Image taken by portable near-infrared fundus camera. (Credit: NAIST)

A new fundus camera small enough to fit on a smartphone may enable people to take a picture of their own eye to send to a doctor for diagnosis. The camera achieves 1000 images per second and acquires images using three kinds of invisible or near infrared light.

When taking a photo of the fundus, the camera must align itself with the path of light that travels through the retina to the back of the eye. The eye, however, makes regular and rapid movements, constantly changing this path.

Another challenge when imaging the fundus is the wavelengths of light detected by the camera. To take a clear fundus image, a strong flush light must be introduced inside an eye through a pupil because it is completely dark inside the eye.

For this second problem, the researchers modified CMOS cameras. The new module was developed on a miniaturized sensor and incorporates three near infrared filters. These filters acquire three signals that can be given a red, green, and blue value to generate a color photograph of the eye while using near infrared light that is not sensed.

Importantly, at 2.3 mm2 in size, the module is small enough to be mounted on a smartphone without compromising the power necessary for capturing highly detailed images with which a user can take a fundus image by him or herself.