The need for a compact and practical source of illumination for certain eye operations and for diagnosis instigated the development of a set of plastic retractors and transilluminators. These devices have been found to be useful and practical for retraction illumination, focal illumination, and transillumination of the eyeball.
A set of five tips, a sturdy flashlight handle, batteries, and an extra light bulb are encased in a compact leather case (see figure). The flashlight handle is made in two sizes. The small handle accommodates the no. 912 Eveready batteries, and the larger handle accommodates the regular no. 915 Eveready batteries, as well as the new long-life mercury batteries. The handles are machined from aluminium and are clear anodized, to prevent tarnishing. They contain no springs nor switches to wear out and are controlled by turning the base of the small flashlight and the base or top of the larger one.
Berens C. TRANSILLUMINATORS AND ILLUMINATED RETRACTORS FOR RETINAL DETACHMENT AND SURGERY. JAMA. 1955;159(16):1532. doi:10.1001/jama.1955.02960330032010a