Abstract Background The slit-lamp biomicroscope is a fundamental diagnostic tool in ophthalmology for detailed examination of the eye. Current camera-equipped digital slit lamps were designed with a single optical channel, which results in the loss of depth information. Without that information, it can be challenging to visualize subtle anatomical variations in teleophthalmology applications and perform procedures guided by the digital view. Objective This study aimed to present a feasibility study of the mixed reality (MR)–based slit lamp (MR-SLP) capable of transmitting real-time stereoscopic views of the slit lamp to local and remote MR headsets, enabling stereoscopic teleophthalmology. Methods A prototype MR-SLP was built by integrating a calibrated stereoscopic camera pair on the left and right viewing channels of a conventional slit lamp and a real-time streaming network. The stereoscopic diagnostic images were transmitted to multiple MR headsets through the streaming network at 1080p and 30 frames per second (fps). The spatial resolution of the system was quantified using a US Air Force 1951 resolution target (Edmund Optics Inc). The 3D spatial accuracy and coordination were evaluated quantitatively by performing a tube-threading test. Five participants (mean age 42.2, SD 16.5 years) with normal visual function, best-corrected visual acuity of 20/20 or better, and a minimum stereoacuity of approximately 40 arc seconds participated in the tube-threading test. Teleophthalmology capability was assessed through real-time streaming across multiple remote sites at Florida International University and Bascom Palmer Eye Institute. Results The measured spatial resolution reached 102 line pairs/mm at 25× optical magnification. The tube-threading task was performed under 4 conditions. Task performance differed significantly between nonstereoscopic (2D) and direct eyepiece views ( P =.03, Kruskal-Wallis test), but not between stereoscopic (3D) MR and direct views ( P >.05, Kruskal-Wallis test). In the real-time remote streaming tests across multiple sites, the system achieved stable, low-latency transmission with an average round-trip time below 40 milliseconds. Participating ophthalmologists reported user experience and image quality comparable to traditional slit lamps. Conclusions The MR-SLP can provide real-time stereoscopic slit-lamp examination images and videos through a broadcasting network to local and remote locations. The spatial resolution and visuomotor performance are comparable to direct viewing through the eyepieces of a traditional slit lamp. This study demonstrated the feasibility of the MR-SLP for high-quality stereoscopic teleophthalmology.
Zhou et al. (Thu,) studied this question.