The Shiley Eye Institute (SEI) and the Viterbi Family Department of Ophthalmology at UC San Diego Health have recently constructed two new visual mobility courses (or mazes) near the La Jolla campus. These full-size, human visual mobility courses are designed to test visual function in retinal degeneration patients. Research patients are tested to learn how they navigate through the mazes under different lighting conditions and are asked to negotiate obstacles just as they would in the real world.

The new mazes are being utilized under the leadership of Shyamanga Borooah, MBBS, PhD, Director of the Retinal Degeneration Clinic at SEI. He plans to apply these mazes to test the effectiveness of novel trial therapies for retinal degeneration as part of the new Retinal Degeneration Clinic.

Dr. Borooah and a patient enter the maze.

Dr. Borooah states, “These mazes are an exciting new addition to our department. We are fortunate to have been selected as one of only a handful of sites around the world participating in a number of landmark clinical trials targeting retinal degeneration which will utilize our mobility courses. They give us the capability to test visual function before and after treatment to help assess the effectiveness of potential new therapies. Ultimately, the mazes and these ground-breaking studies will contribute to the global efforts to prevent sight loss in retinal degeneration.”

Retinal degenerations are the leading cause of blindness worldwide. The retina is the light-sensitive tissue at the back of the eye that contains photoreceptors. Photoreceptors are the cells that begin the process of seeing by absorbing and converting light into electric signals that are sent to the optic nerve and the brain. Retinal degeneration, or death of the retinal cells, has many causes but ultimately all causes lead to sight loss. Common retinal degenerations include age-related macular degeneration and inherited retinal diseases such as retinitis pigmentosa.

Inherited retinal degenerations (IRD) often result in advanced visual loss due to genetic changes. In many IRD patients, standard ophthalmic assessments, like eye charts or visual fields, do not work. Therefore, an alternative vision test was developed to measure visual function – the visual mobility course.

Intricate lighting system over the maze

Utilizing these mazes, IRD patients’ can be assessed for walking accuracy, number of errors, and speed through the course. These measures can be used to reliably and objectively assess patient visual function. The courses have real-life obstacles that the patient must distinguish while walking through. Obstacles can be representations of walls, people, plants, or pets. These courses can accommodate various types and severities of vision loss by modifying light levels.

The primary aim of the new SEI Retinal Degeneration Clinic is to combine world-class clinical care with the latest research for patients with retinal degenerations. The center is fully structured around retinal degeneration patients’ needs.

The center’s experienced team utilizes state-of-the-art diagnostics and imaging, genetic testing, and genetic counseling. It also connects patients to visual or low vision rehabilitation. Patients also have the opportunity to participate in pioneering studies, such as gene therapy and gene editing clinical trials, which utilize the new mazes to test new treatment approaches.


Major Gift Focuses Efforts on a Rare, but Devastating, Genetic Eye Disease

Funding from the Nixon Visions Foundation will support studies of the PRPH2 gene linked to macular dystrophy and boost stem cell research aimed at developing early diagnosis and a cure

In healthy vision, a gene called PRPH2 provides instructions to make a protein called peripherin 2 (PRPH2), which plays a key role in the normal functioning of photoreceptors that detect light and color and which line the back of the eye.

When there are mutations in the PRPH2 gene, the result can be macular dystrophy, an impairment of the retina that progressively diminishes the ability to see clearly and may eventually result in vision loss. Currently, there are no effective treatments to slow or prevent the condition.

From L to R: Radha Ayyagari, PhD, Robert N. Weinreb, MD, Chancellor Pradeep Khosla, Janine Marks Nixon, Brandon L. Nixon, and Shyamanga Borooah, MD, PhD

Macula dystrophy can occur when photoreceptor cells comprising the retina at the back of the eye progressively become impaired and unable to function fully, leading to loss of full vision and perhaps blindness. Photo credit: Ralf Roletschek

The Nixon Visions Foundation, led by philanthropists Brandon and Janine Nixon, has given a significant gift to the Viterbi Family Department of Ophthalmology and Shiley Eye Institute, both part of UC San Diego Health, to launch the Nixon Visions Foundation Macular Dystrophy-PRPH2 Research Fund, which will focus studies of the PRPH2 gene and related mutations and help upgrade stem cell technologies that may eventually provide a proven therapeutic remedy. Nixon Visions Foundation is also building capacity with the Foundation Fighting Blindness to further advance national and global research in this space as part of this effort.

“We are impressed with the impactful work at UC San Diego and specifically in the Department of Ophthalmology and at Shiley Eye Institute,” said the Nixons. “We believe this gift can accelerate efforts to make a tremendous impact for people with this inherited eye disease and will improve the lives of others for generations to come.”

“Macular dystrophy is such a challenging disease for people who have it, but UC San Diego Health has the expertise to discover new ways of treating this illness and creating a healthier world,” said UC San Diego Chancellor Pradeep Khosla. “Thanks to the generosity of the Nixon Visions Foundation, we can pursue the most promising leads and follow the science wherever it takes us.”

Macular dystrophy is a relatively rare eye condition. It affects the central retina or macula, which has the highest concentration of light-sensitive cells or photoreceptors. It is different from the more common eye disease known as macular degeneration, which is often caused by age-related deterioration of the retina and macula. Macular dystrophy is associated with genetic mutations that — for no known reason — trigger degradation of retinal cells. Some forms of the disease appear in childhood; some in adulthood.

“There really aren’t viable therapies for macular dystrophy and even fewer promising leads to develop them, but in our work we believe we’ve found one. But that work is still in its fairly early phases so for myself and my colleagues, such as Dr. Radha Ayyagari, funding like this from the Nixon Visions Foundation is crucial to understanding causes and treating the disease,” said Shyamanga Borooah, MD, assistant professor of ophthalmology at Shiley Eye Institute and one of the investigators on the PRPH2 research project.

Faculty in the Viterbi Family Department of Ophthalmology and at Shiley Eye Institute are among the leaders in basic research investigating the causes of eye disease and finding remedies. The institute is home to the Joan and Irwin Jacobs Retina Center.
“Shiley Eye Institute is at the leading edge of vision research and eye care, and we know that macular dystrophy is a devastating diagnosis,” said Robert Weinreb, MD, director of Shiley Eye Institute, chair of the Viterbi Family Department of Ophthalmology, and Distinguished Professor of Ophthalmology. “We are confident that there is no place better to understand this illness and innovate therapies for it than UC San Diego Health.”

Patty Maysent, CEO of UC San Diego Health agreed: “Shiley Eye Institute represents some of the finest ophthalmological research and care in the world. We are honored to have the support of the Nixon Visions Foundation in such a tangible, meaningful way.”
Philanthropic gifts, like the one from Brandon and Janine Nixon, contribute to the Campaign for UC San Diego — a university-wide comprehensive fundraising effort concluding in 2022. Alongside UC San Diego’s philanthropic partners, the university is continuing its nontraditional path toward revolutionary ideas, unexpected answers, lifesaving discoveries and planet-changing impact. To learn more about supporting the excellent research, education and care taking place at UC San Diego Health Sciences, visit

About the Nixon Visions Foundation

Nixon Visions Foundation is dedicated to the support of organizations and individuals who are striving to reach their potential.  Based in San Diego, the foundation provides scholarships and other funding for education, training, social welfare, public information, and research.  Its newest initiative is to provide meaningful support for scientific research leading to critical treatments and, ultimately, cures for rare inherited retinal degenerative diseases through partnerships with UC San Diego Health’s Shiley Eye Institute and the Foundation Fighting Blindness, each targeting rare gene mutations such as those of the PRPH2 gene. Visit