Active mutual conjoint estimation of multiple contrast sensitivity functions.

Recent advances in nonparametric contrast sensitivity function (CSF) estimation have yielded a new tradeoff between accuracy and efficiency not available to classical parametric estimators. An additional advantage of this new framework is the ability to independently tune multiple aspects of the estimator to seek further improvements. Machine learning CSF estimation with Gaussian processes allows for design optimization in the kernel, acquisition function, and underlying task representation, to name a few. This article describes a novel kernel for CSF estimation that is more flexible than a kernel based on strictly functional forms. Despite being more flexible, it can result in a more efficient estimator. Further, trial selection for data acquisition that is generalized beyond pure information gain can also improve estimator quality. Finally, introducing latent variable representations underlying general CSF shapes can enable simultaneous estimation of multiple CSFs, such as from different eyes, eccentricities, or luminances. The conditions under which the new procedures perform better than previous nonparametric estimation procedures are presented and quantified.

Assessing the impact of glazing and window shade systems on view clarity.

Windows provide access to daylight and outdoor views, influencing building design. Various glazing and window shade materials are used to mitigate glare, overheating and privacy issues, and they affect view clarity. Among them, we evaluated the effect of window films, electrochromic (EC) glass, and fabric shades on view clarity. We conducted an experiment with 50 participants using visual tests adapted from clinical vision tests (visual acuity, contrast sensitivity, color sensitivity) and images displayed on a computer monitor in a controlled laboratory. Window films and EC glass tints outperformed fabric shades in visual acuity, contrast sensitivity and view satisfaction with the exception of the darkest EC tint state and dark grey VLT 3% shade for color sensitivity and view satisfaction. The EC tints pose internal reflection issues and fabric shades are preferred for visual privacy. Window films and EC glass hinder participants' blue-green color discrimination while fabric shades also decrease red-yellow color discrimination. Visual acuity predicts view satisfaction and contrast sensitivity is the strongest predictor for visual privacy. Generally, higher visible light transmittance and lower solar reflectance (darker color) enhance human visual performance. The proposed workflow provides an experimental procedure, identifies the primary variables and establishes a predictive framework for assessing view clarity of fenestration.

Combination of a monofocal and one type of extended depth-of-focus (zonal refractive) intraocular lens (COMEDI) in bilateral cataract surgery protocol: a monocentric, randomised, parallel group trial in cataract surgery.

INTRODUCTION: Modern intraocular lens (IOL) designs for cataract treatment can be broadly classified into three focal range categories; monofocal, extended depth-of-focus (EDOF) and multifocal IOLs.Monofocal IOLs allow spectacle independence for one focus, typically distance. In contrast, EDOF IOLs provide a greater range of vision, extending spectacle independence to intermediate distance, while multifocal IOLs enable spectacle independence at all distances with the drawback of positive dysphotopsias and reduced contrast perception.EDOF lenses are an attractive compromise with fewer dysphotopic side effects than multifocals. The purpose of this study is to assess whether implanting an EDOF IOL in the second eye of a patient who received a monofocal IOL in the first eye can improve spectacle independence while maintaining the same optical quality as bilateral monofocal IOL implantation. METHODS AND ANALYSIS: This study compares combined monofocal and EDOF IOL implantation versus bilateral monofocal IOL implantation in terms of clinical and patient-reported outcomes in a monocentric, randomised, patient-masked and assessor-masked, parallel group trial in 88 bilateral cataract patients. The primary outcome measure is binocular photopic distance corrected intermediate visual acuity. The secondary outcome measures include (un)corrected distance and near visual acuity, reading speed at intermediate distance, quality of visual function assessments, patient-reported spectacle independence, contrast sensitivity, aberrometry, stereopsis and straylight measurement at the 3-month follow-up. ETHICS AND DISSEMINATION: The protocol was approved by the ethical committee of the University Hospital of Brussels (BUN 23219_EDOF). TRIAL REGISTRATION NUMBER: NCT06002399.

Clinical outcomes and optical performance of a new segmental refractive extended depth-of-focus intraocular lens.

BACKGROUND: The visual performance and the optical quality of a segmental refractive extended depth-of-focus (EDoF) intraocular lens (IOL) were evaluated in a prospective, single-arm, single-center study. METHODS: A total of 20 patients (40 eyes) after bilateral implantation of the refractive segmental EDoF Acunex Vario AN6V were included. Assessment procedure: refraction outcome, monocular and binocular uncorrected (UCVA) and distance-corrected visual acuity (DCVA), defocus curve, contrast sensitivity (CS), higher-order aberrations (HOAs) and patient satisfaction were evaluated 1 and 3 months after surgery. RESULTS: At 3-month follow-up, mean spherical equivalent was - 0.23 ± 0.32 D. Binocular uncorrected distance visual acuity (VA) at distance, intermediate and near was - 0.08 ± 0.06 logMAR at 4 m, -0.03 ± 0.06 logMAR at 66 cm and 0.16 ± 0.06 logMAR at 40 cm, respectively. The binocular defocus curve showed a VA better than 0.20 logMAR over a range from + 1.50 to - 2.45 D. Contrast sensitivity aligned with monofocal lenses, highlighting the lens's clinical value. Aberrometry showed minimal changes in corneal aberrations. NEI-RQL-42-Questionnaire showed a high patient satisfaction for daily activities and revealed reduced dependence on glasses, particularly for near and intermediate vision. The Acunex Vario AN6V demonstrated minimal dysphotopsias, making it a promising option for those seeking spectacle independence. CONCLUSION: This segmental refractive EDoF IOL provides a high degree of spectacle independence for far and intermediate distances with functional near VA. Although inducing residual coma aberrations, it showed subjectively good results with little dysphotopsias. TRIAL REGISTRATION: This study protocol was reviewed and approved by ethics committee of Charité University, Berlin, Germany, with approval number EA4/126/20.

[First experience of implantation of extended depth of focus intraocular lenses in patients with glaucoma]. / Pervyi opyt implantatsii intraokulyarnykh linz s uvelichennoi glubinoi fokusa u patsientov s glaukomoi.

PURPOSE: This study evaluates the effectiveness of implantation of extended depth of focus (EDOF) intraocular lenses (IOL) in patients with cataract and glaucoma. MATERIAL AND METHODS: The study included 13 patients (16 eyes) who underwent implantation of the Lentis Comfort EDOF IOL (Teleon Surgical BV, Netherlands). Standard phacoemulsification cataract surgery with IOL implantation was performed in a planned manner after the hypotensive surgery stage in two eyes; a combined procedure was performed in 14 cases. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), near visual acuity, and intraocular pressure (IOP) measured with a Maklakov tonometer were assessed preoperatively, on the first day, and 3-6 months after surgery. Computer perimetry using the 30-2 program and spatial contrast sensitivity (SCS) assessment were also performed preoperatively and at the same follow-up time points. RESULTS: On the first day after surgery, UCVA was 0.53±0.65, BCVA was 0.85±0.45. Near UCVA (at 40 cm) was 0.5±0.14 on the first day after surgery and 0.56±0.18 at 3-6 months. According to computer perimetry data, retinal light sensitivity values increased in all patients in the long-term (-3.1±2.9 dB). SCS values increased for objects of all sizes compared to preoperative values. CONCLUSION: Implantation of EDOF IOL contributes to improved vision without reducing contrast sensitivity and retinal light sensitivity in patients with concomitant cataract and glaucoma.

Does using a bioptic telescope improve visual recognition of the on-road environment?

SIGNIFICANCE: Individuals with reduced visual acuity (VA) may drive with bioptic telescopes in some jurisdictions. The effect of bioptic telescope use on on-road recognition distances is important for driving safety, as increased recognition distances increase the time available to react to road signs or driving events. PURPOSE: This study aimed to investigate the impact of bioptic telescope use on visual recognition of road signs, traffic lights, and hazards in an on-road driving environment in individuals with reduced VA. METHODS: Ten individuals (mean ± standard deviation age, 39.1 ± 19.1 years) with reduced VA (trained to use bioptic telescopes) participated in a repeated-measures on-road experiment for two viewing conditions, with and without a bioptic telescope (randomized order). Participants underwent a clinical low vision assessment, including high-contrast VA with and without the bioptic telescope aligned, visual fields, and contrast sensitivity testing. For the driving component, participants seated in the front passenger seat of a moving car reported all road signs, traffic lights, and hazards (unpredictable road events that represent a risk to driving safety including other vehicles, cyclists, pedestrians) seen along a route that included suburban roads and highways. Video cameras captured participants' viewing behavior, verbal commentary, and the distance at which three pre-selected road signs were reported. RESULTS: In the eye with the bioptic telescope, high-contrast VA improved from 0.75 ± 0.17 (without) to 0.25 ± 0.1 logMAR with the bioptic telescope. Bioptic telescope use did not affect the percentage of road signs, traffic lights, or hazards correctly recognized but did result in 2.6 times longer recognition distances (49 ± 23 vs. 19 ± 11 m, t9 = 5.02, p<0.001). CONCLUSIONS: Road signs were recognized at significantly longer distances when using a bioptic telescope, confirming their positive impact on timely visual recognition of objects within the driving scene. Future work should explore whether this effect generalizes to individuals using bioptic telescopes when driving a vehicle.

The impact of vision loss on attitudes toward autonomous vehicles: A vision-centric analysis.

SIGNIFICANCE: Autonomous vehicles (AVs) have the promise to be an alternative transportation solution for those with vision loss. However, the impact of vision loss on the perceptions and concerns of AVs is unknown. This study therefore examined whether AVs are perceived differently by blind, visually impaired (VI), and normally sighted people. PURPOSE: This study compared the perceptions of AVs among the blind, VI, and normally sighted. METHODS: Participants' opinions on four perception measures (general opinion, trust, impact on quality of life, and intention to use AVs) and nine concerns regarding AVs were measured. The survey was administered to 51 normally sighted, 68 VI, and 65 blind participants. Analyses of covariance assessed whether the four perception measures and nine concerns varied by vision status (normal vision, VI, blind) and driving status (driver, nondriver). Univariate correlations and multiple regression analyses identified associations and predictors of AV perceptions and concerns from demographic, mood, cognition, travel behavior, and vision measures, which included visual acuity, contrast sensitivity, and visual field. RESULTS: The blind (p<0.001), VI (p<0.001), and nondrivers (p<0.001) showed a greater intention to use AVs compared with those with normal vision and drivers. Similar findings were found for the other perception measures. As visual acuity, contrast sensitivity, and visual field extent declined, positivity toward AVs increased (p<0.001). Visual field extent best predicted general opinion and trust in AVs, whereas driving measures were the best predictors of impact on quality of life and intention to use AVs. Concerns about AVs showed no differences based on vision (p=0.94) or driving (p=0.63) status. CONCLUSIONS: Individuals with vision loss expressed more acceptance of AVs despite their concerns. How positive someone is toward AVs appears to be dependent on their visual field extent and driving status.

The effect of illumination on the visibility of steps and ramps for people with low vision.

SIGNIFICANCE: Poor visibility of indoor features such as steps and ramps can pose mobility hazards for people with low vision. For purposes of architectural design, it is important to understand how design parameters such as the illumination level of an indoor space affect the visibility of steps and ramps. PURPOSE: This study was aimed to examine the effect of typical variation in photopic illumination level in an indoor space on the visibility of steps and ramps for individuals with low vision. METHODS: Steps and ramps were constructed in a large windowless room illuminated by overhead lights. Subjects with low vision completed a 5-alternative forced choice task to recognize the targets at three levels of photopic illumination, i.e., 800, 80, and 8 lux, and gave confidence ratings about their judgments on a 5-point scale. Acuities and contrast sensitivities of the subjects were also measured at each illumination level. For comparison, a group of normally sighted subjects with simulated acuity reduction also completed the step-and-ramp recognition task. RESULTS: For both groups of subjects, recognition accuracy was not affected by illumination level. For subjects with low vision, however, there was a significant effect of illumination level on confidence rating: subjects became more confident about their judgments with increasing illumination. There was also a weak effect of illumination level on acuity and contrast sensitivity, both worsening with decreasing illumination. Recognition performance was best predicted by contrast sensitivity, whereas confidence was best predicted by visual acuity. CONCLUSIONS: Illumination variation over a typical photopic range in an indoor space had minimal effect on the objective visibility of steps and ramps for people with low vision. However, illumination level affected subjects' confidence in hazard recognition. Design decisions on parameters such as illumination should consider the consequences on both the objective and the subjective accessibility of a space.

Postoperative Visual Function of Extended Depth-of-Focus Intraocular Lenses Versus Monofocal Lenses.

PURPOSE: To assess the effects of intraocular lens (IOL) decentration and tilt, as well as age, on postoperative visual function (corrected distance visual acuity [CDVA] and contrast sensitivity) by comparing an extended depth-of-focus IOL using higher order aspheric optics against a monofocal IOL from the same platform. METHODS: This retrospective observational study targeted patients without other eye diseases who underwent surgery to implant the Tecnis Eyhance OptiBlue or the monofocal IOL Tecnis OptiBlue 1-Piece (J&J Vision) during cataract surgery from November 2021 to December 2022. The effects of age, axial length, IOL decentration, tilt, and corneal higher order aberrations (HOAs) on the postoperative 5 m CDVA and area under log contrast sensitivity function (AULCSF) under photopic and scotopic conditions were evaluated within 3 months of surgery. RESULTS: No significant difference was found in postoperative CDVA between the Tecnis Eyhance OptiBlue group (n = 61 eyes) and the Tecnis OptiBlue 1-Piece group (n = 35 eyes), but AULCSF was significantly better in the Tecnis Eyhance OptiBlue group for photopic (1.58 ± 0.13 vs 1.46 ± 0.18; P = .002) and scotopic (1.71 ± 0.11 vs 1.59 ± 0.19; P = .002) eyes. Multivariate analysis showed a negative correlation between AULCSF and IOL decentration and age in the Tecnis Eyhance OptiBlue group (P < .01), with no significant correlation with tilt, axial length, and corneal HOAs. CONCLUSIONS: The Tecnis Eyhance OptiBlue yielded significantly better contrast sensitivity under photopic and scotopic conditions than the Tecnis OptiBlue 1-Piece. However, it is important to consider the effects of IOL decentration and age when evaluating the contrast sensitivity of the Tecnis Eyhance OptiBlue. [J Refract Surg. 2024;40(7):e499-e505.].

Evaluation of the SpotChecks contrast sensitivity test in healthy adults.

PURPOSE: SpotChecks is a new contrast sensitivity (CS) test designed for self-monitoring of vision. This study assessed the test-retest repeatability of take-home SpotChecks, in-office SpotChecks and near Pelli-Robson charts in healthy adults. METHODS: One eye of 61 healthy adults with near visual acuity (VA) of 6/9 or better (age range 22-84, mean 49 [18] years) was tested during two office visits (mean 10 [8] days apart). Each visit included high-contrast VA, then 12 randomly ordered CS tests (6 different SpotChecks and 6 different Pelli-Robson) under the same lighting (luminance 110 cd/m2), all at near in the same eye with habitual correction. The same eye was self-tested with take-home SpotChecks once a day on 6 days between the office visits. SpotChecks was scored by the logCS at the highest line with ≥2 errors. Pelli-Robson was scored by [0.05 × number of letters read correctly - 0.15]. Repeatability of logCS was defined as 1.96 2 Sw, Sw representing within-subject standard deviation. Comparison for repeatability was performed with Bootstrap hypothesis test. RESULTS: SpotChecks and Pelli-Robson showed similar intra-session or inter-visit repeatability (p = 0.14-0.81). Inter-day repeatability for take-home SpotChecks was 0.18 logCS, the same as that from the first measurements of two office visits with SpotChecks or Pelli-Robson. Inter-visit repeatability improved to 0.15 by using the average of two repeated measurements for SpotChecks (p = 0.02) or three repeated measurements for Pelli-Robson (p = 0.04). Age showed a small effect on logCS (-0.015/decade, p = 0.02) for both SpotChecks and Pelli-Robson. Mean logCS was 0.05 lower in those ≥50 years (SpotChecks 1.84 [0.10] and Pelli-Robson 1.77 [0.10]) compared with those <50 years of age (SpotChecks 1.89 [0.07] and Pelli-Robson 1.83 [0.07]). CONCLUSIONS: SpotChecks showed good repeatability with take-home and in-office testing in healthy adults, making it a promising tool for monitoring disease progression at home.

Standard models of spatial vision mispredict edge sensitivity at low spatial frequencies.

One well-established characteristic of early visual processing is the contrast sensitivity function (CSF) which describes how sensitivity varies with the spatial frequency (SF) content of the visual input. The CSF prompted the development of a now standard model of spatial vision. It represents the visual input by activity in orientation- and SF selective channels which are nonlinearly recombined to predict a perceptual decision. The standard spatial vision model has been extensively tested with sinusoidal gratings at low contrast because their narrow SF spectra isolate the underlying SF selective mechanisms. It is less studied how well these mechanisms account for sensitivity to more behaviourally relevant stimuli such as sharp edges at high contrast (i.e. object boundaries) which abound in the natural environment and have broader SF spectra. Here, we probe sensitivity to edges (2-AFC, edge localization) in the presence of broadband and narrowband noises. We use Cornsweet luminance profiles with peak frequencies at 0.5, 3 and 9 cpd as edge stimuli. To test how well mechanisms underlying sinusoidal contrast sensitivity can account for edge sensitivity, we implement a single- and a multi-scale model building upon standard spatial vision model components. Both models account for most of the data but also systematically deviate in their predictions, particularly in the presence of pink noise and for the lowest SF edge. These deviations might indicate a transition from contrast- to luminance-based detection at low SFs. Alternatively, they might point to a missing component in current spatial vision models.

The adaptive global effect: Luminance contrast modulates the global effect zone.

When two peripheral objects are presented in close proximity, saccades towards one of these objects land at a weighted average location between the two objects. This phenomenon, known as the 'global effect' or 'saccade averaging', disappears when the distance between the objects increases. When objects are further apart, outside the averaging zone, saccades land on one of the objects with little or no saccade averaging. Although it is known that the strength of the global effect is dependent on the specific features of the two objects, it is unclear if the size of the zone in which averaging can occur (i.e., the averaging zone) is adaptive. The aim of the current study was to investigate whether the size of the averaging zone adapts to variations in object luminance contrast of the objects. In order to systematically assess changes in the averaging zone, in two experiments, observers made saccadic eye movements while the luminance of the target and the distractor varied. We report three major findings: 1) When a distractor was more luminant relative to the target, the averaging zone increased (Exp. 1). Notably, saccade averaging never entirely ceased to exist, even for remote distractors. 2) When target and distractor were equiluminant, the averaging zone did not change with absolute luminance (Exp. 2). 3) Higher (relative and absolute) luminance increased the averaging zone especially for shorter saccadic response times (SRT). We conclude that the averaging zone is adaptive and becomes larger with increasing relative luminance and especially when SRTs are short.

Pupil constriction by contrast for contrast.

The pupil is the eye's adjustable aperture. Fitzpatrick et al. find that visual contrast constricts the pupil, increasing contrast.1 This process improves behavioral performance. Its retinal origin has unorthodox elements, like interneurons that make connections in unusual locales and photoreceptive ganglion cells.

The effects of simulated monocular and binocular vision impairment on football penalty kick performance.

Sports performance is relatively robust under high levels of binocular blur. However, the limited research studies investigating monocular impairments has shown it has a larger impact on sport performance. This research study is relevant for classification in sports for athletes with vision impairment (VI), where visual acuity (VA) from the better eye is used during classification. Across two experiments, we aimed to establish the point at which binocular and monocular impairments affected performance in a football penalty kick (PK) through simulating varying severities of degraded VA and contrast sensitivity (CS) in active football players. In experiment one, 25 footballers performed PKs as VA and CS were systematically decreased in both eyes, and in one condition, visual field (VF) was reduced. The most severe VA/CS condition and reduced VF significantly impacted outcome, ball velocity and placement (ball kicked closer to the centre of the goal) (p < 0.05). In experiment two, 29 different footballers performed PKs as VA and CS of only the dominant eye were systematically decreased and in one condition the dominant eye was occluded, and participants viewed their environment through the non-dominant eye (monocular viewing). No differences were observed when assessing monocular impairments influence on outcome, velocity and ball placement. PKs have a high resilience to VI, but binocular impairment has a more immediate effect, suggesting binocular measures should be used in classification processes in football.

Consequences of eye movements for spatial selectivity.

What determines spatial tuning in the visual system? Standard views rely on the assumption that spatial information is directly inherited from the relative position of photoreceptors and shaped by neuronal connectivity.1,2 However, human eyes are always in motion during fixation,3,4,5,6 so retinal neurons receive temporal modulations that depend on the interaction of the spatial structure of the stimulus with eye movements. It has long been hypothesized that these modulations might contribute to spatial encoding,7,8,9,10,11,12 a proposal supported by several recent observations.13,14,15,16 A fundamental, yet untested, consequence of this encoding strategy is that spatial tuning is not hard-wired in the visual system but critically depends on how the fixational motion of the eye shapes the temporal structure of the signals impinging onto the retina. Here we used high-resolution techniques for eye-tracking17 and gaze-contingent display control18 to quantitatively test this distinctive prediction. We examined how contrast sensitivity, a hallmark of spatial vision, is influenced by fixational motion, both during normal active fixation and when the spatiotemporal stimulus on the retina is altered to mimic changes in fixational control. We showed that visual sensitivity closely follows the strength of the luminance modulations delivered within a narrow temporal bandwidth, so changes in fixational motion have opposite visual effects at low and high spatial frequencies. By identifying a key role for oculomotor activity in spatial selectivity, these findings have important implications for the perceptual consequences of abnormal eye movements, the sources of perceptual variability, and the function of oculomotor control.

[Evaluation of visual quality and refractive outcomes of myopia with presbyopia after laser blended vision surgery].

Objective: To investigate the postoperative outcomes and visual quality following laser blended vision (LBV) surgery for the correction of myopia with presbyopia. Methods: This is a prospective study. A total of 50 patients (100 eyes) who underwent LBV surgery for myopia with presbyopia at Beijing Tongren Hospital, Capital Medical University, between August 2021 and March 2022 were included. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), best-corrected distance visual acuity (BCDVA), manifest refraction spherical equivalent (MRSE) were measured preoperatively and at 1, 3, 6, 12, and 24 months postoperatively for the dominant eye, non-dominant eye, and both eyes. Effectiveness Index (EI) and Safety Index (SI) were calculated to evaluate refractive outcomes. Accommodation function and contrast sensitivity were assessed to evaluate functional vision. Objective visual quality was assessed using higher-order aberrations (HOAs) and a dual-channel visual quality analysis system. Subjective visual quality was evaluated using a questionnaire. Results: At 24 months postoperatively, the EI and SI for the dominant eye were 1.04±0.23 and 1.14±0.14, respectively, while for the non-dominant eye, they were 0.85±0.21 and 1.06±0.08, respectively. Although there were statistically significant differences in UNVA between the eyes at 1 and 3 months postoperatively (all P<0.05), no significant differences were observed from 6 months onward (all P>0.05). At 6 months postoperatively, the UNVA for the dominant and non-dominant eyes were 0.07±0.13 and 0.03±0.13, respectively, with no significant difference (P>0.05). MRSE showed no significant differences at any follow-up time points up to 24 months. Accommodation function did not decrease compared to preoperative levels at any postoperative follow-up. Increases in HOAs were primarily due to spherical aberrations, and there were no significant differences in objective visual quality before and after surgery. Contrast sensitivity improved significantly at 24 months postoperatively compared to preoperative levels. At 24 months postoperatively, 11 out of 12 patients reported good visual quality in the questionnaire. Conclusions: LBV surgery gradually achieves good binocular blended vision within 6 months postoperatively and demonstrates good safety, efficacy, and stability at 24 months. It maintains good functional vision and visual quality with high postoperative patient satisfaction.

What does visual snow look like? Quantification by matching a simulation.

The primary symptom of visual snow syndrome (VSS) is the unremitting perception of small, flickering dots covering the visual field. VSS is a serious but poorly understood condition that can interfere with daily tasks. Several studies have provided qualitative data about the appearance of visual snow, but methods to quantify the symptom are lacking. Here, we developed a task in which participants with VSS adjusted parameters of simulated visual snow on a computer monitor until the simulation matched their internal visual snow. On each trial, participants (n = 31 with VSS) modified the size, density, update speed, and contrast of the simulation. Participants' settings were highly reliable across trials (intraclass correlation coefficients > 0.89), and they reported that the task was effective at stimulating their visual snow. On average, visual snow was very small (less than 2 arcmin in diameter), updated quickly (mean temporal frequency = 18.2 Hz), had low density (mean snow elements vs. background = 2.87%), and had low contrast (average root mean square contrast = 2.56%). Our task provided a quantitative assessment of visual snow percepts, which may help individuals with VSS communicate their experience to others, facilitate assessment of treatment efficacy, and further our understanding of the trajectory of symptoms, as well as the neural origins of VSS.

A paradigm for characterizing motion misperception in people with typical vision and low vision.

PURPOSE: We aimed to develop a paradigm that can efficiently characterize motion percepts in people with low vision and compare their responses with well-known misperceptions made by people with typical vision when targets are hard to see. METHODS: We recruited a small cohort of individuals with reduced acuity and contrast sensitivity (n = 5) as well as a comparison cohort with typical vision (n = 5) to complete a psychophysical study. Study participants were asked to judge the motion direction of a tilted rhombus that was either high or low contrast. In a series of trials, the rhombus oscillated vertically, horizontally, or diagonally. Participants indicated the perceived motion direction using a number wheel with 12 possible directions, and statistical tests were used to examine response biases. RESULTS: All participants with typical vision showed systematic misperceptions well predicted by a Bayesian inference model. Specifically, their perception of vertical or horizontal motion was biased toward directions orthogonal to the long axis of the rhombus. They had larger biases for hard-to-see (low contrast) stimuli. Two participants with low vision had a similar bias, but with no difference between high- and low-contrast stimuli. The other participants with low vision were unbiased in their percepts or biased in the opposite direction. CONCLUSIONS: Our results suggest that some people with low vision may misperceive motion in a systematic way similar to people with typical vision. However, we observed large individual differences. Future work will aim to uncover reasons for such differences and identify aspects of vision that predict susceptibility.

Playing three-dimensional video games boosts stereo vision.

Playing two-dimensional video games has been shown to result in improvements in a range of visual and cognitive tasks, and these improvements appear to generalize widely1,2,3,4,5,6. Here we report that young adults with healthy vision, surprisingly, showed a dramatic improvement in stereo vision after playing three-dimensional, but not two-dimensional, video games for a relatively short period of time. Intriguingly, neither group showed any significant improvement in binocular contrast sensitivity. This dissociation suggests that the visual enhancement was specific to genuine stereoscopic processing, not indirectly resulting from enhanced contrast processing, and required engaging in a disparity cue-rich three-dimensional environment.

Biomarker evidence of early vision and rod energy-linked pathophysiology benefits from very low dose DMSO in 5xFAD mice.

Here, we test whether early visual and OCT rod energy-linked biomarkers indicating pathophysiology in nicotinamide nucleotide transhydrogenase (Nnt)-null 5xFAD mice also occur in Nnt-intact 5xFAD mice and whether these biomarkers can be pharmacologically treated. Four-month-old wild-type or 5xFAD C57BL/6 substrains with either a null (B6J) Nnt or intact Nnt gene (B6NTac) and 5xFAD B6J mice treated for one month with either R-carvedilol + vehicle or only vehicle (0.01% DMSO) were studied. The contrast sensitivity (CS), external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness (a proxy for low pH-triggered water removal), profile shape of the hyperreflective band just posterior to the ELM (i.e., the mitochondrial configuration within photoreceptors per aspect ratio [MCP/AR]), and retinal laminar thickness were measured. Both wild-type substrains showed similar visual performance indices and dark-evoked ELM-RPE contraction. The lack of a light-dark change in B6NTac MCP/AR, unlike in B6J mice, is consistent with relatively greater mitochondrial efficiency. 5xFAD B6J mice, but not 5xFAD B6NTac mice, showed lower-than-WT CS. Light-adapted 5xFAD substrains both showed abnormal ELM-RPE contraction and greater-than-WT MCP/AR contraction. The inner retina and superior outer retina were thinner. Treating 5xFAD B6J mice with R-carvedilol + DMSO or DMSO alone corrected CS and ELM-RPE contraction but not supernormal MCP/AR contraction or laminar thinning. These results provide biomarker evidence for prodromal photoreceptor mitochondrial dysfunction/oxidative stress/oxidative damage, which is unrelated to visual performance, as well as the presence of the Nnt gene. This pathophysiology is druggable in 5xFAD mice.