Clinical Applications of Microscope-Integrated OCT
Recent advances have improved the utility of intraoperative visualization, with more innovation on the way.
Bani Aguirre, MD, MPH; Anjali Saini, BS; Vahid Ownagh, MD; and Lejla Vajzovic, MD
Retina Today 
KEY TAKEAWAYS The evolution of intraoperative microscope-integrated OCT (MIOCT) connects diagnostic imaging with surgical execution to enhance safety and precision. In the research setting, swept-source MIOCT technology and 4D volumetric imaging allow dynamic visualization of residual membranes, subretinal fluid, and foveal deformations. In the future, transitioning from side-by-side displays to unified, single-channel visualization platforms will provide surgeons with enhanced depth perception and spatial orientation. The high resolution and noninvasive nature of OCT have established it as a cornerstone of retinal disease imaging. Recognizing the diagnostic value of this tool, surgeons have sought to incorporate it into surgical settings to enable real-time intraoperative feedback. Continuous investigation has led to the development of intraoperative microscope-integrated OCT (MIOCT), designed to integrate the optical path of the spectral-domain OCT (SD-OCT) scanner into the surgical microscope, enabling real-time imaging of active vitreoretinal surgical maneuvers.1-3 The feasibility and advantages of MIOCT in macular surgery were reported in a 3-year study, in which information from the device influenced surgical decisions in 29% of cases.4 Today, several commercially available systems offer MIOCT for vitreoretinal surgery, differing in the degree of OCT integration and 3D visualization capabilities. Three SD-MIOCT systems provide real-time cross-sectional B-scan imaging: the Zeiss Rescan 700, the Haag-Streit iOCT, and the Leica Proveo 8 with EnFocus, which offers SD-OCT with en face imaging. The Artevo 800 digital microscope (Carl Zeiss Meditec) and Ngenuity (Alcon) 3D visualization system advance this further by integrating SD-OCT with a stereoscopic 4K heads-up display on a single platform, enabling simultaneous real-time OCT imaging and 3D visualization of the surgical field. Notably, none of these systems currently support real-time volumetric quantification of intraocular structures. However, in the research domain, next-generation models have introduced swept-source technology and 4D volumetric imaging.5 These enhancements allow dynamic visualization of residual membranes, foveal deformations, and subretinal fluid quantification, resulting in more precise real-time surgical adjustments.6-9 Furthermore, MIOCT has facilitated the integration of novel surgical approaches, including subretinal gene therapy delivery, where precise cannula placement and bleb formation are critical for therapeutic efficiency.10 Intraoperative OCT has also proven valuable in educational settings, providing retina fellows with immediate visual feedback while they practice advanced surgical procedures.