Optical coherence tomography (OCT) has evolved from an experimental instrument to a critical clinical diagnostic modality and may have the potential to become a seamless surgical-guidance tool. Recent literature studies^1-10 examining intraoperative OCT (iOCT) support the potential role for iOCT in ophthalmic surgery. These studies have examined the role for iOCT in multiple procedures and conditions, including epiretinal membranes, a macular hole, vitreomacular traction, retinal detachment repair, lamellar keratoplasty, and cataract surgery.^1,3-6,8 The field of OCT-guided surgery remains a nascent field. Many early reports were retrospective with small sample sizes.^3-6,8 The PIONEER (Prospective Intraoperative and Perioperative Ophthalmic Imaging With Optical Coherence Tomography) study,¹ examining the utility of a microscope attached externally to an OCT device during ophthalmic surgery, provided, to our knowledge, the first large prospective data set to examine the feasibility and utility of iOCT.

Significant integrative advances are needed for intraoperative optical coherence tomography (iOCT) to achieve widespread use across ophthalmic surgery. A surgeon feedback system that provides microscope integration, heads-up display and foot pedal control of the OCT scan location represents a major interval advance in ophthalmic surgery. In this report, we describe the preliminary findings of the Determination of feasibility of Intraoperative Spectral domain microscope Combined/integrated OCT Visualisation during En face Retinal and ophthalmic surgery (DISCOVER) study, a multisurgeon investigational device study examining the role of microscope integrated iOCT systems with surgeon heads-up display feedback (eg, Carl Zeiss Meditec RESCAN 700, Cole Eye Institute iOCT prototype). During surgical manoeuvres in anterior segment and posterior segment surgery, this technology provides rapid visualisation of the area of interest and provides the surgeon with information regarding instrument–tissue interactions. This system represents a major advance in iterative technology for iOCT and may provide the first widely available platform for surgeons to seamlessly assimilate this technology into the operating room theatre.

To demonstrate key integrative advances in microscope-integrated intraoperative optical coherence tomography (iOCT) technology that will facilitate adoption and utilization during ophthalmic surgery. We developed a second-generation prototype microscope-integrated iOCT system that interfaces directly with a standard ophthalmic surgical microscope. Novel features for improved design and functionality included improved profile and ergonomics, as well as a tunable lens system for optimized image quality and heads-up display (HUD) system for surgeon feedback. Novel material testing was performed for potential suitability for OCT-compatible instrumentation based on light scattering and transmission characteristics. Prototype surgical instruments were developed based on material testing and tested using the microscope-integrated iOCT system. Several surgical maneuvers were performed and imaged, and surgical motion visualization was evaluated with a unique scanning and image processing protocol. High-resolution images were successfully obtained with the microscope-integrated iOCT system with HUD feedback. Six semi-transparent materials were characterized to determine their attenuation coefficients and scatter density with an 830 nm OCT light source. Based on these optical properties, polycarbonate was selected as a material substrate for prototype instrument construction. A surgical pick, retinal forceps, and corneal needle were constructed with semi-transparent materials. Excellent visualization of both the underlying tissues and surgical instrument were achieved on OCT cross-section. Using model eyes, various surgical maneuvers were visualized, including membrane peeling, vessel manipulation, cannulation of the subretinal space, subretinal intraocular foreign body removal, and corneal penetration. Significant iterative improvements in integrative technology related to iOCT and ophthalmic surgery are demonstrated.

Purpose: To assess the microarchitectural changes occurring during surgery for vitreomacular traction using intraoperative optical coherence tomography (iOCT). Methods: A retrospective, consecutive case series of eyes undergoing pars plana vitrectomy for vitreomacular traction with performance of concurrent iOCT. A custom, microscope-mounted portable spectral domain optical coherence tomography system was used. Clinical characteristics and iOCT images were analyzed. Results: Twelve eyes of 12 patients were included with a mean preoperative visual acuity of 20/78 improving to 20/51 (P = 0.02), postoperatively. Intraoperative optical coherence tomography was successfully performed in 100% of cases. Microarchitectural changes were noted on iOCT after surgical release of the vitreomacular traction particularly in the outer retina with increased subretinal hyporeflectivity (e.g., expansion of the distance between the retinal pigment epithelium and photoreceptor layers). In 5 of 12 eyes (42%), iOCT findings altered the surgical procedure (e.g., internal limiting membrane peeling, gas tamponade) to address the subclinical findings (e.g., full-thickness macular hole formation, residual membrane). Conclusion: Intrasurgical imaging using iOCT during vitreomacular traction surgery may identify subclinical changes (e.g., occult full-thickness macular hole formation) that may impact surgical decision making. Architectural changes may occur after surgical maneuvers that are particularly noted in the outer retina. The functional significance of these changes requires further investigation.