Inexpensive hand-held device detects cataracts at the earliest stages.
Ramesh Raskar, the NEC Career Development Associate Professor of Computer and Communications and director of the MIT Media Lab’s Camera Culture group, says, “I like to think of this as a radar for the human eye.” Just as a weather radar beam sweeps across the sky to detect clouds, the new system — dubbed Catra — sweeps a beam of light across the eye to detect the cloudy patches called cataracts.
While the standard test for cataracts in an ophthalmologist’s office assigns a score on a scale of 1 to 4 — from no cataracts to completely blocked vision — the new, inexpensive test actually provides much more information. Media Lab graduate student Vitor Pamplona, a member of the team developing Catra, explains that it “scans the lens of the eye and creates a map showing position, size, shape and density of cataracts.”
In addition, the new device may be able to detect cataracts at an earlier stage than existing tests, because it can pick up changes in parts of the lens that have not yet become opaque. The current test depends on light reflected back by the lens, to be seen by the doctor performing the test, while Catra relies on light passing through the lens as reported by the patient, who just has to indicate whether a point of light remains steady, dims or disappears.
As the device scans a beam of light across the eye, it uses rays that are perfectly aligned so that the eye’s lens focuses all the beams to the same point on the fovea, the area of the retina where it has maximum resolution. So even though the beam is moving, to the patient it appears as a single stationary point, which sometimes blurs or disappears if cataracts are present.
Today, there are 250 million people in the world who are blind because of preventable causes. An inexpensive, portable device such as Catra, Raskar says, might help make a serious dent in that number.
Finally, a product that will help people in both the developed and developing countries. Cataract is a serious age-related health issue that could be circumvented with proper diagnosis.