Ring Area Research Articles

Damage characteristics and surface description of near-wall materials subjected to ultrasonic cavitation.

For the analysis of ultrasonic cavitation erosion on the surface of materials, the ultrasonic cavitation erosion experiments for AlCu4Mg1 and Ti6Al4V were carried out, and the changes of surface topography, surface roughness, and Vickers hardness were explored. Cavitation pits gradually expand and deepen with the increase of experiment time, and Ti6Al4V is more difficult to erode by cavitation than AlCu4Mg1. After experiments, the cavitation damage characteristics such as the single pit, the rainbow ring area, the fisheye pit, and some small pits were observed, which can be considered to be induced by a single micro-jet impact, ablation effect caused by the high temperature, micro-jet impingement with a sharp angle, and multibeam micro-jets coupling impact or negative pressure in the local area produced by micro-jet impact, respectively. The surface roughness and Vickers hardness of the material increase slowly after rapid growth at different points in time as the experiment time increases. With the increase of the ultrasonic amplitude, both of them first increase and then decrease after the ultrasonic amplitude is greater than 10.8μm. The increases in surface roughness and Vickers hardness tend to decrease as the viscosity coefficient increases. Ultrasonic cavitation can cause submicron surface roughness and increase surface hardness by 20.36%, so it can be used as a surface treatment method.

Optimal location of subtrochanteric osteotomy in total hip arthroplasty for crowe type IV developmental dysplasia of hip

BackgroundWhen reconstructing a hip with developmental dysplasia and high dislocation, sub-trochanteric shortening osteotomy is typically needed for placing the acetabular component in the appropriate anatomical position. However, the procedure can result in complications such as non-union of the osteotomy. We evaluated the contact area and the coincidence rate between the proximal and distal fragments at different femoral osteotomy levels and lengths. We then determined the optimal location of subtrochanteric femoral shortening transverse osteotomy in patients with unilateral Crowe type IV developmental dysplasia of the hip (DDH). The consistency between the proximal and distal segments was assessed as a possible predictive indicator of the union at the osteotomy site.MethodsWe retrospectively reviewed 57 patients with unilateral Crowe type IV DDH who underwent X-ray imaging of both hip joints. We labelled the inner and outer diameters of the circular ring as N (mm) and M (mm), respectively. We defined the overlapped area between the proximal and distal ring as contact area S (mm2), and the ratio of contact area to distal ring area as coincidence rate R.ResultsN varied from 9.8–15.2 mm and M varied from 20.7–24 mm, both demonstrated a decreasing trend in the proximal to distal direction. At osteotomy lengths ranging from 0.5–2 cm, there were no differences in S between the different levels of osteotomy in each group. At osteotomy lengths ≤2.5 cm, a significant higher coincidence rate was noted from 2 cm below the lesser trochanter to other positions below the level. At osteotomy lengths from 3 to 5.5 cm, a significantly higher coincidence rate was observed from the level of 1.5 cm below the lesser trochanter to other positions below the level.ConclusionsOur findings suggest that femoral shortening transverse osteotomy at the optimal subtrochanteric level can predictably increase the contact area and coincidence rate, which may contribute to the union at the osteotomy site. Considering the stability of the prostheses, it appears appropriate that osteotomy location should be shifted slightly distally.Trial registrationRetrospectively registered.

An Investigation of Socioeconomic and Land Use Influence on Car Ownership in Yangon City

Rapid growth in private vehicle ownership and usage is one of the key problems in the development of a sustainable transportation system for Yangon City. Car ownership depends on the land use patterns and socioeconomic characteristics of a city. Socioeconomic factors, including age, gender, income, house type, and family size also affect the choice of transportation mode and destination in the short and long terms, while the choice of housing location is affected in the long term. In this study, aggregate level land use data and disaggregate level individual and household data are used to determine the effects of land use and socioeconomic factors on household decisions to own zero, one, and two or more cars. This research models car ownership by the estimating multinomial logit model using SPSS (Statistical Packages for Social Sciences). The result suggests that income level, house type of a household, and the housing location have influence on car ownership in Yangon City. The car ownership level will be higher if the household number in the central business district (CBD), inner ring area, and outer ring area is increased. Increase in low income and normal income households will reduce the probability of car ownership in the suburban area.

Contractile morning glory disk anomaly: analysis of the cyclic contractions and literature review

To investigate the contraction mechanism of morning glory disk anomaly using computer-assisted analysis of the cyclic contractions frame by frame and to review the literature on contractile morning glory disk anomaly cases. The fundus video of the patient under anesthesia was recorded using RetCam C300 lens. Frames at 1second intervals were extracted to quality-preserving TIFF images and manually selected areas of cup, disk, and pigmented ring were measured with image analysis software. Measurements were repeated twice, and estimated uncertainties were calculated. Two full-contraction phases and 1 half- and 1 full-dilation phase were recorded and analyzed. At the end of the second dilation phase, cup, disk, and pigmented ring were dilated to 93.7%, 97.6%, and 98.3% of their areas after first dilation. At the end of the second contraction cup, disk and pigmented ring areas remained 1.24, 1.01, and 1.01 times larger, respectively, than the areas at the end of the first contraction. Ectopic cholinergic muscle contraction alone is unlikely to explain the cyclic contraction dilation movements under constant stimulus. Potentially present smooth muscle cells can be provoked by the stretch caused by the influx of fluid into the subretinal space. Change in spatial configuration and oscillations with decreasing magnitudes can be explained by decreasing contractions due to decreasing stretch with decreasing fluid influx in each cycle after the initial triggering of outside pressure, causing the greatest pressure gradient and the greatest fluid influx.

Scots pine trees react to drought by increasing xylem and phloem conductivities.

Drought limits the long-distance transport of water in the xylem due to the reduced leaf-to-soil water potential difference and possible embolism-related losses of conductance and of sugars in the phloem due to the higher viscosity of the dehydrated sugary solution. This condition can have cascading effects in water and carbon (C) fluxes that may ultimately cause tree death. We hypothesize that the maintenance of xylem and phloem conductances is fundamental for survival also under reduced resource availability, when trees may produce effective and low C cost anatomical adjustments in the xylem and phloem close to the treetop where most of the hydraulic resistance is concentrated. We analyzed the treetop xylem and phloem anatomical characteristics in coexisting Scots pine trees, symptomatic and non-symptomatic of drought-induced dieback. We selected the topmost 55cm of the main stem and selected several sampling positions at different distances from the stem apex to test for differences in the axial patterns between the two groups of trees. We measured the annual ring area, the tracheid hydraulic diameter (Dh) and cell wall thickness (CWT), the conductive phloem area and the average lumen diameter of the 20 largest phloem sieve cells (Dph). Declining trees grew less than the non-declining ones, and despite the similar axial scaling of anatomical traits, had larger Dh and lower CWT. Moreover, declining trees had wider Dph. Our results demonstrate that even under drought stress, maintenance of xylem and phloem efficiencies is of primary importance for survival, even if producing fewer larger tracheids may lead to a xylem more vulnerable to embolism formation.

Clinical and preclinical therapeutic outcome metrics for USH2A-related disease.

USH2A variants are the most common cause of Usher syndrome type 2, characterized by congenital sensorineural hearing loss and retinitis pigmentosa (RP), and also contribute to autosomal recessive non-syndromic RP. Several treatment strategies are under development; however, sensitive clinical trial endpoint metrics to determine therapeutic efficacy have not been identified. In the present study, we have performed longitudinal retrospective examination of the retinal and auditory symptoms in (i) 56 biallelic molecularly confirmed USH2A patients and (ii) ush2a mutant zebrafish to identify metrics for the evaluation of future clinical trials and rapid preclinical screening studies. The patient cohort showed a statistically significant correlation between age and both rate of constriction for the ellipsoid zone length and hyperautofluorescent outer retinal ring area. Visual acuity and pure tone audiograms are not suitable outcome measures. Retinal examination of the novel ush2au507 zebrafish mutant revealed a slowly progressive degeneration of predominantly rods, accompanied by rhodopsin and blue cone opsin mislocalization from 6 to 12 months of age with lysosome-like structures observed in the photoreceptors. This was further evaluated in the ush2armc zebrafish model, which revealed similar changes in photopigment mislocalization with elevated autophagy levels at 6 days post fertilization, indicating a more severe genotype-phenotype correlation and providing evidence of new insights into the pathophysiology underlying USH2A-retinal disease.

ФИЗИКО-МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ИЗГИБНОГО ВОЛОКОННО-ОПТИЧЕСКОГО ДАТЧИКА СИЛЫ

There is presented a model of an explosion-proof, jam-resistant under conditions of high level electromagnetic fields fiber-optical sensor of tensile force on the basis of a fiber-optical transformer of movements in which a distinctive peculiarity is an application of loss changes in radiation spreading in sensitive elements as ring loops deformed elliptically of multi-mode fiber light-guides forming a bundle that allows using a diode as a radiation source installed without a special alignment device. 
 It is defined that a peculiarity of bending fiber-optical transformers of movement of a successive-parallel type is that in separate areas of rings a radius of curvature increases at the expense of deformation and the losses of radiation in these areas decrease, and in other ones this radius decreases that results in the increase of losses of the radiation spreading by light-guides. Overall losses directed at radiation in light-guides increase lineally with the increase of movement. There is carried out a choice of the optimum number of rings of a sensitive element and a choice of “source-radiation receiver” for obtaining a linear calibration characteristic of the sensor. It is shown that varying the number of coils in the bending fiber-optical transformer it is possible to change a range of movements measured ind a form of calibration characteristic of a transformer.

Relationship between rectal abdominis muscle position and physiological umbilical herniation and return: A morphological and morphometric study.

The herniation of the intestinal loop (IL) in the extraembryonic coelom and its return to abdominal cavity is in parallel with the formation of the rectal abdominis muscle (RAM). Using high-resolution magnetic resonance imaging data of human fetuses (n = 19, CRL22-69 mm; stored at Kyoto Collection), this study aimed to analyze the relationship between the development of RAM and phase of IL herniation. The RAM runs at the lateral part of the abdominal wall in the small samples in the herniation phase. The position was shifted to the midline area in the larger samples in the herniation phase. According to fetal growth, the caudal ends of the muscles extended along the umbilical ring towards the pubis, though the caudal part of the RAMs were thin and faint in most of the samples. Length measurements related with the growth of the abdominal wall including RAM and abdominal circumference showed positive correlation with fetal growth. On the contrary, diastasis of RAMs and the width and area of the umbilical ring were almost constant according to fetal growth. Such morphometric value showed no obvious changes regardless of the phases of herniation. The ratio of the width and diastasis of the RAMs to the circumference was decreased, indicating that the closure of the ventral body wall was influenced by growth differences. The present data indicate that the formation of the abdominal wall including RAM is independent of the phase of IL herniation, whether in the extraembryonic coelom or in the abdominal cavity.

Arbitrary-Oriented Object Detection in Remote Sensing Images Based on Polar Coordinates

Arbitrary-oriented object detection is an important task in the field of remote sensing object detection. Existing studies have shown that the polar coordinate system has obvious advantages in dealing with the problem of rotating object modeling, that is, using fewer parameters to achieve more accurate rotating object detection. However, present state-of-the-art detectors based on deep learning are all modeled in Cartesian coordinates. In this article, we introduce the polar coordinate system to the deep learning detector for the first time, and propose an anchor free Polar Remote Sensing Object Detector (P-RSDet), which can achieve competitive detection accuracy via using simpler object representation model and less regression parameters. In P-RSDet method, arbitrary-oriented object detection can be achieved by predicting the center point and regressing one polar radius and two polar angles. Besides, in order to express the geometric constraint relationship between the polar radius and the polar angle, a Polar Ring Area Loss function is proposed to improve the prediction accuracy of the corner position. Experiments on DOTA, UCAS-AOD and NWPU VHR-10 datasets show that our P-RSDet achieves state-of-the-art performances with simpler model and less regression parameters.

Functional results of spectral correction of vision

To study the data of monocular and binocular multifocal electroretinogram (mfERG), flash visual evoked potential (f-VEP), spatial contrast sensitivity (SCS) with and without yellow filters in healthy elderly people. The study included 16 people (8 male and 8 female) with average age of 51.63±4.7 years. Their visual acuity was 0.5±0.35 without correction and 1.0 with correction. For spectral correction, we used Y1 color filters (CF) (analogue of SN60AT) from the «Lornet-M vision spectral correction kit» set with 80% light transmission and wave cut-off of 460 nm. Patients had mfERG recordings performed monocularly and binocularly, f-VEP monocularly, and their spatial contrast sensitivity (SCS) was measured (Astroinform SPE, Russia). The data acquired before and after applying CF was compared. The data of SCS with light filter was slightly higher at medium and high spatial frequencies (SF): for the right eye on medium SF of 43.8 and 41.8 dB (p≤0.735), 41.5 and 39.8 dB (p≤0.061) for the left eye. The increase of mfERG P1 latency monocularly after application of CF in the R1 ring area was 3.0 ms (40.8-43.8ms) for the right eye (p≤0.05) and 0.9 ms for the left eye (43.7-44.5ms) (p≤0.326). The trend remained for simultaneous mfERG. The influence of yellow filters on spectral vision correction can be manifested in inconsistency of SCS, f-VEP, monocular and binocular mfERG readings. Statistically significant differences in healthy individuals of 5th-6th age decades manifest as elongation of the latency of mfERG peaks.

Research on the operational regional coverage of satellite and spacecraft tracking and controlling

In view of the problem of building ground stations for tracking and controlling of satellites and spacecraft, considering the fixed angle between the orbit of the satellite or spacecraft and the equatorial surface of the earth, and the difference of longitude between the two circles in succession of the satellite or spacecraft caused by the rotation of the earth, the operation area of the satellite or spacecraft was calculated by using the method of spherical projection of satellite orbit rotation, taking the earth as the reference system. The minimum number of ground stations needed for satellite tracking and controlling was calculated in three cases, by using the mathematical model of sphere ring area and honeycomb coverage. This model was validated by the launch and operation data of Shenzhou 7.

Prototype system for real-time IM/DD MDM transmission based on multiple-ring-core FMF and degenerate-mode-selective reception.

Multiple-input-multiple-output digital signal processing (DSP) has become a severe bottleneck for mode division multiplexing (MDM) because of its huge computational complexity. In this paper, we propose a novel scheme for real-time DSP-free intensity-modulation/direct-detection (IM/DD) MDM transmission, in which the transmission few-mode fiber (FMF) is characterized by multiple-ring-core structure to suppress modal crosstalk among each LP mode, while each pair of non-circularly-symmetric degenerate modes is simultaneously demultiplexed by a degenerate-mode-selective fiber coupler for DSP-free reception. Based on a 10 km ultralow-modal-crosstalk double-ring-core FMF and a pair of all-fiber 4-LP-mode MUX/DEMUX, we demonstrate the first IM/DD MDM prototype system using commercial single-mode (SM) 10 Gbps SFP + modules and 4K video transceivers without any hardware modifications. The temperature and wavelength dependence are evaluated. The stable Q2-factor performance proves that it can be a smooth evolution scheme from conventional SM IM/DD systems. Moreover, the scheme can be further extended to support more modes with improved FMF design adopting more ring areas.

Comparison between commercial and synthesised nano flower-like rutile TiO2 immobilised on green super adsorbent towards dye wastewater treatment

Abstract The combination of a semiconductor metal oxide with green low-cost adsorbent materials has prompted the emergence of new natural resources having higher efficiency for treating dye wastewater. This study investigated the characterisation and performance of synthesised nano flower-like rutile TiO2 (F–TiO2) via the facile hydrothermal method and sintered commercial TiO2 (C–TiO2). Both C–TiO2 and F–TiO2 were immobilised on green super adsorbent basil seed. The details of the structural properties were analysed by Rietveld refinement and the deconvolution method to verify the purity. The synthesised F–TiO2 immobilised on basil seed (B–F–TiO2) was found to have optimum physical and morphology properties. Kinetic and equilibrium studies illustrated that the adsorption behaviour of B–F–TiO2 could be better described by pseudo-second-order kinetic (chemisorption). The maximum uptake capacity (49.47 mg g−1) with the highest removal of methylene blue (98.95%) was obtained at an equilibrium time of 180 min following photocatalysis and self-cleaning. A large antibacterial ring area (1.83 mm2) was also obtained from B–F–TiO2. The removal of methylene blue dye for B–F–TiO2 increased as the recycle times increased (3 times) due to the increase of the surface area exposed to methylene blue as the weight of B–F–TiO2 immobilised on basil seed decreased. This demonstrates that B–F–TiO2 provides better potential to apply as a multifunction green super adsorbent for dye wastewater treatment compared to B–C–TiO2.

Morphometric characteristics of the optical disc and thickness of retinal nerve fibre layer using Cirrus 5000 optical coherence tomography in healthy patients attending the National Institute of Ophthalmology

Abstract Objective To describe the morphometric characteristics and thickness of the retinal nerve fibre layer (CFNR) in healthy patients using optical coherence tomography (OCT). Methods A cross-sectional and descriptive study was conducted on a total of 184 eyes of 184 people of mestizo origin enrolled after a complete ophthalmological evaluation at the National Institute of Ophthalmology, Lima-Peru. The morphometric parameters of the optical disc and thickness of the CFNR were measured by OCT ZEISS Cirrus HD Model 5000. Megalopapilla was defined as: area of ​​the optical disc greater than 2.5 mm2 and area greater than the mean plus 2 standard deviations. Results The areas obtained were: optical disc of 2.21 ± 0.43 mm2, neuroretinal ring of 1.37 ± 0.25 mm2, 0.84 ± 0.48 mm2 cup; mean cup/disc ratio of 0.58 ± 0.16, vertical cup/disc ratio of 0.55 ± 0.15, and a CFNR thickness of 100.30 ± 8.54 μm. The prevalence of megalopapilla, being considered as a disc area greater than 2.5 mm2 and 3.07 mm2, was 24% and 4%, respectively. When comparing megalopapilla with normal discs, the area of ​​the ring (P = .08) and thickness of CFNR (P = .73) did not show statistically significant differences. Conclusion The mean disc area was 2.21 ± 0.43 mm2 with a CFNR thickness of 100.30 ± 8.54 μm. The prevalence of megalopapilla was 24% and 4%, considering a disc area greater than 2.5 mm2 and 3.07 mm2, respectively. These results show that the megalopapilla and normal discs are similar in terms of ring area and CFNR thickness.

Pulse pressure loading and erosion pattern of cavitating jet

Various erosion patterns generated through the cavitating water jet impacts under ambient pressure conditions were investigated in experiments and numerical simulations. A series of normalized stand-off distances ∈ [2.5 13.5] were studied during the erosion acceleration period. Two ring-like erosion areas were observed for comparatively low ∈ [2.5 6.5]. To gain insight into the pulse pressure loading on the erosion area, numerical calculations were performed using the volume of fluid (VOF) interface capturing methodology combined with the large-eddy simulation turbulence model. The erosion patterns are clarified based on the mass loss and distribution features of the eroded regions. The first ring, generated by the cavitation clouds impingement outside the central stagnation area, mainly contributes to the mass loss. The second ring moves inward, merges into the inner ring and eventually vanishes with increasing . High pressure pulsation is found around the locations of the maximum erosion and the approximate intermediate radius of the second ring. The pressure pulsation in the first ring area are dominated by the frequency of the vortices shedding from the jet nozzle. Several higher frequencies are found as the spectral features of the eroded regions in each pattern.

Enhancing Packet Delivery Ratio and a lifetime of Wireless Sensor Networks using Energy-Efficient Unequal Clustering Routing Algorithm

Sensors are regarded as significant components of electronic devices. The sensor nodes deployed with limited resources, such as the power of battery inserted in the sensor nodes. So the lifetime of wireless sensor networks(WSNs) can be increased by using the energy of the sensor nodes in an efficient way. A major part of energy is consumed during the communication of data. Also, the growing demand for usage of wireless sensors applications in different aspects makes the quality-of-service(QoS) to be one of the paramount issues in wireless sensors applications. QoS guarantee in WSNs is difficult and more challenging due to the fact that the sensors have limited resources and the various applications running over these networks have different constraints in their nature and requirements. The packet delivery ratio(PDR) is a major factor of QoS. To achieve high QoS the packet delivery ratio should be maximum. The energy-efficient unequal clustering routing protocol (EEUCR) is evaluated and results show that it enhances the packet delivery ratio(PDR) and a lifetime of WSNs. In this protocol, the area of the network is divided into a number of rings of unequal size and each ring is further divided into a number of clusters. Rings nearer to the base station(BS) have smaller area and area of rings keeps on increasing as the distance from BS increases for balanced energy consumption. The nodes with heterogeneous energy are deployed in the network. Nodes nearer to the base station have higher energy as compared to farther nodes. Static clustering is used but cluster heads(CHs) are not fixed and are elected on the basis of remaining energy. This helps to increase lifetime of EEUCR. PDR of EEUCR is improved because multiple rings help to find better route which further aids to ensure safe reception of packets at the destination. Simulation results are compared with existing protocols and show that this algorithm gives better results.

Características morfométricas de disco óptico y espesor de capa de fibras nerviosas de la retina mediante tomografía de coherencia óptica Cirrus 5000 en pacientes sanos atendidos en el Instituto Nacional de Oftalmología

ObjectiveTo describe the morphometric characteristics and thickness of the retinal nerve fibre layer (CFNR) in healthy patients using optical coherence tomography. MethodsA cross-sectional and descriptive study was conducted on a total of 184 eyes of 184 people of mestizo origin enrolled after a complete ophthalmological evaluation at the National Institute of Ophthalmology, Lima-Peru. The morphometric parameters of the optic disc and thickness of the CFNR were measured by optical coherence tomography ZEISS CIRRUS™ HD-OCT Model 5000 (Carl Zeiss Inc., Dublin, CA, EE.UU). Megalopapilla was defined as: area of the optical disc greater than 2.5 mm2 and area greater than the mean plus 2 standard deviations. ResultsThe areas obtained were: optical disc of 2.21±0.43mm2, neuroretinal ring of 1.37±0.25mm2, 0.84±0.48mm2 cup; mean cup/disc ratio of 0.58±0.16, vertical cup/disc ratio of 0.55±0.15, and a CFNR thickness of 100.30±8.54μm. The prevalence of megalopapilla, being considered as a disc area greater than 2.5mm2 and 3.07, was 24% and 4%, respectively. When comparing megalopapilla with normal discs, the area of the ring (P=.08) and thickness of CFNR (P=.73) did not show statistically significant differences. ConclusionThe mean disc area was 2.21±0.43mm2 with a CFNR thickness of 100.30±8.54μm. The prevalence of megalopapilla was 24% and 4%, considering a disc area greater than 2.5 mm2 and 3.07 mm2, respectively. These results show that the megalopapilla and normal discs are similar in terms of ring area and CFNR thickness.

터보차저 V형 커플링의 체결 특성에 관한 유한요소 해석 및 실험적 연구

V-type coupling, which is often applied to turbochargers, is a mechanical fastener where radial forces close turbine housing and bearing housing together. It prevents leakage of exhaust gases by contact pressure of the backplate caused by the load transmitted from the bolt-tightening torque. Therefore, it is important to study the mechanical behaviors of the coupling system in order to establish more accurate sealing assessment technologies. In this study, an experiment was first conducted to obtain the relationship between torque and its resulting axial force in a specially designed gage bolt. Strains were then measured when the torque was applied using the gauge bolts on the turbocharger. Thus, the magnitude of the axial force due to the bolt torque can be obtained inversely. In addition, the circumference and width strains of the turbocharger coupling were measured under the assembly load, and theses results were compared with the finite element results. As a result, they tend to be very similar, but in the ring area, analysis results show a relatively small value, and near the bolt, the analysis results are larger than the experimental strains. This is thought to be due to the reduced strains around the bolt by the hammering process.

Energy-Efficient Unequal Clustering Routing Algorithm for WSNs

Wireless sensor networks(WSNs) are used to monitor the environment where the networks are deployed. The Lifetime of WSNs can be increased by energy-efficient or energy balancing algorithms. Balanced energy consumption among all nodes is the main issue. In this paper, a new energy-efficient unequal clustering routing protocol (EEUCR) has been presented. In this protocol, the area of the network is divided into the number of rings of unequal size and each ring is further divided into a number of clusters. Rings nearer to the base station(BS) have a smaller area and the area of rings keeps on increasing as the distance from BS increases. This helps to balance the energy consumption among the sensor nodes. The nodes with heterogeneous energy are deployed in the network. Nodes nearer to the base station have higher energy as compared to farther nodes. Static clustering is used but cluster heads(CHs) are not fixed and are elected on the basis of the remaining energy of the sensor node. Simulation results are compared with existing protocols and show improvement in energy consumption, which, in turn, increases the network lifetime of WSN and also balance the energy consumption of sensor nodes.

Multimodal Analysis of Hyperautofluorescent Ring Size in Retinitis Pigmentosa.

To determine if a correlation exists between hyperautofluorescent ring size with visual acuity (VA), foveal avascular zone (FAZ) size, and retinal capillary perfusion density (CPD) in retinitis pigmentosa (RP). Eighteen eyes from nine patients with RP were imaged using fundus autofluorescence (AF) to identify autofluorescence defects, and hyperautofluorescent ring size was measured with an image-processing program. Spectral-domain optical coherence tomography angiography was used to measure FAZ area and calculate parafoveal CPD in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) using both a 3 mm × 3 mm and 6 mm × 6 mm strategy. The area of hyperautofluorescence was not strongly correlated with SCP perfusion density (P = .74), DCP perfusion density (P = .25), FAZ area (P = .14), or VA (P = .33). The area of the hyperautofluorescent ring does not correlate with VA, retinal CPD, or FAZ area. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:492-496.].