Evaluating the Persistence of Large Choroidal Hypertransmission Defects using SS-OCT Imaging.

In age-related macular degeneration (AMD), large choroidal hypertransmission defects (hyperTDs) are identified on en face optical coherence tomography (OCT) images as bright lesions measuring at least 250 µm in greatest linear dimension (GLD). These choroidal hyperTDs arise from focal attenuation or loss of the retinal pigment epithelium (RPE). We previously reported that once large hyperTDs formed, they were likely to persist compared with smaller lesions that were more likely to be transient. Due to their relative persistence, these large persistent choroidal hyperTDs are a point-of-no-return in the progression of intermediate AMD to the late stage of atrophic AMD. Moreover, the onset of these large choroidal hyperTDs can serve as a clinical trial endpoint when studying therapies that might slow disease progression from intermediate AMD to late atrophic AMD. To confirm the persistence of these large choroidal hyperTDs, we studied an independent dataset of AMD eyes enrolled in an ongoing prospective swept-source OCT (SS-OCT) natural history study to determine their overall persistence. We identified a total of 202 eyes with large choroidal hyperTDs containing 1725 hyperTDs followed for an average of 46.6 months. Of the 1725 large hyperTDs, we found that 1718 (99.6%) persisted while only 7 hyperTDs (0.4%) were non-persistent. Of the 7 non-persistent large hyperTDs in 6 eyes, their average GLD at baseline was 385 µm. Of the large hyperTDs ranging in size between 250-300 µm when first detected, only one was not persistent with a baseline GLD of 283 µm. In 6 of the non-persistent hyperTDs, the loss of a detectable large hyperTD was due to the accumulation of hyperreflective material along the retinal pigment epithelium (RPE) and in the retina over the area where the hyperTD was located. This hyperreflective material is thought to represent the migration and aggregation of RPE cells into this focal region where the choroidal hyperTD arose due to attenuated or lost RPE.

Evaluation of epiretinal membrane formation after scleral buckling for treating rhegmatogenous retinal detachment: En face optical coherence tomography image-based study.

PURPOSE: To assess epiretinal membrane (ERM) formation, severity, and the associated risk factors after scleral buckling using en face optical coherence tomography (OCT) images. METHODS: Medical records of 61 consecutive patients (66 eyes) with rhegmatogenous retinal detachment who underwent scleral buckling were retrospectively reviewed. Posterior vitreous detachment (PVD) was determined based on B-scan OCT images. En face OCT images were used to visualize the ERM and retinal folds. ERM formation was identified by comparing en face images pre- and post-surgery. The maximum depth of the retinal folds (MDRF) was measured using en face imaging to objectively assess traction strength. RESULTS: ERM formation occurred in 15 (22.7%) eyes at the final visit; the foveal pit was preserved in all cases. Parafoveal retinal folds were present in 5 (7.6%) eyes, with a mean MDRF of 21.8 ± 12.6 µm. No significant difference was observed in best-corrected visual acuity (logarithm of the minimal angle of resolution) between the ERM formation (-0.019 ± 0.128) and non-ERM formation (-0.001 ± 0.213) groups at the final visit (P = 0.593; Mann-Whitney U test). Multivariate logistic regression analysis revealed that older age and the presence of PVD were significant risk factors for ERM formation (odds ratio 1.07, 95% confidence interval 1.01-1.14, P = 0.032; odds ratio 5.26, 95% confidence interval 1.06-26.10, P = 0.042; respectively). CONCLUSION: ERM occurred in 22.7% of cases but was mild and did not affect visual acuity. Older age and the presence of PVD are risk factors for ERM formation.

Regression patterns of central serous chorioretinopathy using en face optical coherence tomography.

PURPOSE: To study the regression patterns of subretinal fluid (SRF) in central serous chorioretinopathy (CSCR) on sequential en face optical coherence tomography (OCT) and its relationship to leak locations. METHODS: Retrospective study on patients with acute CSCR. Inclusion criteria were (i) availability of data, sequential OCT and OCT angiography (B scan and en face OCT) every 2 weeks until resolution of SRF or 6 months, whichever is earlier; (ii) single active leak. Exclusion criteria were (i) presence of macular neovascularization or atypical CSCR, (ii) diffuse pigment epitheliopathy, (iii) multiple leaks. Serial en face OCT scans were evaluated and the area of SRF was measured using ImageJ software. Correlation coefficient was calculated for the regression rate of SRF area and central retinal thickness (CRT) over the first month of follow-up and the time of complete SRF resolution. RESULTS: Out of the 25 eyes, 20 eyes demonstrated a centripetal regression, and 5 eyes demonstrated a centrifugal regression. In eyes with a leakage point <1000µ from the fovea, 86% resolved in a centripetal fashion, and in eyes with leak site ≥1000µ away from fovea, 70% eyes resolved centripetally. There was a correlation (r=-0.47, p=0.018) of the rate regression of SRF area during the first month and timing of resolution. In contrast, this correlation was absent (r=-0.16, p=0.44) for CRT regression. CONCLUSION: Our en face-based analysis of sequential OCTs of regressing CSCR demonstrated a tendency for the subfoveal SRF to resolve towards the end or a centripetal pattern of regression. Prediction of resolution of SRF at 1 month is better with en face area of SRF in comparison to CRT.

Variation of vortex veins at the horizontal watershed in normal eyes.

PURPOSE: To assess the vascular pattern of choroidal vortex veins at the horizontal watershed zone in normal eyes using optical coherence tomography (OCT). METHODS: We retrospectively studied 207 normal eyes of 207 patients whose fellow eyes were diagnosed with unilateral retinal diseases without choroidal involvement. Venous anastomosis between the superior and inferior vortex veins and deviation of the horizontal watershed zone were evaluated using 12 × 12-mm en face OCT images. Central choroidal thickness (CCT) was measured on B-mode OCT images. RESULTS: Vortex vein anastomosis was observed in 92 eyes (44.4%) at the horizontal watershed zone. Superior or inferior deviation of the horizontal watershed was ascertained in 69 eyes (33.3%). The frequency of the anastomosis and deviation did not differ significantly between age groups (P = 0.56 and 0.96, respectively). Mean CCT of all eyes was 221 ± 80 µm. CCT was significantly greater in eyes with anastomosis than in those without (233 ± 73 µm vs 210 ± 83 µm, P < 0.05). However, CCT did not differ significantly between eyes with and without deviation of the horizontal watershed zone (223 ± 74 µm vs 219 ± 82 µm). CONCLUSIONS: Venous anastomosis at the horizontal watershed zone as well as superior or inferior deviation of the zone were frequently observed in normal eyes. CCT was greater in eyes with than in those without anastomosis, suggesting subclinical vortex vein congestion.

Running pattern of choroidal vessel in en face OCT images determined by machine learning-based quantitative method.

PURPOSE: To evaluate the new method to quantitate the running pattern of the vessels in Haller's layer in en face optical coherence tomographic (OCT) images using the new algorithm. METHODS: A retrospective and cross-sectional study. The en face image of top 25% slab of Haller's layer was analyzed. The vascular area in these images was calculated after binarization. Then, the vessels were thinned, and the total length of the vessels and the mean vessel diameter were calculated. Based on the angle of vessel running, "natural oblique vessel" was defined. The ratio of the natural oblique vessel to the whole vessels was defined as the "symmetry index". To examine the reproducibility of the software, the images obtained on two different examination dates of the same subject (25 eyes of 25 healthy subjects) were analyzed. Also, to compare the symmetry index and subjective evaluations, 180 eyes and 180 healthy subjects were analyzed. The subjective evaluations classified the images into 3 groups, the Symmetrical, Semi-symmetrical, and Asymmetrical types. Symmetry index was compared in each group. RESULTS: The inter-measurement correlation coefficient (ICC) of the vessel area, vessel length, and vessel diameter were 0.955, 0.934, and 0.954, respectively. The ICC of the symmetry index was 0.926. The symmetry index of the Symmetrical type was 60.4 ± 7.2%, that of the Semi-symmetry type was 56.2 ± 4.6%, and that of the Asymmetry type was 52.6 ± 5.2%. CONCLUSIONS: The present algorithm can analyze vessels in Haller's layer of the en face images of choroid in an objective manner with good repeatability.

Combined in-depth, 3D, en face imaging of the optic disc, optic disc pits and optic disc pit maculopathy using swept-source megahertz OCT at 1050 nm.

PURPOSE: To demonstrate papillary imaging of eyes with optic disc pits (ODP) or optic disc pit associated maculopathy (ODP-M) with ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. To generate 3D-renderings of the papillary area with 3D volume-reconstructions of the ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation of ODP-characteristics. METHODS: A 1.68 MHz-prototype SS-MHz-OCT system at 1050 nm based on a Fourier-domain mode-locked laser was employed to acquire high-definition, 3D datasets with a dense sampling of 1600 × 1600 A-scans over a 45° field of view. Six eyes with ODPs, and two further eyes with glaucomatous alteration or without ocular pathology are presented. 3D-rendering of the deep papillary structures, virtual 3D-reconstructions of the ODPs and depth resolved isotropic en face images were generated using semiautomatic segmentation. RESULTS: 3D-rendering and en face imaging of the optic disc, ODPs and ODP associated pathologies showed a broad spectrum regarding ODP characteristics. Between individuals the shape of the ODP and the appending pathologies varied considerably. MHz-OCT en face imaging generates distinct top-view images of ODPs and ODP-M. MHz-OCT generates high resolution images of retinal pathologies associated with ODP-M and allows visualizing ODPs with depths of up to 2.7 mm. CONCLUSIONS: Different patterns of ODPs can be visualized in patients for the first time using 3D-reconstructions and co-registered high-definition en face images extracted from a single densely sampled 1050 nm megahertz-OCT (MHz-OCT) dataset. As the immediate vicinity to the SAS and the site of intrapapillary proliferation is located at the bottom of the ODP it is crucial to image the complete structure and the whole depth of ODPs. Especially in very deep pits, where non-swept-source OCT fails to reach the bottom, conventional swept-source devices and the MHz-OCT alike are feasible and beneficial methods to examine deep details of optic disc pathologies, while the MHz-OCT bears the advantage of an essentially swifter imaging process.

Sex differences in choroidal vessels using novel wide-field choroidal en-face images from optical coherence tomography.

This study aims to develop a method to quantify choroidal vessels in normal eyes using wide-field optical coherence tomography (OCT) en-face images. The study included participants with normal eyes in whom wide-angle OCT images were acquired to generate planarized choroidal en-face and thickness map images. The images were segmented into central, midperipheral, and peripheral areas, and the midperipheral and peripheral areas were further segmented into supratemporal, infratemporal, supranasal, and infranasal sectors. The mean planarized choroidal-vessel density (p-CVD), planarized choroidal-vessel size (p-CVS), and choroidal thickness (CT) were calculated in each sector. Sex differences were analyzed using the Mann-Whitney U test. The study included 162 participants comprising 84 female (mean age, 43.5 years; axial length, 24.0 mm) and 78 male (mean age, 44.4 years; axial length, 24.2 mm) participants with no significant differences in demographics (P ≥ 0.107). Men had a higher mean p-CVD in all regions (P < 0.001). The mean p-CVS was greater in men in all regions except for the supratemporal sector (P < 0.001). No significant differences in sex in the mean CT were observed in all regions (P ≥ 0.106). The p-CVD and p-CVS in normal eyes differ between sexes. This finding may contribute to the understanding of the pathophysiology of choroidal diseases.

Visualizing and Manipulating Olfactory Cilia Through Viral Delivery Coupled with En Face Imaging of Intact OE.

Olfactory cilia are the obligate transducers of the odorant signal, and thus their study has been a focus of investigation in the olfactory field. Various methodologies have been established to visualize the cilia of olfactory sensory neurons; however, these approaches are limited to static imaging and often lack the ability to resolve individual cilia projecting from solitary neurons in the postnatal mouse. Here we detail a procedure of the visualization of olfactory cilia by ectopic expression of fluorescently tagged proteins. The procedure can be used for the observation and manipulation of the olfactory cilia and ciliary proteins in both static and dynamic conditions.

A factor for predicting simultaneous internal limiting membrane peeling during epiretinal membrane removal: swept-source optical coherence tomography-based evaluation of epiretinal membrane adhesion to the retina.

PURPOSE: To investigate preoperative factors associated with simultaneous internal limiting membrane (ILM) peeling during epiretinal membrane (ERM) removal. STUDY DESIGN: Observational cross-sectional study. METHODS: We retrospectively reviewed 60 eyes with idiopathic ERM that underwent vitrectomy. The gap between the ERM and ILM was visualized using en face optical coherence tomography. The depth and width of the ERM-ILM gap at the initiation site of ERM removal were measured, and the relationship between preoperative factors including these parameters and simultaneous ILM peeling during ERM removal was investigated. RESULTS: The ILM was simultaneously peeled during ERM removal in 30 eyes, but not in the other 30 eyes. Age was significantly higher (P = 0.017) and the width of the ERM-ILM gap was significantly smaller (P < 0.001) in the simultaneous ILM peeling (+) group than in the simultaneous ILM peeling (-) group. Multivariate logistic regression analysis confirmed the width of the ERM-ILM gap as a significant negative predictor for simultaneous ILM peeling (odds ratio, 0.992; 95% confidence interval, 0.986-0.997; P = 0.003). Receiver operating characteristic curve analysis of the width of the ERM-ILM gap revealed that the optimal cutoff for predicting simultaneous ILM peeling was 187.1 µm. CONCLUSION: The small width of the ERM-ILM gap at the initiation site of ERM removal was significantly associated with simultaneous ILM peeling, indicating that the adhesion strength between the ERM and ILM at the initial ERM grasping site determines whether simultaneous ILM peeling will occur during ERM removal.

En-face widefield optical coherence tomography angiography for understanding vascular networks changes in two cases of acute retinal necrosis.

PURPOSE: The present study assesses the utility of en-face widefield optical coherence tomography angiography (OCTA) imaging for evaluating the retinal vascular network during the course of treatment in acute retinal necrosis(ARN). OBSERVATIONS: OCTA images of two cases of acute retinal necrosis were analyzed. Case 1 was a 15-year-old male with visual crowding in his right eye who had best-corrected visual acuity of 16/20 and intraocular pressure of 25 mmHg in his right eye on initial evaluation. Case 2 was a 57-year-old male with visual crowding in his left eye who had best-corrected visual acuity of 20/20 in his left eye on initial examination and intraocular pressure of 19.3 mmHg. In both patients, dynamic changes could be tracked by en-face ultra-widefield OCTA imaging before and up to 1 year after surgical treatment. The images showed arteriovenous anastomosis and the nonperfused area on the surface of the retina. CONCLUSIONS AND IMPORTANCE: En-face widefield OCTA is useful for monitoring the structure of retinal vessels over time in acute retinal necrosis. Wide-angle OCTA is used to non-invasively examine retinal vascular dynamic changes in ARN. OCTA artifacts due to intraocular inflammation appeared, making interpretation difficult. These will remain as issues in the future. It seems difficult for a while to completely replace FA due to the problem of image clarity.

Review of Retinal Imaging Modalities for Hydroxychloroquine Retinopathy.

This review provides an overview of conventional and novel retinal imaging modalities for hydroxychloroquine (HCQ) retinopathy. HCQ retinopathy is a form of toxic retinopathy resulting from HCQ use for a variety of autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Each imaging modality detects a different aspect of HCQ retinopathy and shows a unique complement of structural changes. Conventionally, spectral-domain optical coherence tomography (SD-OCT), which shows loss or attenuation of the outer retina and/or retinal pigment epithelium-Bruch's membrane complex, and fundus autofluorescence (FAF), which shows parafoveal or pericentral abnormalities, are used to assess HCQ retinopathy. Additionally, several variations of OCT (retinal and choroidal thickness measurements, choroidal vascularity index, widefield OCT, en face imaging, minimum intensity analysis, and artificial intelligence techniques) and FAF techniques (quantitative FAF, near-infrared FAF, fluorescence lifetime imaging ophthalmoscopy, and widefield FAF) have been applied to assess HCQ retinopathy. Other novel retinal imaging techniques that are being studied for early detection of HCQ retinopathy include OCT angiography, multicolour imaging, adaptive optics, and retromode imaging, although further testing is required for validation.

En Face Images Using Ultra-Widefield Optical Coherence Tomography in 2 Cases of Traumatic Hypotony Maculopathy before and after Surgical Intervention.

The aim was to investigate the structural changes of the retina using en face ultra-widefield optical coherence tomography (OCT) images during the treatment of hypotony maculopathy with traumatic cyclodialysis. Case 1 was a 43-year-old male patient with visual crowding in his left eye (metallic wire injury that occurred 3 weeks previously) who was referred to our department. Although best-corrected visual acuity was 20/20 in his left eye on initial evaluation, intraocular pressure was 6 mm Hg. Case 2 was a 20-year-old male patient with visual crowding in his left eye (baseball ball injury that occurred 4 weeks previously) who was referred to our department. Although best-corrected visual acuity was 16/20 in his left eye on initial examination, intraocular pressure was 5 mm Hg. Surgical interventions were performed in both cases. En face ultra-widefield OCT images were able to be used to trace dynamic changes before the intervention and up to 1 year later. The images obtained in these two cases made it possible to confirm the progress from wrinkles on the surface of the retina to normalization of vascular structure and improvement of ellipsoid zone disruption. En face ultra-widefield OCT is useful for monitoring multilayer structures of the retina in hypotony maculopathy cases.

Case Report: Assessing the Position of Pacemaker Leads via Transthoracic Echocardiography: Additional Value of the Subcostal En Face View.

There is an association between presence of cardiac implantable electronic devices (CIED) and development of tricuspid regurgitation (TR). Mechanisms proposed to explain CIED-induced TR can be classified as implantation-related, lead-related, and pacing-related. Lead-related TR results from the direct interaction of the lead with the tricuspid valve (TV). The localization of the lead at the TV level directly influences the probability of subsequent development of significant TR. A transthoracic subcostal en face view of the TV can be acquired in most patients through a 90° rotation from the subcostal 4-chamber view with clear anatomic delineation of the TV and the commissures including lead position. This case-series presents three examples where the transthoracic en face view could add incremental information on the position of the pacemaker leads and on the mechanism of TR. Conclusion: When performing transthoracic echocardiography in patients with trans-tricuspid CIED lead(s), an en face view of the TV with exact reporting of the position of the lead(s) should be included.

Intraretinal Cysts in Macular Hole: A Structure-Function Correlation Based on En Face Imaging.

PURPOSE: To characterize retinal micromorphic changes on en face optical coherence tomography (OCT) and to determine their role in pathogenesis and visual outcomes in macular hole (MH) surgery. PATIENTS AND METHODS: This is a retrospective, interventional, consecutive case series of 28 eyes undergoing successful MH surgery. Pre- and post-operative en face OCT were manually segmented, and the correlation between parameters such as MH basal diameter and minimal inlet area, area of cyst in inner plexiform layer (IPL) and outer plexiform layer (OPL), percentage of cyst in IPL and OPL, and amount of ellipsoid zone (EZ) defect and external limiting membrane (ELM) defect was performed. Their relationship with visual acuity (VA) outcomes (Group 1: ≥20/60; 14 eyes; Group 2: <20/60; 14 eyes) was also evaluated. RESULTS: A significant positive correlation was noted between the cyst area in OPL and IPL (r=0.768; p<0.001), which in turn were positively correlated with the basal diameter of the MH in all eyes. The cyst area was significantly more in IPL as compared to OPL in all eyes (p=0.049) and in group 2 (p=0.03) but not in group 1 (p=0.62). As compared to group 2, eyes in group 1 had significantly better pre- and post-operative VA, and significantly smaller basal diameter, minimal inlet area, area of cyst in IPL and OPL, and amount of defect in the ELM (postoperative) and EZ (pre- and post-operative), respectively. CONCLUSION: An increase in the basal diameter of the MH is associated with a simultaneous congruous enlargement of the area of cyst in IPL and OPL. Based on these imaging findings, we propose that the possible rationale for the origin of these intraretinal cysts could be a breakdown in the physiological retinal pigment epithelium (RPE) pump due to the anatomical separation of the neurosensory retina from the underlying RPE, ie, "RPE contact loss" theory.

Non-invasive imaging of a choroidal macrovessel.

PURPOSE: To describe novel anatomic findings of an apparent choroidal macrovessel, originally misdiagnosed as a choroidal tumor, using non-invasive imaging tools. OBSERVATIONS: Initial ophthalmic examination revealed an elevated hypopigmented choroidal mass in the macular area, with a serpentine track extending temporally to the equator. Enhanced depth imaging optical coherence tomography (EDI-OCT) revealed an optically hollow lesion just outside the choroid-scleral junction (CSJ), indenting the retina and compressing the choroid from the scleral side. Optical coherence tomography angiography (OCTA) at the choroidal level showed relative low flow within the lesion. En face OCT at the level of the choroid demonstrated similar reflectivity to the physiological adjacent choroidal vessels. CONCLUSION AND IMPORTANCE: Non-invasive imaging can be used to demonstrate the presence and anatomy of a choroidal macrovessel. OCTA is presented as a useful diagnostic imaging test that can distinguish this lesion from alternative diagnoses without the use of dye injection. In addition to the previously published reports of such vessels in the choroid, we suggest a possible anatomic variant infra-choroidal location of a macrovessel and hypothesize its origin.

Utility of en-face imaging in diagnosis of occult macular dystrophy with RP1L1 mutation: A case series.

PURPOSE: To report en-face imaging findings at the level of ellipsoid zone (EZ) in two cases of occult macular dystrophy (OMD) with retinitis pigmentosa 1-like 1 (RP1L1) p.Arg45Trp mutation. OBSERVATIONS: In both patients who presented with decreased vision, pupillary examination, intraocular pressure, and anterior examination were normal. Ophthalmoscopic examination showed prominent choroidal marking whereas fundus autofluorescence was unremarkable. Spectral domain optical coherence tomography (SD-OCT) showed subtle gaps between EZ and retinal pigment epithelium (RPE). The photoreceptor disruption became more evident with en-face imaging at the EZ plane. CONCLUSIONS AND IMPORTANCE: This is a report of two patients with EZ en-face imaging that aided in the diagnosis of OMD where other structural imaging was largely unremarkable. The en-face imaging modality can also be used to monitor OMD progression.

Quantitative assessment of rat bone regeneration using complex master-slave optical coherence tomography.

BACKGROUND: The need for hard and soft tissues in oral implantology determined the development of methods and techniques to increase bone volume and their quality with different alternative materials used as substituents of patient's natural bone. In addition, laser radiation can be used to accelerate the repair of fractures and to produce an increased volume of formed callus, as well as an increased bone mineral density. METHODS: The aim of this work is to evaluate the capability of an in-house developed multimodal complex master slave (CMS) enhanced swept source (SS) optical coherence tomography (OCT) imaging instrument to analyze the increase in the quantity and the improvement of the quality of newly-formed bone using low level laser therapy (LLLT). Bone formation is quantitatively assessed in 5 mm cylindrical defects made in the calvaria part of the skull of living rats. Samples are divided in three study groups: A, a negative control group, for which the natural healing process of the defect is investigated; B, a positive control group, for which bovine graft is used to stimulate bone formation, and C, a study group, in which bovine graft is added to the created defects and LLLT is applied throughout the entire healing period. The animals are sacrificed after 14, 21, and 30 days, and the samples are imaged using the multimodal CMS/SS-OCT instrument. RESULTS: The method allows for the simultaneous monitoring of the bone tissue via two perpendicular cross-sections and nine en-face images taken at adjustable depths into the sample. A global image with course axial resolution allows for the positioning of the field-of-view of the system on the area of interest on the tissue. The quantitative assessment of the process of bone formation is completed using the differences in brightness between the native bone, the artificial bone graft, and the newly-formed bone. CONCLUSIONS: Group C is demonstrated to have a higher volume of newly-formed bone than Group B, which is better from this point of view than Group A. By analyzing the evolution of this volume of new bone in time, the most significant difference was after 21 days, therefore approximately after two thirds of the total time interval analyzed. After 30 days, the volumes of bone tend to move closer, as they begin to fill the available gap. The study demonstrates that OCT can assess quantitatively the positive impact of LLLT on bone regeneration.

Multimodal imaging of Bietti's crystalline dystrophy.

Bietti's crystalline dystrophy (BCD) is a rare autosomal recessive retinal dystrophy characterized by deposition of crystals in the retina. The purpose of this article is to describe retinal abnormalities in BCD using multimodal imaging. An 18-year-old girl presented with decrease of vision and nyctalopia. She was assessed with color fundus picture, red-free photographs, short-wave autofluorescence, spectral-domain optical coherence tomography (OCT) and en face OCT and was diagnosed to have BCD based on typical presentation. Retinal crystals were better visualized on en face OCT as compared to conventional B scan OCT.

Spectral domain optical coherence tomography and en-face imaging in presumed ocular chalcosis.

A 35-year-old male, with a history of injury sustained three years back, underwent pars plana vitrectomy with intravitreal copper foreign body removal. Post-operatively, visual acuity improved; however, glistening refractile particles were seen at the macula. Spectral domain optical coherence tomography and en-face imaging were performed to localise the level of the deposits. To the best of our knowledge, this is the first such documentation in presumed ocular chalcosis.

Comparison between Spectral-Domain and Swept-Source OCT Angiography for the Measurement of Persistent Hypertransmission Defects in Age-Related Macular Degeneration.

Purpose: Spectral-domain OCT angiography (SD-OCTA) scans were tested in an algorithm developed for use with swept-source OCT angiography (SS-OCTA) scans to determine if SD-OCTA scans yielded similar results for the detection and measurement of persistent choroidal hypertransmission defects (hyperTDs). Design: Retrospective study. Participants: Forty pairs of scans from 32 patients with late-stage nonexudative age-related macular degeneration (AMD). Methods: Patients underwent both SD-OCTA and SS-OCTA imaging at the same visit using the 6 × 6 mm OCTA scan patterns. Using a semiautomatic algorithm that helped with outlining the hyperTDs, 2 graders independently validated persistent hyperTDs, which are defined as having a greatest linear dimension ≥250 µm on the en face images generated using a slab extending from 64 to 400 µm beneath Bruch's membrane. The number of lesions and square root (sqrt) total area of the hyperTDs were obtained from the algorithm using each imaging method. Main Outcome Measures: The mean sqrt area measurements and the number of hyperTDs were compared. Results: The number of lesions and sqrt total area of the hyperTDs were highly concordant between the 2 instruments (rc = 0.969 and rc = 0.999, respectively). The mean number of hyperTDs was 4.3 ± 3.1 for SD-OCTA scans and 4.5 ± 3.3 for SS-OCTA scans (P = 0.06). The mean sqrt total area measurements were 1.16 ± 0.64 mm for the SD-OCTA scans and 1.17 ± 0.65 mm for the SS-OCTA scans (P < 0.001). Because of the small standard error of the differences, the mean difference between the scans was statistically significant but not clinically significant. Conclusions: Spectral-domain OCTA scans provide similar results to SS-OCTA scans when used to obtain the number and area measurements of persistent hyperTDs through a semiautomated algorithm previously developed for SS-OCTA. This facilitates the detection of atrophy with a more widely available scan pattern and the longitudinal study of early to late-stage AMD. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.