A pocket-sized retina camera, no dilating required

March 20, 2017

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Dr. Shizuo Mukai of Mass. Eye and Ear, at right, with Dr. Bailey Shen of UIC College of Medicine.
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Suzanne Day
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Boston, Mass. — It’s the part of the eye exam everyone hates: the pupil-dilating eye drops. The drops work by opening the pupil and preventing the iris from constricting in response to light and are often used for routine examination and photography of the back of the eye. The drops sting, can take up to 30 minutes to work, and cause blurry vision for several hours afterwards, often making them inconvenient for both patient and doctor.

Now, researchers at Massachusetts Eye and Ear/Harvard Medical School and the University of Illinois at Chicago College of Medicine 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.

"As residents seeing patients in the hospital, there are often times when we are not allowed to dilate patients -- neurosurgery patients for example," said Dr. Bailey Shen, a second-year ophthalmology resident at the UIC College of Medicine. "Also, there are times when we find something abnormal in the back of the eye, but it is not practical to wheel the patient all the way over to the outpatient eye clinic just for a photograph."

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 pictures can 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 is an open-source device that is cheap and easy to build," said Mukai. "We expect that others who build our camera will add their own improvements and innovations."

“The device is currently just a prototype, but it shows that it is possible to build a cheap camera capable of taking quality pictures of the retina without dilating eye drops, “ Shen said. “It would be cool someday if this device or something similar was carried around in the white-coat pockets of every ophthalmology resident and used by physicians outside of ophthalmology as well.”

Adapted from a news release by the University of Illinois at Chicago College of Medicine. This work was supported in part by gifts to the Mukai Fund of Massachusetts Eye and Ear.

About Massachusetts Eye and Ear 
Mass. Eye and Ear clinicians and scientists are driven by a mission to find cures for blindness, deafness and diseases of the head and neck. Now united with Schepens Eye Research Institute, Mass. Eye and Ear is the world's largest vision and hearing research center, developing new treatments and cures through discovery and innovation. Mass. Eye and Ear is a Harvard Medical School teaching hospital and trains future medical leaders in ophthalmology and otolaryngology, through residency as well as clinical and research fellowships. Internationally acclaimed since its founding in 1824, Mass. Eye and Ear employs full-time, board-certified physicians who offer high-quality and affordable specialty care that ranges from the routine to the very complex. In the 2016–2017 “Best Hospitals Survey,” U.S. News & World Report ranked Mass. Eye and Ear #1 in the nation for ear, nose and throat care and #1 in New England for eye care. For more information about life-changing care and research, or to learn how you can help, please visit MassEyeAndEar.org.

About Harvard Medical School Department of Ophthalmology
The Harvard Medical School (HMS) Department of Ophthalmology (eye.hms.harvard.edu) is one of the leading and largest academic departments of ophthalmology in the nation. More than 350 full-time faculty and trainees work at nine HMS affiliate institutions, including Massachusetts Eye and Ear, Schepens Eye Research Institute of Massachusetts Eye and Ear, Massachusetts General Hospital, Brigham and Women’s Hospital, Boston Children’s Hospital, Beth Israel Deaconess Medical Center, Joslin Diabetes Center/Beetham Eye Institute, Veterans Affairs Boston Healthcare System, VA Maine Healthcare System, and Cambridge Health Alliance. Formally established in 1871, the department has been built upon a strong and rich foundation in medical education, research, and clinical care. Through the years, faculty and alumni have profoundly influenced ophthalmic science, medicine, and literature—helping to transform the field of ophthalmology from a branch of surgery into an independent medical specialty at the forefront of science.