Smartphones already have been used to help dress wounds in a disaster situation, remotely diagnose and self-diagnose acute appendicitis, detect melanoma, pinpoint outbreaks of malaria, substitute for microscopes and track heart rhythms.
Now, researchers at the Massachusetts Institute of Technology have developed a method to detect cataracts on a smartphone, significantly lowering two of the barriers to testing for the condition in remote and low-income parts of the world. With the system, called Catra, no longer does the test require a $5,000 device known as a slit lamp, nor does there need to be a physician present to interpret the results, according to the MIT Media Lab.
Catra is a small device that clips on to various brands of smartphones or other "smart" gadgets such as an iPod. Hold it up to the eye and Catra beams light across the eye to search for cloudiness that could indicate cataracts.
The device then goes beyond the simple score of 1 to 4 that ophthalmologists traditionally assign to the degree of blocked vision. It "scans the lens of the eye and creates a map showing position, size, shape and density of cataracts," Media Lab graduate student Vitor Pamplona, says in an MIT-produced news story.
This may someday help physicians determine whether cataract treatment—which currently involves the surgical removal of the eye's lens—could target specific areas of cloudy vision. For now, though, the researchers see the technology as a low-cost way of diagnosing cataracts in underserved parts of the world. It also could help spot cataracts earlier than with traditional testing because the Catra sensor can detect changes in parts of the lens that may not have turned cloudy yet.
With Catra, patients report whether a point of light beamed at their eye stays steady, appears dimmer or completely disappear, instead of relying on a physician to interpret light reflected by the lens. "We turned the problem around," according to Ramesh Raskar, director of MIT Media Lab's Camera Culture group. "Instead of asking the doctor, we ask the patient."
Cataracts are said to be the number one preventable cause of blindness worldwide, but the condition isn't always detected in time, particularly in developing nations. "Since the blindness can be treated by surgically removing the cataract, the diagnosis is important, and patients may not know that they have a treatable condition. If they can be accurately diagnosed, then they are more likely to seek treatment," Massachusetts Eye and Ear Infirmary ophthalmologist Dr. Joseph Ciolino says.