Visual Demands Research Articles

The Visual Working Memory Demands of Processing Conventional Metaphoric Language

Abstract According to the conceptual metaphor theory (CMT; Lakoff & Johnson, 1980), conceptual metaphors, such as “Life is a journey,” are used to map the characteristics of abstract domains (e.g., life) onto more accessible concrete domains (e.g., a journey). Uses such as “dead-end job” and “they’re on the right track” are manifestations of this conceptual metaphor. When and how these mappings might be created remains unclear. Bowdle and Gentner’s (2005) career of metaphor hypothesis suggests that metaphors in “X is a Y” form (e.g., “a lawyer is a shark”) undergo a change in the mode of processing as those metaphors transition from novel conceptual pairings to familiar ones. The current study asks whether the associations between conceptually related concepts are accessed while the metaphoric language is processed in working memory (WM) and, if so, whether the role of WM is moderated by familiarity. If processing linguistic applications of conceptual metaphors involves active access of the concrete source domain, processing metaphoric language, like the concrete language it is being mapped onto, should involve activation of concrete representations and recruit more visual WM resources than literal abstract language. Experiment 1 found no difference in the visual WM demands of processing literal language and conventional expressions of conceptual metaphors. Experiment 2 found that novel expressions of conceptual metaphors placed greater demands on visual WM than familiar expressions. Together, these data provide some support for CMT but suggest that familiarity of the linguistic form of the metaphor plays a role in determining processing modality.

Driver Situation Awareness and Perceived Sleepiness during Truck Platoon Driving – Insights from Eye-tracking Data

ABSTRACT Truck platoon driving technology uses vehicle-to-vehicle communication to allow one truck to follow another in an automated fashion. The first vehicle is operated manually, the second vehicle is driven semi-automatically once platoon-mode is activated. In this mode, the driver merely has to monitor traffic. Semi-automated driving in passenger cars has been shown to increase driver sleepiness and reduce situation awareness. The aim of the present study was to gain first insights whether this also applies to semi-automated platoon driving and whether platoon-specific situations pose special visual demands. In a first on-road experiment, ten professional truck drivers experienced a two-vehicle platooning system on a German highway as platoon follower or leader. In addition, all drivers conducted reference drives with a single truck. Driver situation awareness was measured with eye-tracking recordings, perceived sleepiness with subjective ratings. The results showed that the lead vehicle drivers kept their eyes less time on the road ahead as compared to normal truck driving. In particular in situations that required decoupling, drivers (in the lead vehicle as well as in the following vehicle) spent about 40% of fixations on the HMI. That is, situation awareness was reduced, amounting to potentially risky behavior, as the platoon goes blindfolded when both drivers attend to the display. Drivers did not report higher perceived sleepiness in semi-automated platoon drives than in the manual reference drives. Adequate solutions to reduce the time spent looking away from the road are required. Head-up displays should be investigated for this purpose, as they can simplify driver communication and present platoon-specific information while the eyes remain on the road.

Increased visual and cognitive demands emphasize the importance of meeting visual needs at all distances while driving.

Having an optimal quality of vision as well as adequate cognitive capacities is known to be essential for driving safety. However, the interaction between vision and cognitive mechanisms while driving remains unclear. We hypothesized that, in a context of high cognitive load, reduced visual acuity would have a negative impact on driving behavior, even when the acuity corresponds to the legal threshold for obtaining a driving license in Canada, and that the impact observed on driving performance would be greater with the increase in the threshold of degradation of visual acuity. In order to investigate this relationship, we examined driving behavior in a driving simulator under optimal and reduced vision conditions through two scenarios involving different levels of cognitive demand. These were: 1. a simple rural driving scenario with some pre-programmed events and 2. a highway driving scenario accompanied by a concurrent task involving the use of a navigation device. Two groups of visual quality degradation (lower/ higher) were evaluated according to their driving behavior. The results support the hypothesis: A dual task effect was indeed observed provoking less stable driving behavior, but in addition to this, by statistically controlling the impact of cognitive load, the effect of visual load emerged in this dual task context. These results support the idea that visual quality degradation impacts driving behavior when combined with a high mental workload driving environment while specifying that this impact is not present in the context of low cognitive load driving condition.

The Impact of In-Vehicle Voice Interaction System on Driving Safety

The development of intelligent connected vehicle (ICV) makes voice interaction an important interaction method in the car. The voice interaction system supports natural speech recognition and can complete a large number of secondary tasks. This paper is based on the Chinese market and 5 ICVs are screened out. Application scenarios for voice interaction systems are constructed through pre-survey. Using simulated driving platform which can be connected with mass-produced vehicle, data on visual demand can be obtained. From the visual demand aspects, the corresponding indicators are selected to analyze the impact of in-vehicle voice interaction system on driving safety.

Yoga Ocular Exercises to Maintain Eye Health During Work and Distance Learning in the New Normal Era

The COVID-19 outbreak is a challenge for the world of work and education to change all activities from face-to-face system into remote system with internet and technology-based online system. These online activities lead to increased exposure from digital screen such as computers and mobile phones in the society. Viewing a computer or digital screen often makes our eyes work harder, this high visual demands of digital screen display makes many people susceptible to the development of vision-related symptoms. This article aims to determine the effect of yoga ocular exercises on eye fatigue and increase eye health The method we used was a literature study that focused on yoga ocular interventions in overcoming eye fatigue with databases in the form of PubMed, Willey, Proquest and, Google Scholar published in 2015-2020. Through a review of 8 selected articles, the results showed that yoga ocular practice provides benefits in the form of reduce eye fatigue, relax the mind, prevent asthenopia symptoms, improve binocular vision function by increasing the efficiency of eye motility muscles, and also reduce the intraocular pressure in glaucoma patients. Through the review, it can be seen that yoga ocular practice can prevent vision problems and maintain eye health in the new normal era

Effect of digital device use during COVID-19 on digital eye strain

ABSTRACT Clinical relevance Home-isolation and social distancing during the COVID-19 pandemic caused increased use of digital devices, posing a greater risk of developing digital eye strain-related symptoms. Eye-care professionals should educate patients about limiting screen time and managing digital eye strain symptoms. Background This study aimed to evaluate the COVID-19 isolation’s impact on digital device use by comparing hours spent on digital devices before and during the 24-hour curfew in Saudi Arabia, while assessing the symptoms associated with digital eye strain. Methods A self-reported questionnaire was used to compare the total hours per day, either continuous or intermittent, spent on digital devices during and before curfew, and the association of these durations with digital eye strain. Results A total of 1,939 participants, (mean ± SD: 33 ± 12.2 years and 72% women) were recruited. Results showed a significant difference between usage duration before and during curfew. Digital eye strain incidence was 78% during the curfew. Chi-squared analysis indicated most symptoms are associated with usage duration and employment status. Multivariate analysis revealed significant associations between digital eye strain and the following factors: using more than one device (odds ratio 1.208, 95% confidence interval: 1.068-1.3661), age, optical correction, employment status, gender, using rewetting drops, and usage duration. Conclusions In this population, prolonged use of digital devices significantly increased during home-isolation. Digital eye strain incidence increased during curfew. Regular eye exams should be encouraged to ensure the use of optimum prescription use and meet the specific visual demands required for the use of digital devices. Eye-health strategies and awareness campaigns should be employed on the importance of regular eye exams, decreasing screen time, practising the 20-20-20 rule, and the use of rewetting drops to help reduce the symptoms of digital eye strain during this period.

Multifractal roots of suprapostural dexterity.

Visually guided postural control emerges in response to task constraints. Task constraints generate physiological fluctuations that foster the exploration of available sensory information at many scales. Temporally correlated fluctuations quantified using fractal and multifractal metrics have been shown to carry perceptual information across the body. The risk of temporally correlated fluctuations is that stable sway appears to depend on a healthy balance of standard deviation (SD): too much or too little SD entails destabilization of posture. This study presses on the visual guidance of posture by prompting participants to quietly stand and fixate at distances within, less than, and beyond comfortable viewing distance. Manipulations of the visual precision demands associated with fixating nearer and farther than comfortable viewing distance reveals an adaptive relationship between SD and temporal correlations in postural fluctuations. Changing the viewing distance of the fixation target shows that increases in temporal correlations and SD predict subsequent reductions in each other. These findings indicate that the balance of SD within stable bounds may depend on a tendency for temporal correlations to self-correct across time. Notably, these relationships became stronger with greater distance from the most comfortable viewing and reaching distance, suggesting that this self-correcting relationship allows the visual layout to press the postural system into a poise for engaging with objects and events. Incorporating multifractal analysis showed that all effects attributable to monofractal evidence were better attributed to multifractal evidence of nonlinear interactions across scales. These results offer a glimpse of how current nonlinear dynamical models of self-correction may play out in biological goal-oriented behavior. We interpret these findings as part of the growing evidence that multifractal nonlinearity is a modeling strategy that resonates strongly with ecological-psychological approaches to perception and action.

Response of multiple demand network to visual search demands

Neuroimaging studies for human participants have shown that the activity in the multiple-demand (MD) network is associated with various kinds of cognitive demand. However, surprisingly, it remains unclear how this MD network is related to a core component of cognition, the process of searching for a target among distractors. This was because previous neuroimaging studies of visual search were confounded by task difficulty or time on task. To circumvent these limitations, we examined human brain activity while participants perform two different visual search tasks. The performance of a task was limited by increased attentional demand, while the other task was primarily limited by poor quality of input data or neural noise. Throughout the MD network, increased activity and strengthened functional connectivity among the MD regions were observed under the search task recruiting capacity-limited attentional resources. The present findings provide unequivocal evidence that the MD network mediates visual search, as well as other capacity-limited cognitive processes.

Visual demand, visual ability and vision standards for hairdressers - An observational study from Chennai, Tamil Nadu.

Purpose:The aim of this study was to create vision standards for various tasks performed by hairdressers and to assess the spectacle compliance and its impact at work.Methods:The observational cross-sectional study enrolled hairdressers in and around Chennai, Tamil Nadu. It was done in three phases: (i) Job profiling from visual task analysis, creating vision standards for various hairdressing tasks and arriving at test protocols; (ii) Comprehensive eye examination, and (iii) Assessment of spectacle compliance and its impact on work. Descriptive analysis using Microsoft Excel and SPSS (IBM SPSS Statistics Version 21.0) was performed.Results:There were 305 participants with a mean age of 48 (SD ± 12) years. The visual acuity demand was found to be 6/18 and N15, for distance and near, respectively. Appropriate spectacles were prescribed for 203 (67%) hairdressers. Even with the best possible refractive correction, a few hairdressers did not meet the distance (13) and near (11) visual acuity standard. In all, 54 hairdressers were referred for further examination to a tertiary eye care center for lenticular changes, retinal abnormalities, and glaucoma screening. Among the subjects who were dispensed with spectacles, 181 (86%) were available for telephonic spectacle compliance assessment, and 164 (90%) were compliant with spectacle usage at work. Improved visual ability was reported by 133 (81%) hairdressers at work.Conclusion:This study provides vision standards for hairdressers. From the visual task analysis, hairdressing tasks were found to be visually demanding and hazardous. The study emphasizes that providing appropriate spectacle correction showed a clinically evident positive impact at work.

Evaluation Of The Reading Speed Of Near Visual Acuity After Providing Low Vision Intervention

BACKGROUND: The prevalence of low vision has been increased overtime. So many different types of low vision devices were developed within few years. From so many studies, it has been proved that low vision rehabilitation is the better option for low vision patients to improve their quality of life. Low vision rehabilitation will improve quality of life of patients by enhancing their residual vision for distance as well as for near activities. Reading speed for near activities is also an important part for development of reading ability, their confidence and their performance. So, in this study, reading speed will be measured with the help of MN Read chart (continuous text chart) and thereby evaluate improvement in reading speed after providing low vision devices for near. METHOD: This study is cross sectional in which 102 Patients were enrolled in the study visited at Shri C. H. Nagri Municipal Eye hospital (Tertiary eye care center). All patients were undergoing a standardized ophthalmological examination. Best corrected visual acuity for distance and near has been assessed. Starting point of magnification required for low vision patients has been calculated and was finalized according to their visual ability, needs and demands, occupation and affordability. Then, according to needs of Low Vision Patients, Low Vision Intervention has been given with proper training and finally Reading Speed being measured with final recommended Low Vision Aid. After provision of low vision aids, reading speed is evaluated using standardized MN Read text chart. Reading speed has been measured according to Word per Minute formula. RESULTS: 102 low vision patients were enrolled in the study, who visited tertiary eye care center, among which 53.92% were male population and 46.08% were female population. Mean Reading speed was 43.82±24.73 wpm after provision of low vision aids for the whole group. Three major causes were found more common; Chorio-Retinal Coloboma (22.54%), Retinal detachment (15.68%) and Retinitis Pigmentosa (13.72%). The management of all low Vision patients was found to be different for distance and near according to the patients Visual Acuity, needs and affordability. CONCLUSION:This indicates the great value of low vision rehabilitation through adequate providing of low vision aids for the improvement of reading ability. Low vision Intervention will help patient to maintain and regain their reading ability, which can lead to an increase in independency, mental ability, confidence and quality of life.

Actual Visual Acuity Demands in the Classroom

Purpose: To address the knowledge gap regarding the actual acuity requirements needed in typical kindergarten through grade 12 classrooms by determining an actual logarithm of the minimum angle of resolution (logMAR) and contrast sensitivity requirements in a sample of classrooms for kindergarten through grade 12 in New York City. Methods: Measurements of classroom dimensions with specific attention to viewing distances were made in public and private school classrooms, at various grade levels from kindergarten through grade 12, in New York City. The dimensions of typical text shown to students on classroom smartboards and whiteboards was measured and the mean and range of logMAR values were calculated for various seating locations within the classrooms. Contrast between text and background was estimated by comparing digital images of actual classroom text to Pelli-Robson contrast sensitivity charts. Results: Fourteen classrooms in five schools were evaluated. Classroom dimensions varied from 8 × 10 feet to 23 × 23 feet. Mean logMAR values of lower case text on smartboards and whiteboards varied from 0.93 ± 0.29 (range: 0.83 to 1.32) in the center of the front row to 0.46 ± 0.21 (range: 0.10 to 0.79) in the center of the back row ( P < .001). Contrast was also variable, being highest for black markers on whiteboards (0.00) and lowest on smartboards (0.15 to 0.60). Neither logMAR nor contrast sensitivity values varied significantly by grade level or school ( P > .50 for both). Conclusions: The data reveal that logMAR demands and contrast vary substantially from classroom to classroom and within a classroom based on room dimensions and seating. Although generally supporting current acuity-based pediatric vision screening referral guidelines, the data also provide insight into the potential impact of reduced visual acuity and seating location on visual performance in the classroom. These findings suggest the need to develop logMAR and contrast standards that optimize visual content in classrooms while accommodating a wider range of visual capabilities. [ J Pediatr Ophthalmol Strabismus . 2021;58(1):48–54.]

Cartographic visualization of density: exploring the opportunities and constraints of Heat Maps

Abstract The authors of the review aim to understand and assess cartographic Heat Maps’ (HM) designs, tools, and applications. The paper consists of two parts. First describes HM in the context of neocartography and map design by tackling such issues as definition, input data, methods of density determination and generalization, colour schemes, legend construction, and base maps. The second part assesses the range of 17 tools used for creating HM. Tools are divided into non-GIS tools (visualization tools and programming libraries) and GIS applications (desktop and webGIS). GIS desktop software has been selected due to its popularity and wide application. Paper presents an expert assessment of this software with the use of a research questionnaire. The analysis made it possible to develop a division of tools based on their embedding in computer programs and applications and taking into account the types of visualization. It also made it possible to indicate tools that can be used by both professional GIS users (e.g. analysts, cartographers) and the general public, including teachers using HM to visualize geo data for geography lessons. The limitation of the review was the analysis from the expert’s point of view. It would be desirable to include novices perspectives in future studies due to the wide demand for visualization.

Eye-head coordination and dynamic visual scanning as indicators of visuo-cognitive demands in driving simulator.

Driving is an everyday task involving a complex interaction between visual and cognitive processes. As such, an increase in the cognitive and/or visual demands can lead to a mental overload which can be detrimental for driving safety. Compiling evidence suggest that eye and head movements are relevant indicators of visuo-cognitive demands and attention allocation. This study aims to investigate the effects of visual degradation on eye-head coordination as well as visual scanning behavior during a highly demanding task in a driving simulator. A total of 21 emmetropic participants (21 to 34 years old) performed dual-task driving in which they were asked to maintain a constant speed on a highway while completing a visual search and detection task on a navigation device. Participants did the experiment with optimal vision and with contact lenses that introduced a visual perturbation (myopic defocus). The results indicate modifications of eye-head coordination and the dynamics of visual scanning in response to the visual perturbation induced. More specifically, the head was more involved in horizontal gaze shifts when the visual needs were not met. Furthermore, the evaluation of visual scanning dynamics, based on time-based entropy which measures the complexity and randomness of scanpaths, revealed that eye and gaze movements became less explorative and more stereotyped when vision was not optimal. These results provide evidence for a reorganization of both eye and head movements in response to increasing visual-cognitive demands during a driving task. Altogether, these findings suggest that eye and head movements can provide relevant information about visuo-cognitive demands associated with complex tasks. Ultimately, eye-head coordination and visual scanning dynamics may be good candidates to estimate drivers' workload and better characterize risky driving behavior.

Perspectives of a new sport-specific Para Shooting classification system for athletes with vision impairment

ABSTRACT The International Paralympic Committee (IPC) and individual sports federations have established the need to develop evidence-based systems of classification for athletes with vision impairment (VI) that may differ depending on the visual demands of each sport. As a consequence, research has been conducted that led to a new classification system for athletes competing in VI shooting. The purpose of this study was to canvas the experiences of key stakeholders (athletes, coaches and classifiers) when the new system of classification was implemented. Twenty-eight participants (17 athletes, 7 coaches and 4 classifiers) completed a questionnaire to rate their experiences of the previous and new classification systems and were interviewed to gain richer insights into their opinions. It was apparent that the changes to the classification system were not adequately communicated to the athletes in particular, and that the classifiers may require a better understanding of the principles of evidence-based classification. The new system was perceived to be significantly more specific for VI shooting and intentional misrepresentation was observed to be significantly less likely than when using the old system. This research provides valuable insights into both the positive and negative experiences of key stakeholders experiencing change in a classification system.

Visual load effects on the auditory steady-state responses to 20-, 40-, and 80-Hz amplitude-modulated tones

Ignoring background sounds while focusing on a visual task is a necessary ability in everyday life. If attentional resources are shared between modalities, processing of task-irrelevant auditory information should become attenuated when attentional capacity is expended by visual demands. According to the early-filter model, top-down attenuation of auditory responses is possible at various stages of the auditory pathway through multiple recurrent loops. Furthermore, the adaptive filtering model of selective attention suggests that filtering occurs early when concurrent visual tasks are demanding (e.g., high load) and late when tasks are easy (e.g., low load). To test these models, this study examined the effects of three levels of visual load on auditory steady-state responses (ASSRs) at three modulation frequencies. Subjects performed a visual task with no, low, and high visual load while ignoring task-irrelevant sounds. The auditory stimuli were 500-Hz tones amplitude-modulated at 20, 40, or 80 Hz to target different processing stages of the auditory pathway. Results from bayesian analyses suggest that ASSRs are unaffected by visual load. These findings imply that attentional resources are modality specific and that the attentional filter of auditory processing does not vary with visual task demands.

Evidence-based Classification in Track Athletics for Athletes with a Vision Impairment: A Delphi Study.

The Delphi analysis presented here highlights the need for a sport-specific evidence-based classification system for track athletics for athletes with a vision impairment (VI). This system may differ for different race distances. Further research is required to develop a useful test battery of vision tests for classification. The issue of intentional misrepresentation during classification needs particular attention. At present, athletes with VI are placed into competition classes developed on the basis of legal definitions of VI. The International Paralympic Committee Athlete Classification Code states that all sports should have their own classification system designed to reflect the (visual) demands of that individual sport. This project gathered expert opinion on the specific requirements for an evidence-based sport-specific classification system for VI track athletics and to identify any particular issues within track athletics that require further research into their impact on sport performance. A three-round Delphi review was conducted with a panel of 17 people with expertise in VI track athletics. The panel agreed that the current classification system in VI track athletics does not completely minimize the impact of impairment on competition outcome, highlighting the need for improvements. There was clear agreement that the existing measures of vision may fail to adequately reflect the type of vision loss that would impact running performance, with additional measures required. Intentional misrepresentation, where athletes "cheat" on classification tests, remains a serious concern. The panel has identified measures of vision and performance that will inform the development of an evidence-based classification system by better understanding the relationship between VI and performance in track athletics. Issues such as the use of guides and whether the current class system was equitable gave rise to differing opinions within the panel, with these varying across the different running distances.

THE DEMOGRAPHIC PROFILE AND TASK PERFORMANCE OF LOW VISION LEARNERS ATTENDING INCLUSIVE SCHOOLS IN KAKAMEGA COUNTY, KENYA

Background: Task performance of the low vision learners is a key factor in influencing their comfort while at school and possibly cubing the increasing school dropouts in these schools. Purpose: This study aimed at investigating the task performance of low vision learners attending inclusive schools in Kakamega County. Setting: The study was conducted in public primary inclusive schools which hosts low vision learners in Kakamega County, Kenya. Methods: A census survey identified 21 low vision learners attending 11 primary public inclusive schools in Kakamega County. Out of the 21 low vision learners who were selected, 19 (90.5%) were assessed. The participants were guided to respond to a functional vision questionnaire, the LV Prasad Functional Vision Questionnaire, which was meant to elicit their ease of performing activities of daily living. Data was entered into SPSS version 25 software and analyzed using descriptive statistics. Data was summarized and presented using tables. Results: There were 13 (68.4%) males and 6 (31.6%) females who participated in this study. Participants were aged between 10 and 21 years old. The mean age was 14 while the modal age was 13 years. The highest number of low vision learners, six (31.6%), were in grade eight while the lowest number recorded, one each (5.3%), were in grades two and three. There was poor performance in the activities of daily living among the participants, which majorly included difficulty in participation in sports and games (78.9%), reading (89.5%) and orientation and mobility (57.9%). The findings enabled the study to determine the status of day-to-day task -performance at school. Conclusion: Most low vision learners attending inclusive schools have difficulty in performance of activities of daily living hence the need to device ways of addressing their visual demands in an inclusive school set-up.
 
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Preference and visual cognitive processing demands of alphabetic and QWERTY keyboards of individuals with and without brain injury

ABSTRACT Following a severe brain injury (BI), some literate individuals who require augmentative and alternative communication (AAC) strategies to support communication may benefit from the use of onscreen keyboards to generate text. A range of layouts are available to these individuals within specialized communication software. However, a paucity of information is available to describe user preferences, user perceptions, as well as the visual-cognitive processing demands of such layouts. Such information is critical to guide clinical decision-making for keyboard selection and to provide patient-centered services. This study: (a) described the preferences and perceptions of two onscreen keyboard layouts (QWERTY and alphabetic) and (b) used eye-tracking analysis to investigate the visual-cognitive processing demands between these onscreen keyboards for individuals with and without BI. Results indicated participants in both groups held a strong preference for QWERTY keyboard interfaces and had extensive prior experience using the QWERTY keyboard layout on mobile devices. Eye-tracking analysis revealed less visual-cognitive processing demands using a QWERTY keyboard layout for both groups but were only statistically significant for those without BI. Results suggest that use of a keyboard layout that aligns with client preferences and prior experiences (i.e., the QWERTY keyboard for these participants) may lead to increased satisfaction with the communication experience and increased communication efficiency.

A systematic mapping of feature extraction and feature selection methods of electroencephalogram signals for neurological diseases diagnostic assistance

Electroencephalogram (EEG) is a non-invasive tool used to monitor the electrical activities of the brain. EEG signal analysis has several applications in the medical field. It is widely used for clinical diagnostics and for advances in the Brain-Computer Interface (BCI) area. In recent years, several studies about the automatic execution of this analysis have been proposed, motivated by the fact that the visual inspection demands a long time from an expert, besides being subject to a misdiagnosis. In order to extract and select relevant information from recordings of brain electrical activity, many computerized analysis methods have been developed based on different approaches. Although some proposed methods have achieved good performance, many of them are not suitable for real-world application due to their high computational cost. Thus, there is opportunity in the area to identify and categorize techniques in order to support studies about the influence of these techniques on diagnostic performance and to propose the optimization of this task. In this context, this Systematic Mapping evaluates the 144 primary studies identified according to the criteria defined in the protocol. The purpose is to highlight which neurological disorders have been studied in recent years and which techniques for feature extraction and feature selection have been applied during signal analysis, individually or jointly, to provide specifically an automatic diagnosis of a neurological disorder using a classifier.

Effects of visual short-term memory load and attentional demand on the contrast response function.

Visual short-term memory (VSTM) load leads to impaired perception during maintenance. Here, we fitted the contrast response function to psychometric orientation discrimination data while also varying attention demand during maintenance to investigate: (1) whether VSTM load effects on perception are mediated by a modulation of the contrast threshold, consistent with contrast gain accounts, or by the function asymptote (1 lapse rate), consistent with response gain accounts; and (2) whether the VSTM load effects on the contrast response function depend on the availability of attentional resources. We manipulated VSTM load via the number of items in the memory set in a color and location VSTM task and assessed the contrast response function for an orientation discrimination task during maintenance. Attention demand was varied through spatial cuing of the orientation stimulus. Higher VSTM load increased the estimated contrast threshold of the contrast response function without affecting the estimated asymptote, but only when the discrimination task demanded attention. When attentional demand was reduced (in the cued conditions), the VSTM load effects on the contrast threshold were eliminated. The results suggest that VSTM load reduces perceptual sensitivity by increasing contrast thresholds, suggestive of a contrast gain modulation mechanism, as long as the perceptual discrimination task demands attention. These findings support recent claims that attentional resources are shared between perception and VSTM maintenance processes.