An app uses a smart phone camera to detect leukocoria, a pale reflection from the back of the eye. It can be an early sign of disease. Here it appears light brown compared the healthy eye. An app uses a smart phone camera to detect leukocoria, a pale reflection from the back of the eye. It can be an early sign of disease.

Camera flashes often can make people's pupils look red in photos. More rarely, flashes can make them appear white – which is usually just a trick of the light but can be a sign of disease, including an eye cancer most common in young children. Since 2014, a free app that uses artificial intelligence to scan people's photos for instances of so-called white eye has been available for iOS or Android devices. That app, called the White Eye Detector, has now been tested on 50,000 photos of 20 children with confirmed eye diseases and 20 with normal eyes. The results suggest the affected children could have been diagnosed more than a year earlier on average with the help of the app, even though it spots only one out of every three photos with white eye.