Featured Articles

Low-cost OCT, Lumedica, launches OQ LabScope 3.0, equipped with 3D Rendering, at BiOS and PWEST 2023

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Lumedica Inc., known for manufacturing complete OCT systems at an affordable price, will launch the OQ LabScope 3.0 at BIOS 2023 on January 28-29, 2023. The system retains the same hallmarks of Lumedica design, a complete OCT system at an affordable price, while adding a faster A-scan rate and capability for 3D rendering to standard systems. This improved speed makes 3D rendering within the software more practical as a full volume scan of a 5 x 5 x 7 mm3 area only takes a few seconds. Visit Booth #8259 for a complete demonstration of the OQ LabScope 3.0. Bring your own samples to see how volume scans are transformed into a 3D image. Speak with experts on low-cost OCT and determine a solution that will be your need and budget. Lumedica’s OQ LabScope launched in 2017 as the first complete OCT system commercially available under $10,000. This innovation broke the barrier of entry to OCT for many scientists. At this price point even educators could use limited funds to integra...

Optical Coherence Tomography Is a Promising Tool for Zebrafish-Based Research—A Review

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The zebrafish is an established vertebrae model in the field of biomedical research. With its small size, rapid maturation time and semi-transparency at early development stages, it has proven to be an important animal model, especially for high-throughput studies. Three-dimensional, high-resolution, non-destructive and label-free imaging techniques are perfectly suited to investigate these animals over various development stages. Optical coherence tomography (OCT) is an interferometric-based optical imaging technique that has revolutionized the diagnostic possibilities in the field of ophthalmology and has proven to be a powerful tool for many microscopic applications. Recently, OCT found its way into state-of-the-art zebrafish-based research. This review article gives an overview and a discussion of the relevant literature and an outlook for this emerging field.

Fusing optical coherence tomography and photodiodes for diagnosis of weld features during remote laser welding of copper-to-aluminum

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This study has been designed to investigate whether variations in the features of laser weldments can be isolated and diagnosed by fusing photodiodes and optical coherence tomography (OCT). Two manufacturing scenarios (variation in laser power and focal offset) have been considered during remote laser welding of 0.2 mm thick Cu foils on 2 mm thick Al 1050 plates with an adjustable ring mode laser integrated with a 1D oscillation head. The process was monitored by measuring weld penetration depth with OCT and by process emissions (plasma and back-reflection) via photodiodes. The acquisition frequency of all signals was 40 kHz. Strong correlations (r > 0.75) were shown between plasma, back-reflection, and OCT signals and measured depth and width of the weld. Weak correlations (r < 0.5) between voids, cracks, and sensor signals were observed. Although plasma is the predominant signal that carries most of the information about the process, and the OCT allows direct measurement of ...

Diagnostic Accuracy of Line-Field Confocal Optical Coherence Tomography for the Diagnosis of Skin Carcinomas

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Line-field confocal optical coherence tomography (LC-OCT) is a new, noninvasive imaging technique for the diagnosis of skin cancers. A total of 243 benign (54%) and malignant (46%) skin lesions were consecutively enrolled from 27 August 2020, to 6 October 2021 at the Dermatology Department of the University Hospital of Siena, Italy. Dermoscopic- and LC-OCT-based diagnoses were given by an expert dermatologist and compared with the ground truth. Considering all types of malignant skin tumours (79 basal cell carcinomas (BCCs), 22 squamous cell carcinomas, and 10 melanomas), a statistically significant increase (p = 0.013) in specificity was observed from dermoscopy (0.73, CI 0.64–0.81) to LC-OCT (0.87, CI 0.79–0.93) while sensitivity was the same with the two imaging techniques (0.95 CI 0.89–0.98 for dermoscopy and 0.95 CI 0.90–0.99 for LC-OCT). The increase in specificity was mainly driven by the ability of LC-OCT to differentiate BCCs from other diagnoses. In conclusion, our real-li...

Imaging Modalities Pair to Help Practitioners Discern Tooth Decay

Imaging Modalities Pair to Help Practitioners Discern Tooth Decay To improve dental health, researchers at the University of California, San Francisco evaluated optical imaging techniques for their efficacy in the identification of secondary tooth decay, which can occur even if a tooth has already been filled. The researchers compared two techniques — shortwave infrared (SWIR) radiation reflectance and thermal imaging — with measurements obtained with optical coherence tomography (OCT) and micro-computed tomography (MicroCT). The results demonstrated the potential of SWIR reflectivity and OCT imaging methods for the clinical monitoring of secondary dental caries (i.e., dental cavity) lesions. The researchers considered cavities and methods of treatment as the impetus for the research. Treatment for cavities, known commonly as fillings, often fails over time. The restorative materials used to fill dental lesions do not always bond well to the surrounding healthy tooth structure. Microscopic leaks can form, which enable fluids and bacteria to pe...

Retina and choroid without secrets. STOC tomography enables unprecedented views of eye structure

Retina and choroid without secrets. STOC tomography enables unprecedented views of eye structure Modern imaging of eye tissues would not be possible without the use of Optical Coherence Tomography (OCT) scans. This method, one of the world's most popular and accurate diagnostic techniques, has enabled us to understand more fully the mechanisms of many diseases and to select therapies more effectively. However, OCT is not a perfect technique. Coherent noise and/or limited axial range have prevented high-resolution imaging, as well as precluding full penetration of all layers of the retina and choroid. Researchers at the International Centre for Translational Eye Research (ICTER) found a way around these limitations and developed Spatio-Temporal Optical Coherence Tomography (STOC-T). The latest research by the team led by Prof. Maciej Wojtkowski confirms that this method makes it possible now to view the retina and choroid with high resolution at distinct depths in the frontal section. No one in the world had succeeded previously. The eye only sometimes reveals everything. I...

Demo Thorlabs’ OCT Technologies at BiOS and PWEST 2023

You are invited to visit Thorlabs’ OCT team at SPIE BiOS (Booth #8331) January 28 – 29 and Photonics West (Booth #627) January 31 – February 2 in San Francisco at the Moscone Center. We will have three live OCT systems on site and would like to invite you to bring your samples for a live demo, speak with our experts, and collect the newest Thorlabs T-shirt. For those building their own OCT setups, we can walk you through a variety of integral components, such as SLDs, MEMS-VCSEL benchtop lasers, specialized fibers, and bulk optics, as well as our brand-new OCT spectrometer. Alternatively, if you have an application need but no system, come in and check out our turn-key OCT solutions based on either swept-source or spectral-domain technology. Our systems are ideal for applications in biomedicine, industrial quality control, and more. Learn more at https://youtu.be/erDiuKNoHFI. We look forward to seeing you soon!

Post-Doctoral Fellow (Translational Biomedical Optics) at Massachusetts General Hospital / Harvard Medical School

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Division of Pulmonary and Critical Care Medicine / Department of Pathology Employer: Massachusetts General Hospital / Harvard Medical School The Hariri Optical Imaging Laboratory is a multidisciplinary research group at Massachusetts General Hospital and Harvard Medical School. The focus of the laboratory is on the design, development and clinical translation of endoscopic optical coherence tomography (OCT)-based imaging devices for microscopic detection, diagnosis and monitoring of pulmonary diseases, including lung fibrosis, smoking and vaping-related lung diseases, post-COVID lung disease and interstitial lung abnormalities. A highly motivated, independent, innovative, and organized individual with an interest in translational optical/diagnostic imaging and biomedicine is sought for a Post-Doctoral Research Fellow position. The appropriate candidate will work in a highly collaborative multidisciplinary research environment consisting of engineers, physicians and technici...

Non-invasive investigation of the morphology and optical properties of the upside-down jellyfish Cassiopea with optical coherence tomography

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The jellyfish Cassiopea largely cover their organic carbon demand via photosynthates produced by their microalgal endosymbionts, but how holobiont morphology and optical properties affect the light microclimate and symbiont photosynthesis in Cassiopea remain unexplored. Here, we use optical coherence tomography (OCT) to study the morphology of live Cassiopea medusae at high spatial resolution. We include detailed 3D reconstructions of external micromorphology, and show the spatial distribution of endosymbionts clustered in amoebocytes and white granules in the bell tissue. Furthermore, we use OCT data to extract inherent optical properties from light scattering white granules in Cassiopea and show that white granules enhance local light availability for symbionts in close proximity. Individual granules had a scattering coefficient of μs = 200-300 cm-1, and a scattering anisotropy factor of g = 0.7, while large tissue regions filled with white granules had a lower μs = 40-100 cm-1, a...

World’s First Intracranial Use of a New High-Frequency Imaging System to Directly Visualize Neurovascular Pathologies

First human procedures performed by Prof Vitor Mendes Pereira at St. Michael’s Hospital, a site of Unity Health Toronto Gentuity, LLC, an advanced imaging technology firm, today announced the first human use of the Vis-MTM High-Frequency Optical Coherence Tomography (HF-OCT) imaging system and probe. This represents a significant technological advance for the field of neurointervention, making high resolution intravascular imaging in the brain possible. “This is an incredibly exciting milestone. The direct visualization technology we evaluated here offers unprecedented potential in the diagnosis and treatment of aneurysms, stroke, intra-cranial atherosclerotic disease (ICAD) and other neurological pathologies,” said Vitor Mendes Pereira, MD. “I am proud and honored to have the opportunity to perform the first cases. The system and imaging probes performed very well, integrating with our workflow seamlessly, and provided us with important information that we cannot obtain with any ...

Recent Articles From Around The Web

Images Download Cite Share Favorites Permissions ORIGINAL STUDIES Prediction of Visual Impairment in Epiretinal Membrane and Feature Analysis: A Deep Learning Approach Using Optical Coherence Tomography

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Purpose: The aim was to develop a deep learning model for predicting the extent of visual impairment in epiretinal membrane (ERM) using optical coherence tomography (OCT) images, and to analyze the associated features. Methods: Six hundred macular OCT images from eyes with ERM and no visually significant media opacity or other retinal diseases were obtained. Those with best-corrected visual acuity ≤20/50 were classified as “profound visual impairment,” while those with best-corrected visual acuity >20/50 were classified as “less visual impairment.” Ninety percent of images were used as the training data set and 10% were used for testing. Two convolutional neural network models (ResNet-50 and ResNet-18) were adopted for training. The t-distributed stochastic neighbor-embedding approach was used to compare their performances. The Grad-CAM technique was used in the heat map generative phase for feature analysis. Results: During the model development, the training accuracy w...

QUANTITATIVE ASSESSMENT OF AUTOMATED OPTICAL COHERENCE TOMOGRAPHY IMAGE ANALYSIS USING A HOME-BASED DEVICE FOR SELF-MONITORING NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

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Purpose: To evaluate a prototype home optical coherence tomography (OCT) device and automated analysis software for detection and quantification of retinal fluid relative to manual human grading in a neovascular age-related macular degeneration patient cohort. Methods: Patients undergoing anti-vascular endothelial growth factor therapy were enrolled in this prospective observational study. In 136 OCT scans from 70 patients using the prototype home OCT device, fluid segmentation was performed using automated analysis software and compared with manual gradings across all retinal fluid types using receiver-operating characteristic (ROC) curves. The Dice similarity coefficient (DSC) was used to assess the accuracy of segmentations, and correlation of fluid areas quantified endpoint agreement. Results: Fluid detection per B-scan had area under the ROC curves of 0.95, 0.97, and 0.98 for intraretinal fluid (IRF), subretinal fluid (SRF), and subretinal pigment epithelium (sub-RPE) ...

Local polarization properties extraction using single incident state, single-mode-fiber-based spectral domain polarization-sensitive optical coherence tomography

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Local polarization properties extraction using single incident state, single-mode-fiber-based spectral domain polarization-sensitive optical coherence tomography We showed the local polarization properties extraction method for the single incident state, all-single-mode-fiber-based spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) system that uses the single linear-in-wavenumber spectral camera. Polarization controllers are used in the single-mode-fiber-based SD-PS-OCT system to provide a compact structure with polarization state stability. The local polarization properties of the birefringent sample are extracted from the cumulative polarization properties iteratively. The reconstructed polarization images demonstrate the local polarization properties extraction ability of the system.

The Influence of Topical Perioperative Nepafenac on Retinal Vasculature Following Phacoemulsification Using Optical Coherence Tomography Angiography: A Randomized Clinical Trial

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Purpose: To investigate topical nepafenac drops (TND) effect on retinal vasculature following uneventful phacoemulsification. Methods: 54 eyes were randomly assigned to G1: TND 3 days preoperatively and 1 month postoperatively; G2: TND for 1 month postoperatively; and G3 no TND (control). BCVA, macular OCTA were compared baseline, 1 week and 1 month. Results: No statistically significant differences found between 3 groups in OCTA parameters during study visits. However, at 1 month (compared to baseline) there were a statistically significant increase in superficial capillary plexus (SCP) capillary vessel density (CVD) in G2 (p=0.036); increase in central foveal thickness (CFT) in G2 (p=0.011) and G3 (control) (p=0.001); and reduced number of patients with SCP disorganization in G2 (p=0.04). There were no significant correlation/association between most of OCTA parameters and final BCVA. Conclusion: TND use perioperative did not show any effect on retinal OCTA microvasculatu...

Corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild-to-moderate keratoconus: a comparative study

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Background To compare the characteristics of corneal thickness measurements among the RTVue, Casia-2, and Pentacam in patients with mild-to-moderate keratoconus. Methods We recruited 46 eyes of 46 patients diagnosed with mild-to-moderate keratoconus at our hospital between January and March 2022. The central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Differences and correlations between the CCTs and TCTs, based on the device and influencing factors, were explored. Results The CCTs were highly consistent among the groups (p = 0.434) and correlated with one another (p < 0.001). The TCTs measured by OCTs were thinner than those measured by the Pentacam (p < 0.001); however, all three devices were highly correlated (p < 0.001). The thinnest point location measurements with RTVue and Casia-2 differed significantly from ...

Deep ensemble learning for automated non-advanced AMD classification using optimized retinal layer segmentation and SD-OCT scans

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Background Accurate retinal layer segmentation in optical coherence tomography (OCT) images is crucial for quantitatively analyzing age-related macular degeneration (AMD) and monitoring its progression. However, previous retinal segmentation models depend on experienced experts and manually annotating retinal layers is time-consuming. On the other hand, accuracy of AMD diagnosis is directly related to the segmentation model's performance. To address these issues, we aimed to improve AMD detection using optimized retinal layer segmentation and deep ensemble learning. Method We integrated a graph-cut algorithm with a cubic spline to automatically annotate 11 retinal boundaries. The refined images were fed into a deep ensemble mechanism that combined a Bagged Tree and end-to-end deep learning classifiers. We tested the developed deep ensemble model on internal and external datasets. Results The total error rates for our segmentation model using the boundary refinement approach was...

Onion ring sign on spectral domain optical coherence tomography in diabetic macular edema: Its evolution and outcomes

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Purpose To report evolution and outcomes of hyperreflective crystalline deposit (HCD) on optical coherence tomography (OCT) in diabetic maculopathy (DM). Methods Patients with DM showing HCD on OCT for the first time between June 2017 and May 2021 were included in the study. Demographic, ophthalmic and OCT features were documented and analysed. Factors leading to the development of HCD and its effect on the functional outcome were analysed and described in this study. Results Sixty cases of HCD were identified in 45 (males −33; females – 12) patients for the first-time during the defined study period. Mean age of the eligible patients was 61.53 ± 8.19 years. Average duration of diabetes was 13.82 ± 7.38 years. Mean visual acuity of these patients was 0.902 ± 0.438 logMAR units (Snellen equivalent = 20/160). Patients with HCD showed subretinal hard exudates, were on anti-cholesterol medications (n = 36, 80%) and showed reduced visual acuity (20/160) if the ...

Physiology-guided vs Angiography-guided Non-culprit Lesion Complete Revascularization for Acute MI & Multivessel Disease (COMPLETE-2)

Physiology-guided vs Angiography-guided Non-culprit Lesion Complete Revascularization for Acute MI & Multivessel Disease (COMPLETE-2)COMPLETE-2 is a prospective, multi-centre, randomized controlled trial comparing a strategy of physiology-guided complete revascularization to angiography-guided complete revascularization in patients with acute ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI) and multivessel coronary artery disease (CAD) who have undergone successful culprit lesion Percutaneous Coronary Intervention (PCI). COMPLETE-2 OCT is a large scale, prospective, multi-centre, observational, imaging study of patients with STEMI or NSTEMI and multivessel CAD in a subset of eligible COMPLETE-2 patients.

Swept-source optical coherence tomography-based ocular biometry in an adult Korean population with cataract

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Purpose: To evaluate the characteristics of ocular biometric parameters in adult Korean patients with cataract. Design: Retrospective case series Methods: Ocular biometric values of 5,273 eyes of 5,273 Korean patients undergoing cataract surgery measured with the IOLMaster 700 at the Seoul National University Hospital between November 2019 and December 2021 were reviewed. Results: The mean±SD age was 66.1±12.8 years and 62% were female. Overall, age and ocular biometric parameters were correlated with each other. Especially, age showed negative correlation with anterior chamber depth (ACD; r=-0.357), axial length (AL; r=-0.344), and posterior keratometry (PK; r=-0.054), and positive correlation with lens thickness (LT; r=0.484), angle alpha (r=0.194), total keratometry (TK; r=0.137), anterior keratometry (AK; r=0.129), and angle kappa (r=0.071). AL showed positive correlation with ACD (r=0.503), and PK (r=0.339), and negative correlation with AK (r=-0.342), TK (r=-0.334...

Automatic intraluminal scanning with a steerable endoscopic optical coherence tomography catheter for gastroenterology applications

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Significance Endoscopic optical coherence tomography (OCT) enables real-time optical biopsy of human organs. Endoscopic probes require miniaturization of optics, which in turn limits field of view. When larger imaging areas are needed such as in the gastrointestinal tract, the operator must manually scan the probe over the tissue to extend the field of view, often resulting in an imperfect scanning pattern and increased risk of missing lesions. Automatic scanning has the potential to extend the field of view of OCT, allowing the user to focus on image interpretation during real-time observations. Aim This work proposes an automatic scanning using a steerable OCT catheter integrated with a robotized interventional flexible endoscope. The aim is to extend the field of view of a low-profile OCT probe while improving scanning accuracy and maintaining a stable endoscope’s position during minimally invasive treatment of colorectal lesions. Approach A geometrical model of the steerabl...

Artificial intelligence in glaucoma: posterior segment optical coherence tomography

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Purpose of Review To summarize the recent literature on deep learning (DL) model applications in glaucoma detection and surveillance using posterior segment optical coherence tomography (OCT) imaging. Recent Findings DL models use OCT derived parameters including retinal nerve fiber layer (RNFL) scans, macular scans, and optic nerve head (ONH) scans, as well as a combination of these parameters, to achieve high diagnostic accuracy in detecting glaucomatous optic neuropathy (GON). Although RNFL segmentation is the most widely used OCT parameter for glaucoma detection by ophthalmologists, newer DL models most commonly use a combination of parameters, which provide a more comprehensive approach. Compared to DL models for diagnosing glaucoma, DL models predicting glaucoma progression are less commonly studied but have also been developed. Summary DL models offer time-efficient, objective, and potential options in the management of glaucoma. Although artificial intelligence mode...

Optical coherence tomography biomarkers as predictors of transition to chronic central serous chorioretinopathy after retinal laser photocoagulation

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Objectives: To explore the optical coherence tomography (OCT) biomarkers to predict the transition to chronic central serous chorioretinopathy (cCSC) after retinal laser photocoagulation. Methods: Patients enrolled in this study were from a 12-week clinical trial comparing the efficacy and safety of subthreshold micropulse laser (SML) with threshold conventional laser (TCL) for CSC and had extended follow-up for more than 1year. They were divided into two groups, transited to cCSC group (cCSC group) and did not transited to cCSC group (non-cCSC group) according to fundus examination at the extended follow-up. Collect the best-corrected visual acuity (BCVA) and OCT characteristics of patients at baseline and 12 weeks after laser treatment. Results: Twenty-seven patients were enrolled (42.6±7.7years old), and duration of follow-up was 178.9±88.8 (57.0–312.0)weeks. Nine patients (33.3%) were assigned to cCSC group, and the other 18 patients (66.7%) were assigned to the non-cCSC group. ...

Choroidal Vascular Density Quantification in High Myopia with or without Choroidal Neovascularization Using Optical Coherence Tomography Angiography

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Purpose. The aim of this study was to analyze choroidal vascular density alteration in high myopia with or without choroidal neovascularization by using optical coherence tomography angiography (OCTA). Methods. This was a cross-sectional, observational study that included 60 high-myopia eyes. All the participants had comprehensive ophthalmic assessments with visual acuity, intraocular pressure, slit lamp-assisted biomicroscopy, color fundus photography, axial length, optometry, and OCTA. Age, sex, and comorbidities were collected from their medical charts. Univariate and multiple analyses were made to compare the age, spherical equivalent, choroidal vascular density, gender, and choroidal thickness between normal and patients with choroidal neovascularization. Results. 60 eyes with high myopia were included in our study, including 30 eyes with choroidal neovascularization and 30 eyes without choroidal neovascularization or other fundus pathology. The mean age of high myopic patients...

LONG-TERM CHANGES IN VISUAL FUNCTION AND EN FACE OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN FOVEA-OFF RETINAL DETACHMENT: A 2-Year Prospective Study

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Purpose: To investigate the long-term changes in visual function and outer retinal abnormalities on en face optical coherence tomography after fovea-off rhegmatogenous retinal detachment and to assess associations between functional outcomes and outer retinal abnormalities. Methods: Prospective, observational study. The following data were collected at 1, 3, 6, 12, and 24 months after retinal reattachment: Best-corrected visual acuity, metamorphopsia (M-CHARTS), aniseikonia (New Aniseikonia Test), altered ellipsoid zone reflectivity, outer retinal folds, macular detachment demarcation, and subfoveal fluid. Results: Thirty-eight patients were included. Best-corrected visual acuity improved significantly from 1 to 12 months and from 12 to 24 months (P < 0.001; P = 0.022). Vertical and horizontal metamorphopsia improved significantly from 1 to 12 months (P < 0.001; P = 0.002), and at 24 months, scores of ≥0.2° were present in 54% and 42% of patients, respectively. The de...

CHORIOCAPILLARIS STRUCTURE IN THE FELLOW EYES OF PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: An OCT Angiography Image Averaging Study

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Purpose: Histological choriocapillaris abnormalities have been reported in age-related macular degeneration (AMD). Averaging multiple en face optical coherence tomography angiography improves the quality of imaging of the choriocapillaris. This study used multiple en face swept source optical coherence tomography angiography image averaging to examine the structural changes in the choriocapillaris in the fellow eyes of patients with neovascular AMD. Methods: All patients underwent macular optical coherence tomography angiography imaging. One eye per subject was repeatedly imaged, and nine raster scan sets were obtained. Registered en face images were averaged, and area of flow voids and number of flow voids were measured using ImageJ software. Results: Forty-eight patients with neovascular AMD were recruited for analysis. Twenty-seven patients had polypoidal choroidal vasculopathy, and 22 eyes had soft drusen. Twenty-six eyes of 26 healthy individuals were included as age-m...