Design and Performance Characterization of a Novel, Smartphone-Based, Portable Digital Slit Lamp for Anterior Segment Screening Using Telemedicine.

Purpose: Telemedicine-enabled, portable digital slit lamps can help to decentralize screening to close-to-patient contexts. We report a novel design for a portable, digital slit lamp using a smartphone. It works on an advanced optical design and has the capability of instantaneous, objective photodocumentation to capture anterior segment images and is telemedicine-enabled. Methods: The device is constructed keeping its usability and the importance of design ergonomics for nonspecialized field personnel in mind. The optical design is described, and the resolution and magnification are compared with traditional desktop-based slit lamps. A Health Insurance Portability and Accountability Act (HIPAA)-compliant, patient management software is integrated to synchronize the captured images with a secure cloud server along with a sharpness algorithm to extract the best focused frames of the cornea, iris, and lens, from videos. We demonstrate its photodocumentation ability and teleophthalmology feasibility by capturing images in a pilot study from nine subjects. Results: Images were obtained in various illumination, magnification, and filter settings. Synchronous and asynchronous teleophthalmology consults were conducted. The performance of the device was shown to be limited by the smartphone sensor resolution and not the optical design, because the Air Force target resolution was found to be the same on smartphone-mounted traditional slit lamps despite a lower magnification. Conclusions: The novel, portable, digital slit lamp with advanced optical design using smartphones has the ability to screen for anterior segment pathologies using telemedicine. Translational Relevance: A portable, telemedicine-friendly, ergonomically designed, slit lamp used by nonspecialist personnel allows for both synchronous and asynchronous modes of consultation at remote locations, facilitating mass screening programs.

A novel approach to anterior segment imaging with smartphones in the COVID-19 era.

PURPOSE: To report a novel, telemedicine-friendly, smartphone-based, wireless anterior segment device with instant photo-documentation ability in the COVID-19 era. METHODS: Anterior Imaging Module (AIM) was constructed based on a 50/50 beam splitter design, to match the magnification drum optics of slit-lamps with a three-step or higher level of magnification. The design fills the smartphone sensor fully at the lowest magnification and matches the fixed focus of the slit-lamp. It comes with a smartphone for instant photo-documentation, an in-built software application for data-management and secure HIPAA compliant cloud storage, and a Bluetooth trigger for a one-tap image capture. The construction of the device is explained, and the optical resolution measured using U.S. air-force resolution test. AIM's performance was characterized with traceability to internationally relevant performance standards for digital slit-lamps after image quality assessment through a pilot study. RESULTS: Clinically useful anterior segment images were obtained with both diffuse and slit illumination at different magnification settings with the highest magnification (40X) resolution of 359 lines per cm and the lowest magnification (16X) resolution of 113 lines per cm. CONCLUSION: AIM is a novel, wireless, telemedicine-enabled design that digitizes existing, analog slit lamps with at least three-step magnification. The settings ensure the focus is determined purely by the position of the slit-lamp. Hence, the image viewed and captured on the smartphone is exactly what the clinician sees through the eyepiece. This helps in maintaining distance from the patient in the ongoing COVID-19 pandemic, as well.