Low Luminance Levels Research Articles

15‐4: Improvement of Gradation and Color Shift in Dark Luminance Area with Signal Correction for OLED displays

In recent years, OLED displays have been widely used in smartphones, in‐vehicle displays, and so on. Such applications require a dimming function that responds to external ambient light. It is also necessary to achieve precise gradation and color reproducibility in low luminance levels in dark environments. In this paper, we address two problems of gradation collapse in low luminance levels during low luminance dimming using PWM‐ driven duty ratio control, and color shift due to current leakage between sub‐pixels. In addition, we propose a correction method for improving gradation reproducibility and color reproducibility, using luminance correction.

P‐13: Picture Quality of In‐Plane Switching Liquid Crystal Displays with Deep Black

In‐Plane Switching (IPS) liquid crystal display (LCD) is one of leading technologies in display industrials because of its superior picture quality. This paper provides picture quality of high contrast IPS LCD in terms of color contrast, dynamic range, color expression and PQ‐EOTF accuracy in HDR compared to conventional IPS LCD. Furthermore, to evaluate its performance as a gaming display, reaction time between two IPS LCDs have different contrast ratio was tested. Experimental results indicate that observer's reaction time for high contrast IPS LCD was faster than conventional IPS LCD because of superior color contrast and color gamut at low luminance level.

A Revised Formulation based on CIECAM16 for Cross-media Colour Reproduction via Real Scene Experiment

In order to reproduce the colour appearance between real scene and images on self-luminous display, this study conducted a series of psychophysical experiments using threshold method. Three types of real scenes were built up in a lighting room, including painting, fruit and vegetable, skin colour chart. Sixteen adapting conditions were designed including four CCTs (3000K, 4500K, 6500K, 8000K) and 4 luminance levels (10lux, 100lux, 500lux, 1000lux). Four displays with different sizes were studied. The result indicated that the colour appearance of real scene and the image on the display were different, especially for low CCT and luminance level. The contents of scene and size of display didn’t show a significate impact. The prediction performance of CIECAM16 was tested, and a revised formulation was proposed with high accuracy.

An assessment of ambient noise and other environmental variables in a nonhuman primate housing facility.

Acoustic noise and other environmental variables represent potential confounds for animal research. Of relevance to auditory research, sustained high levels of ambient noise may modify hearing sensitivity and decrease well-being among laboratory animals. The present study was conducted to assess environmental conditions in an animal facility that houses nonhuman primates used for auditory research at the Vanderbilt University Medical Center. Sound levels, vibration, temperature, humidity and luminance were recorded using an environmental monitoring device placed inside of an empty cage in a macaque housing room. Recordings lasted 1 week each, at three different locations within the room. Vibration, temperature, humidity and luminance all varied within recommended levels for nonhuman primates, with one exception of low luminance levels in the bottom cage location. Sound levels at each cage location were characterized by a low baseline of 58-62 dB sound pressure level, with transient peaks up to 109 dB sound pressure level. Sound levels differed significantly across locations, but only by about 1.5 dB. The transient peaks beyond recommended sound levels reflected a very low noise dose, but exceeded startle-inducing levels, which could elicit stress responses. Based on these findings, ambient noise levels in the housing rooms in this primate facility are within acceptable levels and unlikely to contribute to hearing deficits in the nonhuman primates. Our results establish normative values for environmental conditions in a primate facility, can be used to inform best practices for nonhuman primate research and care, and form a baseline for future studies of aging and chronic noise exposure.

Colour Difference Formula for Photopic and Mesopic Vision Incorporating Cone and Rod Responses

The standard colour difference formulas, such as CIEDE2000, operate on colours defined by cone-fundamentals, which ignore the influence of rods on colour perception. In this work, we combine the rod intrusion model by Cao et al. with the popular CIEDE2000 colour difference formula and validate the accuracy of the new formula on three contrast sensitivity datasets. When compared with the standard CIEDE2000 formula, the new colour difference formula improves the perceptual uniformity of the space at low luminance levels.

75‐4: Low Luminance JND and JNCD

As demands for display uniformity at very low luminance are increasing, the importance of accurate JND and JNCD as display quality standard is growing. Perceptional experiments to find out JND and JNCD at a very low luminance level were carried out and the color and luminance difference values at which 50% of people noticed were obtained, which were not accessible in the past.

Perceived contrast on displays with different luminance ranges.

PurposeMedical displays are fundamental in today's healthcare since they provide the link between digitally stored data and the human clinician, and it is thus important that the transfer of information is as effective and reliable as possible. Contrast perception in viewed images is complex due to the nature of the human visual system, and the luminance distribution in the viewed scene plays a major role. Standards and guidelines concerning medical displays are important as they set a baseline image quality. However, as the number of imaging applications as well as display technology has evolved rapidly during the past decades, there may be possible uses not foreseen in the current guidelines. Bright screens may perform as good in bright rooms as less bright displays do in dark rooms, but current guidelines are likely to favor dark rooms due to historical reasons. The purpose of this study was to determine the limits of contrast perception in three very different lighting conditions and relate the outcome to guideline recommendations.MethodsThree different display luminance settings were studied, 1–250, 6–500, and 12–750 cd/m2 with luminance ratios of 250, 85, and 62, respectively. Although the luminance ratios, black levels, and white levels were different, they all covered the same number of just noticeable differences (JNDs). By using a two‐alternative forced‐choice method, contrast thresholds were determined at dark, mid‐gray, and bright pixel values for all luminance settings using bar patterns with two different spatial frequencies. In total, 18 contrast thresholds were determined by each of the 10 observers.ResultsThe contrast thresholds for the low‐frequency patterns were close to 0.5 JNDs and there were no systematic differences between the three luminance conditions at any of the pixel values. The high‐frequency patterns required almost 10 times higher contrast where the highest contrast threshold (worst visibility) was obtained for the luminance setting 1–250 cd/m2 at the dark pixel value.ConclusionsThe differences between the three luminance conditions were mostly minor, which indicate that display settings with low luminance ratios and high minimum luminance levels can be used without compromising displayed image contrast. The number of JNDs enclosed by the luminance range of a display is a reliable metric for global perceived contrast. Luminance ratios are limited regarding the ability to detect low contrast objects when there are large differences in luminance, although they can still be used within a relatively small range of luminance levels. Low luminance levels may cause a loss of visibility, especially for fine details, and should be avoided.

Contributed Session III: Global Luminance and Local Contrast Modulate Interocular Delay in Virtual Reality

Virtual reality (VR) systems take advantage of depth cues to create immersive environments that simulate a three-dimensional world. Most often these cues provide consistent information about depth, but on occasion, such cues conflict with each other to create compelling phenomena that illustrate the function of underlying mechanisms. Here we examine the interaction of depth produced by local contrast, global luminance, and interocular luminance differences (i.e., a Pulfrich effect). We measure depth perception with two adjustment tasks. 1: Two moving streams of balls, one upwards (the standard) and the other sideways; the observer adjusts the depth of the sideways stream to lie in the same plane as the upward stream. 2: Balls move sinusoidally back and forth in the frontal plane; if depth is perceived, the pattern appears as a rotating helix. The observer adjusts the helical path until the balls appear to move in a single depth plane. We report that at low luminance levels dark balls are more effective at creating depth than bright balls; at higher luminance levels the effectiveness of dark balls decreases but the effectiveness of bright balls remains constant. Based on these data, we demonstrate how changes in the luminance of the background (or balls) can lead to shifts in the apparent depth order and the apparent direction of helical rotation. The results suggest a method for investigating potentially conflicting contributions of contrast and Pulfrich depth information.

Night Vision and Carotenoids (NVC): A Randomized Placebo Controlled Clinical Trial on Effects of Carotenoid Supplementation on Night Vision in Older Adults.

Twilight and low luminance levels are visually challenging environments for the elderly, especially when driving at night. Carotenoid rich diets are known to increase macular pigment optical density (MPOD), which in turn leads to an improvement in visual function. It is not known whether augmenting MPOD can lead to a decrease in vision related night driving difficulties. Additionally, it is unknown if carotenoid supplementation provides additional measurable benefits to one’s useful field of view (UFOV) along with a decreased composite crash risk score. The aim of the study was to evaluate changes in night vision function and UFOV in individuals that took carotenoid vitamin supplements for a six-month period compared to a placebo group. Methods: A prospective, randomized, double-blind, six-month trial of a 14 mg zeaxanthin/7 mg lutein-based supplement was carried out. Participants were randomized into active or placebo group (approx 2:1). Results: n = 33 participants (26 males/7 females) participated with 93% capsule intake compliance in the supplemented group (n = 24) and placebo group (n = 9). MPOD (mean/standard error SE) in the active group increased in the Right eye from 0.35 density units (du)/0.04 SE to 0.41 du/0.05 SE; p < 0.001 and in the Left eye from 0.35 du/0.05 SE to 0.37 du, p > 0.05). The supplemented group showed significant improvements in contrast sensitivity with glare in both eyes with improvements in LogMAR scores of 0.147 and 0.149, respectively (p = 0.02 and 0.01, respectively), monocularly tested glare recovery time improved 2.76 and 2.54 s, respectively, (p = 0.008 and p = 0.02), and we also noted a decreased preferred luminance required to complete visual tasks (p = 0.02 and 0.03). Improvements in UFOV scores of divided attention (p < 0.001) and improved composite crash risk score (p = 0.004) were seen in the supplemented group. The placebo group remained unchanged. Conclusions: The NVC demonstrates that augmenting MPOD in individuals with difficulty in night vision showed measurable benefits in numerous visual functions that are important for night vision driving in this small sample RCT. Additionally, we observed an improvement in UFOV divided attention test scores and decreased composite risk scores.

The Effect of Blue-blocking Lenses on Photostress Recovery Times.

The selective reduction in visible wavelengths transmitted through commercially available blue-blocking lenses (BBLs) is known to influence the appearance and contrast detection of objects, particularly at low light levels. This influence may impair the human retinal receptor response time to dynamic light changes during photostress events. This study aimed to assess whether BBLs selectively affect photostress recovery times (PSRTs) for chromatic and achromatic stimuli of different Weber contrasts that were viewed on a dark black background. Photostress recovery times were measured in 12 younger participants (18 to 39 years old) with no history of ocular disease or abnormal vision. Photostress recovery times were evaluated for four brands of BBLs, which were compared with a control lens. In these experiments, after exposure to an intense light source for 5 seconds, the time taken to recover vision and correctly identify a computer-generated letter stimulus viewed under low and high luminance levels was determined, which means perception is likely to be governed by mesopic and photopic conditions. Across conditions, the letter stimulus was achromatic and chromatic and could differ in luminance contrast. Under photopic stimulus conditions, although reducing luminance contrast increased PSRTs, BBLs had no significant effect on PSRTs relative to control lens. However, under mesopic stimulus conditions, BBLs significantly affect PSRTs for both achromatic (F2.006,8.02 = 61.95, P < .0001) and chromatic stimuli (F3,16 =139.01, P < .0001), particularly for blue targets, which had considerably longer PSRTs (38.40 seconds). The brand of BBL was also shown to selectively affect PSRTs, with those with transmittance profiles that block the most blue light having longer PSRTs. The present study suggests that, although the color and contrast of the target stimuli affected recovery times, the difference in recovery times between different types of BBLs was noticed only under low-light-level stimulus conditions.

A dichoptic presentation device and a method for measuring binocular temporal function in the visual system

Recent studies highlight the importance of the temporal domain in visual processing. Critical Flicker Frequency (CFF), the frequency at which a flickering light is perceived as continuous, is a widely used measure for evaluating visual temporal processing. Another important issue to investigate is the cortical interactions arising between the flicker stimuli of both eyes.This paper presents a robust and reliable dichoptic tool for evaluating the CFF threshold in both eyes. This system is based on an analog output device used to independently drive two LEDs through a custom-written MATLAB code (using a laptop PC) for eliciting sinusoidal flickering stimuli and for psychophysically measuring the perceived CFF threshold. The luminance and phases of each LED are individually controlled, enabling the investigation of the effect of phase and luminance differences on binocular summation in subjects with different ocular pathologies. Experiments were designed to evaluate the CFF threshold through a psychophysical test, based on a discrimination task with a stimulus duration of 1 s, based on a temporal alternative forced-choice paradigm. The target stimulus temporal features were modulated using the staircase method. Subjects were requested to discriminate between a target stimulus (a flickering light at various frequencies) and a flickering light at a frequency of 120 Hz, which is significantly higher than the CFF in humans; therefore, it is perceived as constant.One of the main advantages of the introduced dichoptic presentation system is that it enables the visual temporal performance to be measured under both monocular and binocular conditions where phenomena such as temporal binocular summation (BS) can be evaluated. Moreover, the system offers great flexibility by introducing a stimulus phase shift, which enables studying how stimulus timing affects the temporal function at millisecond scale resolution. Our results confirm that no crosstalk exists between the eyes and that the system can reliably separate the stimuli presented to the eyes. Using this set-up, we observed the binocular summation of CFF for low target luminance levels. The CFF was significantly (p = 0.011) higher (5.2%) under binocular compared with monocular viewing conditions. More importantly, introducing an inter - ocular phase shift reduced the binocular CFF in normally sighted subjects. Finally, in amblyopic subjects the amblyopic eye showed a decrease of 3.9 Hz (15%) in CFF, compared with the fellow eye (p = 0.001).The ability to assess binocular temporal performance using a dichoptic display can shed light on visual temporal performance in general, and on binocular temporal summation processes in particular, both for subjects with normal binocular vision and for subjects with impaired binocular vision (e.g., amblyopic subjects). Furthermore, such a presentation set-up may facilitate the development of training paradigms aimed at improving binocular vision performance.In this paper we describe the system and methods in detail and provide all necessary computer code and other details that will enable an easy and quick adaptation of the method by scientists interested in studying the temporal resolution of the visual system in general, and in studying inter-ocular differences or interactions in particular.

Background luminance effects on pupil size associated with emotion and saccade preparation

Pupil dilation is consistently evoked by affective and cognitive processing, and this dilation can result from sympathetic activation or parasympathetic inhibition. The relative contributions of the sympathetic and parasympathetic systems on the pupillary response induced by emotion and cognition may be different. Sympathetic and parasympathetic activity is regulated by global luminance level. Higher luminance levels lead to greater activation of the parasympathetic system while lower luminance levels lead to greater activation of the sympathetic system. To understand the contributions of the sympathetic and parasympathetic nervous systems to pupillary responses associated with emotion and saccade preparation, emotional auditory stimuli were presented following the fixation cue whose color indicated instruction to perform a pro- or anti-saccade while varying the background luminance level. Pupil dilation was evoked by emotional auditory stimuli and modulated by arousal level. More importantly, greater pupil dilation was observed with a dark background, compared to a bright background. In contrast, pupil dilation responses associated with saccade preparation were larger with the bright background than the dark background. Together, these results suggest that arousal-induced pupil dilation was mainly mediated by sympathetic activation, but pupil dilation related to saccade preparation was primarily mediated by parasympathetic inhibition.

Speckle noise reduction and image segmentation based on a modified mean filter

Image segmentation is an essential process in many fields involving digital images. In general, segmentation is the process of dividing the image into objects and background image. Image segmentation is an important step in the object detection process. It becomes more critical if a given image is corrupted by noise. Most digital images are corrupted by noises such as salt and pepper noise, Gaussian noise, Poisson noise, speckle noise, etc. Speckle noise is a multiplicative noise that affects pixels in a gray-scale image, and mainly occurs in low level luminance images such as Synthetic Aperture Radar (SAR) images and Magnetic Resonance Image (MRI) images. Image enhancement is an essential task to reduce specklenoise prior to performing further image processing such as object detection, image segmentation, edge detection, etc. Here, we propose a neighborhood-based algorithm to reduce speckle noise in gray-scale images. The main aim of the noise reduction technique is to segment the noisy image. So that the proposed algorithm applies some luminance to the original image. The proposed technique performs well at maximum noise variance. Finally, the segmentation process is done by the modified mean filter. The proposed technique has three phases. In phase 1, the speckle noise is reduced and the contrast adjustment is made. In phase 2, the segmentation of the enhanced image is processed. Finally, in phase 3, the isolated pixels in the segmented image are eliminated and the final segmented image is generated. This technique does not require any threshold value to segment the image; it will be automatically calculated based on the mean value.

Optical effects on HDR calibration via a multiple exposure noise-based workflow

High dynamic range (HDR) technology allows more of the lighting in a specific scene to be captured at a set point in time, and thus is capable of delivering an overall view of the scene that more closely correlates with our visual experience in the real world, compared to standard, or low dynamic range (LDR) technology. Although HDR capabilities of single exposure capture systems are improving, the traditional method for creating HDR images still includes combing a number of different exposures, captured with an LDR system, into a single HDR image. Several use cases requiring absolute calibration of the resulting HDR luminance map have been undertaken, but none of these have provided a detailed analysis of the optical effects of glare on the results. We develop a calibrated HDR radiance map, including methodical linearization of captured image data, while characterizing the limitations due to the effects of optical glare. A purposely designed controlled test scene is used to challenge the calibrated reconstruction efforts, including low luminance levels, spatial inclusion of lens vignette over the full imaged area, and optical glare. Results demonstrate that even with careful processing and recombination of the LDR data, radiometric accuracy is limited as a result of glare. The proposed approach performs better than calibration methods in commercially available HDR recombination software.

Effects of Black Luminance Level on Image Quality

The image quality is affected by the black luminance level of the image. This research aimed to investigate how low luminance levels are required to maintain image quality. The psychophysical experiment was carried out in a dark room using OLED display. Total of 6 different black luminance levels (0.003, 0.05, 0.1, 0.2, 0.3, and 1 cd/m2) were used in the experiment. Total of 20 participants was invited to evaluate the image quality. For the experiment, twelve test images are used and these test images categorized into three groups as dark, medium bright and bright image group by image histogram distribution. Each image is rendered by adjusting six different black luminance levels. Result found that the black level is higher than 0.1 cd/m2, the preference for the image is decreased. The best performance is achieved when the black level is 0.003 cd/m2, but there is no big difference from 0.1 cd/m2. The final result shows that a change in black level between about 0.003 cd/m2 and 0.1 cd/m2 does not significantly affect image quality.

Efficiency in Street Lighting Projects by Employing LED Luminaires and Mesopic Photometry

This paper discusses the importance of adapting conventional photometric quantities when lighting systems with low luminance levels are under analysis, as public lighting or external lighting in general. In this sense, it is presented an alternative methodology for lighting projects in street lighting, considering the mesopic photometry. The CIE recommendation 191:2010 proposes correc-tion factors that convert conventional photometric quantities (photopic) into quantities adapted to the corresponding mesopic level. However, a necessary parameter to obtain these correction factors is the relationship between the scotopic and photopic light fluxes of a light source (S/P ratio), which requires special equip-ment that it is not easily available to engineers, technicians and lighting designers. Thus, this paper proposes a general equation that provides the S/P ratio as a function of the correlative color temperature and the color rendering index of the light source, which are information provided in the manufacturers’ catalogs or electric lamp packages. To illustrate the application of the exper-imentally derived relationship, a typical street lighting project is considered, specifically a retrofit from HPS lamps to modern LED luminaires. In this case, the conventional routine must be changed, allowing the adaptation of conventional quantities to mesopic quantities without need for specialized equipment. The case study evidences that the use of mesopic photometry in con-junction with more appropriate technologies, such as LED lumi-naires, lead to a higher energy efficiency of the system.

The Case for Further Advancing the Performance of Displays

Timo Kunkel Robert Wanat If there is one word to describe the difference between displays today and at the turn of the last century, it’s ubiquity. Modern consumers are surrounded by displays in their everyday lives, from the mobile devices we use when on the move to the TVs we enjoy at home for entertainment to the cinema screens we watch while socializing. It has become difficult to spend a day without once looking at a display. At the same time, expectations regarding the performance of these screens have steadily increased. This motivates display manufacturers to improve the capabilities of their devices and increasingly accommodate the challenges that changing viewing environments impose. Despite those complex challenges, amazing progress has been made in the last few decades in understanding how human visual perception works and how to use that information to create displays with improved image rendering consistency, accuracy, and overall capability. Though there is still a ways to go, the viewer experience today is more compelling than it has ever been. In this edition of Information Display, we pay close attention to high-performance displays, particularly in the Frontline Technology section. The articles there are centered around high dynamic range (HDR) imaging, which is currently one of the most prominent technological subfields. We believe that the lessons about the development of HDR pipelines that are explored in this issue will also benefit other high-performance display trends, such as AR/;VR, folding displays, 8K (see page 17 for an in-depth look at this trend), and very high framerate displays. The articles also focus on cutting-edge display technologies for home entertainment and automotive applications. Both of these contexts present different and sometimes unique challenges that have to be approached with a focus on how the visual system performs within the framework of the specific environment. One example discussed in the pages ahead is the effect of screen reflections and surround light, which are major challenges for image display and therefore need to be addressed as such. We can be even more specific with this illustration: Rendering accurate colors at very low ambient luminance levels is not as important for a TV display that is observed at high peak ambient illuminance levels–for example, a living room during the daytime—as colors rendered at very low luminance levels are likely less perceivable under this condition. Rather, in this case, the benefit from ambient compensation approaches that retarget those colors to improve their visibility exceeds that of having chromatic accuracy in the low luminances. However, accurate color rendering in low luminance levels becomes crucial in dark ambient environments, such as a living room at night or in a cinema. For automotive displays, accurate low-luminance appearance becomes even more important as there is a safety factor: Information must be communicated to drivers without distracting them while they’re in traffic. Many more concepts and examples are discussed in further detail. Ultimately, each article tells a part of the story and showcases how our industry is actively working on not only improving the status quo but also seamlessly rendering more accurate image quality, regardless of how consumers want to view their content. Timo Kunkel is a senior color and imaging researcher in the CTO office of Dolby Laboratories, Inc. His main areas of interest are advanced display and imaging technologies and exploring how we can continue to bring them closer to human perception. Kunkel can be reached at Timo.Kunkel@dolby.com. Robert Wanat is a senior color scientist for Dolby Laboratories, Inc. His work revolves around creating models of the human visual system that simulate visual perception and how it is affected by changing viewing conditions. Wanat can be reached at Robert.Wanat@dolby.com.

The impact of the luminance, size and location of LED billboards on drivers’ visual performance—Laboratory tests

A proper visual performance by drivers can be ensured by, among else, a correct distribution of luminance in their field of view. At night, when the driver’s sight is adapted to low luminance levels, high luminance level objects located near the road may be a source of glare, which is not only a nuisance, but it may also blind the driver. For many years, LED billboards (light-emitting diode billboards) have been installed near roads. Such billboards are usually large, have high luminance and show dynamically changing images. These parameters have a significant impact on the drivers’ visual performance and, in turn, on road traffic safety.The study on the impact of the luminance, size and location of LED billboards on the drivers' visual performance was conducted on a volunteer group. Testing the impact of LED billboards on the visual performance of drivers in real-life conditions is very difficult. Therefore, the tests have been conducted in laboratory conditions, using a car driving simulator. The paper describes the testing procedure and tests results. The permissible luminance and areas of LED screens in two locations near the road, which significantly reduce the drivers’ visual performance in municipal traffic at night, were determined by conducting an analysis of the results. Recommendations on the permissible luminance and areas of LED billboards were formulated.

Optimum perceived-brightness level considering the practical use environment for the mobile organic light-emitting diode display

ABSTRACTThe white-luminance display is generally considered the representative value for screen brightness, but it is not always proportional to the users’ perceived brightness. The demand for the brightness of the display also changes depending on the actual use conditions, such as the ambient condition, contents, viewing object, and display device characteristics. It is important to differentiate the perceived brightness of the display by considering the device characteristics and the use conditions. A display device with a lower black level and a high saturated primary color can make the users satisfied by emitting even a relatively low luminance level. This is the result of the simultaneous contrast and Helmholtz–Kohlrausch effect. A visual experiment considering various illuminant conditions and actual use contents proved that the perceived brightness for OLED is different from the white-luminance value. It is expected that the new luminance criteria developed herein will be used for reproducing high-quality videos like those made with HDR, one of the newly rising image-quality technologies.

Google Glass Glare: disability glare produced by a head-mounted visual display.

Head mounted displays are a type of wearable technology - a market that is projected to expand rapidly over the coming years. Probably the most well known example is the device Google Glass (or 'Glass'). Here we investigate the extent to which the device display can interfere with normal visual function by producing monocular disability glare. Contrast sensitivity was measured in two normally sighted participants, 32 and 52 years of age. Data were recorded for the right eye, the left eye and then again in a binocular condition. Measurements were taken both with and without the Glass in place, across a range of stimulus luminance levels using a two-alternative forced-choice methodology. The device produced a significant reduction in contrast sensitivity in the right eye (>0.5 log units). The level of disability glare increased as stimulus luminance was reduced in a manner consistent with intraocular light scatter, resulting in a veiling retinal illuminance. Sensitivity in the left eye was unaffected. A significant reduction in binocular contrast sensitivity occurred at lower luminance levels due to a loss of binocular summation, although binocular sensitivity was not found to fall below the sensitivity of the better monocular level (binocular inhibition). Head mounted displays such as Google Glass have the potential to cause significant disability glare in the eye exposed to the visual display, particularly under conditions of low luminance. They can also cause a more modest binocular reduction in sensitivity by eliminating the benefits of binocular summation.