Intra-operative microscope-integrated swept-source optical coherence tomography guided placement of Argus II retinal prosthesis.
Ontology highlight
ABSTRACT:
SUBMITTER: Grewal DS
PROVIDER: S-EPMC6023398 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:PURPOSE:To evaluate the use of live volumetric (4D) intraoperative swept-source microscope-integrated optical coherence tomography in vitrectomy for proliferative diabetic retinopathy complications. METHODS:In this prospective study, we analyzed a subgroup of patients with proliferative diabetic retinopathy complications who required vitrectomy and who were imaged by the research swept-source microscope-integrated optical coherence tomography system. In near real time, images were displayed in stereo heads-up display facilitating intraoperative surgeon feedback. Postoperative review included scoring image quality, identifying different diabetic retinopathy-associated pathologies and reviewing the intraoperatively documented surgeon feedback. RESULTS:Twenty eyes were included. Indications for vitrectomy were tractional retinal detachment (16 eyes), combined tractional-rhegmatogenous retinal detachment (2 eyes), and vitreous hemorrhage (2 eyes). Useful, good-quality 2D (B-scans) and 4D images were obtained in 16/20 eyes (80%). In these eyes, multiple diabetic retinopathy complications could be imaged. Swept-source microscope-integrated optical coherence tomography provided surgical guidance, e.g., in identifying dissection planes under fibrovascular membranes, and in determining residual membranes and traction that would benefit from additional peeling. In 4/20 eyes (20%), acceptable images were captured, but they were not useful due to high tractional retinal detachment elevation which was challenging for imaging. CONCLUSION:Swept-source microscope-integrated optical coherence tomography can provide important guidance during surgery for proliferative diabetic retinopathy complications through intraoperative identification of different complications and facilitation of intraoperative decision making.
| S-EPMC6039290 | biostudies-literature
Project description:We describe a simple and low-cost technique for resolving the complex conjugate ambiguity in Fourier domain optical coherence tomography (OCT) that is applicable to many swept source OCT (SSOCT) systems. First, we review the principles of coherence revival, wherein an interferometer illuminated by an external cavity tunable laser (ECTL) exhibits interference fringes when the two arms of the interferometer are mismatched by an integer multiple of the laser cavity length. Second, we report observations that the spectral interferogram obtained from SSOCT systems employing certain ECTLs are automatically phase modulated when the arm lengths are mismatched this way. This phase modulation results in a frequency-shifted interferogram, effectively creating an extended-depth heterodyne SSOCT system without the use of acousto-optic or electro-optic modulators. We suggest that this phase modulation may be caused by the ECTL cavity optical pathlength varying slightly over the laser sweep, and support this hypothesis with numerical simulations. We also report on the successful implementation of this technique with two commercial swept source lasers operating at 840nm and 1040nm, with sweep rates of 8kHz and 100kHz respectively. The extended imaging depth afforded by this technique was demonstrated by measuring the sensitivity fall-off profiles of each laser with matched and mismatched interferometer arms. The feasibility of this technique for clinical systems is demonstrated by imaging the ocular anterior segments of healthy human volunteers.
| S-EPMC3296548 | biostudies-literature
Project description:PurposeTo investigate the visualization capabilities of high-speed swept-source optical coherence tomography (SS-OCT) in cataract surgery.MethodsCataract surgery was simulated in wet labs with ex vivo porcine eyes. Each phase of the surgery was visualized with a novel surgical microscope-integrated SS-OCT with a variable imaging speed of over 1 million A-scans per second. It was designed to provide four-dimensional (4D) live-volumetric videos, live B-scans, and volume capture scans.ResultsFour-dimensional videos, B-scans, and volume capture scans of corneal incision, ophthalmic viscosurgical device injection, capsulorrhexis, phacoemulsification, intraocular lens (IOL) injection, and position of unfolded IOL in the capsular bag were recorded. The flexibility of the SS-OCT system allowed us to tailor the scanning parameters to meet the specific demands of dynamic surgical steps and static pauses. The entire length of the eye was recorded in a single scan, and unfolding of the IOL was visualized dynamically.ConclusionsThe presented novel visualization method for fast ophthalmic surgical microscope-integrated intraoperative OCT imaging in cataract surgery allowed the visualization of all major steps of the procedure by achieving large imaging depths covering the entire eye and high acquisition speeds enabling live volumetric 4D-OCT imaging. This promising technology may become an integral part of routine and advanced robotic-assisted cataract surgery in the future.Translational relevanceWe demonstrate the visualization capabilities of a cutting edge swept-source OCT system integrated into an ophthalmic surgical microscope during cataract surgery.
| S-EPMC11019595 | biostudies-literature
Project description:PurposeTo compare biometry and prediction of postoperative refractive outcomes obtained by two swept-source optical coherence tomography (SS-OCT) biometers (IOLMaster 700 and Argos), and a partial coherence interferometry (IOLMaster ver 5.4).MethodsBiometric values were measured using two SS-OCT and PCI device and evaluated against one another. Predictive errors were compared at one month after cataract surgery.ResultsOne hundred forty six eyes were considered. Axial length (AXL) measurements were not successful in 3 eyes measured by IOLMaster 700 and Argos devices, and in 17 eyes measured by IOLMaster ver. 5.4 devices. AXL as measured by Argos showed a tendency to be shorter in long eyes with AXL more than 26.0 mm (p < .001) and to be longer in short eyes with AXL less than 22.5 mm (p = .005). Anterior chamber depth as measured by IOLMaster ver. 5.4 was longer than that measured by the other two SS-OCT devices (vs. IOLMaster 700: p = .003; vs. Argos: p = .006). White-to-white diameter measured using Argos was significantly different measurements obtained using two IOLMaster (p < .001, respectively). The mean absolute postoperative prediction errors were 0.41 ± 0.31 diopters (D), 0.42 ± 0.32 D, and 0.35 ± 0.30 D for IOLMaster ver. 5.4, IOLMaster 700, and Argos, respectively.ConclusionThe ocular biometric measurements using three devices showed high agreement. AXL measured by Argos showed a significant difference compared with the measurements from two IOLMaster. ACD was highly correlated between two SS-OCT devices except IOLMaster ver 5.4. LT and CCT values between IOLMaster 700 and Argos were different significantly. SS-OCT devices demonstrated a superior ability to successfully perform measurements compared with PCI device.
| S-EPMC6788676 | biostudies-literature
Project description:PurposeTo evaluate the level of agreement between ANTERION (Heidelberg Engineering, Heidelberg, Germany), OA-2000 (Tomey, Nagoya, Japan), and IOLMaster 500 (Carl Zeiss AG, Jena, Germany).MethodsFifty-one eyes of 51 patients were included in the study. Flat keratometry (K) and steep K, vector component of astigmatism (Jackson cross-cylinder at 0° and 90° [J0] and Jackson cross-cylinder at 45° and 135° [J45]), anterior chamber depth, and axial length were compared using the three devices. Repeated measures analysis of variance was conducted to compare the mean values of the biometrics. Pearson correlation test was conducted to analyze the correlations of the measured values, and a Bland-Altman plot was used to assess the agreement between the three devices. The predicted intraocular lens power of each device was compared to the others using the SRK/T, Haigis, Barrett Universal II, and Kane formulas.ResultsAll K values measured using ANTERION were flatter than those of other instruments. However, good agreement was observed for flat K (ANTERION - OA-2000; 95% limits of agreement [LoA], 0.86 diopters [D]) and steep K (ANTERION - OA2000; 95% LoA, 0.93 D) and OA-2000 - IOLMaster 500 (95% LoA, 0.93 D). J0 and J45 vector components of astigmatism were not statistically different; however, the agreements were poor between the devices (95% LoA ≥1.97 D). Anterior chamber depth values of ANTERION and OA-2000 were interchangeable (95% LoA, 0.15 mm). The axial length showed a high agreement (95% LoA ≤0.17 mm) among the three devices. The predicted intraocular lens powers of the three devices were not interchangeable regardless of formulas (95% LoA ≥1.04 D).ConclusionsSignificant differences in ocular biometrics were observed between ANTERION and the other two devices. This study demonstrated that only axial length showed good agreement among devices.
| S-EPMC9388892 | biostudies-literature
Project description:ObjectivesTo report the swept-source optical coherence tomography angiography (SS-OCTA) findings in choroidal and retinal tumors.MethodsA retrospective noncomparative interventional case series of 60 eyes having various choroidal and retinal tumors imaged with SS-OCTA (Topcon DR1 Triton Plus, Tokyo, Japan) between September 2018 and February 2020 was conducted. Inclusion criteria were tumor thickness <4 mm, tumor base diameter <10 mm, and tumor location at the posterior pole.ResultsChoroidal nevi usually demonstrated well-defined borders, hyperreflective internal structure, and no outer retinal involvement on SS-OCTA. Choroidal melanoma, in contrast to nevi, usually had ill-defined borders (p = 0.018), mixed hyperreflective-hyporeflective or hyperreflective internal structure (p = 0.014), and demonstrated outer retinal involvement (p < 0.001). Circumscribed choroidal hemangioma usually presented with well-defined borders, a hyperreflective internal tumor structure with multiple dilated interconnected tumor vessels intermixed with signal void areas representing connective tissue. Optic disc melanocytomas showed a hyporeflective plexus related to blocking of signal by the pigment and an intact radial peripapillary capillary network. There was flow on the surface and slightly deeper within the lesion on B-scan angiography overlay. Retinal astrocytic hamartomas had well-defined borders and a hyperreflective vascular plexus in the superficial and deep retina. Outer retina and choriocapillaris showed hyporeflective change due to shadowing/masking from calcium or high blood flow in the lesion.ConclusionsEach of the different retinal and choroidal tumors studied in this series presented with different SS-OCTA features to aid in the differential diagnosis of these conditions. Good quality images are obtained in patients with good fixation and tumors <3 mm in thickness located at the posterior pole.
| S-EPMC7853135 | biostudies-literature
Project description:We describe the first handheld, swept source optical coherence tomography (SSOCT) system capable of imaging both the anterior and posterior segments of the eye in rapid succession. A single 2D microelectromechanical systems (MEMS) scanner was utilized for both imaging modes, and the optical paths for each imaging mode were optimized for their respective application using a combination of commercial and custom optics. The system has a working distance of 26.1 mm and a measured axial resolution of 8 μm (in air). In posterior segment mode, the design has a lateral resolution of 9 μm, 7.4 mm imaging depth range (in air), 4.9 mm 6dB fall-off range (in air), and peak sensitivity of 103 dB over a 22° field of view (FOV). In anterior segment mode, the design has a lateral resolution of 24 μm, imaging depth range of 7.4 mm (in air), 6dB fall-off range of 4.5 mm (in air), depth-of-focus of 3.6 mm, and a peak sensitivity of 99 dB over a 17.5 mm FOV. In addition, the probe includes a wide-field iris imaging system to simplify alignment. A fold mirror assembly actuated by a bi-stable rotary solenoid was used to switch between anterior and posterior segment imaging modes, and a miniature motorized translation stage was used to adjust the objective lens position to correct for patient refraction between -12.6 and + 9.9 D. The entire probe weighs less than 630 g with a form factor of 20.3 x 9.5 x 8.8 cm. Healthy volunteers were imaged to illustrate imaging performance.
| S-EPMC4646558 | biostudies-literature
Project description:PurposeTo determine the choroidal thickness (CT) profile in keratoconus (KC) patients using swept-source optical coherence tomography (SS-OCT).MethodsThis was a prospective, cross-sectional study. One hundred two eyes of 52 KC patients were studied using Pentacam and SS-OCT. The macular CT profile was created by manually measuring the distance between the retinal pigment epithelium and the choroid-sclera junction on horizontal b-scans at nine different macular locations. The results were compared to 93 eyes of 93 healthy controls.ResultsMean age of the KC group was 34.9 ± 13.5 years and mean axial length (AL) was 24.1 ± 1.3 mm. Mean topographic KC classification (TKC) was 2.0; 39 eyes were classified as early KC (TKC <1-2), 34 eyes as moderate (TKC 2, 2-3), and 29 as advanced (TKC 3+). Mean subfoveal CT was 383.2 μm in KC patients and 280.5 μm in control group (P < 0.001). CT in KC patients was statistically thicker in all measure locations (P < 0.001). CT in KC eyes decreased with age, approaching control group at >45 years old, losing statistical significance (P = 0.37).ConclusionsCT in KC patients is statistically thicker than in healthy population. After age 45, CT decreases approaching control group values.Translational relevanceThis study describes changes in the CT profile of KC patients, a disease that was considered purely corneal. These choroidal changes argue that KC is a disease that likely involves several ocular structures other than the cornea, and could open new research lines related to the pathophysiology of KC.
| S-EPMC5991807 | biostudies-literature
Project description:AIM:To determine choroidal thickness in healthy Indian subjects using Swept source optical coherence tomography (SS-OCT). METHODS:In this prospective, observational, cross-sectional study; healthy Indian subjects (n = 230) with no history of ocular and/or systemic disorders were enrolled in the study. Choroidal thickness was measured for 230 eyes using SS-OCT. Subjects were divided into six age groups. Main outcome measures were subfoveal choroidal thickness (SFCT) and macular choroidal thickness (MCT) up to 3 mm at 500-micron interval from the fovea was measured in eight different quadrants. RESULTS:The mean SFCT was 307±79 μm and mean MCT was 285±75 μm. No difference in the choroidal thickness was found among genders. Mean SFCT of the different age groups was 327±68 μm (12-18 years), 364±70 μm (18.1-30 years), 321±78 μm (30.1-40 years), 304±79 μm (40.1-50 years), 283±69 μm (50.1-60 years) and 262±72μm (above 60 years; p <0.001; One way ANOVA). Mean macular choroidal thickness was 305±60 μm, 342±61 μm, 306±72 μm, 282±79 μm, 261±66 μm, 238±68μm respectively (p<0.001; one way ANOVA). A significant weak negative correlation was found between age with SFCT (r = -0.368, p<0.001) and MCT (r = -0.40, p<0.001). No significant correlation was found with refractive error, axial length and ocular perfusion pressure. CONCLUSION:This study showed that mean SFCT and MCT was 307±79μm and 285±75 μm, respectively, among healthy Indian subjects. Mean CT was found to decrease with age, although there was no difference in CT between genders.
| S-EPMC5955571 | biostudies-literature
Project description:PurposeTo devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT).MethodsParticipants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions.ResultsThere were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory.ConclusionsUsing an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans.Translational relevanceNFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.
| S-EPMC5804304 | biostudies-literature