Now, researchers at the University of Illinois at Chicago College of Medicine and Massachusetts Eye and Ear/Harvard Medical School have developed a cheap, portable camera that can photograph the retina without the need for pupil-dilating eye drops. Made out of simple parts mostly available online, the camera’s total cost is about $185.
The prototype camera can be carried in your pocket, Shen said, and can take pictures of the back of the eye without eye drops. The Retcan be shared with other doctors, or attached to the patient’s medical record.
The camera is based on the Raspberry Pi 2 computer, a low-cost, single-board computer designed to teach children how to build and program computers. The board hooks up to a small, cheap infrared camera, and a dual infrared- and white-light-emitting diode. A handful of other components – a lens, a small display screen and several cables – make up the rest of the camera.
The camera works by first emitting infrared light, which the iris – the muscle that controls the opening of the pupil – does not react to. Most retina cameras use white light, which is why pupil-dilating eye drops are needed.
The infrared light is used to focus the camera on the retina, which can take a few seconds. Once focused, a quick flash of white light is delivered as the picture is taken. Cameras exist that use this same infrared/white light technique, but they are bulky and often cost thousands of dollars.
Shen’s camera photos show the retina and its blood supply as well as the portion of the optic nerve that leads into the retina. It can reveal health issues that include diabetes, glaucoma and elevated pressure around the brain.
Shen and his co-author, Dr. Shizuo Mukai, associate professor of ophthalmology at Harvard Medical School and a retina surgeon at Massachusetts Eye and Ear, describe their camera and provide a shopping list of parts, instructions for assembly, and the code needed to program the camera in the Journal of Ophthalmology.
This work was supported in part by gifts to the Mukai Fund of Massachusetts Eye and Ear.