Radial Scanning Research Articles

MIXED PATHOPHYSIOLOGIES OF LAMELLAR MACULAR HOLES AND RELATED DISEASES: A Multimodal Optical Coherence Tomography-Based Study.

To investigate the characteristics of mixed pathophysiologies in lamellar macular holes (LMHs) and related diseases using multimodal optical coherence tomography. Overall, 126 eyes diagnosed with LMH, epiretinal membrane foveoschisis, or macular pseudohole using the horizontal B-scan image according to the definition proposed by Hubschman et al in 2020 were analyzed using multimodal optical coherence tomography imaging including horizontal and vertical 5-line B-scan, radial scan, and macular three-dimensional volume scan images. If at least two diagnostic criteria for LMH, epiretinal membrane foveoschisis, or macular pseudohole were satisfied in these scans, the patient was diagnosed as having a "mixed type." Retinal traction force was quantitatively evaluated by measuring the maximum depth of the retinal folds using en-face images. Mixed types constituted 34.1% of the cases. The LMH-related mixed group demonstrated intermediate characteristics between the epiretinal membrane foveoschisis/macular pseudohole and true LMH groups in terms of retinal traction and LMH-specific features and had a significant positive correlation between the maximum depth of the retinal folds and mean M-CHARTS scores (P = 0.034). A thorough optical coherence tomography analysis is necessary to accurately diagnose LMH and related diseases. A significant positive correlation was observed between the maximum depth of the retinal folds and the degree of metamorphopsia in the LMH-related mixed group.

Development of an automated radial scanning microscopy-based imaging system and its use for measuring resin canal size and frequency in Pinus taeda

Summary Resin canals produce and transport oleoresins that are important for tree defenses within the Pinaceae family. Rapid measurement techniques are needed to better understand how resin canal characteristics vary due to genetic and environmental effects. Here we describe a semi-automated microscopy imaging system that was built for quantifying longitudinal resin canals. Tree increment cores from 210 loblolly pine (Pinus taeda L.) trees were prepared into radial strips and the transverse surface of the samples polished with 400 and then 600 grit sandpaper. Each sample was imaged along its entire length (pith to bark) with the images collected from a monochrome camera connected to a Plan Fluorite 4× objective lens. The samples were imaged on the transverse surface via transmitted 850 nm near-infrared light directed at the radial surfaces of the samples. A total of 24 153 images were collected and then processed offline in Python using the Open Computer Vision Library (OpenCV) using a series of algorithms including contrast correction, noise removal, thresholding, contour identification, erosion, and dilation. A total of 24 491 resin canals were identified and their size quantified. The resin canals were assigned into annual rings and positioned within the earlywood or latewood of a ring using cross-correlation whereby a pseudo-density value was derived from the images and matched with density values measured by X-ray densitometry. Of the total resin canals identified, 51.5% were in the earlywood and 48.5% in the latewood, with the majority being detected in the earlywood in the first six years and the latewood in years 7 and above. This study represents the most information collected on the resin canals of loblolly pine. The detailed description of the hardware and image analysis methods should serve as a useful guide to others interested in imaging resin canals as well as other anatomical features.

Optic Nerve Head Morphology and Macula Ganglion Cell Inner Plexiform Layer Thickness in Axially Anisometropic Rhesus Monkeys.

The purpose of this study was to determine the effects of axial elongation on optic nerve head morphology and macula inner retinal thickness in young rhesus monkeys. Both eyes of 26 anisometropic, 1-year-old rhesus monkeys were imaged using optical coherence tomography (OCT). Before imaging, the animals were sedated, their eyes were dilated, and axial length was measured using an optical biometer. OCT imaging included a 20 degrees, 24-line radial scan centered on the optic nerve head (ONH) and two 20 degrees × 20 degrees raster scans, one centered on the ONH and the other on the macula. Radial scans were analyzed using programs written in MATLAB to quantify the Bruch's membrane opening (BMO) area and position, minimum rim width (MRW), anterior lamina cribrosa surface (ALCS) position, size of any scleral crescent, circumpapillary retinal nerve fiber layer (RNFL), and choroid thickness (pCh). Macula total retinal thickness (mTRT) and ganglion cell inner plexiform layer (GCIPL) thicknesses were quantified from macula scans. Linear least square regression was determined for OCT measures and axial length of the right eye, and for inter-eye differences. Animals were 341 ± 18days old at the time of imaging. BMO area (R2 = 0.38), ALCS position (R2 = 0.45), scleral crescent area (R2 = 0.35), pCh thickness (R2 = 0.21), mTRT (R2 = 0.24), and GCIPL thickness (R2 = 0.16) were correlated with the axial length (all P < 0.05). For each of these parameters, the right-eye regression slope did not differ from the slope of the interocular difference (P > 0.57). There are posterior segment morphological differences in anisometropic rhesus monkeys related to axial length. Whether these differences increase the risk of pathology remains to be investigated.

Posterior Eye Shape in Myopia

PurposeTo explore prevalence and associated factors of abnormalities of the posterior eye shape in dependence of axial length. DesignPopulation-based study. ParticipantsOut of the participants (n=3468) of the Beijing Eye Study, we included all eyes with an axial length of ≥25 mm, and a randomized sample of eyes with an axial length of <25 mm. MethodsUsing 30°-wide, serial horizontal, and fovea-centered radial, optical coherence tomographic (OCT) images, we examined location and depth of the most posterior point of the retinal pigment epithelium/Bruch´s membrane line (PP-RPE/BML). Main Outcome ParametersPrevalence and depth of an extrafoveal PP-RPE/BML. ResultsThe study included 366 eyes (314 individuals;age:63.7±9.7 years). On the radial OCT scans, the PP-RPE/BML was located in the foveola in 190 (51.9%;95%CI:46.9,56.9) eyes, in 121 (33.1%;95%CI:28.1,38.1) eyes in the 6 o´clock part of the vertical meridian at a mean distance of 1.73±0.70mm from the foveola, and in 54 (14.8%;95%CI:11.1,18.4) eyes in the 12 o´clock part of the vertical meridian at a distance of 2.01±0.66mm from the foveola. Deeper PP-RPE/BML depth increased with longer axial length (beta:0.28;B:12.3;95%CI:7.5,17.1;P<0.001), female sex (beta:0.17;B:30.2;95%CI:10.7,49.6;P=0.002), and higher corneal astigmatism (beta:0.12;B:13.9;95%CI:1.50,26.3;P=0.03). On the horizontal OCT scans, the PP-RPE/BML was located in the foveola in 304 (83.1%;95%CI:79.2,86.9) eyes, between the foveola and the optic disc in 36 (9.8%;95%CI:6.8,12.9) eyes (mean depth: 119±142μm; mean distance:1.59±0.76mm from the foveola), and temporal to the foveola in 26 (7.1%;95%CI:4.5,9.8) eyes (depth:71±46μm; distance:1.20±0.60mm). Higher prevalence of an extrafoveal PP-RPE/BML correlated with longer axial length (OR:1.55;95%CI:1.28,1.89;P<0.001), higher corneal astigmatism (OR:1.78;95%CI:1.14,2.79;P=0.01) and female sex (OR:2.74;95%CI:1.30,5.77;P=0.008). The curvature of the RPE/BM line at the posterior pole was similar to the RPE/BM line curvature outside of the posterior pole in 309 (84.4%;95%CI:80.7,88.2) eyes, and it was steeper (i.e., smaller curvature radius) in 57 (15.6%;95%CI:12.1,19.1) eyes. In these eyes, axial length was longer (24.41±1.78mm versus 27.74±1.88mm;P<0.001). ConclusionsWith longer axial length, the foveola is more often located outside of the geometrical posterior pole. It may be of importance for biometric axial length measurements. An extrafoveal location of the PP-RPE/BML may be due to an axial elongation-associated, meridionally asymmetric enlargement of Bruch´s membrane in the fundus midperiphery.

Complete spatiotemporal quantification of cardiac motion in mice through enhanced acquisition and super-resolution reconstruction.

The quantification of cardiac motion using cardiac magnetic resonance imaging (CMR) has shown promise as an early-stage marker for cardiovascular diseases. Despite the growing popularity of CMR-based myocardial strain calculations, measures of complete spatiotemporal strains (i.e., three-dimensional strains over the cardiac cycle) remain elusive. Complete spatiotemporal strain calculations are primarily hampered by poor spatial resolution, with the rapid motion of the cardiac wall also challenging the reproducibility of such strains. We hypothesize that a super-resolution reconstruction (SRR) framework that leverages combined image acquisitions at multiple orientations will enhance the reproducibility of complete spatiotemporal strain estimation. Two sets of CMR acquisitions were obtained for five wild-type mice, combining short-axis scans with radial and orthogonal long-axis scans. Super-resolution reconstruction, integrated with tissue classification, was performed to generate full four-dimensional (4D) images. The resulting enhanced and full 4D images enabled complete quantification of the motion in terms of 4D myocardial strains. Additionally, the effects of SRR in improving accurate strain measurements were evaluated using an in-silico heart phantom. The SRR framework revealed near isotropic spatial resolution, high structural similarity, and minimal loss of contrast, which led to overall improvements in strain accuracy. In essence, a comprehensive methodology was generated to quantify complete and reproducible myocardial deformation, aiding in the much-needed standardization of complete spatiotemporal strain calculations.

Short-Term Myopic Defocus and Choroidal Thickness in Children and Adults.

Studies report conflicting findings regarding choroidal thickness changes in response to myopic defocus in humans. This study aimed to investigate the choroidal response to myopic defocus in children and adults using automated analysis. Participants (N = 46) were distance-corrected in both eyes and viewed a movie on a screen for 10 minutes. Two optical coherence tomography (OCT) radial scans were collected for each eye, then +3 diopters was added to one eye. Participants continued to watch the movie, OCT scans were repeated every 10minutes for 50minutes, and then recovery was assessed at 60 and 70minutes. Defocus was interrupted for approximately two out of each 10minutes for OCT imaging. OCT images were analyzed using an automated algorithm and trained neural network implemented in MATLAB to determine choroidal thickness at each time point. Repeated-measures ANOVA was used to assess changes with time in three age groups (6-17, 18-30, and 31-45 years) and by refractive error group (myopic and nonmyopic). Choroidal thickness was significantly associated with spherical equivalent refraction, with the myopic group having a thinner choroid than the nonmyopic group (P<0.001). With imposed myopic defocus, there were no significant changes in choroidal thickness at any time point for any age group and for either refractive error group (P>0.05 for all). Findings demonstrate that, using the described protocol, the choroidal thickness of children and adults does not significantly change in response to short-term, full-field myopic defocus, in contrast to several previously published studies.

Presence of subfoveal hyperreflective dots as an anatomic and functional prognostic biomarker in macular holes

ObjectiveTo evaluate the presence of subfoveal hyperreflective dots (SfHD) using optical coherence tomography (OCT) in macular holes (MH) and establish whether there is a relationship with postoperative anatomical and functional outcomes. MethodsAn observational cross-sectional study was conducted at the Dr. Elías Santana Hospital. Sixty-eight eyes of 67 patients with a tomographic diagnosis of full-thickness MH who underwent pars plana vitrectomy (PPV) and internal limiting membrane (ILM) peeling were included. Preoperative and postoperative measurements were obtained using radial macular scans and HD raster scans with Optovue and Cirrus 5000 (Zeiss) OCT machines. The main outcome measures were anatomical closure by OCT and functional outcome through best-corrected visual acuity (BCVA). ResultsThe anatomical closure rate in our study was 63%. MHs that failed to achieve anatomical closure exhibited a higher number of hyperreflective dots and worse postoperative BCVA. A statistically significant association was found between exposed retinal pigment epithelium (RPE) in microns and the number of SfHD (P = .001). ConclusionSfHD is a common tomographic finding in MH, and the presence of a higher number of these points is associated with poorer anatomical and functional outcomes. This imaging finding is a potential prognostic biomarker in this pathology.

Presencia de puntos hiperreflectivos subfoveales como biomarcador pronóstico anatómico y funcional en agujero macular

ObjectiveTo evaluate the presence of subfoveal hyperreflective dots (SfHD) using optical coherence tomography (OCT) in macular holes (MH) and establish whether there is a relationship with postoperative anatomical and functional outcomes. MethodsAn observational cross-sectional study was conducted at the Dr. Elías Santana Hospital. Sixty-eight eyes of 67 patients with a tomographic diagnosis of full-thickness MH who underwent pars plana vitrectomy (PPV) and internal limiting membrane (ILM) peeling were included. Preoperative and postoperative measurements were obtained using radial macular scans and HD raster scans with Optovue and Cirrus 5000 (Zeiss) OCT machines. The main outcome measures were anatomical closure by OCT and functional outcome through best-corrected visual acuity (BCVA). ResultsThe anatomical closure rate in our study was 63%. MHs that failed to achieve anatomical closure exhibited a higher number of hyperreflective dots and worse postoperative BCVA. A statistically significant association was found between exposed retinal pigment epithelium (RPE) in microns and the number of SfHD (p=0.001). ConclusionSfHD is a common tomographic finding in MH, and the presence of a higher number of these points is associated with poorer anatomical and functional outcomes. This imaging finding is a potential prognostic biomarker in this pathology.

Comparisons of choroidal thickness and volume in eyes with central serous chorioretinopathy to that of control eyes determined by ultra-widefield optical coherence tomography.

To compare choroidal thickness and volume in eyes with central serous chorioretinopathy (CSC) and healthy control eyes over a wide area of the fundus using ultra-widefield optical coherence tomography (UWF-OCT). Thirty-three eyes of 29 patients with CSC and 36 eyes of 21 healthy controls were examined retrospectively. Choroidal images were obtained with a prototype UWF-OCT device with a field of view of 105° or approximately 31.5-mm wide by 10.9-mm deep. Choroidal thickness and volume were measured in the images of 12 radial scans (every 15°) from the horizontal scan. The "new index" of the extent of focal choroidal protrusion was defined as the maximum steepness of choroidal thickness (MSCT). Choroidal volume in CSC eyes was significantly larger than in control eyes within the central 50° (P < 0.001). However, there was no significant difference in choroidal volume in the peripheral 50 to 105° (P = 0.071). The MSCTs were significantly steeper in CSC eyes than in control eyes at scan lines 1, 6, 7, 8, and 10 (P < 0.01, P < 0.001, P < 0.05, P < 0.01, P < 0.05). The choroid in CSC eyes was thickened only at the posterior pole, and its protrusion was significant mainly in the vertical direction. Focal choroidal thickening at the posterior pole, which we speculate includes congenital scleral changes, may affect the pathophysiology of CSC.

Vascular changes of the choroid and their correlations with visual acuity in diabetic retinopathy.

To investigate changes in the choroidal vasculature and their correlations with visual acuity in diabetic retinopathy (DR). The cohort was composed of 225 eyes from 225 subjects, including 60 eyes from 60 subjects with healthy control, 55 eyes from 55 subjects without DR, 46 eyes from 46 subjects with nonproliferative diabetic retinopathy (NPDR), 21 eyes from 21 subjects with proliferative diabetic retinopathy (PDR), and 43 eyes from 43 subjects with clinically significant macular edema (CSME). Swept-source optical coherence tomography (SS-OCT) was used to image the eyes with a 12-mm radial line scan protocol. The parameters for 6-mm diameters of region centered on the macular fovea were analyzed. Initially, a custom deep learning algorithm based on a modified residual U-Net architecture was utilized for choroidal boundary segmentation. Subsequently, the SS-OCT image was binarized and the Niblack-based automatic local threshold algorithm was employed to calibrate subfoveal choroidal thickness (SFCT), luminal area (LA), and stromal area (SA) by determining the distance between the two boundaries. Finally, the ratio of LA and total choroidal area (SA + LA) was defined as the choroidal vascularity index (CVI). The choroidal parameters in five groups were compared, and correlations of the choroidal parameters with age, gender, duration of diabetes mellitus (DM), glycated hemoglobin (HbA1c), fasting blood sugar, SFCT and best-corrected visual acuity (BCVA) were analyzed. The CVI, SFCT, LA, and SA values of patients with DR were found to be significantly lower compared to both healthy patients and patients without DR (P< 0.05). The SFCT was significantly higher in NPDR group compared to the No DR group (P < 0.001). Additionally, the SFCT was lower in the PDR group compared to the NPDR group (P = 0.014). Furthermore, there was a gradual decrease in CVI with progression of diabetic retinopathy, reaching its lowest value in the PDR group. However, the CVI of the CSME group exhibited a marginally closer proximity to that of the NPDR group. The multivariate regression analysis revealed a positive correlation between CVI and the duration of DM as well as LA (P < 0.05). The results of both univariate and multivariate regression analyses demonstrated a significant positive correlation between CVI and BCVA (P = 0.003). Choroidal vascular alterations, especially decreased CVI, occurred in patients with DR. The CVI decreased with duration of DM and was correlated with visual impairment, indicating that the CVI might be a reliable imaging biomarker to monitor the progression of DR.

Diagnosis of posterior staphyloma using the radius of steepest curvature among retinal pigment epithelium segmentation line measured by optic coherent tomography

PurposeTo investigate a novel marker to diagnose posterior staphylomas by measuring the radius of the steepest curvature on the retinal pigment epithelium (RPE) segmentation line using optical coherence tomography (OCT).Study DesignRetrospective Cross-sectional Study.MethodsThe authors developed a prototype software to measure the radius of curvature on the RPE segmentation line of OCT. Twelve images of 9-mm radial OCT scans were used. The radius of curvature was measured at the steepest area of the RPE segmentation line, and the macular curvature (MC) index was calculated based on its reciprocal. Based on the wide-field fundus findings, the study sample was divided into three groups: definite posterior staphyloma, no posterior staphyloma, and undetermined. The differences of MC index among the groups and the correlation between the MC index, age, and axial length were analyzed.ResultsThe present study analyzed 268 eyes, with 54 (20.1%) with definite posterior staphyloma, 202 (75.4%) with no posterior staphyloma, and 12 (4.5%) with undetermined disease status. A maximum MC index of 37.5 was observed in the group with no posterior staphyloma, which was less than the minimum MC index of 42.7 observed in the group with definite posterior staphyloma. The MC index had strong correlations with the axial length and age in eyes with high myopia.ConclusionsEyes with posterior staphyloma have a steeper curvature than those with radius 8.44 mm, while eyes without posterior staphyloma do not. MC index 40 (radius 8.44 mm) might act as a reference to distinguish between those with and those without posterior staphyloma.

Glaucoma detection model by exploiting multi-region and multi-scan-pattern OCT images with dynamical region score.

Currently, deep learning-based methods have achieved success in glaucoma detection. However, most models focus on OCT images captured by a single scan pattern within a given region, holding the high risk of the omission of valuable features in the remaining regions or scan patterns. Therefore, we proposed a multi-region and multi-scan-pattern fusion model to address this issue. Our proposed model exploits comprehensive OCT images from three fundus anatomical regions (macular, middle, and optic nerve head regions) being captured by four scan patterns (radial, volume, single-line, and circular scan patterns). Moreover, to enhance the efficacy of integrating features across various scan patterns within a region and multiple regional features, we employed an attention multi-scan fusion module and an attention multi-region fusion module that auto-assign contribution to distinct scan-pattern features and region features adapting to characters of different samples, respectively. To alleviate the absence of available datasets, we have collected a specific dataset (MRMSG-OCT) comprising OCT images captured by four scan patterns from three regions. The experimental results and visualized feature maps both demonstrate that our proposed model achieves superior performance against the single scan-pattern models and single region-based models. Moreover, compared with the average fusion strategy, our proposed fusion modules yield superior performance, particularly reversing the performance degradation observed in some models relying on fixed weights, validating the efficacy of the proposed dynamic region scores adapted to different samples. Moreover, the derived region contribution scores enhance the interpretability of the model and offer an overview of the model's decision-making process, assisting ophthalmologists in prioritizing regions with heightened scores and increasing efficiency in clinical practice.

Magnetic resonance imaging of monocrotaline-induced pulmonary hypertension in rats using radial scanning with retrospective gating

Magnetic resonance imaging of monocrotaline-induced pulmonary hypertension in rats using radial scanning with retrospective gating

Research on the technology of casing inspection through tubing in the Saertu Development Zone of Daqing Oilfield

With the further development of Daqing Oilfield, the occurrence of widespread casing damage in the Saertu Development Area has been on the rise annually.In order to promptly prevent, detect and address casing damage, the management departments of the oil extraction plants must schedule regular casing inspection operations. This approach not only raises production costs but also prolongs the well shutdown period, further impacting crude oil output.This article focuses on the technical needs of oilfield development and has developed tubing and casing detection technology, the radial magnetic scanning system is integrated with the sixteen arm wellbore diameter, the synchronous tubing and casing inspection instrument represents the latest in concurrent inspection technology, developed specifically for the technical demands of oilfield development Without displacing the tubing column, it simultaneously captures data on tubing inner diameter, tubing continuity, the extent of casing damage via magnetic scanning, and continuous 3D imaging of the tubing at standard inspection speeds, the workload of checking and matching tasks were significantly reduced. Between 2022 and 2023, the through-tubing casing inspection technology was utilized in 525 wells, with 356 wells verified by mobilizing the tubing column, achieving a predictive accuracy of 87.6% and generating economic benefits of 69.6 million yuan.

Analysis of macula structural changes in Moyamoya disease using AI-assisted OCT

ObjectiveTo investigate macula structure thickness and volume changes in patients with moyamoya disease (MMD). MethodIn this cross-sectional study, we used artificial intelligence (AI) -assisted optical coherence tomography (OCT) to analyze the thickness and volume of macula in Moyamoya patients. ETDRS zoning divides the macula into nine different regions. In 15 patients with radial scanning OCT, the average thickness and volume of retina, RNFL, GCL, and choroid in these regions were measured. In 30 patients with radial or horizontal scanning OCT, based on the anatomical structure, the macula is divided into seven segments. Mean Sattler layer–choriocapillaris complex thickness (SLCCT), Haller layer thickness, and total choroidal thickness were measured for each segment using AI-assisted OCT. ResultsWe recruited 30 patients (59 eyes) with MMD. In the 15 patients (29 eyes) who underwent radial scanning OCT, no significant change in retina, RNFL, GCL, and choroidal thickness was identified between the two groups (p > 0.05). There was no significant change in retina, RNFL, or choroidal volume between the two groups in different ETDRS macula regions (p > 0.05). The GCL volume in the macula's inner ring nasal portion (IN) was significantly lower. SLCCTs were considerably reduced in six macula regions in moyamoya groups (p < 0.05). There was no statistically significant change in Haller layer thickness. Only the nasal perifovea (PE_N) exhibited a significant variation in choroidal thickness. The Moyamoya group showed reduced choroidal thickness in PE_N segment. ConclusionIn patients with MMD, there is thinning of the Sattler layer–choriocapillaris complex in the choroid.

Subfoveal and Parafoveal Choroidal Thickening in Patients with Keratoconus Using the ETDRS Grid on Swept-Source OCT.

There is growing evidence that confirms morphological changes in the posterior structures in patients with keratoconus (KC); however, isolated alterations could have been missed. This study assesses choroidal thickness (CT) in the fovea and beyond in KC eyes. This prospective case-control and non-randomized study enrolled 107 eyes, 62 eyes of 62 patients with KC, and 45 age-matched eyes of 45 control subjects with axial length in the range of 22-26mm. Swept-source optical coherence tomography (SS-OCT) was performed to manually measure the subfoveal choroidal thickness (SCT) using a single-line scan. CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid using the 12-lines radial scan pattern. A two-way repeated-measures analysis of variance (ANOVA) was conducted to evaluate CT variations among macular eccentricity, parafoveal area, and the interaction between both factors. CT was compared in all parafoveal areas between groups and subgroups of KC. SCT was significantly thicker in KC eyes (357 ± 57µm) than in healthy eyes (325 ± 63µm) (p < 0.001). Significant choroidal thickening was observed in the central ring and outer and inner rings of the temporal, superior, and inferior parafoveal macular areas (p < 0.001), except in the outer ring of the nasal macular zone (p > 0.05) of KC compared to healthy eyes. The CT significantly decreased from the center to the outer ring regardless of the presence of KC (p < 0.001). The choroid in the nasal macular zone was significantly thinner than that in the temporal, superior, and inferior parafoveal areas (p < 0.001). The choroidal structure increased its thickness not only in the subfoveal area, but also in eight parafoveal areas of the ETDRS grid encompassing a wider area of macular examination. These findings demonstrate and corroborate that keratoconus is not a purely corneal disease. Furthermore, it confirms the role that the choroidal structure has in the pathophysiology of keratoconus.

Peripapillary intrachoroidal cavitation at the crossroads of peripapillary myopic changes.

To analyze the prevalence of peripapillary intra-choroidal cavitation (PICC) in eyes with gamma peripapillary atrophy (γPPA), in eyes with peripapillary staphyloma (PPS) and in those combining γPPA and PPS and to analyze border tissue discontinuity in PICC. This prospective cross-sectional non interventional study included highly myopic eyes. Non-highly myopic eyes were used as control. Radial and linear scans centered on the optic nerve head were performed using spectral-domain optical coherence tomography. Variables were analyzed along the twelve hourly optical coherence tomography sections in both eyes of each subject. A total of 667 eyes of 334 subjects were included: 229 (34.3%) highly myopic eyes and 438 (65.7%) non highly myopic eyes. The mean age of the highly myopic group was 48.99±17.81y. PICC was found in a total of 40 eyes and in 13.2% (29/220) of highly myopic eyes. PICC was found in 10.4% (40/386) of eyes with γPPA, in 20.5% (40/195) of eyes with PPS and in 22.7% (40/176) of those combining γPPA and PPS. All the eyes with PICC showed the co-existence of γPPA and PPS whereas none of the eyes presenting only one of these entities exhibited PICC. A border tissue discontinuity in the γPPA area was found in all eyes with PICC. We confirm the presence of a border tissue discontinuity in the γPPA area of all eyes with PICC. These findings suggest the involvement of mechanical factors in the pathogenesis of PICC which may contribute to PICC-related visual field defects.

Displacement of the Lamina Cribrosa With Acute Intraocular Pressure Increase in Brain-Dead Organ Donors.

To examine deformations of the optic nerve head (ONH) deep tissues in response to acute elevation of intraocular pressure (IOP). Research-consented brain-dead organ donors underwent imaging by spectral domain optical coherence tomography (OCT). OCT imaging was repeated while the eye was sequentially maintained at manometric pressures of 10, 30, and 50mm Hg. Radial scans of the ONH were automatically segmented by deep learning and quantified in three dimensions by a custom algorithm. Change in lamina cribrosa (LC) depth and choroidal thickness was correlated with IOP and age by linear mixed-effect models. LC depth was computed against commonly utilized reference planes. Twenty-six eyes from 20 brain-dead organ donors (age range, 22-62years; median age, 43years) were imaged and quantified. LC depth measured against a reference plane based on Bruch's membrane (BM), BM opening, and an anterior sclera canal opening plane showed both a reduction and an increase in LC depth with IOP elevation. LC depth universally increased in depth when measured against a sclera reference plane. Choroidal (-0.5222µm/mm Hg, P < 0.001) and retinal nerve fiber layer thickness (-0.0717µm/mm Hg, P < 0.001) significantly thinned with increasing IOP. The magnitude of LC depth change with IOP was significantly smaller with increasing age (P < 0.03 for all reference planes). LC depth changes with IOP reduce with age and are significantly affected by the reference plane of choice, which highlights a need for standardizing LC metrics to properly follow progressive remodeling of the loadbearing tissues of the ONH by OCT imaging and for the definition of a reference database.

Identification of Choroidal Vascular Abnormalities in Patients with Hereditary Hemorrhagic Telangiectasia (HHT)

Purpose: To evaluate the frequency of ocular imaging in patients with HHT at a large academic medical institution; characterize the choroidal vascular changes on indocyanine green angiography (ICGA) and optical coherence tomography (OCT); and explore the relationship of these ocular features with HHT genotypes and systemic manifestations. Methods: Retrospective review of patients with HHT who were seen in the Mayo Clinic ophthalmology department between 2011 to 2021. Results: Of the 71 patients with HHT identified, 7 (10%) individuals had qualifying imaging defined as radial or raster spectral-domain OCT scans and/or ICGA. 4 (57%) patients had enlarged choroidal vessels detected on OCT and/or ICGA. 3 (43%) patients had retinal telangiectasias. Patients with choroidal changes (mean age 67 years) had the endoglin gene mutation, gastrointestinal arteriovenous malformations (AVM), and facial and mucocutaneous telangiectasias. In contrast, patients without choroidal changes (mean age 45 years) included the activin A receptor type-like kinase 1 gene mutation. Conclusion: Only a small proportion of patients with HHT undergo ophthalmic imaging at our institution. The presence of choroidal abnormalities is associated with the endoglin gene mutation, older age, corroborating retinal vascular changes, and increased systemic manifestations.

A Stable, Efficient, and High-Precision Non-Coplanar Calibration Method: Applied for Multi-Camera-Based Stereo Vision Measurements.

Traditional non-coplanar calibration methods, represented by Tsai's method, are difficult to apply in multi-camera-based stereo vision measurements because of insufficient calibration accuracy, inconvenient operation, etc. Based on projective theory and matrix transformation theory, a novel mathematical model is established to characterize the transformation from targets' 3D affine coordinates to cameras' image coordinates. Then, novel non-coplanar calibration methods for both monocular and binocular camera systems are proposed in this paper. To further improve the stability and accuracy of calibration methods, a novel circular feature points extraction method based on region Otsu algorithm and radial section scanning method is proposed to precisely extract the circular feature points. Experiments verify that our novel calibration methods are easy to operate, and have better accuracy than several classical methods, including Tsai's and Zhang's methods. Intrinsic and extrinsic parameters of multi-camera-systems can be calibrated simultaneously by our methods. Our novel circular feature points extraction algorithm is stable, and with high precision can effectively improve calibration accuracy for coplanar and non-coplanar methods. Real stereo measurement experiments demonstrate that the proposed calibration method and feature extraction method have high accuracy and stability, and can further serve for complicated shape and deformation measurements, for instance, stereo-DIC measurements, etc.