Ring Diameter Research Articles

Topographic analysis of retinal and choroidal microvasculature according to diabetic retinopathy severity using optical coherence tomography angiography

To investigate the topographic changes in the retinal capillary plexus and the choriocapillaris according to the severity of diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA). Subjects were recruited and classified into one of the following four groups: normal controls (n = 52), diabetes without DR (n = 49), non-proliferative DR (n = 51) and proliferative DR (n = 38). Using OCTA, the superficial capillary plexus (SCP), deep capillary plexus (DCP) and the choriocapillaris vessel densities were measured and compared in different macular areas: the fovea (1-mm diameter circular area), parafovea (1-3-mm diameter ring) and perifovea (3-6-mm ring). With DR progression, vessel densities in the SCP and DCP as well as the choriocapillaris decreased, while the foveal avascular zone area increased (p < 0.001 for all). Compared with controls, the SCP and DCP vessel densities of the diabetes without DR group were decreased in all areas of the macula (p < 0.020 for all), while the choriocapillaris vessel density was decreased only in the perifoveal area (p = 0.823 for the foveal area; p = 0.631 for the parafoveal area; p = 0.039 for the perifoveal area). Multivariate linear regression analyses revealed that all retinal and choroidal microvascular indices were significantly associated with the DR severity. The morphological changes in the macular microvasculature were associated with DR severity. Also, the changes were found to be more vulnerable in the retinal capillary plexuses than the choriocapillaris.

Isolation, identification, and whole genome sequence analysis of the alginate-degrading bacterium Cobetia sp. cqz5-12

Alginate-degrading bacteria or alginate lyases can be used to oligomerize alginate. In this study, an alginate-degrading bacterium with high alginolytic activity was successfully screened by using Sargassum fusiforme sludge. When the strain was grown on a plate containing sodium alginate, the transparent ring diameter (D) was 2.2 cm and the ratio (D/d) of transparent ring diameter to colony diameter (d) was 8.8. After 36 h in culture at a temperature of 28 °C shaken at 150 r/min, the enzymatic activity of the fermentation supernatant reached 160 U/mL, and the enzymatic activity of the bacterial precipitate harvested was 2,645 U/mL. The strain was named Cobetia sp. cqz5-12. Its genome is circular in shape, 4,209,007 bp in size, with a 62.36% GC content. It contains 3,498 predicted coding genes, 72 tRNA genes, and 21 rRNA genes. The functional annotations for the coding genes demonstrated that there were 181 coding genes in the genome related to carbohydrate transport and metabolism and 699 coding genes with unknown functions. Three putative coding genes, alg2107, alg2108 and alg2112, related to alginate degradation were identified by analyzing the carbohydrate active enzyme (CAZy) database. Moreover, proteins Alg2107 and Alg2112 were successfully expressed and exhibited alginate lyase activity.

Enhanced nonparametric control charts under simple and ranked set sampling schemes

Investigation and removal of unnatural variation in the processes of manufacturing, production and services require application of statistical process control. Control charts are the most famous and commonly used statistical process control tools to trace changes in the manufacturing and nonmanufacturing processes parameter(s). The nonparametric control charts become necessary when the distribution of underlying process is unknown or questionable. The nonparametric charts are robust alternative along with holding property of quick shift detection ability in process parameter(s). In this article, we have proposed nonparametric double exponentially weighted moving average chart based on Wilcoxon signed rank test under simple and ranked set sampling schemes for efficient monitoring of the process location. The proposed control charts are compared with classical exponentially weighted moving average, double exponentially weighted moving average, nonparametric exponentially weighted moving average sign, nonparametric exponentially weighted moving average signed rank, nonparametric cumulative sum signed rank charts using average run length and some other characteristics of run length distribution as performance measures. Comparison reveals that the proposed control charts performs better to detect all kinds of shifts in the process location than existing counterparts. A real-life application related to manufacturing process (the variable of interest is the diameter of piston ring) is also provided for the practical implementation of the proposed chart.

Formation dynamics of exciton-polariton vortices created by nonresonant annular pumping

We study the spontaneous formation of exciton polariton vortices in an all-optical non-resonantly excited annular trap, which is formed by ring-shaped subpicosecond laser pulses. Since the light emitted by these vortices carries orbital angular momentum (OAM) corresponding to their topological charge, we apply a dedicated OAM spectroscopy technique to detect the OAM of the measurement signal with picosecond time resolution. This allows us to identify the formation of OAM modes and investigate the dynamics of the vortex formation process. We also study the power dependence of this process and how the ring diameter influences the formation of OAM modes.

Laparoscopic assisted percutaneous internal ring suturing for inguinal hernia repair in pediatrics

Several laparoscopic techniques used in treatment of pediatric inguinal hernia differ in their approach to the internal inguinal ring, suturing and knotting techniques, number of ports, endoscopic instruments used and hernia sac dissection technique. The aim of this study was to evaluate efficacy and safety of laparoscopic assisted percutaneous internal ring suturing for inguinal hernia repair in pediatrics. Laparoscopic assisted percutaneous internal ring suturing was performed under general endotracheal anesthesia on 54 children with 64 hernias during the period from July 2018 to June 2019. Under laparoscopic-guided vision a 2-0 Prolene® thread inside an 18-gauge epidural needle was placed through the abdominal wall into the peritoneal cavity, then the thread passed under the peritoneum around the internal ring. The knot was tightened from outside and placed in the subcutaneous space. The mean operative time was 14.18 min for unilateral and 21.2 min for bilateral hernias. Cosmetic results are excellent with almost invisible scars. There were no intraoperative and six postoperative complications (recurrence in three cases, transient hydroceles in two boys and one patient had stitch sinus). Laparoscopic assisted percutaneous needle repair of congenital inguinal hernia seems to be a simple minimally invasive procedure in small ring diameter with excellent cosmetic results. But I do not recommend this technique due to high rate of complications and recurrence, also simplicity of the technique can be regarded as a hindrance to the surgeons in training from challenging their skills to be ready for the more complex scenarios.

Cell size sets the diameter of the budding yeast contractile ring

The formation and maintenance of subcellular structures and organelles with a well-defined size is a key requirement for cell function, yet our understanding of the underlying size control mechanisms is limited. While budding yeast cell polarization and subsequent assembly of a septin ring at the site of bud formation has been successfully used as a model for biological self-assembly processes, the mechanisms that set the size of the septin ring at the bud neck are unknown. Here, we use live-cell imaging and genetic manipulation of cell volume to show that the septin ring diameter increases with cell volume. This cell-volume-dependence largely accounts for modulations of ring size due to changes in ploidy and genetic manipulation of cell polarization. Our findings suggest that the ring diameter is set through the dynamic interplay of septin recruitment and Cdc42 polarization, establishing it as a model for size homeostasis of self-assembling organelles.

Software simulation of residual stresses in high frequency longitudinal welded pipes

Abstract - This paper presents results obtained via experimental measurements of residual stresses in the cross sections of longitudinal welded pipes. The experiment was carried out in different dimensions and thickness of the pipes where it is noticed that the smaller the diameter of the pipe, the greater the residual stresses because the degree of deformation during the production of pipes with smaller diameter is greater. Residual stresses are measured with strain gages set upon the outside wall of the pipes. The results received from the gages show considering amount of stress captured in the pipe wall because of cold plastic formation process [1]. After cutting the rings, their opening is recorded, which is variable and depends on several parameters such as: ring diameter, thickness, type of material and its reinforcement as well as the degree of plastic deformation when forming the pipe sheath [2]. The difference in the display of the measuring tape when the ring is in the open and closed position is the residual deformation that corresponds to the residual stresses that occurs in the ring.&#x0D;

Cyclic behavior of an energy dissipation system with steel dual-ring dampers (SDRDs)

In this paper, the energy absorption system of a steel dual-ring damper (SDRD) is presented and its cyclic behavior is studied analytically and numerically. The energy dissipation mechanism of the SDRD occurs through the formation of moment plastic hinges in steel rings. The purpose of this study is to provide an analytical relationship for estimating the yield strength, yield displacement, and elastic stiffness of the proposed SDRDs. An analytical relationship is presented for calculating the elastic stiffness of SDRDs using the structural analysis method. Also, using plastic analysis and considering the mechanism of plastic hinge formation, a relation has been obtained for estimating the yield strength and yield displacement of SDRDs. Extensive parametric studies have been carried out using a nonlinear finite element method to examine the accuracy of the obtained analytical relationships. The parametric studies include investigating the influence of thickness parameters as well as the inner and outer ring diameters of SDRDs. Nonlinear static analysis is employed to analyze finite element (FE) models under cyclic loading. Also, validation of the results of the finite element models is performed with experimental specimens. There is a good agreement between the results of yielding capacity, yielding displacement, and elastic stiffness of the analytical relationship and FE models parametric studies. The results of the parametric models and the proposed relationship reveal that with elevation of the steel ring diameter, the energy dissipation has increased. Also, as the diameter to thickness (D/t) ratio increases, ductility and equivalent viscous damping ratio are reduced.

Impacts of sampling design on the abundance estimation of Portunus trituberculatus using crab pots

Fishery-independent surveys can provide high-quality data and support fishery assessment and management. Optimization of sampling design is crucial to increase the quality of fishery surveys. Crab pots are important fishing gears used to catch crabs. We analyzed the impacts of sampling design of crab pots on the abundance of Portunus trituberculatus in the Changjiang (Yangtze) River estuary to the Hangzhou Bay and its adjacent waters in East China Sea. The crab pots were cylindrical, 240 mm in height and 600 mm in diameter of the iron ring. Our sampling designs (including fixed-station sampling, simple random sampling, stratified fixed-station sampling, and stratified random sampling), three number of stations (9, 16, and 24), and three numbers of crab pots (500, 1 000, and 3 000) were simulated and compared with the “true” abundance that obtained from bottom trawl surveys in the study area in 2007. The scenarios with 16 stations were set in stratification as a control group for comparison with unstratified designs. Results show that simple random sampling can obtain more stable results than fixed-station sampling in the abundance estimation of P. trituberculatus. In addition, stratified sampling resulted in more accurate abundance than unstratified sampling. The accuracy of the simulated results improved with the increase of the number of stations. No remarkable differences in the results were found among the scenarios of different number of crab pots at each station. However, resource-intensive areas exerted great impacts on simulation results. Thus, prior information or pre-survey results about resource abundance and density distribution are necessary. This study may serve as a reference for future sampling designs of crab pots of P. trituberculatus and other species.

Detection of lysozyme in body fluid based on two-dimensional colloidal crystal sensor

It is significant to detect lysozyme both in fundamental research and in clinical practice, since its concentration in body fluid is associated with many diseases. In this study, a new kind of sensor for rapid screening the lysozyme was fabricated based on the two-dimensional (2D) polystyrene colloidal crystal array together with the optimized hydrogel containing acrylamide-based functional groups. Distinct hydrogel volume shrink was observed due to the hydrogel crosslink induced by the functional ligand–protein interactions while the protein bound to the sensor. Therefore, the analyte concentration could be accessed by of the lattice spacing of the 2D colloidal crystal array, which was detected by a change in the Debye diffraction ring diameter. The lysozyme concentration could be easily monitored by measuring the diameter of the Debye diffraction ring in the pathophysiologic range. The particle spacing of 2D colloidal crystal hydrogel sensor increased to about 22 nm while lysozyme concentration increased from zero to 1.0 mg/mL, meanwhile the structural color of the sensor blue shifted from red to yellow. The detection limit was confirmed as 1.38 × 10−3 mg/mL. The selective response to other common proteins in body fluids was also exhibited, indicating the great selective response properties to lysozyme. In addition, the 2D colloidal crystal hydrogel sensor was reusable to detect the lysozyme solution reversibly due to its thermal sensitivity. Moreover, the determination of lysozyme in artificial tears and human urine samples by this sensor demonstrated its feasibility in potential clinical analysis diagnosis.

Analysis of deformation behavior and microscopic characteristics of asphalt mixture based on interface contact-slip test

To analyze the slip deformation behavior of asphalt mixture, an interface contact-slip tester of asphalt mixture was developed in this investigation. Four evaluation indicators, including the maximum slip shear stress τsl, the slip shear strain εS, the slip failure modulusES and the interface slip energy index ET, were proposed. According to the correlation and sensitivity analysis, the optimum evaluation indicator was determined. By analyzing the variation coefficient of test results, the key experiment parameters were recommended. The gray binarization method of MATLAB software was adopted to process the slip failure surface of specimen, and the bonding ratio Bn was calculated to analyze the effect of asphalt bonding on strength formation. Based on the deformation curve, the slip deformation behavior of asphalt mixture and the influence factors were analyzed from the microscopic perspective. Results obtained indicated that the optimum test conditions are the loading head of 28.5 mm, the diameter of the support ring of 80 mm, and the loading rate of 5 mm/min. The τsl was selected as the evaluation indicator of slip deformation behavior due to the best correlation with RD, good stability and sensitivity. The bonding effect of asphalt binder is greater than particle contact effect for suspended-dense asphalt mixture. The slip deformation of asphalt mixture can be divided into five stages, including densification, elastic deformation, viscoelastic deformation, initial cracking and plasticity slip deformation. The contact from coarse aggregates and bonding from asphalt binder can enhance the slip deformation resistibility. While the interference of fine particles and the lubrication of asphalt can accelerate the slip deformation of asphalt mixture.

Tuning the resolution and depth of field of a lens using an adjustable ring beam illumination

A pair of axicons with an adjustable separation between them is used to generate a variable diameter ring beam with high efficiency. This beam illuminates a lens to produce quasi-diffraction-free beams with a tunable spot size and depth of field. We studied the generated beam characteristics while changing either the ring diameter or its thickness. Such a scheme has applications in adjustable imaging, including nondiffracting beam microscopy, material processing with an irradiance above a certain threshold value, and particle trapping/manipulation.

Numerical investigation on the effect of toroidal rings in a parabolic trough receiver with the operation of gases: An energy and exergy analysis

In this study, the influence of toroidal rings in an absorber tube of a solar parabolic trough collector (SPTC) operating with air, carbon dioxide (CO2) and helium (He) is investigated with detailed energy and exergy analysis. Nine different cases of the modified absorber have been investigated and compared with the smooth absorber tube (SAT). Under varying fluid flow rate and inlet temperatures, the heat transfer tendency in the absorber tube has been numerically studied and validated. The modified absorber having a diameter ratio (H) of 0.88 and 0.90 are the thermally and exergetically efficient optimal cases, respectively, with ˋH′ being the ratio of inner to outer diameter of the toroidal ring. The bottom periphery temperature difference for the case H = 0.88 operating with He is found to be 8 K, and it is the lowest among all the examined cases. A maximum exergy efficiency of about 41.23% is achieved for the case H = 0.90 with He. For thermal efficiency, air has higher magnitude with tremendous increase in pressure drop followed by CO2 and He. Hence, the outcomes reveal that He is the appropriate working fluid exhibiting higher exergetic performance and lower pressure drop followed by CO2 and air.

In-vitro antibacterial effect of tea polyphenols combined with common antibiotics on multidrug-resistant Klebsiella pneumoniae.

To investigate the bactericidal effect of tea polyphenols on multidrug resistant Klebsiella pneumoniae and its antibacterial efficacy in combination with common antibiotics, and to explore its mechanism. The VITEK 2 Compact automatic microbial identification system was used to identify 20 strains of Klebsiella pneumoniae isolated from clinical isolates. The KB method was used to detect sensitivity of common drugs such as imipenem, piperacillin, piperacillin/tazobactam and cefepime, cefotaxime and ceftazidime; agar dilution method was used for detection of minimum inhibitory concentration (MIC) of tea polyphenols; the variation of the diameter of the antibacterial ring after different concentrations (0.25 MIC, 0.5 MIC) of tea polyphenols in combination with commonly used antibacterial drugs was detected to judge the feasibility of the inhibition of the multidrug-resistant Klebsiella pneumoniae by the combination of tea polyphenols and commonly used antibacterial drugs. Congo red and crystal violent staining was used to detect the impact on bacterial biofilm formation and extracellular mucus-like substance (slime). The K-B values of 20 strains of Klebsiella pneumoniae against common antibiotics were 6-14 mm; the MIC of tea polyphenols against 20 strains of multi-drug resistant Klebsiella pneumoniae was 1024 ug/mL; 0.5 MIC tea polyphenols can increase the diameter of the bacteriostatic ring of imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime by 3-28 mm. Tea polyphenols at sub-inhibitory concentrations significantly inhibited the production of Klebsiella pneumoniae biofilm and extracellular mucus (slime). Tea polyphenols could be used in combination with commonly used antibiotics (imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime) against multidrug-resistant Klebsiella pneumoniae. It has a synergistic bactericidal effect and affects the formation of bacterial outer membrane and the production of extracellular slime-like substances (slime).

Comparative Analysis of Functional and Structural Decline in Retinitis Pigmentosas.

Retinitis pigmentosa (RP) is a category of inherited retinal dystrophies that is best prognosticated using electroretinography (ERG). In this retrospective cohort study of 25 patients with RP, we evaluated the correlation between 30 Hz flicker ERG and structural parameters in the retina. Internationally standardized 30 Hz flicker ERG recordings, short-wavelength autofluorescence (SW-AF), and spectral domain–optical coherence tomography (SD-OCT) were acquired at two visits at least one year apart. Vertical and horizontal hyperautofluorescent ring diameter measurements with SW-AF, as well as ellipsoid zone (EZ) line width measurements with SD-OCT, were used as structural parameters of disease progression. The 30 Hz flicker ERG amplitude decreased by 2.2 ± 0.8 µV/year (p = 0.011), while implicit times remained unchanged. For SD-OCT, the EZ line decreased by 204.1 ± 34.7 µm/year (p < 0.001). Horizontal and vertical hyperautofluorescent ring diameters decreased by 161.9 ± 25.6 µm/year and 146.9 ± 34.6 µm/year, respectively (p = 0.001), with SW-AF. A correlation was found between the progression rates of the 30 Hz flicker amplitude recorded with Burian–Allen electrodes and both the horizontal ring diameter (p = 0.020) and EZ line (p = 0.044). SW-AF and SD-OCT, two readily available imaging techniques, may be used to prognosticate disease progression because of the reliability of their measurements and correlation with functional outcome.

In vitro performance of trans-valve left ventricular assist device installed at aortic valve position.

In this study, we developed a trans-valve left ventricular assist device (LVAD) that unites a rear-impeller axial-flow blood pump (AFBP) and a polymer membrane valve placed at the aortic valve position. The diameter and length of the rear impeller AFBP was 12 and 63mm, respectively. The polymer membrane valve was similar to the jelly-fish valve consisting of a valve leaflet made of silicone rubber (thickness 0.5mm), valve ring (diameter: 25mm), and valve spokes. The trans-valve LVAD was examined in a mock circulation. An implantable pulsatile flow (PF) VAD was connected to an atrial reservoir to simulate the left ventricle (LV), and the Hall valve was worn in the inflow port, and the trans-valve LVAD was placed in the outflow port as an outflow valve. When the motor rotational speed increasedto 26400rpm, the mean aortic flow increased from 4.2 to 5.3 L/min, mean aortic pressure increased from 83.4 to 100mm Hg, and mean motor current of the implantable PF VAD decreased from 1.18 to 0.94 A (unloading effect on LV -21%). The energy equivalent pressure increased from 85.2 to 102mm Hg, and surplus hemodynamic energy (SHE) decreased by -15.4% from the baseline. In conclusion, the trans-valve LVAD has an advantage of preserving pulsatility without any complicated mechanism and is a novel and promising LV support device.

Glycated albumin based photonic crystal sensors for detection of lipopolysaccharides and discrimination of Gram-negative bacteria

We present two types of two-dimensional (2D) photonic crystals (PC) hydrogel sensors based on glycated albumin (G-alb) as a proof-of-concept for utilizing recognition between G-alb and bacterial cell surface lipopolysaccharides (LPS) to detect and discriminate Gram-negative bacteria. The G-alb functionalized PC-G-alb hydrogel provides recognition of different LPS via hydrogen bonding and can discriminate different Gram-negative bacteria based on their LPS types. The hydrogel delivered LOD of 0.87 ng mL−1 for E.coli LPS, 153 CFU mL−1 for E.coli, 1.22 ng mL−1 for P.aeruginosa LPS and 225 CFU mL−1 for P.aeruginosa. On the other hand, LPS bioimprinted hydrogel (PC-G-alb-LPSimp) provides selective recognition of E.coli LPS with LOD 0.76 ng mL−1 and for E.coli 58 CFU mL−1, via generation of flexible specific cavities for E.coli and its LPS. The two hydrogels showed remarkable recoveries for both LPS and Gram-negative bacteria in the relevant samples of milk, orange juice, river water, and serum with a short response time of 6–12 min. In the binding process, the hydrogels shrink, and 2D PC particle spacing decreases with diffraction shift from green to blue. The diffraction shifts can be visually observed, measured through Debye’s diffraction ring diameter by a laser pointer or determined from a spectrometer.

2,4‐Dichlorophenol molecularly imprinted two‐dimensional photonic crystal hydrogels

AbstractA novel molecularly imprinted two‐dimensional (2‐D) photonic crystal hydrogels (MIPH) for sensitive and label‐free recognition of 2,4‐dichlorophenol (2,4‐DCP) was prepared. The 2‐D photonic crystal template was fabricated by using air‐water interface self‐assembly method. And then the template was embedded with molecularly imprinted polymer, which was synthesized with 2,4‐DCP as imprinted molecules, dimethyl sulfoxide as solvent, acrylic acid and acrylamide as functional monomers, N,N‐methylene bis acrylamide as cross‐linker, azobisisobutyronitrile as initiator. The imprinted molecules were removed by 0.01 M ammonia solution. The results indicated that the 2,4‐DCP molecularly imprinted 2‐D photonic crystal hydrogels has good response and recognition ability to 2,4‐DCP. When the molar ratio of cross‐linking density of MIPH is 2.3% and the molar ratio of imprinting molecule is 5.0%, the change of Debye ring diameter is the largest. The diameter of Debye ring increased by 7.1 mm when the concentration of 2,4‐DCP changed from 0 to 1 × 10−6 M, and the particle spacing of MIPH reduced 38 nm. In addition, the diameter of the Debye ring hardly changed in the solution of analogues of 2,4‐DCP such as, phenol, 2‐chlorophenol, 2,4,6‐trichlorophenol and so on, indicating that the MIPH has highly sensitivity and specificity.

Numerical and analytical investigation of cyclic behavior of steel ring dampers (SRDs)

In this study, the cyclic behavior of steel ring damper (SRD) was investigated through numerical and analytical methods. The present study was carried out to evaluate ductility and energy dissipation and providing an analytical equation to estimate the yielding capacity of SRDs. For this purpose, extensive parametric studies were performed using the finite element method. Parametric studies included investigating the effect of thickness, length, and diameter of steel ring on the behavior of SRD. Nonlinear static analysis was used to analyze finite element models under cyclic loading. Geometrical nonlinear behavior of materials and large deformations were considered in the modeling. Also, validation experiments were performed on experimental specimens for finite element models. Using the lower bound limit analysis and considering the effects of strain hardening, an equation was obtained to estimate the capacity of the steel ring. A good agreement was observed between results obtained from the measurement of yielding capacity using analytical equations and parametric studies. Also, yield force was found to be directly related to the length and diameter of the steel ring and yield stress. Results of parametric models and analytical relations showed that by increasing steel ring diameter, ductility and energy dissipation decreases and increases, respectively. Also, by increasing the diameter to thickness ratio (D/t), yield force, ductility, and energy dissipation decreased, respectively. • The cyclic behavior of steel ring damper (SRD) was investigated. • The numerical model of SRD was developed to predict the hysteresis behavior. • The effects of key parameters on the performance of the SDRs were studied. • Using the analytical method, was obtained the capacity of the SRDs. • A good agreement was observed between the results of numerical and analytical methods.

Multimodal Imaging Correlation of the Concentric Macular Rings Sign in Foveal Hypoplasia: A Distinctive Henle Fiber Layer Geometry

To expand the multimodal imaging correlation of the concentric macular rings (CMR) sign seen on ultra-widefield fundus photography in patients with foveal hypoplasia. Retrospective case series. Thirty-two patients with foveal hypoplasia who demonstrated the CMR sign on ultra-widefield fundus photography. Inclusion criterion was the presence of a CMR sign detected on ultra-widefield fundus photography. Noninvasive multimodal retinal imaging, including ultra-widefield fundus photography, structural OCT, near-infrared reflectance, and blue fundus autofluorescence, were investigated. Horizontal dense B-scans and en face OCT images were acquired. Evaluation of all patients (n= 32 patients) demonstrated a CMR sign on ultra-widefield fundus photography. Structural OCT scans were consistent with foveal hypoplasia in all patients. En face OCT images acquired at the level of the Henle fiber layer highlighted similar concentric rings around the location of the incipient fovea. The series of concentric rings was not visible at any other level of the macula. A significant correlation was found between the horizontal diameter of the largest outer ring and foveal hypoplasia grades (P < 0.0001). The CMR sign seen on ultra-widefield fundus imaging may be a distinctive feature of foveal hypoplasia and can support this diagnosis, especially in patients in whom OCT cannot be performed (patients with poor fixation or nystagmus or young children). Multimodal imaging correlation suggests that these concentric rings occur exclusively at the level of the Henle fiber layer. This distinctive Henle fiber layer geometry may reflect an arrested development stage in the timeline of foveal maturation.