Peek: Portable Eye Examination Kit. The smartphone Ophthalmoscope

Purpose: Create hardware and software solutions allowing the smartphone to be used to visualise the retina. Methods: The target device under investigation is the Samsung Galaxy S3 (Samsung Group). Accompanying software was designed for the android platform to automate such features as optic cup:disc ratio calculation, with a view to aiding diagnosis of glaucomatous optic neuropathy. An adaptor clip was designed with Rhinoceros 3D (McNeel and Associates), and manufactured in PolyLactic Acid (PLA) by Fused Filament Fabrication using an Up! Plus 3D printer (PP3DP, China). The optics blanks were cut on a CTR E5 (CTR Lasers, UK) laser cutter and polished by hand using diamond lapping compound, to create a miniature prismatic solution re-routing light from the native flash to become coincident with the optical path. Results: Peek provides high-resolution images of the retina sufficient for clinical examination, with a greater field than conventional direct ophthalmoscopy. Images obtained with Peek, along with comparative images using conventional disc photography are demonstrated in Figure 1. The relative differences in field between Peek and other ophthalmoscopic modalities are demonstrated in Figure 2. Conclusions: Peek is a low-cost alternative to the direct ophthalmoscope, comprising a smartphone adaptor that circumvents many of the technically challenging aspects of fundoscopy. The technology takes advantage of the intrinsic auto-focussing features within the smartphone to provide a high-resolution view of the retina through an undilated pupil. The adaptor couples the native mobile LED flash to optical path of the camera, allowing clinicians access to a previously unobtainable view of the retina using a smartphone. The connectivity of smartphone devices adds capacity to transmit retinal findings to secondary care for more effective triage in cases of diagnostic doubt. This low-cost technology has been designed with a view to improving access to ophthalmic diagnostics in resource-poor settings. Trials are underway to assess the impact of the technology in the diagnosis of glaucomatous optic neuropathy in a related cluster randomised controlled trial based in Kenya