Photoreceptor Imaging Breakthrough Expected to Improve Diagnosis, Assessment for Retinal Conditions
New VIS-OCT Technology Will Help Clinicians Assess Extent of Vision Loss
A collaborative Bascom Palmer Eye Institute and Florida International University (FIU) biomedical engineering team has developed a breakthrough retinal imaging technology that could help clinicians diagnose and assess the extent of vision loss in patients with a wide range of conditions.
After three years of work, the researchers at the University of Miami’s Bascom Palmer Eye Institute and at FIU successfully tested the first visible-light optical coherence tomography (VIS-OCT) technology for imaging rhodopsin, the light-sensing molecule contained in the retinal photoreceptors that convert light signals to neuronal signals sent to the brain.
Shuliang Jiao, Ph.D., associate professor of biomedical engineering at Florida International University and a Bascom Palmer alumnus, led the project. He designed and built the first VIS-OCT capable of imaging rhodopsin, and is the senior author of an article describing the novel VIS-OCT technology, “Depth-resolved rhodopsin molecular contrast imaging for functional assessment of photoreceptors,” published recently in Scientific Reports. The research was supported by grants from the National Institutes of Health.
Tan Liu, Ph.D., a postdoctoral associate in the FIU biomedical engineering program, was first author of the paper. Co-authors were Bascom Palmer professors of ophthalmology Rong Wen, M.D., Ph.D., and Byron L. Lam, M.D., the Robert Z. and Nancy J. Greene Chair in Ophthalmology; and Carmen A. Puliafito, M.D., M.B.A, Dean of the Keck School of Medicine of the University of Southern California. Puliafito, the former chair of Bascom Palmer, was one of the pioneers in the development of OCT, which allows ophthalmologists to map and measure the layers of the retina.
“OCT has been used extensively in ophthalmology clinics,” said Jiao. “Our work shows the new technology can be used to construct an accurate map showing the distribution of rhodopsin – a functional biomarker of the rod photoreceptors in the retina. We now are working on making this imaging equipment more patient-friendly to move it into the clinical setting.”
Jiao added that the VIS-OCT created map could help determine the effectiveness of treatments in retinal disorders that affect the photoreceptors. For example, the progressive loss of photoreceptors in patients with hereditary retinal degeneration can be objectively measured and documented for clinical care and evaluation of treatments.
“This technology can be used to monitor disease progression for retinitis pigmentosa, age-related macular degeneration and other retinal diseases,” said Lam, a physician-scientist who specializes in photoreceptor degeneration. “It can also be used to objectively measure the outcomes for treatments and clinical trials of new therapies.”
Wen, a photoreceptor cell biologist, believes VIS-OCT technology will also be useful to study future photoreceptor regeneration, including transplant stem cell-derived photoreceptors, gene therapies, neuroprotection therapies using neurotrophic factors and other neuroprotective agents.
“The rapid development in regenerative medicine to restore vision has raised a hope that regeneration of photoreceptors and restoration of photoreceptor function will become reality in the near future,” he said. “When the time comes, this technology will be used to see whether the new photoreceptors are functional.”
This work started three years ago when Jiao, Wen, and Lam were seeking an objective way to measure the function of photoreceptors in patients. The prototype rhodopsin VIS-OCT is an important step toward clinical application of the new technology.