EyeWorld Asia-Pacific December 2012 Issue

27 EWAP CATARACT/IOL December 2012 Dialing in possible cataract diagnosis Smartphone technology for cataract detection I magine being able to use your smartphone to diagnose your owncataracts. Such is the promise of a new device dubbed CATRA, according to Vitor Pamplona, visiting PhD student, Massachusetts Institute of Technology, Cambridge. The CATRA system, which is akin to a weather radar beam used to sweep the sky for clouds, scans the eye for hazy areas of the lens where a cataract may be brewing. Prior to the CATRA system, Mr. Pamplona and others on the team were working on a similar system known as NETRA, another prototype that used the smartphone to measure refractive error. “That prototype gives you spherical cylindrical (error) and axis of astigmatism,” Mr. Pamplona said. “In that case, we were serving approximately 2 billion people who have refractive errors worldwide.” However, this was not solving the worldwide avoidable blindness issue. “That interested us because it is a huge problem—people are blind, and they don’t know that they can be cured,” Mr. Pamplona said. Calling on CATRA The CATRA device will clip onto a smartphone. “When you use this very close to the eye, the CATRA will have the ability to shoot light rays to different parts of the pupil,” Mr. Pamplona said. “The idea is the subject will look at by Maxine Lipner Senior EyeWorld Contributing Writer it and if that region has a cataract, the pattern or the image that is being displayed on the phone will get blurred or will disappear.” The process is an interactive one, calling on subjects to play with the phone displaying different images, looking for the point at which the image fades away. Using this scanning information, the CATRA can generate a map showing position, size, shape, and density of a cataract. “It’s a binary map, so for each part of the pupil you have a ‘yes’ or ‘no’ if you have cataracts or not,” Mr. Pamplona said. When it comes to density, the system can generate a number to show how far along the cataract has progressed. “You have a value from zero to one, from completely clear to completely blocked for every part of the pupil,” Mr. Pamplona said. In addition, the system offers a scattering profile, as well as the “angle of spreading” of the brightness. Ring of clinical promise The most common way to get these measurements in a traditional office is with an ophthalmoscope or through use of a slit lamp. This, of course, is reliant on the practitioner’s ability to determine when the cataract is ripe for removal. “The problem is this is a function of clinicians’ ability to look at it and say that it is severe enough,” Mr. Pamplona said. “They don’t have information to make a very accurate diagnosis—it’s qualitative.” In that sense, he sees the CATRA as offering more information to the Worker in India using the CATRA, which can show position, size, shape, and density of a cataract. Source: Ethan Solomon Child in Kenya benefiting from use of the CATRA. Source: Edward Wong continued on page 29