New study finds antidepressant drug effective in treating “lazy eye” in adults

Irvine, Calif. – September 30, 2020 – In a new study, published in Current Biology, researchers from the University of California, Irvine School of Medicine reveal how subanesthetic ketamine, which is used for pain management and as an antidepressant in humans, is effective in treating adult amblyopia, a brain disorder commonly known as “lazy eye.”

“Our study, demonstrates how a single-dose of subanesthetic ketamine reactivates adult visual cortical plasticity and promotes functional recovery of visual acuity defects resulting from amblyopia,” explained Xiangmin Xu, PhD, a professor of anatomy and neurobiology and director of the Center for Neural Circuit Mapping at the UCI School of Medicine. 

Subanesthetic ketamine, commonly used to treat depression and pain, evokes rapid and long-lasting antidepressant effects in human patients. There was evidence that ketamine may control how the nervous system makes structural changes in response to internal and external demands, a process called neural plasticity.  But, how the drug worked remained elusive, until now. 

“Our research team showed that ketamine down-regulates NRG1 expression in PV inhibitory cells, resulting in sustained cortical disinhibition to enhance cortical plasticity in adult visual cortex,” said Steven F. Grieco, PhD, a postdoctoral scholar in the Xu lab and lead author. “Through this neural plasticity-based mechanism, ketamine mediated functional recovery from adult amblyopia.”  Xin Qiao, PhD, a postdoctoral staff in the Xu lab is a co-first author for the published paper. 

Amblyopia is a vision disorder in which the brain fails to process inputs from one eye, favoring the other eye. The condition can result in decreased vision in the affected eye. Each year, between one and five percent of children worldwide, are diagnosed with this condition. 

Fast and sustained ketamine actions show promise for therapeutic applications that rely on reactivating adult cortical plasticity.  Further testing is needed to determine the full implications of this discovery.

This study was supported in part by grants from the National Institutes of Health.

About the UCI School of Medicine

Each year, the UCI School of Medicine educates more than 400 medical students, and nearly 150 doctoral and master’s students. More than 700 residents and fellows are trained at UCI Medical Center and affiliated institutions. The School of Medicine offers an MD; a dual MD/PhD medical scientist training program; and PhDs and master’s degrees in anatomy and neurobiology, biomedical sciences, genetic counseling, epidemiology, environmental health sciences, pathology, pharmacology, physiology and biophysics, and translational sciences. Medical students also may pursue an MD/MBA, an MD/master’s in public health, or an MD/master’s degree through one of three mission-based programs: the Health Education to Advance Leaders in Integrative Medicine (HEAL-IM), the Leadership Education to Advance Diversity-African, Black and Caribbean (LEAD-ABC), and the Program in Medical Education for the Latino Community (PRIME-LC). The UCI School of Medicine is accredited by the Liaison Committee on Medical Accreditation and ranks among the top 50 nationwide for research. For more information, visit som.uci.edu.