Head-Mounted Smartphone Fundus Imaging

Abstract

Purpose : Smartphone fundoscopic imaging is a useful tool to communicate the health of the retina and optic nerve to other ophthalmologists without the need for expensive equipment. Although smartphone fundus imaging has been established in the literature there is limited adoption because current technologies and techniques have a steep learning curve and are dependent on patient cooperation. Currently, at least one hand is needed to operate the smartphone, which can be difficult in patients who are intolerant to fundus exams. Therefore we have developed a 3D printed head-mountable smartphone holder for fundus imaging so that two hands are available to position the condensing lens and open the patient's eyelids.

Methods : Fundus images were taken on an iPhone 11 using the native camera app (main camera lens with 1x optical zoom) and led flash at full illumination. A Volk 20 diopter lens was used as a condenser lens to focus the patient’s fundus for imaging. The head-mounted smartphone holder was designed in Fusion 360 and all components (including screws) were completely 3D printed on a Prusa MK3S using black Polyethylene terephthalate glycol. An elastic head strap was used to secure the smartphone holder to the head. The head-mounted smartphone holder was designed to hold the iPhone 11 in landscape position at a distance of approximately 22 cm from the examiner’s eyes. To acquire images, patient’s were positioned in the standard fashion for an indirect ophthalmoscopy examination, pharmacologically-dilated and fixating at a distant target.

Results : Fundus imaging using the head-mounted smartphone holder allowed the examiner to visualize the fundus including the macula, optic disc, retinal vessels and peripheral retina with a high quality comparable to the view seen with an indirect ophthalmoscope.

Conclusions : Our head-mounted smartphone holder is similar to the indirect ophthalmoscope, which reduces the learning curve and allows two hands to help open patients’ eyelids and maneuver the condensing lens. The total cost of materials excluding the lens and smartphone is less than $5.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

A) Digital rendering of head-mounted smartphone holder.
B) Live image of head-mounted slit-lamp with elastic head strap.

 

A) Third-person view of the examiner using the head mount secured to the head by an elastic head strap and an iPhone 11 in landscape orientation.
B) Image from the iPhone 11 using 1x optical zoom. A Volk 20 diopter lens is used to visualize a patient’s left nasal retina.