Given that iPhones can already be used to perform skin exams, perhaps it shouldn't come as a surprise that they're now able to do eye exams, too. Researchers from Harvard Medical School's Massachusetts Eye and Ear Infirmary have devised a way of using the phones to perform fundus photography, which is the photographing of the retina. While the iPhone just requires an app and a lens to perform the task, a complete fundus camera can cost tens or even hundreds of thousands of dollars.

According to Dr. Shizuo Mukai, senior author of a paper on the system, iPhones are already used to document ocular conditions, but have some limitations. More specifically, the built-in camera app doesn't allow users to manually control focus and exposure while recording video, leading to poor-quality images.

Instead, the scientists used the FiLMiC Pro videography app (on an iPhone 4 or 5) along with an ophthalmology-specific 20D lens, which generally cost less than US$200 each. That lens was in some cases combined with a Koeppe lens, another standard tool in the field of ophthalmology. As a result, the researchers were able to capture "excellent, high-quality fundus images in both children under anesthesia and in awake adults." Rabbits were also used in the experiments.

While the best images were captured using both lenses together in an operating room, footage shot using only the 20D lens in a clinic or emergency room was also described as being excellent.

Not only is the setup portable and reportedly quite easy to use, but the comparatively low costs involved should also make fundus photography possible in developing nations that otherwise couldn't afford it.

Dr. Mukai and his colleagues' paper was recently published in the Journal of Ophthalmology.

An unrelated but somewhat similar Android-based system known as Peek is currently being tested in Kenya.