For countering the global issue of cataract detection, researchers at MIT have created an affordable device called Catra which can be clipped onto any normal smartphone and identify the disorder in a matter of minutes. Cataracts are one of the main causes of preventable blindness globally and most of its cases are unfortunately detected in the later stages. The reason for this is that for a general test to identify blurry spots in the eyes, a tool called a slit lamp of about $5000 and a trained doctor are needed. However they are not affordable and hence not available easily in rural areas and non affluent countries.
In a doctor’s clinic, the patient is generally given a score between one and four after the cataract test. While one stands for clear vision, four means totally blocked vision. By this new device patients can obtain much more information in an inexpensive way. Some years ago, a method was developed to map local variations in the eye’s refraction which provided lot more information than the three numbers required for a simple prescription. At first the detailed information wasn’t really valued. However, a comprehensive refraction map of the lens became important later after the advent of Lasik laser eye surgery.
Ramesh Raskar, the NEC Career Development Associate Professor of Computer and Communications and director of the MIT Media Lab’s Camera Culture group states, “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.”
Catra, the new affordable device developed by MIT researchers can supposedly be a boon to remote rural areas which are not connected to the advanced world. The machine can identify changes in parts of the lens which have not yet become opaque. Thus it can possibly detect cataracts at an earlier stage than general tests do. General cataract tests rely on the light reflected back by the lens which is seen by the doctor conducting the test. On the other hand, Catra depends on the light passing through the lens and is seen by the patient, who just has to say whether a point of light remains steady, dims or disappears.
Catra apparently uses rays that are perfectly aligned so that the eye’s lens focuses all the beams to the same point on the fovea which is an area in the retina where it has maximum resolution. Thus even if the beam is moving, it looks like a single stationary point to the patient which sometimes appears foggy or disappears if cataracts are present.
This latest device is a follow-up to the researchers’ previous creation of a system called Netra, which employees a smartphone with a different clip-on attachment to analyze refractive errors of the eye.
Manuel M. Oliveira, a visiting professor from Brazil’s Universidade Federal do Rio Grande do Sul and a member of the team commented, “Together, Netra and Catra may become extremely valuable tools for screening patients that need eye-care assistance, especially in regions where eye doctors are not readily available.”
Researchers says that Catra, which is in preliminary testing with 22 subjects, detected cataracts in a previously undiagnosed subject who’d had an eye test in a doctor’s clinic a few months before. The detection was confirmed later in a follow-up test using general methods.
“Cataracts are the leading cause of blindness worldwide and a large problem in the developing world. 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.” Joseph Ciolino, an ophthalmologist at the Massachusetts Eye and Ear Infirmary and Harvard Medical School, commented when asked about this new device.
Considering that approximately 250 million people across the globe are blinded by preventable causes, Raskar says that affordable and compact devices such as Catra are needed to reduce these numbers.