Intraoperative Spectral-domain Optical Coherence Tomography Research Articles

Spectral-Domain OCT Lens Meridian Position as a Metric to Estimate Postoperative Anatomical Lens Position.

To evaluate the prediction of postoperative anatomical lens position (ALP) using intraoperative spectral-domain optical coherence tomography (SD-OCT) lens anatomy metrics in patients who underwent femtosecond laser-assisted cataract surgery. Intraoperative SD-OCT (Catalys; Johnson & Johnson Vision) and postoperative optical biometry (IOLMaster 700; Carl Zeiss Meditec AG) were used to assess anterior segment landmarks, including lens thickness, lens volume, anterior chamber depth, lens meridian position (LMP), and measured ALP. LMP was defined as the distance from the corneal epithelium to the lens equator, and ALP was defined as the distance from the corneal epithelium to the IOL surface. Eyes were divided into groups according to axial length (> 22.5 mm, 22.5 to 24.5 mm, and > 24.5 mm) and IOL type (Tecnis ZCB00 [Johnson & Johnson Vision]; AcrySof SN-60WF [Alcon Laboratories, Inc], or enVista MX60E [Bausch & Lomb]) to further analyze the correlation between LMP and ALP. Theoretical effective lens position was back-calculated using a specific formula. Primary outcome was correlation between postoperative measured ALP and LMP. A total of 97 eyes were included in this study. Linear regression analysis displayed a statistically significant correlation between intraoperative LMP and postoperative ALP (R2 = 0.522; P < .01). No statistically significant correlation was observed between LMP and lens thickness (R2 = 0.039; P = .06) or between ALP and lens thickness (R2 = 0.02; P = .992). The greatest predictor for ALP was LMP (β = 0.766, P < .001; R2 = 0.523). Intraoperative SD-OCT-measured LMP correlated better than anterior chamber depth and axial length to postoperative ALP. Further studies are necessary to analyze the impact of preoperative or intraoperative LMP measurements on postoperative refractive outcomes. [J Refract Surg. 2023;39(3):165-170.].

Intraoperative Mounted Optical Coherence Tomography Findings Following Reversal of Optic Nerve Head Cupping in Childhood Glaucoma

To examine the structural changes occurring in the optic nerve head (ONH) and macula in infants with childhood glaucoma and clinically observed ONH cupping reversal following intraocular pressure (IOP)-reducing glaucoma surgery, as captured by intra-operative spectral-domain optical coherence tomography (SD-OCT). Retrospective observational case series from an ongoing prospective cohort study. Included were 18 eyes of 14 patients with childhood glaucoma. All eyes had SD-OCT imaging pre- and post-glaucoma intervention and clinically identified ONH cupping reversal. Patients with poor quality images or persistent optic nerve swelling following IOP reduction were excluded. Outcome measurements included IOP, cup-to-disc ratio, axial length and SD-OCT measurements of the peripapillary retinal nerve fiber layer (pRNFL), transverse horizontal diameter of Bruch membrane opening (BMO-D), cup depth, and macula. Mean age at surgery was 1.14±0.93 years and mean interval between pre- and post-operative imaging was 127 days (range 35-595). Following intervention, mean IOP reduction was 45%, accompanied by significant reductions in the cup-to-disc ratio (0.30±0.12, p<0.001), axial length (0.43±0.28mm, p<0.001) and cup depth (46%, p<0.001). Mean global pRNFL thickness pre- vs. post-treatment was 93.1±14.7µm vs. 93.1±17.1µm, respectively, p=1.0. There was no significant difference in pre- and post-treatment global or sectoral pRNFL, 3mm macular total and segmented retinal layer volumes, or the BMO-D. Clinical ONH cupping reversal after IOP-lowering surgery was associated with axial length reduction and decrease in cup depth, but no significant change in the pRNFL or macular volume measures. ONH cupping reversal likely marks stabilization but any pre-intervention ONH damage persists.

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography.

To assess the agreement between the measurements of the distance from the medial rectus muscles insertion to the limbus measured by intra-operative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT). An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation. Mean age was 36.3±16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7±16.9 prismatic dioptres (PD) (range 16-65), being +1.3±6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7±2.1mm (range 5.5-12.0) and by OCT at 7.7±1.2mm (range 5.3-10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; p<0.001), with a correlation of R=0.792 (p=0.011). A better agreement was observed in those MR that were less retro-inserted. SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

The relationship between reversal of optic nerve head cupping and morphometric changes as measured by intraoperative mounted optical coherence tomography in childhood glaucoma

Optic nerve head (ONH) cupping reversal after intraocular pressure (IOP) reduction has been considered an indicator of treatment success in childhood glaucoma, however, the functional significance of cupping reversal in infants and young children remains unknown. Here we examine structural changes occurring in the ONH and macula in infants with childhood glaucoma, as captured by intraoperative spectral-domain optical coherence tomography (SD-OCT), following clinically observed IOP reduction and ONH cupping reversal.

Agreement between intraoperative anterior segment spectral-domain OCT and 2 swept-source OCT biometers

ABSTRACT Purpose: To evaluate the agreement of different biometric parameters obtained using intraoperative spectral-domain optical coherence tomography (SD-OCT) and two swept-source optical coherence tomography (SS-OCT) based biometers. Methods: 102 eyes were assessed using the intraoperative SD-OCT integrated into the Catalys femtosecond-laser, and the IOLMaster 700 and Anterion SS-OCT-based-biometers. Central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW), and lens thickness (LT) were measured. Results: There were statistically significant differences for CCT, ACD, WTW and LT between devices (p < 0.001). The mean difference for ACD ranged from −0.067 to −0.250 mm, with the largest mean difference being between the IOLMaster 700 and Catalys. CCT mean differences ranged from 7 to 32 µm, with the largest mean difference being between the Anterion and Catalys. For WTW, the comparison between the IOLMaster 700 vs Catalys showed the largest mean difference (0.38 mm). However, the mean differences for LT from all three devices were quite similar, ranging from −0.02 to −0.08 mm. Conclusions: SS-OCT biometers showed good agreement for ACD, CCT, WTW and LT. The SD-OCT showed ACD, CCT and WTW values that do not seem to be interchangeable with the SS-OCT biometers; however, this device did show excellent agreement in the case of LT.

Dynamic intraoperative optical coherence tomography for inverted internal limiting membrane flap technique in large macular hole surgery.

To assess the efficacy of dynamic intraoperative spectral-domain optical coherence tomography (iSD-OCT) imaging for inverted internal limiting membrane (ILM) flap technique (IILMFT) in large macular hole (MH) surgery. Prospective, non-randomized, observational study was conducted on 8 eyes of 7 patients with large, chronic and recurrent MHs, which were treated by pars plana vitrectomy (PPV) with IILMFT. All patients underwent standard pre- and postoperative examination. The iSD-OCT imaging was performed using microscope integrated systems before, during, and after ILM peeling. The iSD-OCT data were post-processed using graphic software and reviewed for tissue behavior and instruments position. The real-time iSD-OCT-assisted IILMFT allowed for real-time imaging of the entire surgery with visualization of the MH, vitreoretinal instruments, and all steps of inverted ILM flap formation. In spite of shadowing created by the steel instruments, it was possible to follow and control the distance between the instrument tips and retinal layers. Dynamic imaging of the surgical maneuvers including ILM peeling and mechanical apposition of MH edges revealed the iatrogenic impact on the retina (depression and appearance of hyporeflective zones). iSD-OCT imaging could confirm the proper position of the inverted ILM flap at the very end of the surgery after fluid-air exchange. iSD-OCT imaging is an effective tool for learning and performing a well-controlled and safe inverted ILM flap technique in patients with large MH. Clinical significance of the structural iSD-OCT findings has to be further studied.

Influence of optic media of the human eye on the imaging of Argus® II retinal prosthesis with intraoperative spectral-domain optical coherence tomography

This study aimed to evaluate the influence of the optic media of the human eye on intraoperative spectral-domain optical coherence tomography (iSD-OCT) of an Argus® II retinal prosthesis (AIIRP) during its implantation. One AIIRP was implanted in a human eye with end-stage retinitis pigmentosa and another one in a test eye. Intraoperative imaging was performed using the Rescan™ 700, a microscope-integrated iSD-OCT system. The feasibility of iSD-OCT imaging for AIIRP implantation was assessed during different surgical steps. Data were post-processed postoperatively using the ImageJ graphic software. The quality of imaging of the AIIRP during its implantation was good and almost the same in the human eye and in the training eye. The histograms showed that the optic media had no impact on the quality of iSD-OCT scans, as the difference between the pixel values was not statistically significant. Additionally, the quality of iSD-OCT imaging of the retina under the AIIRP array was not decreased by the array itself. The iSD-OCT-assisted surgical approach facilitates imaging of the AIIRP during its implantation. Uncompromised human optic media do not reduce the quality of AIIRP array imaging throughout all the surgical steps. The influence of the opaque cornea in long-lasting surgeries on the iSD-OCT scan quality during AIIRP implantation has to be investigated.

Intraoperative optische Kohärenztomographie bei explorativer Vitrektomie an Patienten mit Glaskörperblutung – eine Fallserie

High-resolution spectral domain optical coherence tomography (SD-OCT) is agold standard technique for diagnosis, management and monitoring of patients with vitreoretinal diseases. Preoperative diagnostics for evaluation of intraocular and retinal status in patients with vitreous haemorrhage are limited, thus final therapeutic decisions can only be made during explorative vitrectomy. We evaluated the use of intraoperative SD-OCT (iSD-OCT) as areal-time additional diagnostic tool during explorative vitrectomy in patients with vitreous haemorrhage. We report on 9patients (11eyes) with vitreous haemorrhage. Preoperative ultrasound was performed to evaluate intraocular status. Subsequently, an explorative 23G pars plana vitrectomy was performed under visualisation with the OPMI Lumera700 surgical microscope (Carl Zeiss Meditec, Jena, Germany) equipped with afully integrated iSD-OCT device (Rescan 700, Carl Zeiss Meditec, Jena, Germany) as areal-time diagnostic tool. In all patients, intraoperative iSD-OCT allowed real-time evaluation of the preretinal, intraretinal and subretinal structures in addition to the intraoperative en face image. The further surgical strategy, i. e. necessity for peeling of epiretinal membranes (ERM) or of the inner limiting membrane (ILM), application of intravitreal medication and selection of the appropriate tamponade, was based on and optimised according to the iSD-OCT images. Intraoperative iSD-OCT is highly useful as an additional intraoperative diagnostic tool in patients with vitreous haemorrhage. In addition to the en face microscope image, it facilitates intraoperative real-time diagnosis and aids therapeutic decision-making during surgery.

Evaluation of intraocular lens position during phacoemulsification using intraoperative spectral-domain optical coherence tomography

To assess the position of intraocular lenses (IOLs) at the end of standard phacoemulsification with intraoperative spectral-domain optical coherence tomography (SD-OCT). Department of Ophthalmology, Rudolf Foundation Hospital, Vienna, Austria. Prospective case series. Standard phacoemulsification with IOL implantation was performed. The Rescan 700SD-OCT system was used for intraoperative imaging. The anterior segment of the eye was scanned using SD-OCT at the end of the surgery. The distance from the IOL optic center and the IOL optic edge to the posterior capsule was measured postoperatively using graphic software. The study comprised 74 patients (101 eyes). The mean axial length was 23.97mm (range 21.43 to 28.61mm). The mean IOL power was 20.39 diopters (D) (range 6.5 to 27.5 D). Contactbetween the IOL and posterior capsule was absent in 88 cases (87.13%), and partial or full contact was present in 13 cases (12.87%). The mean distance between the IOL central optic and posterior capsule was 0.71 pixel (range 0.06 to 1.38 pixels) in 99 cases (98.02%). In 42 cases (57.53%), partial contact between the IOL edges and the posterior capsule was noticed. The mean distance between the IOL edge and posterior capsule was 0.21 pixel (range 0.04 to 0.92 pixel). Intraoperative SD-OCT facilitated the imaging of IOL position during standard phacoemulsification. Contact between the IOL central optic and posterior capsule at the end of the surgery occurred rarely. Improved IOL design should be considered. Drs. Binder and Glittenberg are consultants to Carl Zeiss Meditech AG. None of the other authors has a financial or proprietary interest in any material or method mentioned.

Does perfluoro-n-octane use in 23G vitrectomy for retinal detachment surgery affect the integrity of the ellipsoid zone?

To examine the integrity of the ellipsoid zone after perfluoro-n-octane use for reattachment of the central retina in macula-off retinal detachment cases. Intraoperative video documentation with microscope-integrated intraoperative spectral-domain optical coherence tomography (OCT) of 10 consecutive patients with macula-off retinal detachment, scheduled for primary vitrectomy for retinal detachment repair, was retrospectively examined for defects in the integrity of the ellipsoid zone due to perfluoro-n-octane use. Successful intraoperative visualization was possible in all cases, retinal detachment was reattached in all cases, but residual islands of subretinal fluid persisted directly after perfluoro-n-octane use in 80% of cases. These were resorbed in all cases in the postoperative OCTs. Disturbances in the integrity of the ellipsoid zone or intraoperative macular hole formation did not present in any of our cases. Perfluoro-n-octane use seems to be a safe procedure regarding integrity of the ellipsoid zone in cases scheduled for primary vitrectomy for retinal detachment repair.

A Pilot Study on Feasibility and Effectiveness of Intraoperative Spectral-Domain Optical Coherence Tomography in Glaucoma Procedures.

To demonstrate the use of a spectral-domain optical coherence tomography (SDOCT) integrated surgical microscope in glaucoma surgery. An SDOCT system was used to interface directly with an ophthalmic surgical microscope, to allow real-time intraoperative SDOCT (iOCT) imaging during glaucoma procedures like phaco-trabeculectomy, Ahmed glaucoma valve (AGV) implantation, gonio-synechiolysis, and bleb needling. The various surgical steps during glaucoma surgeries where iOCT can be of potential help in guiding the surgeon were recorded. High-resolution, cross-sectional images of the relevant structures were achieved with the iOCT system in all procedures. The surgeon could determine the depth of the scleral dissection, the intrastomal bed, the path of the AGV tube in the eye, the release of peripheral anterior synechiae and the efficacy of needling with respect to breakage of loculations; most of these are technically 'blind' procedures, where the outcomes are determined postoperatively. Metallic instruments cast a shadow on tissues below, thereby restricting the use of the device in its current state. The iOCT system provided high quality, intraoperative, real-time imaging, which could possibly improve the safety and efficacy of the surgical procedures in glaucoma. Further studies and modifications to the iOCT are required to better understand and increase the uptake of this technology in daily practice. The iOCT, with further advancements in its technology, could potentially provide the surgeon both quantitative and qualitative, real-time depth and tissue proximity details, thus improving the safety and accuracy of glaucoma surgery.

Macular Surgery Using Intraoperative Spectral Domain Optical Coherence Tomography.

Purpose:To report the use of intraoperative spectral domain optical coherence tomography (SD-OCT) for detecting anatomical changes during macular surgery.Methods:In a consecutive case series, 32 eyes of 32 patients undergoing concurrent pars plana vitrectomy and intraoperative SD-OCT for macular hole (MH), epiretinal membrane (ERM) and vitreomacular traction (VMT) were enrolled. Intraoperative changes in retinal thickness and dimensions of the macular hole were measured in patients with ERM and VMT following surgical manipulation using a hand-held SD-OCT device (iVue, Optovue Inc., Fremont, CA, USA).Results:SD-OCT images of sixteen eyes with macular hole were subjected to quantitative and qualitative analysis. All MH dimensions remained stable during consecutive stages of surgery except for MH apex diameter, which showed a significant decrease after internal limiting membrane (ILM) peeling (P=0.025). Quantitative analysis of ten patients with ERM showed a significant decrease in retinal thickness after membrane removal (P=0.018) which did not remain significant until the end of the procedure (P=0.8). In three cases, subretinal fluid was formed after ILM peeling. Quantitative analysis of five patients with VMT showed a decrease in retinal thickness during consecutive steps of the surgery, although these changes were not significant. In two cases, subretinal fluid was formed after ILM peeling.Conclusion:Intraoperative SD-OCT is a useful imaging technique which provides vitreoretinal surgeons with rapid awareness of changes in macular anatomy during surgery and may therefore result in better anatomical and visual outcomes.

Visualization of Real-Time Intraoperative Maneuvers with a Microscope-Mounted Spectral Domain Optical Coherence Tomography System

The advent of optical coherence tomography (OCT) has revolutionized our diagnostic and therapeutic capabilities in ophthalmology and vitreoretinal disease. In the clinic setting, OCT has touched nearly every aspect of vitreoretinal disease. More recently, OCT has been introduced the operating room theater. Intraoperative OCT (iOCT) has been used to successfully further our understanding of optic pit maculopathy, macular holes, epiretinal membranes, and retinopathy of prematurity.1–6 Limited systems are available for intraoperative use. All commercially available systems are handheld OCT devices or modified tabletop units, which allow for intraoperative imaging but require cessation of the surgical procedure to complete imaging. This precludes real-time feedback to the surgeon of the anatomical impact of surgical maneuvers and increases the duration of the surgical procedure. A microscope-mounted/integrated OCT (MMOCT) system allows for the integration of OCT into the real-time surgical platform.7,8 At the time of this report, two unique prototype systems have been described in the literature.5,7,8 Using a prototype MMOCT system, we previously demonstrated the feasibility of intraoperative imaging of surgical instruments, retinal effects of surgical contact, and primarily static surgical steps.7 To further seamlessly integrate OCT into the surgical platform, visualization of intraoperative motion and manipulation will be critical. Another critical component of integration will include the rapid localization of the surgical area of interest with the intraoperative spectral domain OCT (SD-OCT) device and quantitative information regarding the relative locations of the surgical instruments to the retinal tissue layers of interest. In this report, we describe a novel technique for visualizing intraoperative motion of surgical instruments with an MMOCT system.

Intraoperative SD-OCT in Macular Surgery

Intraoperative use of spectral-domain optical coherence tomography (SD-OCT) using an OCT-mounted surgical microscope could provide additional information to predict visual outcomes of macular surgery and identify intraoperative changes in the macular anatomy that affect visual recovery. This interventional retrospective case study included 5 eyes of 5 consecutive patients with various macular pathologies. All patients underwent the standard surgery for idiopathic macular holes and epiretinal membranes (ERMs) using the same 25-gauge three-port pars plana technique. If present, the ERM was removed. The dye procedure was then repeated to stain and remove the internal limiting membrane (ILM). OCT images were obtained with the retinal map or cross-section program preincision, post-hyaloid elevation (if applicable), post-residual ERM peel (if applicable), and post-ILM peel. In 3 of 5 patients, the intraoperative scan revealed an increased area of subretinal hyporeflectivity corresponding with a clinically visible "cuff" of retinal detachment. In 2 patients, the SD-OCT scan taken immediately after ERM removal helped find a cleavage plane for the subsequent ILM peeling, which could be further confirmed by a scan taken immediately after it. In 2 cases, the scans identified intraoperative complications that otherwise would not have been noted and allowed the surgeon to modify the next procedures during surgery. Use of this technology in an operative setting can provide greater insight into the changes in retinal anatomy created during macular surgery.

Analysis of Pars Plana Vitrectomy for Optic Pit–Related Maculopathy With Intraoperative Optical Coherence Tomography

Optimal management of optic pit-related maculopathy remains to be determined. The fluid source for the maculopathy also remains controversial. In this article, we present a unique surgical technique for internal drainage of the intraretinal fluid and describe the intraoperative use of spectral-domain optical coherence tomography to assist in the surgical management of this condition. Pars plana vitrectomy was performed with elevation of the posterior hyaloid. Following an air-fluid exchange, aspiration over the optic nerve pit was performed. Following aspiration, intraoperative spectral-domain optical coherence tomography demonstrated collapse of the retinoschisis, strongly suggesting a connection between the vitreous cavity and the intraretinal fluid.

Intraoperative Microscope-Mounted Spectral Domain Optical Coherence Tomography for Evaluation of Retinal Anatomy during Macular Surgery

To evaluate the use of microscope mounted spectral domain optical coherence tomography (SD-OCT) to detect changes in retinal anatomy during macular surgery. Retrospective, observational case series. We included 25 eyes of 24 consecutive patients who underwent SD-OCT during macular surgery. A retrospective review of operative techniques, outcomes, and imaging for all patients who underwent intraoperative microscope mounted SD-OCT during surgery for macular hole or epiretinal membrane (ERM) from April 2009 to April 2010 was performed. Qualitative and quantitative characteristics of intraoperative and postoperative changes in retinal anatomy were studied. Intraoperative change in macular hole dimensions and retinal thickness in patients with ERM owing to surgical manipulation measured using SD-OCT. Intraoperative SD-OCT from 13 eyes of 13 patients undergoing surgery for macular hole was reviewed. Two cases had images of suboptimal quality and were excluded. The remaining 11 eyes were subjected to quantitative analysis, which revealed stability of macular hole height and central hole diameter after internal limiting membrane (ILM) peeling, but an increase in the diameter of subretinal fluid under the macula in ten of 11 eyes (average 87% wider). Intraoperative imaging from 12 eyes of 11 patients undergoing surgery for ERM was analyzed. Quantitative analysis revealed an average increase of retinal thickness after ILM peel of <2%. Ten of 12 eyes developed a new subretinal hyporeflectance, which likely represents shallow detachment of the macula, after uncomplicated membrane peel. Use of intraoperative SD-OCT has provided new insight into the changes to retinal anatomy during macular surgery and may prove to be a useful tool for vitreoretinal surgery. Further study is warranted to determine whether intraoperative changes such as the creation of shallow retinal detachments during uncomplicated macular surgery affects visual recovery. Proprietary or commercial disclosure may be found after the references.

Intraoperative Spectral-Domain Optical Coherence Tomography During Complex Retinal Detachment Repair

Spectral-domain optical coherence tomography (SD-OCT) is a non-invasive imaging modality that generates detailed images of retinal microstructure. In this study, this technology was employed to investigate changes that occur intraoperatively during repair of complex rhegmatogenous retinal detachment using perfluorocarbon liquids. Intraoperative SD-OCT images were obtained for two patients who underwent pars plana vitrectomy, perfluoro-n-octane instillation, and silicone oil fill for rhegmatogenous retinal detachment. The results demonstrate the ability to obtain high-resolution images of retinal architecture intraoperatively through perfluoro-n-octane and silicone oil. Residual subretinal fluid may be identified intraoperatively despite tamponade with perfluoro-n-octane.

INTRAOPERATIVE USE OF HANDHELD SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING IN MACULAR SURGERY

To describe the intraoperative use of handheld spectral domain optical coherence tomography (SDOCT) imaging in macular surgery. Prospective, observational case series. A handheld SDOCT device was used to obtain preincision optical coherence tomography imaging in patients undergoing vitrectomy for macular diseases. After removal of the internal limiting membrane or the epiretinal membrane, repeat intraoperative imaging was obtained. Spectral domain optical coherence tomography findings were characterized. An efficient technique was established for obtaining intraoperative SDOCT imaging. A total of eight patients were included in the study. Four patients underwent surgery for macular hole, three patients for epiretinal membrane, and one for vitreomacular traction. Comparison of the preincision and intraoperative SDOCT images demonstrated distinct changes in retinal contour and macular hole configuration. Intraoperative SDOCT imaging identified additional membranes in two patients. The intraoperative use of handheld SDOCT imaging provides an efficient method for visualizing macular pathology. This technology may, in certain cases, help confirm or identify diseases that may be difficult to visualize during surgery.