Product News: Early Detection of Blinding Eye Disease Could be as Easy as Scanning a BarcodeA new optical device puts the power to detect eye disease in the palm of a hand. The tool—about the size of a hand-held video camera—scans a patient’s entire retina in seconds and could aid primary care physicians in the early detection of a host of retinal diseases including diabetic retinopathy, glaucoma and macular degeneration. Researchers at the Massachusetts Institute of Technology (MIT) describe their new ophthalmic-screening instrument in a paper published today in the open-access journal Biomedical Optics Express, published by The Optical Society (OSA).
Although other research groups and companies have created hand-held devices using similar technology, the new design is the first to combine cutting-edge technologies such as ultrahigh-speed 3-D imaging, a tiny micro-electro-mechanical systems (MEMS) mirror for scanning, and a technique to correct for unintentional movement by the patient. These innovations, the authors say, should allow clinicians to collect comprehensive data with just one measurement.
Normally, to diagnose retinal diseases, an ophthalmologist or optometrist must examine the patient in his or her office, typically with table-top instruments. However, few people visit these specialists regularly. To improve public access to eye care, the MIT group, in collaboration with the University of Erlangen and Praevium/Thorlabs, has developed a portable instrument that can be taken outside a specialist’s office.
"Hand-held instruments can enable screening a wider population outside the traditional points of care," said researcher James Fujimoto of MIT, an author on the Biomedical Optics Express paper. For instance, they can be used at a primary-care physician's office, a pediatrician's office or even in the developing world.
The instrument uses a technique called optical coherence tomography (OCT), which the MIT group and collaborators helped pioneer in the early 1990s. The technology sends beams of infrared light into the eye and onto the retina. Echoes of this light return to the instrument, which uses interferometry to measures changes in the time delay and magnitude of the returning light echoes, revealing the cross sectional tissue structure of the retina—similar to radar or ultrasound imaging. The researchers were able to shrink what has been typically a large instrument into a portable size by using a MEMS mirror to scan the OCT imaging beam. In their tests, the researchers found that their device can acquire images comparable in quality to conventional table-top OCT instruments used by ophthalmologists.
The next step, Fujimoto said, is to evaluate the technology in a clinical setting. But the device is still relatively expensive, he added, and before this technology finds its way into doctors' offices or in the field, manufacturers will have to find a way to support or lower its cost.
In the future, Fujimoto envisions that hand-held OCT technology can be used in many other medical specialties beyond ophthalmology – for example, in applications ranging from surgical guidance to military medicine.
"The hand-held platform allows the diagnosis or screening to be performed in a much wider range of settings,” Fujimoto said. “Developing screening methods that are accessible to the larger population could significantly reduce unnecessary vision loss.”
Paper: “Handheld Ultrahigh Speed Swept Source Optical Coherence Tomography Instrument using a MEMS Scanning Mirror
,” Lu, C.D. et al.
, Biomedical Optics Express
, Vol. 5, Issue 1, pp. 293-311 (2013).