In India, cataract screening takes place via smartphone

Photographing eyes with a smartphone and having the images evaluated remotely by an ophthalmologist could make it possible to identify people who need further treatment even in areas where specialists are difficult to reach. In 1,093 patients examined in rural areas of southern India, the decision made by ophthalmologists based on images collected with a smartphone coincided in 96% of cases with that made by specialists who had examined the same patients in person.

The result was obtained by Prabhu Krishna Ravillaof the Aravind Eye Hospital in Madurai, and colleagues, in an observational study carried out in collaboration between Aravind Eye Care System and Johns Hopkins University and presented at the 44th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS). The system does not make the diagnosis itself: instead it allows healthcare professionals with minimal ophthalmology training to capture images of the eye, which are then transmitted to an ophthalmologist for remote evaluation. The objective is to separate the moment of screening from the physical presence of the specialist, making it possible to reach populations who today have difficulty accessing an ophthalmological examination.

The solution made in India

The device developed by the researchers is a small portable accessory that attaches to an Android smartphone. It contains a lens that magnifies the front part of the eye, two small white LEDs powered by the phone and a silicone holder that rests around the eye socket, blocks ambient light and keeps the distance between camera and eye constant. It is made in India and costs, including the smartphone, less than £150. The system is paired with a telemedicine application designed to work even with low-bandwidth connections, available in English and Tamil.

A popular test for cataracts

To test whether images like this could actually be used for screening, community health workers received just three hours of training. They then screened 1,093 patients at 19 “eye camps” held in five locations near Pondicherry in Tamil Nadu: Chengam, Tiruvannamalai, Cheyyar, Arani and Cuddalore. Remote ophthalmologists formulated diagnoses and decisions on whether to send the patient to hospital by looking at images obtained with the smartphone, then compared them with those of ophthalmologists who had directly examined the same patients in rural clinics.

The data provided by the smartphone

The main data concerns the most important clinical decision for a screening tool: determining who should undergo further tests and treatments. Remote ophthalmologists and on-site doctors reached the same decision in 96 cases out of 100. Agreement on the presence of any cataract was 89%, rising to 96% for mature cataracts and 85% for immature cataracts. The agreement was 89% in the identification of eyes without cataracts and 97% in the recognition of pseudophakia, i.e. the presence of an already implanted artificial lens. For pterygium, a growth of tissue on the white part of the eye, agreement was 94%. Operators were also able to reduce the time required for screening to less than two and a half minutes per eye, with agreement between specialists increasing as image quality increased.

“These findings call into question the assumption that specialist presence is necessary for accurate cataract screening,” Ravilla said. “They suggest a model in which a qualified ophthalmologist’s time is used for diagnosis and decisions, where it is most valuable, rather than for travel and in-person visits.”