Handheld device takes high-resolution images of children’s retinas

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Handheld device takes high-resolution images of children's retinas
Izatt -- Handheld OCT 4 -- A clinician use the new handheld device. Previous technologies weighed several pounds, were difficult to hold in place for long periods of time and did not have nearly the resolution demonstrated by the new device. Credit: Joseph Izatt, Duke University.

There are various technologies to analyze or imaging eye. But they are quite difficult with important structures buried millimeters below its various surfaces. So, a wide range of technologies is needed to study it. Researchers and engineers from Duke University have developed a new handheld device, which takes high-resolution images of children’s retinas. This device has the capability of capturing images of a retina with natural resolution. This new research will allow scientists to gain detailed structural information about the eyes of infants and toddlers for the first time.

There is a diagnostic tool available for capturing ratina for adults. But they are very difficult to use in infants and young children. Earlier it’s not possible to measure the effect of injury or disease on their photoreceptors. Photoreceptors are the cells in the eye in which light is first converted into nerve signals. Optical coherence tomography (OCT), is one of them, which is being used over the past three decades. But, they are bulky and make holding them still over a child’s eye tiresome and difficult. They also don’t provide a high enough resolution to see individual photoreceptors.

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But this new handheld device is able to directly measure the density of photoreceptors called cones in infants. According to scientists, this will open the door to new research that may become as key in future diagnosis and care of hereditary diseases.

Some key features of this new handheld device:

  • Its size is similar to a packet of cigarettes.
  • Weight is nearly about as few slices of bread.
  • Gathers detailed information and captures high-resolution images about the retina’s cellular structure.
Handheld device takes high-resolution images of children's retinas
An image of a retina taken with the new handheld probe. The tiny white dots are photoreceptors called cones, which were not visible with previous handheld technologies. The concentrated circular area is called the fovea. It is believed that, as the eye matures, photoreceptors migrate to this area, making it much more densely populated than others. Credit: Joseph Izatt, Duke University.

Joseph Izatt, the Michael J. Fitzpatrick Professor of Engineering at Duke and a pioneer of OCT technology, said, “Without the ability to gather this sort of information, there is little to no data about how a child’s retina develops, as it matures by the age of 10. This limits our knowledge of how diseases affect a child’s vision early in life and makes a diagnosis of these diseases more difficult.”

Izatt, Sina Farsiu, professor of ophthalmology and biomedical engineering at Duke, and Toth detail the developments that made their new handheld device possible.

A new type of smaller scanning mirror recently reached a point where it could replace larger, older models. A new design using converging instead of compiled light cut the telescoping length of the device by a third. Francesco LaRocca designed and fabricates custom lenses detailing curvature, thickness and glass type. A mechanical design to hold and combine the components was designed by Derek Nankivil with LaRocca and fabricated in a machine shop on Duke’s campus.

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Next, the device then submitted to clinicians for testing on adults. These showed that it was capable of getting exact photoreceptor density information. It also used for research imaging in children who were already having an eye exam under anesthesia.

LaRocca said, “But because children have never been imaged with these systems before, there’s no gold standard that we can compare it to. The results do, however, match theories of how cones migrate as the eye matures. The tests also showed different microscopic pathological structures that are not normally possible to see with current lower-resolution clinical-grade handheld systems.”

With the prototype, the amount of information being gained from children’s scans could eventually create a database to give a much better picture of how the retina matures with age. The group is now working on the design after getting feedback from clinicians on what can be improved.