By Kristen Mulvihill
Scheie Vision Annual Report 2020
In June 2020, Geoffrey K. Aguirre, MD, PhD, Associate Professor of Neurology, received the Research to Prevent Blindness (RPB) / the Lions Club International Foundation (LCIF) Low Vision Research Award. The award supports scientists launching innovative research that focuses on damage to the visual system.
RPB, founded in 1960, is the leading nonprofit organization that funds eye research targeting the treatment and prevention of vision-threatening diseases. This year, the foundation celebrated its 60th anniversary.
As a behavioral neurologist and neuroscientist, Dr. Aguirre studies cortical organization for vision, and how this is altered by neurologic and ophthalmic diseases. Dr. Aguirre is one of the many vision scientists across the University of Pennsylvania who collaborates with the Department of Ophthalmology. His RPB-funded project focuses on examining retinal ganglion cell (RGC) function in retinitis pigmentosa (RP) by measuring brain responses. Dr. Aguirre’s research will also examine the neural basis of photophobia (i.e. light sensitivity) in RP, which is a common symptom.
RP is a group of rare, genetic disorders involving the breakdown and loss of cells in the retina. The disease alters how the retina responds to light, causing those affected to slowly lose their vision.
The retina contains RGCs, which transmit visual information to the brain. Numerous blinding diseases adversely affect the function of RGCs, including RP. Although RGCs serve a critical role in vision, it has proven difficult to accurately measure from the eye how these cells are altered in individuals with RP. Dr. Aguirre’s project will instead measure responses from the brain, where these signals are amplified and spread over the visual cortex.
To accomplish this, Dr. Aguirre will have individuals look at special kinds of flickering light while their brain activity is measured using an MRI machine. By flickering the light at different rates and by varying the color information in the light, the stimulation will target the different kinds of RGCs in the retina. The different classes of RGCs carry separate information important for vision and visual health, and little is known regarding how the different classes are impacted by diseases like RP.
An MRI scanner will be used to measure brain activity produced by the different kinds of lights. Using techniques developed previously in his lab, Dr. Aguirre can then map the brain activity back to the location of the source of the signal from the retina. This will result in maps of the functional health of each of the RGC classes.
Dr. Aguirre will collaborate with Tomas Aleman, MD, an accomplished retinal degeneration specialist and Associate Professor of Ophthalmology, to obtain these measurements in patients with RP. Dr. Aleman is an expert in the measurement of the structure of the retina in these diseases, and together, Drs. Aguirre and Aleman will work to relate alterations in structure to alterations in retinal function.
This novel technique may be used to target the growing set of retinal gene and stem cell therapies, an area of intense research focus in the Department of Ophthalmology.
“I am thrilled for the opportunity to continue a long history of collaboration with the Department of Ophthalmology. Dr. Aleman and I are eager to understand the changes in vision that accompany RP,” said Dr. Aguirre. “It turns out that the brain is the perfect place to measure the function of the eye. Even when the eye moves, brain signals remain locked in place to the retina, allowing us to make precise measurements. We are optimistic that what we learn will help better target therapy for retinal disease.”
Other researchers and trainees to receive individual awards from RPB spanning the last ten years include Hannah Schultz; Tianyu Liu; Kenneth Shindler, MD, PhD; Devang Bhoiwala; David Brainard, PhD; Joshua Dunaief, MD, PhD; and Artur Cideciyan, PhD.