Mary A. Johnson

Mary A. Johnson, PhD is an Associate Professor in the Department of Ophthalmology and Visual Sciences at the University of Maryland School of Medicine. She serves as Director of the Visual Electrodiagnostics Laboratory, where she applies her expertise in clinical electrophysiology and psychophysics directly to patient care and research.

Education:

• B.A. with Distinction in Biology & Psychology, University of Delaware (1977)
• M.A. in Physiological Psychology, Johns Hopkins University (1980)
• Ph.D. in Physiological Psychology, Johns Hopkins University (1982)
• Post-doctoral fellowship in Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine (1982-1983)

Dr. Johnson is a renowned vision scientist specializing in the clinical applications of electrophysiology and psychophysics to study how disease affects visual function. Her groundbreaking work focuses on retinal diseases caused by poor blood flow to the eye, including diabetic retinopathy, central retinal vein and artery occlusions, and carotid artery occlusion. She developed the unifying concept explaining the mechanism behind blinding complications in these disorders. Her research also includes studies on drug toxicity (particularly vigabatrin), traumatic brain injury effects on vision, and biomarkers for Huntington's disease. Dr. Johnson has developed several diagnostic protocols now used worldwide, including an ERG protocol for assessing visual field loss in patients taking vigabatrin who cannot perform visual field tests.

Dr. Johnson's publication record demonstrates a consistent focus on advancing diagnostic techniques in visual electrophysiology. Her research spans from basic mechanisms of retinal function to clinical applications, with a particular emphasis on ischemic disorders and neuroprotective strategies. Over her career, she has developed numerous electrophysiological protocols that have become standard in clinical practice, particularly for assessing retinal sensitivity in ischemic conditions and monitoring drug toxicity.

Scientific Awards and Honors:

• Fellow, Optical Society of America (1993)
• Research to Prevent Blindness Disney Award (2003)
• Fellow (silver), Association for Research in Vision and Ophthalmology (2010)
• Member, Board of Directors of the International Society for the Clinical Electrophysiology of Vision (2014-present)
• Editorial Board Member, Documenta Ophthalmologica (2012-present)

Dr. Johnson has held numerous leadership positions in professional organizations and has served on editorial boards for major optics and ophthalmology journals. Her work has been supported by various research grants focused on understanding mechanisms of visual function loss and developing improved diagnostic techniques. She offers a "boutique" visual electrophysiology service where she personally performs all testing using detailed history and personalized protocols to better interpret results.

As Director of the Visual Electrodiagnostics Laboratory, Dr. Johnson oversees a comprehensive service offering pattern-reversal and flash visual evoked potentials (VEPs), ganzfeld full-field flash electroretinograms (ERGs), electro-oculograms (EOGs), and color vision testing. Her laboratory serves as both a clinical diagnostic facility and a research center investigating new methods for detecting and monitoring visual system disorders, with current studies focusing on traumatic brain injury, NAION, and Huntington's disease biomarkers.