Evaluating Red Reflex and Surgeon Preference Between Nearly-Collimated and Focused Beam Microscope Illumination Systems.

PURPOSE To evaluate the intensity and stability of the red reflex produced by ophthalmic surgical microscopes with nearly-collimated versus focused illumination systems and to assess surgeon preference in a simulated surgical setting. METHODS This two-part evaluation consisted of postproduction surgical video analysis of red reflex intensity and a microscope use and preference survey completed by 13 experienced cataract surgeons. Survey responses were based on bench testing and experience in a simulated surgical setting. A microscope with nearly-collimated beam illumination and two focused beam microscopes were assessed. RESULTS Red reflex intensity and stability were greater with the nearly-collimated microscope illumination system. In the bench testing survey, surgeons reported that the red reflex was maintained over significantly greater distances away from pupillary center, and depth of focus was numerically greater with nearly-collimated illumination relative to focused illumination. Most participating surgeons (≥64%) reported a preference for the microscope with nearly-collimated illumination with regard to red reflex stability, depth of focus, visualization, surgical working distance, and perceived patient comfort. CONCLUSIONS The microscope with nearly-collimated illumination produced a more intense and significantly more stable red reflex and was preferred overall by more surgeons. TRANSLATIONAL RELEVANCE This is the first report of an attempt to quantify red reflex intensity and stability and to evaluate surgically-relevant parameters between microscope systems. The data and methods presented here may provide a basis for future studies attempting to quantify differences between surgical microscopes that may affect surgeon preference and microscope use in ophthalmic surgery.