Optical coherence tomography (OCT) is a high-resolution imaging technique that can be used for early detection of retinal diseases, such as age-related macular degeneration (AMD), diabetes-related conditions, glaucoma, or vascular occlusions. The technique works in a similar way to ultrasound scanning, but is contact-free and uses light to produce high-resolution cross-sectional images of biological tissue. However, to obtain cellular resolution of the retina and even better results, it has so far been necessary to use expensive adaptive lenses to correct the image aberrations that occur.
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Knowing this, a team of researchers at the Center for Medical Physics and Biomedical Technology at the Medical University of Vienna (MedUni Vienna; Austria) has developed a new OCT technique they call line-field OCT (LF-OCT), which simplifies looking into the cellular processes in the eye to allow even more accurate diagnosis.
"Our new technique enables us to make digital corrections without the need for expensive hardware-based adaptive lenses," explains PhD student Laurin Ginner. "The linear illumination that is used allows very rapid frame rates, which are extremely important for these corrections. This enables us to correct aberrations over the entire three-dimensional volume of the retina."
Linear illumination functions a bit like a scanner, where a strip of light scans the eye, allowing better images to be produced. In this way, it is possible to resolve individual photoreceptors, capillary blood vessels, and individual nerve fibers in the same image. It is also possible to refocus, realign, and digitally process the image data obtained to provide a doctor with the best possible results for diagnostic purposes.
OCT is currently also being used in dermatology for early detection of skin cancers. However, the LF-OCT technique could also open other areas of medical diagnostics, such as in surgery or dentistry, because it allows for more-specific personalized medicine.
"This technique can conceivably also be used for diagnosing neurodegenerative diseases," says Rainer Leitgeb, head of the Christian Doppler Laboratory for Innovative Optical Imaging and its Translation into Medicine, who supervised Ginner. "The eye is the 'window' into the brain. Our hope is that the higher resolution will help to improve diagnostic accuracy in general."
Once a few additional clinical studies complete, the LF-OCT technology will be commercialized soon in collaboration with partner Carl Zeiss Meditec (Jena, Germany).
Full details of the work appear in the journalOptica.