Research Funded to Study Efficacy of Early Visual Training after Occipital Stroke
Friday, April 16, 2021
Up to half-a-million people each year suffer occipital strokes that cause loss to some portion of their vision, permanently affecting how they navigate through life.
A team at the University of Rochester recently showed that visual rehabilitation can more effectively reverse some of this blindness if patients are treated in the first few months after their stroke. Such patients will now have the opportunity to become part of a research study at the Flaum Eye Institute of the University of Rochester, sponsored by the National Institutes of Health.
“In occipital strokes, there is a loss of conscious vision opposite the side of the brain where the stroke occurred,” said James V. Aquavella Professor of Ophthalmology Krystel Huxlin, Ph.D. The occipital lobe of the brain contains the primary visual cortex, the first cerebral region responsible for complex visual processing and interpretation of signals received from the eye via the optic nerve.
“After two decades of discovery in our lab, we believe we have arrived at a critical point in our understanding of how to maximize vision restoration for cortically-blinded patients,” she said. “Within the first few months of having an occipital stroke, retinal ganglion cells, which transmit signals from the eye to the brain, are still largely intact. After six months, these cells show signs of degeneration, making later-onset rehabilitation more difficult to achieve. And any vision recovered at later stages is grainy and limited to the border of the patients’ blind fields. It’s as if we are looking at a window of opportunity slowly closing.”
The $2.5 million National Eye Institute-sponsored R01 grant, which includes funding for a small clinical trial, will support a collaborative team under Huxlin’s leadership, which brings together cross-campus expertise from Duje Tadin, Ph.D. (Department of Brain & Cognitive Sciences, UR) and Brent Johnson, Ph.D. (Department of Biostatistics, UR). NYU’s Dr. Marisa Carrasco (Department of Psychology and Neural Science) will also contribute to the research.
Patients who have recently suffered a visual stroke--within zero to five months--will be divided into groups to receive vision rehabilitation training. Their first week will be spent in Huxlin’s laboratories at the Flaum Eye Institute and Center for Visual Science. Here, a team of graduate students, postdoctoral fellows and ophthalmic imaging specialists will measure each participant’s baseline visual functions, and ocular and brain structures, before teaching them the complex rehabilitation routine they must perform. Each patient will then receive equipment to take home, where their therapy will be performed with remote monitoring. They will return to the Flaum laboratory at 6 and 12 months post-stroke for assessments of training efficacy, as well as to measure changes in their ocular and brain structures.
This study is designed to assess how visual restoration potential changes with time after occipital stroke in humans. It will first measure structural and mechanistic aspects of progressive degeneration along the early visual pathways induced by the stroke, correlating them with changes in visual performance in the blind field. It will then contrast the impact of visual training administered at different stages of degeneration, both on the magnitude of recovery and on the process of degeneration itself. These findings will be key to ascertain the degree to which visual training interventions administered early after stroke can prevent or slow retrograde degeneration, preserve the vision that is still present, and help recover some of the vision already lost.
In addition, knowing how long blind-field visual abilities are preserved after stroke and how this relates to the rate of structural degeneration of early visual pathways is critical to assess if interventions that promote neuronal survival and regeneration could be beneficial for this condition. The project is designed to advance scientific knowledge, technical capability and, ultimately, clinical practices for restoring vision and quality of life for people suffering from occipital strokes.
Lab model offers hope for macular degeneration patients
Monday, March 29, 2021
Age-related macular degeneration (AMD), which leads to a loss of central vision, is the most frequent cause of blindness in adults 50 years of age or older, affecting an estimated 196 million people worldwide. There is no cure, though treatment can slow the onset and preserve some vision.
Recently, however, researchers at the University of Rochester have made an important breakthrough in the quest for an AMD cure. Their first three-dimensional (3D) lab model mimics the part of the human retina affected in macular degeneration.
Their model combines stem cell-derived retinal tissue and vascular networks from human patients with bioengineered synthetic materials in a three-dimensional "matrix." Notably, using patient-derived 3D retinal tissue allowed the researchers to investigate the underlying mechanisms involved in advanced neovascular macular degeneration, the wet form of macular degeneration, which is the more debilitating and blinding form of the disease.
The researchers have also demonstrated that wet-AMD-related changes in their human retina model could be targeted with drugs.
"Once we have validated this over a large sample, the next hope would be to develop rational drug therapies and potentially even test the efficacy of a specific drug to work for individual patients," says Ruchira Singh, an associate professor of ophthalmology at the University's Flaum Eye Institute.
The lab of Danielle Benoit, professor of biomedical engineering and director of the Materials Science Program, engineered the synthetic materials for the matrix and helped configure it, as described in a paper in Cell Stem Cell.Read More: Lab model offers hope for macular degeneration patients
Susana Marcos to lead Center for Visual Science
Thursday, February 11, 2021
Susana Marcos, an internationally recognized expert in the optics of the eye and the interactions of light with the retina, will become the David R. Williams Director of the Center for Visual Science at the University of Rochester.
Her appointment will take effect July 1. The named position is endowed with a $2 million gift from John and Barbara Bruning. John, a member of the University’s Board of Trustees and retired CEO of Corning Tropel Corporation, and his wife, Barbara, have been generous supporters of the University.
Marcos will also hold a joint appointment in the Department of Ophthalmology, and will be the inaugural holder of the Nicholas George Professorship at the University’s Institute of Optics, which was named in 2015 for George, a professor emeritus of optics and former director of the institute, in recognition of his influence in the world of optics and on his students.
Marcos, a professor at the Instituto de Óptica, Consejo Superior de Investigaciones Científicas (IO-CSIC) in Madrid, Spain, succeeds Williams, who has served as director of the Center for Visual Science for the last three decades. His research group pioneered the use of adaptive optics to image individual retinal cells in the living eye. The methods that Williams’s team developed are also used throughout the world to improve vision correction technologies such as contact lenses and laser refractive surgery. Williams will continue his research.
“The Center for Visual Science has established itself as the world standard for vision research under the leadership of David Williams,” Marcos says. “Moreover, the University of Rochester has a global reputation as a hub of optics and photonics. And coming from the Instituto de Óptica, which is the oldest in Spain, to the Institute of Optics here, with an even longer tradition, is a dream come true.”
Her goals for the center include fostering internal and international multidisciplinary collaborations in vision science, attracting talented students, creating inspirational models for women in science and technology, and accelerating the transfer of research discoveries to industry.
“Dr. Marcos is a respected scientist globally, pioneering new directions in visual sciences that bridge the basic sciences to commercial applications. She is a perfect fit for the University of Rochester,” says Rob Clark, the University’s provost and senior vice president for research.
Leaders of Medical Center and River Campus optical and vision science programs also praised the appointment.
“We are thrilled to have Susana Marcos join us in Rochester,” says David DiLoreto Jr., professor and chair of ophthalmology and director of the Flaum Eye Institute. “Her understanding of optics and ophthalmology gives her an unparalleled ability to translate her work from the bench to the eye. This work not only is helping to improve vision but is helping us improve our understanding of vision.”Read More: Susana Marcos to lead Center for Visual Science
New Research Sheds Light on Vision Loss in Batten Disease
Friday, February 5, 2021
Progressive vision loss, and eventually blindness, are the hallmarks of juvenile neuronal ceroid lipofuscinosis (JNCL) or CLN3-Batten disease. New research shows how the mutation associated with the disease could potentially lead to degeneration of light sensing photoreceptor cells in the retina, and subsequent vision loss.
“The prominence and early onset of retinal degeneration in JNCL makes it likely that cellular processes that are compromised in JNCL are critical for health and function of the retina,” said Ruchira Singh, Ph.D., an associate professor in the Department of Ophthalmology and Center for Visual Science and lead author of the study which appears in the journal Communications Biology. “It is important to understand how vision loss is triggered in this disease, what is primary and what is secondary, and this will allow us to develop new therapeutic strategies.”
Batten disease is caused by a mutation in the CLN3 gene, which is found on chromosome 16. Most children suffering from JNCL have a missing part in the gene which inhibits the production of certain proteins. Rapidly progressive vision loss can start in children as young as 4, who eventually go on to develop learning and behavior problems, slow cognitive decline, seizures, and loss of motor control. Most patients with the disease die between the ages of 15 and 30.
It has been well established that vision loss in JNCL is due to degeneration of the light-sensing tissue in the retina. The vision loss associated with JNCL can precede other neurological symptoms by many years in some instances, which often leads to patients being misdiagnosed with other more common retinal degenerations. However, one of the barriers to studying vision loss in Batten disease is that mouse models of CLN3 gene mutation do not produce the retinal degeneration or vision loss found in humans. Additionally, examination of eye tissue after death reveals extensive degeneration of retinal cells which does not allow researchers to understand the precise mechanisms that lead to vision loss.
URMC is a hub for Batten disease research. The Medical Center is home to the University of Rochester Batten Center (URBC), one of the nation’s premier centers dedicated to the study and treatment of this condition. The URBC is led by pediatric neurologist Jonathan Mink, M.D., Ph.D., who is a co-author of the study. Batten disease is also one of the key research projects that will be undertaken by the National Institute of Child Health and Human Development-supported University of Rochester Intellectual and Development Diseases Research Center.
To study Batten disease in patient’s own cells, the research team reengineered skin cells from patients and unaffected family members to create human-induced pluripotent stem cells. These cells, in turn, were used to create retinal cells which possessed the CLN3 mutation. Using this new human cell model of the disease, the new study shows for the first time that proper function of CLN3 is necessary for retinal pigment epithelium cell structure, the cell layer in the retina that nourishes light sensing photoreceptor cells in the retina and is critical for their survival and function and thereby vision.
Singh points out that understanding how RPE cell dysfunction contributes to photoreceptor cell loss in Batten disease is important first step, and it will enable researchers to target specific cell type in the eye using potential future gene therapies, cell transplantation, and drug-based interventions.
Additional co-authors of the study include Cynthia Tang, Jimin Han, Sonal Dalvi, Kannan Marian, Lauren Winschel, Celia Soto, Chad Galloway, Whitney Spencer, Michael Roll, Lisa Latchney, Erika Augustine, Vamsi Gullapalli, and Mina Chung with URMC, David Williams and Stephanie Volland with the University of California, Los Angeles, Vera Boniha with the Cleveland Clinic, and Tyler Johnson with Sanford Research. The research was supported with funding from the National Eye Institute BrightFocus Foundation, the David Bryant Trust, the Foundation of Fighting Blindness, the Knights Templar Eye Foundation, the Retina Research Foundation, and Research to Prevent Blindness.Read More: New Research Sheds Light on Vision Loss in Batten Disease