat from the carbon arc. To obviate desiccation of the cornea, the eye must either be irrigated with saline at frequent intervals (our method) or have a special contact lens fitted to it (method of Clasen and associates2).
SAUNDERS LZ, SMITH RF. Fundus Photography in Color with Zirconium Arc Lamp as Light Source. AMA Arch Ophthalmol. 1955;53(3):429-431. doi:10.1001/archopht.1955.00930010431018