A head-mounted iPhone-based ophthalmoscope is the latest step in the rapidly evolving world of smartphone fundoscopy
Mark Hillen |
While a number of smartphone fundus imaging methods have been developed recently, all of them would struggle in the pediatric ophthalmology setting - as do conventional fundus cameras. The specialized equipment can be bulky, and getting children to behave long enough to successfully perform ophthalmoscopy with an iPhone in one hand and a condensing lens in another is extremely difficult. Recent developments include an adaptor that attaches a condensing lens to the iPhone, but the entire apparatus can be awkward to use as ophthalmologists are not used to the technique. Now a group of ophthalmologists at the Wilmer Eye Institute, in Baltimore, MD, USA have come up with a solution: head-mounting a smartphone (see Figure).
One member of the development team, Aaron Wang, says that their method "preserves the familiar reflexes the ophthalmologist already uses for the indirect ophthalmoscopic exam." What inspired the team to come up with the idea, he says, "was a need to obtain fundus videos/ pictures of babies with retinopathy of prematurity. Babies can't look in a desired direction for a conventional fundus camera."
There were other issues at stake. "The Keeler digital indirect ophthalmoscope places the camera aperture in between the examiner's pupils, often resulting in vignetted images and images that differ from what the examiner sees," explains Wang. “Our method is truly 'what you see is what you get,' and we added an eyepiece lens for easy viewing of the smartphone display." One drawback is that that the exam isn't stereoscopic, but the portability, ease of use and low cost of entry with smartphones compensate for this.
So far, the team have been able to capture good quality videos of retinal hemorrhages, swollen optic nerves and fungus balls as well as videos of scleral depression.