LAUSR

T he recent pandemic has forced us from our usual practice of medicine to alternative means including telehealth visits for the safety of the patients and practitioners. These virtual office visits have left us with few of the tools that we normally rely on. Therefore, there is a greater reliance on clinical skills that can translate in the virtual visit and be helpful for diagnosis. Here we bring to attention the evaluation of a relative afferent pupillary defect (RAPD), a sign of optic neuropathy, through an old-fashioned method. Galen's second century observation about pupillary reactivity was remarked on by Hirschberg in 1901 (1) that the uncovered eye's dilation was worth observing. Although alternate cover testing was not explicitly described by Gunn, he was doing it in bright light to describe his observation that completely covering the good eye would paradoxically dilate the bad eye. Alfred Kestenbaum measured this difference in pupil size (2), and it was termed Kestenbaum's pupil number (KPN) by Dr. H. Stanley Thompson in his beautifully written treatise in the Second Hoyt Lecture on the history of pupillary function (3). This method is still perfectly suited for today's available technology in the era of tele–neuro-ophthalmology that we outline below: