The use of extreme cold in lieu of diathermy application to the scleral surface in retinal detachment surgery has required several modifications in technique. Surface localization of a retinal hole was conveniently accomplished by placing one or more diathermy applications to the scleral surface overlying the hole while visualizing the fundus with indirect ophthalmoscopy. The diathermy usually produced small visible scleral lesions which were necessary for the proper placement of scleral implants or encircling elements. Since cold application to the scleral surface usually leaves no visible lesion, the need for a suitable scleral marker arose. Figure 1 depicts an instrument which has proved of value. It is patterned after the thimble-type scleral depressor now widely used in this country. A piece of hollow, stainless steel tubing, 1½ mm in diameter and about 1 mm in length, is welded to the tip of the instrument after the removal of the crossbar.
GASS JDM. Scleral Marker for Retinal Detachment Surgery. Arch Ophthalmol. 1966;76(5):700-701. doi:10.1001/archopht.1966.03850010702014