Mean Response Time Research Articles

Human Performance in Highly Automated, Cyber Vulnerable Unmanned Aerial Systems: Effects of Operators’ Background and Task Load

This article evaluated the effects of operator background and task load on operator ability to detect and respond to cyber events while controlling multiple unmanned aerial systems (UAS). Cyber physical systems (CPS) are susceptible to cyber threats and associated events via connections critical to their operations. The effects of cyber intrusions on UAS operator performance as a function of background and task load have been understudied. Fifty-one operators with different backgrounds (Aviators, Gamers and Non-Gamers; n = 17 per group) were evaluated across two levels of task load (in-the-loop (ITL) and out-of-the-loop (OTL)) while controlling a simulation of multiple UAS involving cyber events. Cyber events represented spoofed information that could not be corroborated with available secondary information/displays. Multivariate analysis of variance was used to analyze the effect of background and task load on operator performance, subjective perception of workload (assessed using the NASA Task Load Index), and trust. Nongamers responded to cyber events 62.8% and 67.7% slower than aviators and gamers, respectively. Mean response times across task load conditions were substantially longer for cyber events (128.9 s) than for noncyber, “real” events (42.8 s). Scenario type (ITL/OTL) was statistically significant for workload, cyber classification, and cyber action response. The findings may inform recruitment criteria for future UAS operators. Individuals with gaming experience may be as adept at responding to cyber events while operating multiple UAS as aviators. Cyber events are likely to affect the performance of the overall CPS due to their impact on the human operator.

The effect of increasing work rate amplitudes from a common metabolic baseline on the kinetic response of V̇O2p, blood flow, and muscle deoxygenation.

A step-transition in external work rate (WR) increases pulmonary O2 uptake (V̇O2p) in a monoexponential fashion. While the rate of this increase, quantified by the time constant (τ), has frequently been shown to be similar between multiple different WR amplitudes (ΔWR), the adjustment of O2 delivery to the muscle (via blood flow; BF), a potential regulator of V̇O2p kinetics, has not been extensively studied. To investigate the role of BF on V̇O2p kinetics, ten participants performed step-transitions on a knee-extension ergometer from a common baseline WR (3 W) to: 24, 33, 45, 54, and 66 W. Each transition lasted 8 min and was repeated 4-6 times. Volume turbinometry and mass spectrometry, Doppler ultrasound, and near-infrared spectroscopy were used to measure V̇O2p, BF, and muscle deoxygenation (deoxy[Hb+Mb]), respectively. Like transitions were ensemble-averaged and phase II V̇O2p, BF, and deoxy[Hb+Mb] were fit with a monoexponential non-linear least squares regression equation. With increasing ΔWR, τV̇O2p became larger at the higher ΔWRs (p < 0.05), while τBF did not change significantly, and the mean response time (MRT) of deoxy[Hb+Mb] became smaller. These findings that V̇O2p kinetics become slower with increasing ΔWR, while BF kinetics are not influenced by ΔWR, suggest that O2 delivery could not limit V̇O2p in this situation. However, the speeding of deoxy[Hb+Mb] kinetics with increasing ΔWR does imply that the O2 delivery-to-O2 utilization of the microvasculature decreases at higher ΔWRs. This suggests that the contribution of O2 delivery and O2 extraction to V̇O2 in the muscle change with increasing ΔWR.

Combination of hyperoxia and a right-shifted HbO2 dissociation curve delays V̇o2 kinetics during maximal contractions in isolated muscle.

Acute enhancement of peripheral O2 diffusion may accelerate skeletal muscle O2 uptake (V̇o2) kinetics and lessen fatigue during transitions from rest to maximal contractions. Surgically isolated canine gastrocnemius muscles in situ (n = 6) were studied during transitions from rest to 4 min of electrically stimulated isometric tetanic contractions at V̇o2peak, in two conditions: normoxia (CTRL) and hyperoxia ([Formula: see text] = 1.00) + administration of a drug (RSR-13), which right shifts the Hb-O2 dissociation curve (Hyperoxia + RSR-13). Before and during contractions, muscles were pump-perfused with blood at constant elevated flow ([Formula: see text]) and infused with the vasodilator adenosine. Arterial ([Formula: see text]) and muscle venous ([Formula: see text]) O2 concentrations were determined at rest and at 5- to 7-s intervals during contractions; V̇o2 was calculated as [Formula: see text]·([Formula: see text] - [Formula: see text]). Po2 at 50% of Hb saturation (standard P50) and mean microvascular Po2 ([Formula: see text]) were calculated by the Hill equation and a numerical integration technique. P50 [42 ± 7 (means ± SD) mmHg vs. 33 ± 2 mmHg, P = 0.02] and [Formula: see text] (218 ± 73 mmHg vs. 49 ± 4 mmHg, P = 0.003) were higher in Hyperoxia + RSR-13. Muscle force and fatigue were not different in the two conditions. V̇o2 kinetics (monoexponential fitting) were unexpectedly slower in Hyperoxia + RSR-13, due to a longer time delay (TD) [9.9 ± 1.7 s vs. 4.4 ± 2.2 s (P = 0.001)], whereas the time constant (τ) was not different [13.7 ± 4.3 s vs. 12.3 ± 1.9 s (P = 0.37)]; the mean response time (TD + τ) was longer in Hyperoxia + RSR-13 [23.6 ± 3.5 s vs. 16.7 ± 3.2 s (P = 0.003)]. Increased O2 availability deriving, in Hyperoxia + RSR-13, from higher [Formula: see text] and from presumably greater intramuscular O2 stores did not accelerate the primary component of the V̇o2 kinetics, and delayed the metabolic activation of oxidative phosphorylation.NEW & NOTEWORTHY In isolated perfused skeletal muscle, during transitions from rest to V̇o2peak, hyperoxia and a right-shifted oxyhemoglobin dissociation curve increased O2 availability by increasing microvascular Po2 and by presumably increasing intramuscular O2 stores. The interventions did not accelerate the primary component of the V̇o2 kinetics (as calculated from blood O2 unloading) and delayed the metabolic activation of oxidative phosphorylation. V̇o2 kinetics appear to be mainly controlled by intramuscular factors related to the use of high-energy "buffers."

Visualizing ordered bivariate data on node-link diagrams

Node-link visual representation is a widely used tool that allows decision-makers to see details about a network through the appropriate choice of visual metaphor. However, existing visualization methods are not always effective and efficient in representing bivariate graph-based data. This study proposes a novel node-link visual model – visual entropy (Vizent) graph – to effectively represent both primary and secondary values, such as uncertainty, on the edges simultaneously. We performed two user studies to demonstrate the efficiency and effectiveness of our approach in the context of static node-link diagrams. In the first experiment, we evaluated the performance of the Vizent design to determine if it performed equally well or better than existing alternatives in terms of response time and accuracy. Three static visual encodings that use two visual cues were selected from the literature for comparison: Width-Lightness, Saturation-Transparency, and Numerical values. We compared the Vizent design to the selected visual encodings on various graphs ranging in complexity from 5 to 25 edges for three different tasks. The participants achieved higher accuracy of their responses using Vizent and Numerical values; however, both Width-Lightness and Saturation-Transparency did not show equal performance for all tasks. Our results suggest that increasing graph size has no impact on Vizent in terms of response time and accuracy. The performance of the Vizent graph was then compared to the Numerical values visualization. The Wilcoxon signed-rank test revealed that mean response time in seconds was significantly less when the Vizent graphs were presented, while no significant difference in accuracy was found. The results from the experiments are encouraging and we believe justify using the Vizent graph as a good alternative to traditional methods for representing bivariate data in the context of node-link diagrams.

Response Latencies as Evidence of Social Desirability Bias in Voter Turnout Overreports

Most vote validation studies assume that socially desirable responding is the cause of turnout overreports. Still, very little has been done to test this assertion. Using response latency measures from the 2020 Cooperative Election Study and its vote validation data, I examine the relationship between overreporting turnout and response latencies. Emulating research on the effect of deception on response latencies I test whether turnout overreports have a similar effect to that of deception on the response latencies for self-reported turnout. I find that the respondents who overreport turnout have higher mean response times than validated voters on average, and address the role memory in predicting the length of response latencies for the turnout self-reports. This study sheds light on the cognitive mechanism that underlies the occurrence of overreports in survey research, and provides new evidence to support the view that overreports of voter turnout occur due to socially desirable responding.

Electrical analysis of logical complexity: an exploratory eeg study of logically valid/invalid deducive inference

IntroductionLogically valid deductive arguments are clear examples of abstract recursive computational procedures on propositions or on probabilities. However, it is not known if the cortical time-consuming inferential processes in which logical arguments are eventually realized in the brain are in fact physically different from other kinds of inferential processes.MethodsIn order to determine whether an electrical EEG discernible pattern of logical deduction exists or not, a new experimental paradigm is proposed contrasting logically valid and invalid inferences with exactly the same content (same premises and same relational variables) and distinct logical complexity (propositional truth-functional operators). Electroencephalographic signals from 19 subjects (24.2 ± 3.3 years) were acquired in a two-condition paradigm (100 trials for each condition). After the initial general analysis, a trial-by-trial approach in beta-2 band allowed to uncover not only evoked but also phase asynchronous activity between trials.Resultsshowed that (i) deductive inferences with the same content evoked the same response pattern in logically valid and invalid conditions, (ii) mean response time in logically valid inferences is 61.54% higher, (iii) logically valid inferences are subjected to an early (400 ms) and a late reprocessing (600 ms) verified by two distinct beta-2 activations (p-value < 0,01, Wilcoxon signed rank test).ConclusionWe found evidence of a subtle but measurable electrical trait of logical validity. Results put forward the hypothesis that some logically valid deductions are recursive or computational cortical events.

LAPIS is a fast web API for massive open virus sequencing data

BackgroundRecent epidemic outbreaks such as the SARS-CoV-2 pandemic and the mpox outbreak in 2022 have demonstrated the value of genomic sequencing data for tracking the origin and spread of pathogens. Laboratories around the globe generated new sequences at unprecedented speed and volume and bioinformaticians developed new tools and dashboards to analyze this wealth of data. However, a major challenge that remains is the lack of simple and efficient approaches for accessing and processing sequencing data.ResultsThe Lightweight API for Sequences (LAPIS) facilitates rapid retrieval and analysis of genomic sequencing data through a REST API. It supports complex mutation- and metadata-based queries and can perform aggregation operations on massive datasets. LAPIS is optimized for typical questions relevant to genomic epidemiology. Using a newly-developed in-memory database engine, it has a high speed and throughput: between 25 January and 4 February 2023, the SARS-CoV-2 instance of LAPIS, which contains 14.5 million sequences, processed over 20 million requests with a mean response time of 411 ms and a median response time of 1 ms. LAPIS is the core engine behind our dashboards on genspectrum.org and we currently maintain public LAPIS instances for SARS-CoV-2 and mpox.ConclusionsPowered by an optimized database engine and available through a web API, LAPIS enhances the accessibility of genomic sequencing data. It is designed to serve as a common backend for dashboards and analyses with the potential to be integrated into common database platforms such as GenBank.

Responses to Raven matrices: Governed by visual complexity and centrality.

Raven matrices are widely considered a pure test of cognitive abilities. Previous research has examined the extent to which cognitive strategies are predictive of the number of correct responses to Raven items. This study examined whether response times can be explained directly from the centrality and visual complexity of the matrix cells (edge density and perceived complexity). A total of 159 participants completed a 12-item version of the Raven Advanced Progressive Matrices. In addition to item number (an index of item difficulty), the findings demonstrated a positive correlation between the visual complexity of Raven items and both the mean response time and the number of fixations on the matrix (a strong correlate of response time). Moreover, more centrally placed cells as well as more complex cells received more fixations. It is concluded that response times on Raven matrices are impacted by low-level stimulus attributes, namely, visual complexity and eccentricity.

Cerebral blood flow dynamics: Is there more to the story at exercise onset?

A monoexponential model characterizing cerebral blood velocity dynamics at the onset of exercise may mask dynamic responses by the cerebrovasculature countering large fluctuations of middle cerebral artery blood velocity (MCAv) and cerebral perfusion pressure (CPP) oscillations. Therefore, the purpose of this study was to determine whether the use of a monoexponential model attributes initial fluctuations of MCAv at the start of exercise as a time delay (TD). Twenty-three adults (10 women, 23.9 ± 3.3 yrs; 23.7 ± 2.4 kg/m2 ) completed 2 min of rest followed by 3 mins of recumbent cycling at 50 W. MCAv, CPP, and Cerebrovascular Conductance index (CVCi), calculated as CVCi = MCAv/MAP × 100 mmHg, were collected, a lowpass filter (0.2 Hz) was applied, and averaged into 3-second bins. MCAv data were then fit to a monoexponential model [ΔMCAv(t) = Amp(1 - e-(t-TD)/τ )]. TD, tau (τ), and mean response time (MRT = TD + τ) were obtained from the model. Subjects exhibited a TD of 20.2 ± 18.1 s. TD was directly correlated with MCAv nadir (MCAvN ), r = -0.560, p = 0.007, which occurred at similar times (16.5 ± 15.3 vs. 20.2 ± 18.1 s, p = 0.967). Regressions indicated CPP as the strongest predictor of MCAvN ( = 0.36). Fluctuations in MCAv were masked using a monoexponential model. To adequately understand cerebrovascular mechanisms during the transition from rest to exercise, CPP and CVCi must also be analyzed. A concurrent drop in cerebral perfusion pressure and middle cerebral artery blood velocity at the start of exercise forces the cerebrovasculature to respond to maintain cerebral blood flow. The use of a monoexponential model characterizes this initial phase as a time delay and masks this large important response.

Analyses of response time data in the same–different task.

The Same-Different task presents two stimuli in close succession and participants must indicate whether they are completely identical or if there are any attributes that differ. While the task is simple, its results have proven difficult to explain. Notably, response times are characterized by a fast-same effect whereby Same responses are faster than Different responses even though identical stimuli should be exhaustively processed to be accurate. Herein, we examine a little more than a quarter million response times (N = 255,744) obtained from 327 participants who participated in one of 14 variants of the task involving minor changes in the stimuli or their durations. We performed distribution fitting and analyzed estimated parameters stemming from the ex-Gaussian, lognormal, and Weibull distributions to infer the cognitive processing characteristics underlying this task. The results exclude serial processing of the stimuli and do not support dual-route processing. The fast-same effect appears only through a shift of the entire response time distributions, a feature impossible to detect solely with mean response time analyses. An attention-modulated process driven by entropy may be the most adequate model of the fast-same effect. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Characteristics of out-of-hospital cardiac arrest patients in Riyadh province, Saudi Arabia: a cross-sectional study.

Little work has been done on out-of-hospital cardiac arrest (OHCA) in Saudi Arabia. Our goal is to report the characteristics of OHCA patients and predictors of bystander cardiopulmonary resuscitation (CPR). This cross-sectional study utilized data from the Saudi Red Crescent Authority (SRCA), a governmental emergency medical service (EMS). A standardized data collection form based on the "Utstein-style" guidelines was developed. Data were retrieved from the electronic patient care reports that SRCA providers fill out for every case. OHCA cases that were attended by SRCA in Riyadh province between June 1st, 2020 and May 31st, 2021 were included. Multivariate regression analysis was performed to assess independent predictors of bystander CPR. A total of 1,023 OHCA cases were included. The mean age was 57.2 (±22.6). 95.7% (979/1,023) of cases were adults and 65.2% (667/1,023) were males. Home was the most common location of OHCA [784/1,011 (77.5%)]. The initial recorded rhythm was shockable in 131/742 (17.7%). The EMS mean response time was 15.9 min (±11.1). Bystander CPR was performed in 130/1,023 (12.7%) and was more commonly performed in children as compared to adults [12/44 (27.3%) vs. 118/979 (12.1%), p = 0.003]. Independent predictors of bystander CPR were being a child (OR = 3.26, 95% CI [1.21-8.82], p = 0.02) and having OHCA in a healthcare institution (OR = 6.35, 95% CI [2.15-18.72], p = 0.001). Our study reported the characteristics of OHCA cases in Saudi Arabia using EMS data. We observed young age at presentation, low rates of bystander CPR, and long response time. These characteristics are distinctly different from other countries and call for urgent attention to OHCA care in Saudi Arabia. Lastly, being a child and having OHCA in a healthcare institution were found to be independent predictors of bystander CPR.

Catchment response times – understanding runoff dynamics from catchment distances and celerities

ABSTRACT In this study we explore how varying the river network (RN) density affects the distribution of hillslope to RN distances, the subsurface water celerities and hence the response times. Eleven Norwegian catchments (with areas of 0.007 to 500 km2) were used for the analysis, and the Distance Distribution Dynamics (DDD) hydrological model was calibrated for each catchment and RN. Equally good Kling-Gupta efficiency scores suggest a degree of equifinality in that many constellations of RNs and subsurface celerities have equally good model performance. All catchments display a linear relationship between the calibrated mean subsurface water celerity and mean hillslope to RN distance, consistent with a constant mean response time (MRT). The MRTs vary from 1 to 49 days for the different catchments and agree with MRT estimated from recession analysis and regionalized through regression and catchment characteristics. The latter aids in the estimation of model parameters for ungauged basins.

Electrochemically nanotuned surface comprising 3D bimetallic dendrites fabricated on MWCNT for detection of 1,4-dioxane in water

Water quality has become one of the most serious environmental problems throughout the globe. The recalcitrant molecule, 1,4-Dioxane (1,4-D) has been recognized as a pollutant of rising concern in water, according to the World Health Organization (WHO), and can cause harm to aquatic organisms, animals, and even humans. Thus, it is important to detect 1,4-D in water bodies accurately and sensitively. In light of this, by fine-tuning the electrodeposition conditions, a novel bimetallic copper and gold nanodendritic structure was fabricated on the multiwalled carbon nanotube (MWCNT) functionalized glassy carbon electrode (GCE). The nanosensor was characterized by several physical and electrochemical techniques. The sensor probe exhibits good analytical performance and possess linear dynamic ranges (LDR) between 5 to 103 nM and 0.5 × 105 to 2 × 105 nM. The sensor showed limit of detection (LOD) and limit of quantification (LOQ) of 3.27 ± 0.04 pM and 10.92 ± 0.07 pM, respectively, with a mean response time of 1.65 ± 0.05 s. The sensor's performance was analyzed using tap water and Ganga water, with 90.24–99.57 % and 90.05–98.88 % of 1,4-D recovered without interference, respectively. The entire process of fabricating the surface and testing the 1,4-D takes hardly around 30 min, showing the sensor's applicability in monitoring 1,4-D in the environment.

Response-repetition costs in task switching do not index a simple response-switch bias: Evidence from manipulating the number of response alternatives

Response repetitions aid performance when a task repeats but impair performance when a task switches. Although this interaction is robust, theoretical accounts remain controversial. Here, we used an un-cued, predictable task-switching paradigm with univalent targets to explore whether a simple bias to switch the response when the task switches can explain the interaction. In Experiment 1A (n = 40), we replicated the basic interaction in a two-choice task. In Experiment 1B (n = 60), we observed the same interaction in a three-choice task, wherein a bias to switch the response when the task switches cannot prime a specific alternative response because both remaining response alternatives are equally likely. Exploratory comparisons revealed a larger interaction between task repetition and response repetition in the three-choice task than in the two-choice task for mean response time (RT) and the opposite pattern for mean error rate (ER). Critically, in the three-choice task, response-repetition costs in task switches were significant in both RT and ER. Since a bias to switch the response cannot prime a specific response alternative in a three-choice task, we conclude that such a bias cannot account for response-repetition costs in task-switch trials.

An Experimental Study on Automatic Traffic Light System using IR Sensors

Traffic jam turns out to be key crisis in these days. Traffic jam mainly occurs in urban areas. Due to traffic jam, there are several problems arise such as increase in noise pollution, air pollution, accidents and delay in travel time etc. The present traffic signals deployed in all parts of the cities are not enough to solve above mentioned problems because these have specific pre- determined time for red and green signals. In this view various attempts were done for traffic lights to behave smartly based on density of vehicles on the road. Therefore, many techniques have been used in traffic control systems. This paper summarizes different techniques of traffic control system that were used for the improvement of conventional traffic control system. Congestion is a serious issue due to vehicular traffic. One of the known causes of traffic congestion is the amount of time spend waiting for the red light to change to green. The changing of traffic light is hard-coded and it is not reliant on traffic volume. There is therefore need to simulate and optimize traffic control to better accommodate density based traffic rather than time based. This system attempts to lessen Possibilities of traffic jams brought about by traffic lights to a reasonable degree. This project, a density-based traffic control system is been implemented to solve this problem. The system entails programming an Arduino using Arduino integrated development environment to enable traffic lights give the right of access to the road by selecting the lane with the high number of cars. The traffic lights are modified to chip away at an auspicious premise until there is a signal identified by the infrared sensors. The sensor identifies an object (i.e., a vehicle, a motorcycle etc.) and signals the Arduino to control the traffic lights for its individual path. Once there is no sign identified by any of the four sensors the traffic lights keep on dealing with an auspicious premise. The mean response time of the sensor was found to be 0.39 seconds. Further research is recommended to produce the device on a large scale to be deployed to all roads in the country.

Tackling Heterogeneous Traffic in Multi-access Systems via Erasure Coded Servers

In cloud systems, the number of servers is fixed, and each server is usually dedicated to a job type. However, the traffic of various jobs can vary across time, and hence, a rigid allocation of servers does not perform well. In this paper, we propose the addition of erasure-coded servers that can flexibly serve multiple job types without additional storage cost. We show that coding expands the service capacity region, thus enabling the system to handle variable traffic. Moreover, we characterize the response time of the coded system in various arrival rate regimes and show that adding even a small number of coded servers can significantly reduce the mean response time.

Performance Analysis of Modified SRPT in Multiple-Processor Multitask Scheduling

In this paper we study the multiple-processor multitask scheduling problem in both deterministic and stochastic models, where each job have several tasks and is complete only when all its tasks are finished. We consider and analyze Modified Shortest Remaining Processing Time (M-SRPT) scheduling algorithm, a simple modification of SRPT, which always schedules jobs according to SRPT whenever possible, while satisfying the non-preemptive constraint. The M-SRPT algorithm is proved to achieve a competitive ratio of θ(log α + β) for minimizing response time, where α denotes the ratio between maximum job workload and minimum job workload, β represents the ratio between maximum non-preemptive task workload and minimum job workload. In addition, the competitive ratio achieved is shown to be optimal (up to a constant factor), when there are constant number of machines. We further consider the problem under Poisson arrival and general workload distribution (i. e., M/GI/N system), and show that M-SRPT achieves asymptotic optimal mean response time when the traffic intensity ρ approaches 1, if job size distribution has finite support. Beyond finite job workload, the asymptotic optimality of M-SRPT also holds for infinite job size distributions with certain probabilistic assumptions, for example, M/M/N system with finite task workload.

Patient Satisfaction and Utilization of Ambulance Services in Prehospital Services at a Tertiary Care Hospital: A Cross-Sectional Study in Peshawar, Khyber Pakhtunkhwa, Pakistan

ObjectivePatients reporting to emergency departments frequently use different ambulance services; therefore, the measurement of patient satisfaction is relevant to encouraging those services to meet patient expectations. The aim of this study was to determine the patients’ satisfaction and utilization of different ambulance services at a tertiary health care hospital in Peshawar relating to prehospital services. MethodsThis cross-sectional study was conducted at Lady Reading Hospital, Peshawar, Khyber Pakhtunkhwa, Pakistan, from July 2019 to January 2020 using a consecutive sampling technique with a total sample size of 378. The patients reporting to the emergency department using any ambulance service were included in this study. Different types of ambulance services were used as an outcome variable. Proportions were compared for the categoric variables using the chi-square test, whereas the 1-way analysis of variance test was used to determine the mean response time and age. Results were considered significant at a P value ≤ .050. All analyses were completed using SPSS version 20 (IBM Corp, Armonk, NY). ResultsOf the total 378 study participants, approximately 166 (43.9%) used Rescue 1122 services, 99 (26.2%) used private ambulance services, and 44 (11.6%) used public ambulance services. Road traffic accidents were the most common complaint by 98 (25.9%, P < .003) participants. The mean response time for Rescue 1122 was 13.2 ± 18 minutes followed by the Chippa Foundation (private) at 17.8 ± 20 minutes (P < .005). Males (n = 254) were the predominant users of all services. Participants from the urban region (n = 112) used Rescue 1122, whereas the public ambulance service was used only by 31 patients (P < .005). Among all the ambulance services, 19 (61.3%) participants were not satisfied with the Chippa service regarding vehicle cleanliness, whereas participants were highly satisfied with Rescue 1122. ConclusionOverall, the patients were more satisfied with the services provided by the Rescue 1122 ambulances compared with all other ambulance services.

Contrast Increment and Decrement Processing in Individuals With and Without Diabetes.

Animal models suggest that ON retinal ganglion cells (RGCs) may be more vulnerable to diabetic insult than OFF cells. Using three psychophysical tasks to infer the function of ON and OFF RGCs, we hypothesized that functional responses to contrast increments will be preferentially affected in early diabetes mellitus (DM) compared to contrast decrement responses. Fifty-two people with DM (type 1 or type 2) (mean age = 34.8 years, range = 18-60 years) and 48 age-matched controls (mean age = 35.4 years, range = 18-60 years) participated. Experiment 1 measured contrast sensitivity to increments and decrements at four visual field locations. Experiments 2 and 3 measured visual temporal processing using (i) a response time (RT) task, and (ii) a temporal order judgment task. Mean RT and accuracy were collected for experiment 2, whereas experiment 3 measured temporal thresholds. For experiment 1, the DM group showed reduced increment and decrement contrast sensitivity (F (1, 97) = 4.04, P = 0.047) especially for the central location. For experiment 2, those with DM demonstrated slower RT and lower response accuracies to increments and decrements (increments: U = 780, P = 0.01, decrements: U = 749, P = 0.005). For experiment 3, performance was similar between groups (F (1, 91) = 2.52, P = 0.137). When assessed cross-sectionally, nonselective functional consequences of retinal neuron damage are present in early DM, particularly for foveal testing. Whether increment-decrement functional indices relate to diabetic retinopathy (DR) progression or poorer visual prognosis in DM requires further study.

Visual function in eyes with diffractive extended depth-of-focus and monofocal intraocular lenses: 2-year comparison.

To compare long-term visual function after implantation of diffractive extended depth-of-focus (EDF) intraocular lenses (IOLs) using echelett optics and monofocal IOLs with the same platform. In this prospective comparative case series, diffractive EDF or monofocal IOLs were implanted binocularly and followed up for 2years. At the last visit, distance-corrected binocular visual acuities were measured at distances of 0.3, 0.5, 0.7, 1, 2, 3, and 5m. Photopic and mesopic contrast sensitivity was also examined. Dynamic visual function was evaluated in terms of functional visual acuity (FVA), standard deviation of visual acuity (SDVA), visual maintenance ratio (VMR), mean response time, and number of blinks. The outcomes were compared between the two IOLs, and the influence of posterior capsule opacification (PCO) on contrast sensitivity and FVA was examined. Binocular visual acuity of eyes with EDF IOLs was better at distances of 0.5 and 0.7m than that of eyes with monofocal IOL (P < 0.026). There were no differences in binocular visual acuity at other distances, contrast sensitivities, or dynamic visual functions. The influence of PCO on the visual functions was not found in eyes with EDF IOLs. Up to 2years postoperatively, eyes with diffractive EDF IOLs sustained superior intermediate visual acuity together with visual function comparable to that of eyes with monofocal IOLs.