Swept-source Optical Coherence Tomography Device Research Articles

Comparison of ocular biometric parameters between two swept-source optical coherence tomography devices and Scheimpflug tomography in patients with cataract.

To assess and compare the variations and agreements across different ocular biometric parameters using swept-source optical coherence tomography (SS-OCT) and Scheimpflug tomography in patients diagnosed with cataract. This prospective case series was conducted at Tianjin Medical University Eye Hospital. In total, 212 eyes from 212 patients scheduled for phacoemulsification were included. Eyes were evaluated preoperatively using two SS-OCT devices (IOLMaster700 and CASIA2) and Scheimpflug tomography (Pentacam). Central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), white-to-white distance (WTW), flat simulated keratometry (Kf), steep simulated keratometry (Ks), mean keratometry (Km), and total corneal keratometry (TKm) were measured. Intraclass correlation coefficient (ICC), 95% confidence intervals (CI) and limits of agreement (LoA) widths were conducted to assess differences and correlations between devices. All parameters, except for Ks, were significantly different. Pairwise comparison revealed no significant differences between keratometry obtained by IOLMaster 700 and Pentacam. LoA widths of all paired comparisons for Ks were >0.80 D. Except for WTW between IOLMaster 700 and CASIA2 and between CASIA2 and Pentacam, other Pearson's coefficients between devices showed a strong correlation (all r>0.95). The ICC of WTW (ICC=0.438, 95%CI 0.167-0.625) showed poor reliability. The reliability of CCT, ACD, and AQD was excellent (all ICC>0.95), whereas that of TKm was good (ICC=0.827, 95%CI 0.221-0.939). A significant linear correlation was also observed among devices. The ocular parameters derived from the use of IOLMaster700, CASIA2, and Pentacam exhibit significant discrepancies; as such, measurements from these devices should not be deemed as interchangeable.

Deep Learning Versus Corneal Tomography Features to Detect Subclinical Corneal Edema in Fuchs Endothelial Corneal Dystrophy

Purpose: To compare a deep learning model with corneal tomography features for detecting subclinical corneal edema in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: We trained a deep learning model to detect corneal edema on 379 optical coherence tomography B-scans of normal and edematous corneas. 51 eyes of 32 patients with FECD were analyzed and compared with 100 eyes of 50 normal patients. For each eye, the cornea was scanned on the same day using 2 modalities of the same swept-source optical coherence tomography device (Anterion): corneal tomography maps and 6 high-resolution radial B-scans. The 6 radial B-scans were analyzed using our model from which an en face map of edema was reconstructed. The location exhibiting the highest probability of edema was derived from that map. Two corneal surgeons assessed the tomography maps and labeled the location of the supposed highest edema. This location was compared with our model's en face map. Results: According to tomography features, 64.7% of eyes presented subclinical edema. Our model and tomography features agreed in 80% of cases for the presence or absence of subclinical edema. The average distance between the location of maximal edema determined by human experts on tomography maps and that derived from our model's en face map was 1.91 ± 1.15 mm. Our model detected superior peripheral edema in a majority of eyes. Conclusions: Despite being based on different approaches, both methods agreed in the detection of subclinical edema in most cases. The location of detected edema was very similar in both methods. In cases where both methods disagree, our approach provides new objective results that might help the surgeon in making a decision in difficult cases.

Association of refractive outcome with postoperative anterior chamber depth measured with 3 optical biometers.

This study evaluated the relationship between refractive outcomes and postoperative anterior chamber depth (ACD, measured from corneal epithelium to lens) measured by swept-source optical coherence tomography (SS-OCT), optical low-coherence reflectometry (OLCR), and Scheimpflug devices under the undilated pupil. Patients undergoing cataract phacoemulsification with intraocular lens (IOL) implantation in a hospital setting were enrolled. Postoperative ACD (postACD) was performed with an SS-OCT device, an OLCR device, and a Scheimpflug device at least 1month after cataract surgery. After adjusting the mean predicted error to 0, differences in refractive outcomes were calculated with the Olsen formula using actual postACD measured from 3 devices and predicted value. Overall, this comparative case study included 69 eyes of 69 patients, and postACD measurements were successfully taken using all 3 devices. The postACD measured with the SS-OCT, OLCR, and Scheimpflug devices was 4.59 ± 0.30, 4.50 ± 0.30, and 4.54 ± 0.32mm, respectively. Statistically significant differences in postACD were found among 3 devices (P < 0.001), with intraclass correlation coefficients (ICCs) and Bland-Altman showing good agreement. No significant difference in median absolute error was found with the Olsen formula using actual postACD obtained with 3 devices. Percentage prediction errors were within ± 0.50D in 65% (OLCR), 70% (Scheimpflug), and 67% (SS-OCT) calculated by actual postACD versus 64% by predicted value. Substantial agreement was found in postACD measurements obtained from the SS-OCT, OLCR, and Scheimpflug devices, with a trend toward comparable refractive outcomes in the Olsen formula. Meanwhile, postACD measurements may be potentially superior for the additional enhancement of refractive outcomes.

Comparison of two swept-source optical coherence tomography devices, a Scheimpflug camera system and a ray-tracing aberrometer in the measurement of corneal power in patients with cataract

PurposeTo assess the differences and similarities in the corneal curvature obtained by two swept-source optical coherence tomography (SS-OCT) devices, Scheimpflug imaging system and one ray tracing aberrometer in patients with cataracts. Moreover, this study aimed to compare the differences in posterior corneal (PK), total corneal (TK) and true net power (TNP) measurements among the IOLMaster 700, CASIA2, and Pentacam.MethodsA total of 200 eyes of 200 patients (116 female, 58%) were enrolled in this study, with a mean age of 65.9 ± 9.5 years. The flattest (Kf), steepest (Ks), and mean cornal powers (Km), J0, and J45 were obtained using two SS-OCT-based biometric devices, one rotating camera system and one ray-tracing aberrometer. The PK, TK and TNP values were also measured using these devices. To evaluate the differences and similarities between the devicves, the Friedman test, Pearson correlation coefficient (r), intraclass coefficient correlation (ICC) and Bland‒Altman plots with 95% limits of agreement (LoA) were used, and boxplots and stacked histograms were generated to describe the distributions of the data.ResultsThere were no significant differences between the IOLMaster 700 and Pentacam for any of the keratometry values. Additionally, there were no significant differences between the IOLMaster 700 and iTrace in evaluating J0 and J45. Bland‒Altman plots revealed relatively wide LoA widths, almost larger than 1 diopter for the keratometry values and almost larger than 0.5 diopter for J0 and J45 values among the four devices. In terms of PK and TK values, significant differences and low ICCs were found among the three devices.ConclusionsAlthough strong correlations and good agreement were found among the IOLMaster700, CASIA2, Pentacam and iTrace for Kf, Ks, Km and J0, J45, it seems that the measurements should not be used interchangeably because of the wide LoA widths and the presence of significant differences among the devices. Similarly, due to significant differences and low ICCs, the PK, TK and TNP values obtained by IOLMaster 700, CASIA2, and Pentacam should not be used interchangeably.

Diagnostic Validation of the Screening Corneal Objective Risk of Ectasia Analyzer Evaluated by Swept Source Optical Coherence Tomography for Keratoconus in an Asian Population.

We aimed to investigate the diagnostic accuracy of Screening Corneal Objective Risk of Ectasia (SCORE) Analyzer software using ANTERION, a swept-source optical coherence tomography device, for keratoconus diagnosis in an Asian population. A total of 151 eyes of 151 patients were included in this retrospective study as follows: 60, 45, and 46 keratoconus, keratoconus suspects, and normal control eyes, respectively. Parameters in the SCORE calculation, including six indices, were compared for the three groups. The receiver operating characteristic curve analysis and cut-off value were estimated to assess the diagnostic ability to differentiate keratoconus and keratoconus suspect eyes from the normal group. The SCORE value and six indices were significantly correlated-"AntK max" (R = 0.864), "AntK oppoK" (R = 0.866), "Ant inf supK" (R = 0.943), "Ant irre 3mm" (R = 0.741), "post elevation at the thinnest point" (R = 0.943), and "minimum corneal thickness" (R = -0.750). The SCORE value showed high explanatory power (98.1%), sensitivity of 81.9%, and specificity of 78.3% (cut-off value: 0.25) in diagnosing normal eyes from the keratoconus suspect and keratoconus eyes. The SCORE Analyzer was found to be valid and consistent, showing good sensitivity and specificity for keratoconus detection in an Asian population.

Comparison of ocular biometry in Chinese patients using two swept-source optical coherence tomography devices

Comparison of ocular biometry in Chinese patients using two swept-source optical coherence tomography devices

MACULAR NEUROVASCULAR ABNORMALITIES IN A CHILD WITH INCONTINENTIA PIGMENTI ON HANDHELD OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

To report macular neurovascular abnormalities in a child with incontinentia pigmenti using handheld optical coherence tomography (OCT) and OCT angiography (OCT-A). An eye of a child with incontinentia pigmenti enrolled in BabySTEPS was imaged using an investigational noncontact, handheld swept-source OCT device during examination under anesthesia. Custom MATLAB scripts were used to generate depth-resolved vascular slabs, B-scans with flow overlay, and retinal thickness maps. Depth-resolved OCT and OCT-A imaging demonstrated focal areas of decreased capillary flow that corresponded to areas of both inner retinal and outer retinal thinning on retinal thickness maps. Atypical diving of superficial retinal vessels occurred as they traversed from thin retina to normal-thickness retina. Depth-resolved OCT and OCT-A identified retinal vascular abnormalities that were not evident on fundus photography or fluorescein angiography. This case depicted concurrent, localized abnormalities in retinal thickness and microvasculature in an eye with incontinentia pigmenti.

Impact of a Swept Source-Optical Coherence Tomography Device on Efficiency in Cataract Evaluation and Surgery: A Time-and-Motion Study

This study aims to assess the time impact of ARGOS® (image-guided swept-source optical coherence tomography biometer integrated with operating room (OR) technologies (SS-OCT w/ORT)) compared to LENSTAR LS 900 (optical low-coherence reflectometry (OLCR)), IOLMaster 500 (partial coherence interferometry (PCI)), and IOLMaster 700 (SS-OCT) on efficiency in the cataract evaluation and surgery. Data from 212 patients (two study sites) who underwent evaluation and/or cataract surgery were collected. The primary objective was to compare the performance of four biometers; statistical analyses were conducted to compare 1) biometer measurement times for all patients (ANOVA w/post-hoc Dunnett's test) and stratified by cataract density (ANOVA) and 2) rate of biometer acquisition failure (Chi-square test w/post-hoc Bonferroni correction). Real-world observational data collected were then used to develop a practice-based time-efficiency model to demonstrate the combined effect that adopting an SS-OCT w/ORT has on a practice's cataract workflow. Real-world data inputs included assessment of patient's eyes' cataract grade density, time taken for optical biometry, Manual A-scan (ultrasound biometer) when acquisition failed, and measurement times associated with other devices used in cataract evaluation and surgery. For 208 patients (56% non-dense, 44% dense), the SS-OCT w/ORT biometer had a 0% acquisition failure (SS-OCT: 3% (p = 0.05); OLCR: 5% (p = 0.004); PCI: 15% (p < 0.0001)) and an average time savings of 30 seconds/patient compared to the other biometers in this study (p < 0.05). When acquisition failed, ultrasound biometry resulted in an additional 2.5 minutes/patient. For a cohort of 1000 patients, an SS-OCT w/ORT and an image-guidance system adopted at a practice using an SS-OCT, femtosecond laser, and intraoperative aberrometer offer up to 58% efficiency gain across the cataract workflow. Results from this study demonstrate an SS-OCT w/ORT's efficiencies in cataract evaluation and surgery driven by faster measurement times, reducing the need for ultrasound biometry, and its integration benefits with other devices.

Comparison of Astigmatism Prediction Accuracy for Toric Lens Implantation from Two Swept-Source Optical Coherence Tomography Devices.

To compare the astigmatism prediction accuracy for toric intraocular lens (IOL) implantation between two swept-source optical coherence tomography (SS-OCT) devices: Argos (Movu, a Santec Company) and the IOLMaster 700 (Carl Zeiss Meditec). This was a retrospective chart review of 59 eyes (44 patients) with corneal astigmatism and cataract that underwent cataract surgery or refractive lens exchange surgery with a toric IOL. Biometry was performed on all patients prior to cataract surgery and the Barrett toric IOL calculator was used. Visual acuity was measured postoperatively. Manifest refraction was measured at 1 month and compared to the predicted postoperative residual refraction. Preoperative K measurements between devices were also compared. Mean cylinder prediction error was -0.17 ± 0.43 for Argos and 0.12 ± 0.56 for IOLMaster 700. The cylinder prediction error 0.5 D or less was not significantly different between the devices, with 83.1% (49 eyes) for Argos and 76.3% (45 eyes) for IOLMaster 700 (p = 0.206). Spherical equivalent prediction error was 0.13 ± 0.39 for Argos and 0.25 ± 0.50 for IOLMaster 700. The mean spherical equivalent prediction error 0.5 D or less was significantly different between the devices, with 79.7% (47 eyes) for Argos and 61.0% (36 eyes) for IOLMaster 700 (p = 0.016). The prediction accuracies were similar between the devices, except for spherical equivalent, where a higher percentage of eyes were 0.5 D or less of the prediction with the Argos compared to the IOLMaster.

Automatic Quantitative Assessment of Lens Opacities Using Two Anterior Segment Imaging Techniques: Correlation with Functional and Surgical Metrics.

The purpose of this study is to quantitatively assess lens opacity, using a swept-source optical coherence tomography (SS-OCT) device for anterior segment assessment, and establish the correlation with Scheimpflug imaging, corrected distance visual acuity (CDVA) and cumulative dissipated energy (CDE). This prospective cross-sectional single-center study enrolled 51 patients (51 eyes) with crystalline lens opacity. Patients with previous ocular surgery, pathologies or general disorders affecting vision were excluded. Eyes were scanned with an SS-OCT device, and lens densitometry was automatically analyzed using a custom MATLAB script which examined lens density, nuclear density and linear density. The same analyses were performed on Scheimpflug images. Preoperative CDVA and CDE during phacoemulsification were recorded. Spearman’s (ρ) and Pearson’s (r) correlation coefficients were assessed according to data normality. Statistically significant correlations were established between SS-OCT and Scheimpflug imaging using lens analysis (ρ = 0.47, p < 0.001), nuclear analysis (ρ = 0.73, p < 0.001) and linear analysis (r = 0.44, p < 0.001). A significant correlation with CDE was found with all the SS-OCT methods (r = 0.57, p < 0.001). Only the nuclear analysis of the SS-OCT scans (Tb = −0.33, p < 0.01) and Pentacam Nucleus Staging (Tb = −0.26, p < 0.05) showed a statistically significant correlation with CDVA. Good inter-device agreement in lens densitometry was found. However, SS-OCT yielded improved lens imaging compared with the Scheimpflug device and a higher correlation with clinical parameters. Thus, high-resolution SS-OCT has the potential to become a preferable option for automatic cataract grading and preoperative planning.

IMPACT OF PENETRATION AND IMAGE ANALYSIS IN OPTICAL COHERENCE TOMOGRAPHY ON THE MEASUREMENT OF CHOROIDAL VASCULARITY PARAMETERS.

To investigate the impact of penetration and image analysis in different optical coherence tomography (OCT) instruments on the measurement of choroidal vascularity parameters. Twenty-three healthy volunteers were imaged using two swept-source OCTs and one spectral-domain OCT. A fully automatic segmentation method based on ResNet-UNet and Niblack local threshold binarization was performed to quantify the relevant choroidal vascular parameters, including choroidal vascularity index, total choroidal volume, and luminal volume. The intraclass correlation coefficient (ICC) and coefficient of repeatability (COR) were used to analyze the repeatability and consistency of automatic and manual segmentation, respectively. Both swept-source OCT devices showed good consistency of luminal volume and total choroidal volume measurements (all ICC value >0.98 with COR% < 8.53%) based on manual segmentation, whereas the consistency of the spectral-domain OCT was lower (ICC value <0.60 with COR% > 40%), which was greatly improved after using the automatic algorithm (ICC value >0.99 with COR% < 4%). The repeatability of choroidal vascularity index obtained from different OCT images using manual or automatic segmentation showed good agreement (all ICC values >0.85), whereas the choroidal vascularity index measurement from the spectral-domain OCT was larger than the other two swept-source OCT devices (ICC value <0.65). For healthy youngsters, the penetration of OCT plays a role in the measurement precision for choroidal vascularity parameters, and automatic segmentation can improve the ability of choroidal boundary identification with deficient penetration, suggesting these factors need to be considered in clinical work.

Three-Dimensional Choroidal Vascularity Index in High Myopia Using Swept-Source Optical Coherence Tomography

ABSTRACTPurposeTo characterize the choroidal vasculature in high myopic eyes by three-dimensional choroidal vascularity index (CVI) using swept-source optical coherence tomography (SS-OCT).Subjects and MethodsA cross-sectional observational study of 98 right eyes from 98 consecutive nonpathological myopic patients, including 46 high myopes (HM) and 52 low to moderate myopes (LMM). OCT and OCT angiography covering an area of 6 × 6 mm2 centered on the fovea was conducted with a commercially available SS-OCT device. Three-dimensional CVI was defined as the ratio of choroidal vessel volume (CVV) to total choroidal volume. With the built-in automated quantification software, we assessed choroidal vascular and stromal features: three-dimensional CVI; CVV; choriocapillaris flow density and choroidal stroma volume (CSV) apart from choroidal thickness (CT).ResultsCompared to LMM, there was a significant reduction in three-dimensional CVI, CVV and CSV along with choroidal thinning in HM at both subfoveal and macular regions (all P < .01). The nasal quadrant had both the lowest CVI and the thinnest choroid. The greatest CVI was at the subfovea, while the choroid at the subfovea was thinner than that at the superior, temporal, and inferior quadrants. Multiple linear regression indicated that choroidal characteristics (CVI, CVV, CSV, CT) were mainly negatively correlated with axial length (all P < .01) instead of myopic spherical equivalent (all P > .05).ConclusionsBesides two-dimensional choroidal thinning, we also found the axial length-related reduction of three-dimensional choroidal vessel and stroma components in high myopic eyes without myopic maculopathy. The quadrantal distribution characteristics of three-dimensional CVI indicate the subfovea and the nasal quadrant to be the essential quadrants for monitoring the choroidal vasculature alteration in the progression of myopia. The novel quantitative analyses of the choroidal vasculature by three-dimensional CVI may help to characterize the underlying pathophysiology of nonpathological high myopia.

Comparison of choroidal hyperreflective spots on optical coherence tomography images between both eyes of normal subjects.

Advancement of optical coherence tomography (OCT) technology allows for better in vivo visualization of the choroidal architecture, which comprises vessels and stroma. However, most OCT studies using image binarization methods have focused only on choroidal vessels represented by dark pixels. This study aimed to compare the distribution of choroidal hyperreflective spots on swept-source OCT (SS-OCT) images between both eyes of normal subjects. In this observational comparative study, we included SS-OCT images of healthy subjects, which were prospectively obtained to compare images among the devices. SS-OCT images acquired using PLEX Elite 9000 and DRI-OCT Triton were analyzed. En-face OCT images were obtained at five different depth positions of the inner choroid at the macula. The mean reflectivity of the choroidal slabs, the number, total area, and circularity of hyperreflective spots were quantitatively compared between the devices and between both eyes of the same subjects. In 30 eyes of 15 healthy subjects, the mean reflectivity of the choroidal slabs varied with the scan depth on both devices (P<0.001 and P<0.001). Hyperreflective spots were similarly distributed in the images from both devices, but at different depths. The number and area of hyperreflective spots in the second and third layers of the DRI-OCT Triton were positively correlated with those in the fourth and fifth layers of the PLEX Elite 9000, respectively (all P<0.05). The intraclass correlation coefficients (ICC) for the area of hyperreflective spots were excellent for the third slab of the DRI-OCT and the fifth slab of the PLEX Elite (ICC =0.798; 95% CI, -0.576-0.904). The number and area of hyperreflective spots were correlated between both eyes in the third, fourth and fifth layers on DRI-OCT Triton (all P<0.05) and in the first, second, and fifth layers on PLEX Elite 9000 (all P<0.05). Hyperreflective spots in en-face images from two different SS-OCT devices were similarly observed between both eyes of the same person. The distributions of spots between the two eyes of the same person were correlated. These findings suggest that the distribution of hyperreflective spots on the choroid reflects the choroidal characteristics of the subject.

Repeatability of 2 swept-source OCT biometers and 1 optical low-coherence reflectometry biometer.

To compare the repeatability of 2 swept-source optical coherence tomography (SS-OCT) biometers, IOLMaster 700 (biometer A, Carl Zeiss Meditec AG) and ANTERION (biometer B, Heidelberg Engineering GmbH) and 1 optical low-coherence reflectometry (OLCR) device (biometer C, LENSTAR, LS900; Haag-Streit AG). Department of Ophthalmology, Hanusch Hospital, Vienna Institute for Research in Ocular Surgery-Karl Landsteiner Institute, Vienna, Austria. Prospective study that included patients scheduled for cataract surgery. Three consecutive measurements were performed with 2 SS-OCT devices and 1 OLCR device. The repeatability of the following biometry variables was compared: keratometry, central corneal thickness, anterior chamber depth (ACD), lens thickness (LT), and axial eye length (AL). To assess the repeatability of each parameter, the within-subject SD (Sw) and coefficient of variation (CoV) were calculated. Fifty eyes of 50 patients were included. The CoV values were below 0.5 for all variables, except for ACD and LT for biometer C. The Sw values for mean keratometry were 0.018 for biometer A, 0.083 for biometer B, and 0.137 for biometer C. For the ACD, the Sw values were 0.039 and 0.004 for biometer A and biometer B, respectively, and 0.134 for biometer C. For the AL, the values were 0.006 for biometer A, 0.008 for biometer B, and 0.012 for biometer C. All biometry devices included in the analysis presented a high repeatability. The SS-OCT devices showed a higher repeatability performance compared with the OLCR device.

Diagnostic imaging of the ciliary body: Technologies, outcomes, and future perspectives.

The ciliary body (CB) is part of the uvea and is a complex, highly specialized structure with multiple functions and significant relationships with nearby structures. Its functions include the aqueous humor (AH) production in the ciliary processes, the regulation of the AH output through the uveoscleral pathway, and accommodation, which depends on the ciliary muscle. Also, the CB is an important determinant of angle width as it forms part of the ciliary sulcus. Until recently, knowledge of the CB was based on histological studies. However, this structure can currently be assessed in vivo using imaging techniques such as ultrasound biomicroscopy (UBM) and optical coherence tomography (OCT). Both techniques have shown good reproducibility of their measurements allowing for quantification of CB dimensions and their localization. In effect, studies have shown a larger CB in myopia and its diminishing size with age. Swept-source OCT devices offer fast, non-invasive high-resolution imaging allowing the identification of multiple structures. UBM requires contact and is uncomfortable for the patient. However, this technique offers deeper imaging and therefore remains the gold standard for assessing the posterior chamber, ciliary processes, or zonula. The clinical utility of CB imaging includes its assessment in different types of glaucoma such as angle-closure, malignant or plateau iris. Diagnostic CB imaging is also invaluable for the assessment of ciliochoroidal detachment when suspected, the position after the implantation of a pre-crystalline or sulcus-sutured lenses, diagnosis or monitoring of cysts or tumors, sclerotomies after retinal surgery, intermediate uveitis, or accommodation.

Effect of Capsular Tension Ring on Refractive Outcomes in Patients With Implantation of the Quadrifocal Acrysof PanOptix TFNT00 IOL.

To evaluate the effect of a capsular tension ring (CTR) on refractive outcomes in eyes undergoing implantation of the quadrifocal Acrysof PanOptix TFNT00 intraocular lens (IOL) (Alcon Laboratories, Inc). A retrospective case-control study was undertaken of 91 eyes implanted with the TFNT00 IOL. Of these 91 eyes, a CTR was implanted in 33 and these eyes were compared to the 58 eyes in which a CTR was not implanted. The main outcome measure was the mean absolute error (MAE) of the refractive prediction error. To evaluate the consistency of refractive outcomes, variance of MAE was measured. Using a swept-source optical coherence tomography device, postoperative aqueous depth (AQD) was measured to estimate the position of the IOL. Eyes with a CTR showed a significantly smaller MAE when compared with eyes without a CTR (P = .038 at 1 m, P = .003 at 2 m, and P = .001 at 6 m). There was a lower variance of MAE in the eyes implanted with a CTR, with higher precision of refraction (P = .058 at 1 m, P = .007 at 2 m, and P = .001 at 6 m). There was a significant difference in the percentage of the eyes showing more than 0.50 D from the estimated target of the Barrett Universal II formula (P = .007 at 1 m, P = .064 at 2 m, and P = .004 at 6 m, respectively). AQD was significantly shallower in eyes with a CTR than in eyes without a CTR (P = .006). Use of the CTR enhanced the accuracy of postoperative refractive outcomes after TFNT00 IOL implantation by preventing the posterior bowing of the optic-haptic junction. [J Refract Surg. 2021;37(3):174-179.].

Comparison of ocular biometric measurements in patients with cataract using three swept-source optical coherence tomography devices

BackgroundPrecise measurement of ocular biometry is critical for determining intraocular lens power. Newly developed swept-source optical coherence tomography (SS-OCT) - based ocular biometric devices, ANTERION and CASIA2 provide ocular biometric measurements as IOLMaster 700. This study aimed to assess agreement between three devices.MethodsThis retrospective comparative study includes patients with cataract who underwent ocular biometric measurements with three devices, ANTERION, CASIA2, and IOLMaster 700, at Seoul National University Hospital, in April 2020. Anterior keratometry, total keratometry, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were the main parameters for the comparison. To assess the agreement between the devices, intraclass coefficient (ICC) and Bland-Altman analysis with 95% limits of agreement (LoA) were used.ResultsA total of 47 eyes of 29 patients were measured with three devices. Average anterior keratometry showed excellent agreement (ICC ≥ 0.989), and the mean difference was less than 0.1 D. However, the ICC of the total average keratometry ranged from 0.808 to 0.952, and the difference was more than 0.43 D. The AL measured by ANTERION and IOLMaster 700 showed excellent agreement (ICC = 0.999), and the mean difference was 0.005 mm. The ANTERION and IOLMaster 700 did not obtain AL in six (12.8%) and three (6.4%) cases, respectively (P = 0.001 by Fisher’s exact test). The CCT, ACD, and LT also showed excellent agreement (ICC > 0.9).ConclusionsThe new SS-OCT-based devices, ANTERION, and CASIA2 showed a good agreement with IOLMaster 700 in measuring ocular biometry except for the total keratometry. The AL of ANTERION and IOLMaster 700 showed excellent agreement.

Assessment of precision of astigmatism measurements taken by a sweptsource optical coherence tomography biometer - IOLMaster 700.

Purpose:To assess the repeatability of ocular measurements, particularly astigmatism, taken using the latest version of an swept-source optical coherence tomography (SS-OCT) device, IOLMaster 700.Methods:This prospective observational study done in a private eye care centre. Study included 213 eyes of 152 patients diagnosed with cataract. Axial length (AL), Anterior corneal astigmatism (ΔK), Total corneal astigmatism (ΔTK), Aqueous depth (AD), Lens thickness (LT), Iris barycentre distance (IBD) and White to white distance (WTW) were analysed; three measurements were taken for each patient in the same sitting by the same examiner in an undilated state using the SS-OCT device. Repeatability was analysed using intraclass coefficient (ICC) and coefficient of variation (CV) measures, and astigmatism values were transformed into vector components (J0/J45) and categorised based on magnitude.Results:Astigmatism vector components (J0/J45) showed poor repeatability (ICC < 0.5 and CV > 0), while iris coordinates (IBD) and astigmatism magnitude had good correlation (ICC > 0.9) but more variations between the readings which was least for magnitude ≥ 1.5D; however, rest of the parameters demonstrated excellent repeatability (ICC > 0.9 with P value < 0.05).Conclusion:IOLMaster 700 demonstrated good reliability for the parameters measured, although, for astigmatism and iris barycentre distance, more number of readings and cross reference with other devices may be required to get clinically accurate results.

Prospective study to compare axial position stability after fellow-eye implantation of 2 distinct intraocular lens designs.

To compare the dynamics of axial intraocular lens (IOL) position and stability in the capsular bag after fellow-eye implantation of a 1-piece C-loop and a 4-point haptic IOL. Hanusch Hospital, Vienna. Prospective, comparative, randomized bilateral study. One hundred eyes of 50 patients were randomly implanted with a C-loop IOL (CT LUCIA 611P) in 1 eye and a 4-point haptic IOL (CT ASPHINA 409MP) in the other eye. Anterior chamber depth (ACD) was measured at 1 week (W1), 1 month (M1), and 4 to 6 months (M4-6) postoperatively using a swept-source optical coherence tomography device (IOLMaster 700). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, and subjective refraction outcomes were assessed at M4-6 postoperative follow-up. Hundred eyes of 50 patient were included. Pseudophakia ACD values at W1, M1, and M4-6 timepoints were significantly different in eyes implanted with the C-loop IOL compared with the 4-point haptic IOL (P < .001). The overall IOL shift was 0.25 ± 0.16 mm for the 4-point haptic IOL and 0.14 ± 0.09 mm for the C-loop IOL (P < .001). The M4-6 mean monocular UDVA outcome for eyes with C-loop IOL was 0.06 ± 0.14 logarithm of the minimum angle of resolution (logMAR) and 0.03 ± 0.10 logMAR for the eyes with 4-point haptic IOL. M4-6 mean spherical equivalent was -0.32 ± 0.48 diopter (D) in the C-loop IOL group and -0.33 ± 0.42 D in the 4-point haptic IOL group. Statistically significant differences in IOL design results in different postoperative ACD values. No relevant or statistically significant differences were found in refraction or visual acuity between the groups.

Early diagnosis of multiple sclerosis by OCT analysis using Cohen's d method and a neural network as classifier

BackgroundThe consequences of inflammation, demyelination, axonal degeneration and neuronal loss in the central nervous system, typical of the development of multiple sclerosis (MS), are manifested in thinning of the retina and optic nerve. The purpose of this work is to diagnose early-stage MS patients based on analysis of retinal layer thickness obtained by swept-source optical coherence tomography (SS-OCT). MethodOCT (Triton® SS-OCT device -Topcon, Tokyo, Japan-) recordings were obtained from 48 control subjects and 48 recently diagnosed MS patients. The following thicknesses were measured on a 45 × 60 grid: retinal nerve fibre layer (RNFL), ganglion cell layer (GCL+), GCL++, retinal thickness and choroid. Using Cohen's d effect size, it was determined the regions and layers with greatest capacity to discriminate between control subjects and patients. Points exceeding the threshold set were used as inputs for an automatic classifier: support vector machine and feed-forward neural network. ResultsIn MS at clinical onset the layer with greatest discriminant capacity is GCL++ [AUC = 0.83] which exhibits a horseshoe-like macular topographic distribution. It is followed by retina, GCL+ and RNFL; choroidal thicknesses do not provide discriminatory capacity. Using a neural network as a classifier between controls and MS patients, obtains sensitivity of 0.98 and specificity of 0.98. ConclusionsThis work suggest that OCT may serve as an important complementary role to other clinical tests, particularly regarding neurodegeneration. It is possible to characterise structural alterations in retina and diagnose early-stage MS with high degree of accuracy using OCT and artificial neural networks.