The National Institutes of Health’s National Eye Institute is combining two imaging techniques to see live neurons, epithelial cells and blood vessels deep in the light-sensing retina of the eye.
The two imaging techniques, called adaptive optics and angiography, could help the NEI change how eye diseases are detected and how conditions like age-related macular degeneration can be treated.
“For studying diseases, there’s no substitute for watching live cells interact. However, conventional technologies are limited in their ability to show such detail,” Johnny Tam, the study’s lead author and an investigator in the clinical and translational imaging unit at NEI, said in a press release.
Postmortem and biopsied tissues are typically used to study disease at cellular levels. However, the tissues are not ideal for watching subtle changes that happen as a disease progresses over time. The technologies that are available today also hamper imaging of retinal tissues as light passes through the cornea, lens and gel-like vitreous in the center of the eye.
Tam and the other researchers decided to use adaptive optics to deal with the distortion problems. Adaptive optics improves the resolution of optical systems by using deformable mirrors and computer algorithms, according to the NIH. The method got its start in ophthalmology in the mid-1990s.
The researchers used a combination of adaptive optics and indocyanine green angiography. Indocyanine green angiography is an imaging technique that uses an injectable dye and cameras to show vessel structures and the movement of fluids in the structures. The researchers performed the study with 23 participants and found that the multimodal method allowed them to see a complex unit of cells and tissues that interact with the outermost part of the retina for the first time.
The researchers then tested the multimodal imaging technique in patients who had retinitis pigmentosa and found that there were well-preserved RPE and blood vessels in the parts of the retina where photoreceptors died.
“In the past, we have not been able to reliably asses the status of photoreceptors alongside RPE cells and choriocapillaris in the eye,” Tam said. “Revealing which tissue layers are affected in different stages of diseases – neurons, epithelial cells or blood vessels – is a critical first step for developing and evaluating targeted treatments for disease.”
The research was published in the journal Communications Biology and was funded by the Intramural Research Program at the NEI.
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