The focal nature of retinal illumination from the operating microscope

A photographic demonstration of the focal nature of the retinal illumination from the operating microscope is presented. It illustrates that under normal anterior segment operating procedures, the side-mounted and coaxial illuminators are imaged as small, intense spots on the retina. The irradiance (in watts per square centimeter) of these spots is reduced by their defocusing in aphakia. Cautionary attention is drawn to the danger of allowing these retinal hot spots to be imaged on or near the macula during surgery.