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1.
Eur J Sport Sci ; 24(7): 918-929, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38956797

ABSTRACT

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.


Subject(s)
Athletic Performance , Soccer , Vision, Binocular , Visual Acuity , Humans , Soccer/physiology , Vision, Binocular/physiology , Visual Acuity/physiology , Male , Athletic Performance/physiology , Young Adult , Adult , Vision Disorders/physiopathology , Contrast Sensitivity/physiology , Vision, Monocular/physiology , Visual Fields/physiology
2.
Brain Behav ; 14(7): e3582, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38956813

ABSTRACT

BACKGROUND/OBJECTIVES: Stroke damage to the primary visual cortex induces large, homonymous visual field defects that impair daily living. Here, we asked if vision-related quality of life (VR-QoL) is impacted by time since stroke. SUBJECTS/METHODS: We conducted a retrospective meta-analysis of 95 occipital stroke patients (female/male = 26/69, 27-78 years old, 0.5-373.5 months poststroke) in whom VR-QoL was estimated using the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ) and its 10-item neuro-ophthalmic supplement (Neuro10). Visual deficit severity was represented by the perimetric mean deviation (PMD) calculated from 24-2 Humphrey visual fields. Data were compared with published cohorts of visually intact controls. The relationship between VR-QoL and time poststroke was assessed across participants, adjusting for deficit severity and age with a multiple linear regression analysis. RESULTS: Occipital stroke patients had significantly lower NEI-VFQ and Neuro10 composite scores than controls. All subscale scores describing specific aspects of visual ability and functioning were impaired except for ocular pain and general health, which did not differ significantly from controls. Surprisingly, visual deficit severity was not correlated with either composite score, both of which increased with time poststroke, even when adjusting for PMD and age. CONCLUSIONS: VR-QoL appears to improve with time postoccipital stroke, irrespective of visual deficit size or patient age at insult. This may reflect the natural development of compensatory strategies and lifestyle adjustments. Thus, future studies examining the impact of rehabilitation on daily living in this patient population should consider the possibility that their VR-QoL may change gradually over time, even without therapeutic intervention.


Subject(s)
Quality of Life , Stroke , Humans , Female , Middle Aged , Male , Stroke/physiopathology , Stroke/complications , Aged , Adult , Retrospective Studies , Vision Disorders/physiopathology , Vision Disorders/etiology , Occipital Lobe/physiopathology , Visual Fields/physiology
3.
Invest Ophthalmol Vis Sci ; 65(8): 15, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38975942

ABSTRACT

Purpose: To investigate the contributions of the microstructural and metabolic brain environment to glaucoma and their association with visual field (VF) loss patterns by using advanced diffusion magnetic resonance imaging (dMRI), proton magnetic resonance spectroscopy (MRS), and clinical ophthalmic measures. Methods: Sixty-nine glaucoma and healthy subjects underwent dMRI and/or MRS at 3 Tesla. Ophthalmic data were collected from VF perimetry and optical coherence tomography. dMRI parameters of microstructural integrity in the optic radiation and MRS-derived neurochemical levels in the visual cortex were compared among early glaucoma, advanced glaucoma, and healthy controls. Multivariate regression was used to correlate neuroimaging metrics with 16 archetypal VF loss patterns. We also ranked neuroimaging, ophthalmic, and demographic attributes in terms of their information gain to determine their importance to glaucoma. Results: In dMRI, decreasing fractional anisotropy, radial kurtosis, and tortuosity and increasing radial diffusivity correlated with greater overall VF loss bilaterally. Regionally, decreasing intra-axonal space and extra-axonal space diffusivities correlated with greater VF loss in the superior-altitudinal area of the right eye and the inferior-altitudinal area of the left eye. In MRS, both early and advanced glaucoma patients had lower gamma-aminobutyric acid (GABA), glutamate, and choline levels than healthy controls. GABA appeared to associate more with superonasal VF loss, and glutamate and choline more with inferior VF loss. Choline ranked third for importance to early glaucoma, whereas radial kurtosis and GABA ranked fourth and fifth for advanced glaucoma. Conclusions: Our findings highlight the importance of non-invasive neuroimaging biomarkers and analytical modeling for unveiling glaucomatous neurodegeneration and how they reflect complementary VF loss patterns.


Subject(s)
Tomography, Optical Coherence , Visual Field Tests , Visual Fields , Humans , Male , Female , Middle Aged , Visual Fields/physiology , Tomography, Optical Coherence/methods , Aged , Vision Disorders/physiopathology , Vision Disorders/metabolism , Diffusion Magnetic Resonance Imaging , Glaucoma/physiopathology , Glaucoma/metabolism , Brain/metabolism , Brain/diagnostic imaging , Brain/pathology , Glaucoma, Open-Angle/metabolism , Glaucoma, Open-Angle/physiopathology , Visual Cortex/metabolism , Visual Cortex/diagnostic imaging , Proton Magnetic Resonance Spectroscopy , Adult , Intraocular Pressure/physiology
4.
Adv Gerontol ; 37(1-2): 72-79, 2024.
Article in Russian | MEDLINE | ID: mdl-38944776

ABSTRACT

A study was conducted to investigate the associations of the diseases of the organ of vision and its accessory apparatus with anxiety and depression in the elderly people. The study included 678 participants of the ESSE-RF3 population study in the Arkhangelsk region in the age of 60-74 years. We used a questionnaire, including the hospital scale of anxiety and depression score (HADS), and the assessment of the ophthalmological status. It was found that all the study participants had diseases of the visual organ. Elevated depression scores were associated with sex, age, marital status (being single), and disability, elevated anxiety scores - with sex. The scores on the anxiety scale were on average 25% higher in participants whose visual acuity decreased to 0,5 units, and showed no independent associations with diagnosed ophthalmological diseases. The scores on the depression scale were on average 33% higher in participants with visual acuity 0,5 units, and 22% higher in the presence of retinopathy. In conclusion, anxiety and depression in the elderly people were more associated with visual deficits rather than with the presence of ophthalmological diseases underlying a decrease in functional status.


Subject(s)
Anxiety , Humans , Male , Female , Aged , Middle Aged , Russia/epidemiology , Anxiety/epidemiology , Anxiety/diagnosis , Anxiety/psychology , Visual Acuity , Depression/epidemiology , Depression/diagnosis , Depression/psychology , Depression/etiology , Eye Diseases/epidemiology , Eye Diseases/diagnosis , Eye Diseases/psychology , Eye Diseases/physiopathology , Surveys and Questionnaires , Vision Disorders/epidemiology , Vision Disorders/psychology , Vision Disorders/physiopathology , Vision Disorders/diagnosis
5.
Magn Reson Med Sci ; 23(3): 316-340, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38866532

ABSTRACT

Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods that use dMRI to assess the properties of brain tissue within the long-range connections comprising brain networks. We focus specifically on the major white matter tracts that convey visual information. These connections are particularly important because vision provides rich information from the environment that supports a large range of daily life activities. Many of the diseases of the visual system are associated with advanced aging, and tractometry of the visual system is particularly important in the modern aging society. We provide an overview of the tractometry analysis pipeline, which includes a primer on dMRI data acquisition, voxelwise model fitting, tractography, recognition of white matter tracts, and calculation of tract tissue property profiles. We then review dMRI-based methods for analyzing visual white matter tracts: the optic nerve, optic tract, optic radiation, forceps major, and vertical occipital fasciculus. For each tract, we review background anatomical knowledge together with recent findings in tractometry studies on these tracts and their properties in relation to visual function and disease. Overall, we find that measurements of the brain's visual white matter are sensitive to a range of disorders and correlate with perceptual abilities. We highlight new and promising analysis methods, as well as some of the current barriers to progress toward integration of these methods into clinical practice. These barriers, such as variability in measurements between protocols and instruments, are targets for future development.


Subject(s)
Visual Pathways , White Matter , Humans , White Matter/diagnostic imaging , Visual Pathways/diagnostic imaging , Diffusion Tensor Imaging/methods , Brain/diagnostic imaging , Diffusion Magnetic Resonance Imaging/methods , Image Processing, Computer-Assisted/methods , Vision Disorders/diagnostic imaging , Vision Disorders/physiopathology
6.
In Vivo ; 38(4): 1947-1956, 2024.
Article in English | MEDLINE | ID: mdl-38936949

ABSTRACT

BACKGROUND/AIM: To investigate the treatment outcomes and determinants of prognosis in patients experiencing visual acuity (VA) deterioration due to inflammatory isolated sphenoid sinus disease (ISSD) who underwent endonasal endoscopic surgery (EES). PATIENTS AND METHODS: Thirteen patients with 14 lesions treated with EES between March 2010 and April 2022 were included. Evaluation included improvements in VA using the logarithm of the minimum angle of resolution (LogMAR) scale, resolution rates of associated symptoms, and identification of factors predicting VA recovery. A literature review was conducted to assess the outcomes for ISSD-related VA impairments. RESULTS: The most common etiology is mycetoma (n=5), followed by an equal representation of mucocele and sphenoiditis (n=4). The mean interval from symptom onset to intervention was 4.7 months, with an average follow-up duration of 14.4 months. Seven eyes exhibited preoperative VA of 2.1 LogMAR or worse, with diplopia/ptosis (n=8) and headache (n=5) being the predominant co-occurring symptoms. After surgery, all ancillary symptoms improved, with an overall VA recovery rate of 87.5% (improvement more than 0.2 logMAR units). Mucocele exhibited the best improvements, whereas sphenoiditis showed the least progress (p=0.021). Poor baseline VA (p=0.026) and combined diplopia/ptosis (p=0.029) were identified as negative prognostic factors for VA recovery. CONCLUSION: Our findings suggest a favorable prognosis for VA recovery following EES in patients with inflammatory ISSDs, with response variations based on disease entity. However, further research is needed to personalize therapeutic strategies for enhanced outcomes.


Subject(s)
Visual Acuity , Humans , Female , Male , Middle Aged , Adult , Aged , Treatment Outcome , Sphenoid Sinus/surgery , Sphenoid Sinusitis/complications , Sphenoid Sinusitis/surgery , Sphenoid Sinusitis/physiopathology , Endoscopy/methods , Prognosis , Young Adult , Inflammation , Vision Disorders/etiology , Vision Disorders/physiopathology
9.
J Vis ; 24(6): 3, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38837169

ABSTRACT

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.


Subject(s)
Visual Fields , Humans , Adult , Male , Female , Visual Fields/physiology , Young Adult , Photic Stimulation/methods , Middle Aged , Contrast Sensitivity/physiology , Perceptual Disorders/physiopathology , Perceptual Disorders/etiology , Visual Perception/physiology , Computer Simulation , Vision Disorders/physiopathology
10.
J AAPOS ; 28(3): 103933, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38729256

ABSTRACT

PURPOSE: To assess the feasibility and performance of Vivid Vision Perimetry (VVP), a new virtual reality (VR)-based visual field platform. METHODS: Children 7-18 years of age with visual acuity of 20/80 or better undergoing Humphrey visual field (HVF) testing were recruited to perform VVP, a VR-based test that uses suprathreshold stimuli to test 54 field locations and calculates a fraction seen score. Pearson correlation coefficients were calculated to evaluate correlation between HVF mean sensitivity and VVP mean fraction seen scores. Participants were surveyed regarding their experience. RESULTS: A total of 37 eyes of 23 participants (average age, 12.9 ± 3.1 years; 48% female) were included. All participants successfully completed VVP testing. Diagnoses included glaucoma (12), glaucoma suspect (7), steroid-induced ocular hypertension (3), and craniopharyngioma (1). Sixteen participants had prior HVF experience, and none had prior VVP experience, although 7 had previously used VR. Of the 23 HVF tests performed, 9 (39%) were unreliable due to fixation losses, false positives, or false negatives. Similarly, 35% of VVP tests were unreliable (as defined by accuracy of blind spot detection). Excluding unreliable HVF tests, the correlation between HVF average mean sensitivity and VVP mean fraction seen score was 0.48 (P = 0.02; 95% CI, 0.09-0.74). When asked about preference for the VVP or HVF examination, all participants favored the VVP, and 70% were "very satisfied" with VVP. CONCLUSIONS: In our cohort of 23 pediatric subjects, VVP proved to be a clinically feasible VR-based visual field testing, which was uniformly preferred over HVF.


Subject(s)
Feasibility Studies , Virtual Reality , Visual Acuity , Visual Field Tests , Visual Fields , Humans , Visual Field Tests/methods , Child , Female , Male , Pilot Projects , Adolescent , Visual Fields/physiology , Visual Acuity/physiology , Glaucoma/diagnosis , Glaucoma/physiopathology , Reproducibility of Results , Vision Disorders/diagnosis , Vision Disorders/physiopathology , Ocular Hypertension/diagnosis , Ocular Hypertension/physiopathology
11.
Ophthalmic Physiol Opt ; 44(5): 840-853, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38757445

ABSTRACT

PURPOSE: To compare the objective performance, acceptance and usability of head-mounted displays (HMDs) to provide evidence-based data that could be used to increase the efficiency of device referrals based upon a person's vision loss and functional needs. METHODS: A cross-sectional, counterbalanced, individually controlled crossover study was performed on 15 adults with various eye conditions. Performance was measured when using four HMDs: eSight4, Eyedaptic EYE3, Eyedaptic EYE4 and IrisVision Inspire. Performance on clinical visual acuity tests and contrast were assessed, as well as vision-related activities of daily living (ADL) which were divided into three categories: Reading, Searching & Identifying and Eye-hand Coordination. User-experience was also assessed. Logistic regression analyses, Friedman one-way repeated measure analyses of variance by ranks and multivariate permutation testing were used for analysis. RESULTS: There was a significant improvement in visual acuity when using all devices. For contrast tasks, only the eSight4 and Eyedaptic EYE3 improved performance relative to baseline. For most Reading and Searching & Identifying tasks, the odds of being able to perform the tasks were significantly higher while using the devices. However, the actual performance with most devices (e.g., number of words read or reading speed) did not improve significantly over baseline for most tasks. For the Eye-hand Coordination tasks, participants performed equivalent to or significantly poorer than baseline when using the devices. No demographic or clinical predictors of outcomes were identified. Participants expressed dissatisfaction with the devices' effectiveness, acceptability and usability. CONCLUSIONS: While performance on clinical tests was better when using the devices, performance on most real-world ADLs was equal to or worse than baseline. No single device improved performance on all tasks, and performance on any one task was not improved with all the devices. The overall dissatisfaction with the devices paralleled the lack of objective improvement in the performance of real-world tasks.


Subject(s)
Activities of Daily Living , Cross-Over Studies , Visual Acuity , Humans , Male , Female , Visual Acuity/physiology , Middle Aged , Cross-Sectional Studies , Adult , Aged , Vision, Low/physiopathology , Vision, Low/rehabilitation , Visually Impaired Persons/rehabilitation , Vision Disorders/physiopathology , Reading
13.
J AAPOS ; 28(3): 103930, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38719139

ABSTRACT

PURPOSE: To assess the utility of 3D, tablet-based, glasses-free Accurate STEReotest (ASTEROID) in children compared with the Titmus test. METHODS: Children aged 5-13 years were enrolled in a single-center, nonrandomized, observational comparison study and analyzed by age (5-7 vs 8-13 years) and visual acuity (20/25 or better in both eyes vs abnormal). Each participant underwent both the ASTEROID and Titmus stereoacuity tests. Stereoacuity was defined as fine (≤60 arcsec), moderate (61-200 arcsec), coarse (201-1199 arcsec), or very coarse to nil (≥1200 arcsec). Agreement between the tests was assessed using a weighted kappa (κ) statistic based on all four categories. RESULTS: A total of 112 children were included: 28 aged 5-7 with normal visual acuity, 30 aged 5-7 with abnormal visual acuity, 34 aged 8-13 with normal visual acuity, and 20 aged 8-13 with abnormal visual acuity. Mean ASTEROID score was 688 ± 533 arcsec (range, 13-1200 arcsec). Agreement between ASTEROID and Titmus test scores for participants overall was moderate (κ = 0.52). By subgroup, agreement was fair for children 5-7 with abnormal visual acuity (κ = 0.31), moderate for children 5-7 with normal visual acuity (κ = 0.47) and children 8-13 with normal visual acuity (κ = 0.42), and substantial for children 8-13 with abnormal visual acuity (κ = 0.76). Where ASTEROID and Titmus score group varied, ASTEROID score was poorer in 94% (47/50) of cases. CONCLUSIONS: ASTEROID is a digital, tablet-based test that evaluates global stereopsis, does not require glasses, and provides a continuum of scores. Among children, ASTEROID has good agreement with the Titmus test; however, it may be more sensitive at detecting stereovision deficits. Further study is necessary to determine which test is more accurate.


Subject(s)
Computers, Handheld , Depth Perception , Vision Tests , Visual Acuity , Humans , Child , Visual Acuity/physiology , Vision Tests/methods , Child, Preschool , Adolescent , Female , Male , Depth Perception/physiology , Vision Disorders/physiopathology , Vision Disorders/diagnosis , Reproducibility of Results , Imaging, Three-Dimensional
14.
Brain Behav ; 14(5): e3525, 2024 May.
Article in English | MEDLINE | ID: mdl-38773793

ABSTRACT

INTRODUCTION: Visual field defects (VFDs) represent a debilitating poststroke complication, characterized by unseen parts of the visual field. Visual perceptual learning (VPL), involving repetitive visual training in blind visual fields, may effectively restore visual field sensitivity in cortical blindness. This current multicenter, double-blind, randomized, controlled clinical trial investigated the efficacy and safety of VPL-based digital therapeutics (Nunap Vision [NV]) for treating poststroke VFDs. METHODS: Stroke outpatients with VFDs (>6 months after stroke onset) were randomized into NV (defective field training) or Nunap Vision-Control (NV-C, central field training) groups. Both interventions provided visual perceptual training, consisting of orientation, rotation, and depth discrimination, through a virtual reality head-mounted display device 5 days a week for 12 weeks. The two groups received VFD assessments using Humphrey visual field (HVF) tests at baseline and 12-week follow-up. The final analysis included those completed the study (NV, n = 40; NV-C, n = 35). Efficacy measures included improved visual area (sensitivity ≥6 dB) and changes in the HVF scores during the 12-week period. RESULTS: With a high compliance rate, NV and NV-C training improved the visual areas in the defective hemifield (>72 degrees2) and the whole field (>108 degrees2), which are clinically meaningful improvements despite no significant between-group differences. According to within-group analyses, mean total deviation scores in the defective hemifield improved after NV training (p = .03) but not after NV-C training (p = .12). CONCLUSIONS: The current trial suggests that VPL-based digital therapeutics may induce clinically meaningful visual improvements in patients with poststroke VFDs. Yet, between-group differences in therapeutic efficacy were not found as NV-C training exhibited unexpected improvement comparable to NV training, possibly due to learning transfer effects.


Subject(s)
Stroke Rehabilitation , Stroke , Virtual Reality , Visual Fields , Visual Perception , Humans , Double-Blind Method , Male , Female , Middle Aged , Aged , Visual Fields/physiology , Stroke/complications , Stroke/therapy , Stroke/physiopathology , Visual Perception/physiology , Stroke Rehabilitation/methods , Stroke Rehabilitation/instrumentation , Learning/physiology , Vision Disorders/etiology , Vision Disorders/rehabilitation , Vision Disorders/therapy , Vision Disorders/physiopathology
15.
Invest Ophthalmol Vis Sci ; 65(5): 20, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38727692

ABSTRACT

Purpose: Vision-degrading myodesopsia (VDM) from vitreous floaters significantly degrades vision and impacts visual quality of life (VQOL), but the relationship to light scattering is poorly understood. This study compared in vitro measures of light scatter and transmission in surgically excised human vitreous to preoperative indexes of vitreous structure, visual function, and VQOL. Methods: Pure vitreous collected during vitrectomy from 8 patients with VDM had wide-angle straylight measurements and dark-field imaging, performed within 36 hours of vitrectomy. Preoperative VQOL assessment with VFQ-25, contrast sensitivity (CS) measurements with Freiburg acuity contrast testing, and quantitative ultrasonography were compared to light scattering and transmission in vitro. Results: All indices of vitreous echodensity in vivo correlated positively with straylight at 0.5° (R = 0.708 to 0.775, P = 0.049 and 0.024, respectively). Straylight mean scatter index correlated with echodensity (R = 0.71, P = 0.04) and VQOL (R = -0.82, P = 0.0075). Dark-field measures in vitro correlated with degraded CS in vivo (R = -0.69, P = 0.04). VQOL correlated with straylight mean scatter index (R = -0.823, P = 0.012). Conclusions: Increased vitreous echodensity in vivo is associated with more straylight scattering in vitro, validating ultrasonography as a clinical surrogate for light scattering. Contrast sensitivity in vivo is more degraded in the presence of dark-field scattering in vitro and VQOL is decreased in patients whose vitreous has increased light scattering. These findings could form the basis for the development of optical corrections for VDM or support new laser treatments, as well as novel pharmacotherapy.


Subject(s)
Contrast Sensitivity , Light , Scattering, Radiation , Visual Acuity , Vitrectomy , Vitreous Body , Humans , Vitreous Body/diagnostic imaging , Female , Male , Middle Aged , Visual Acuity/physiology , Contrast Sensitivity/physiology , Aged , Quality of Life , Vision Disorders/physiopathology , Adult , Ultrasonography , Eye Diseases/physiopathology , Eye Diseases/diagnostic imaging
16.
BMC Ophthalmol ; 24(1): 213, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38755573

ABSTRACT

The inconsistency in terminology for Cortical Visual Impairment or Cerebral Visual Impairment presents challenges: (1) different levels of changes in visual pathway and other cerebral areas do not allow discrimination; (2) different visual and oculomotor aspects are not adequately considered. We open a debate to consider a more appropriate diagnosis.


Subject(s)
Terminology as Topic , Vision Disorders , Humans , Vision Disorders/physiopathology , Vision Disorders/diagnosis , Visual Cortex/physiology , Visual Pathways/physiopathology
17.
Sci Rep ; 14(1): 10183, 2024 05 03.
Article in English | MEDLINE | ID: mdl-38702452

ABSTRACT

The perception of halos and other night vision disturbances is a common complaint in clinical practice. Such visual disturbances must be assessed in order to fully characterize each patient's visual performance, which is particularly relevant when carrying out a range of daily tasks. Visual problems are usually assessed using achromatic stimuli, yet the stimuli encountered in daily life have very different chromaticities. Hence, it is important to assess the effect of the chromaticity of visual stimuli on night vision disturbances. The aim of this work is to study the influence of the chromaticity of different visual stimuli on night vision disturbances by analyzing straylight and visual discrimination under low-light conditions. For that, we assessed the monocular and binocular visual discrimination of 27 subjects under low illumination using the Halo test. The subjects' visual discrimination was assessed after exposure to different visual stimuli: achromatic, red, green, and blue, both at the monitor's maximum luminance and maintaining the same luminance value for the different visual stimuli. Monocular straylight was also measured for an achromatic, red, green, and blue stimuli. The blue stimulus had the greatest effect on halos in both monocular and binocular conditions. Visual discrimination was similar for the red, green, and achromatic stimuli, but worsened at lower luminance. The greatest influence of straylight was observed for the blue stimulus. In addition, visual discrimination correlated with straylight measurements for achromatic stimuli, wherein greater straylight values correlated with an increased perception of halos and other visual disturbances.


Subject(s)
Photic Stimulation , Humans , Male , Female , Adult , Night Vision/physiology , Young Adult , Light , Vision, Binocular/physiology , Visual Perception/physiology , Color Perception/physiology , Vision Disorders/physiopathology , Lighting , Middle Aged
18.
Invest Ophthalmol Vis Sci ; 65(5): 38, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38787547

ABSTRACT

Purpose: Visual snow is the hallmark of the neurological condition visual snow syndrome (VSS) but the characteristics of the visual snow percept remain poorly defined. This study aimed to quantify its appearance, interobserver variability, and effect on measured visual performance and self-reported visual quality. Methods: Twenty-three participants with VSS estimated their visual snow dot size, separation, luminance, and flicker rate by matching to a simulation. To assess whether visual snow masks vision, we compared pattern discrimination thresholds for textures that were similar in spatial scale to visual snow as well as more coarse than visual snow, in participants with VSS, and with and without external noise simulating visual snow in 23 controls. Results: Mean and 95% confidence intervals for visual snow appearance were: size (6.0, 5.8-6.3 arcseconds), separation (2.0, 1.7-2.3 arcmin), luminance (72.4, 58.1-86.8 cd/m2), and flicker rate (25.8, 18.9-32.8 frames per image at 120 hertz [Hz]). Participants with finer dot spacing estimates also reported greater visibility of their visual snow (τb = -0.41, 95% confidence interval [CI] = -0.62 to -0.13, P = 0.01). In controls, adding simulated fine-scale visual snow to textures increased thresholds for fine but not coarse textures (F(1, 22) = 4.98, P = 0.036, ηp2 = 0.19). In VSS, thresholds for fine and coarse textures were similar (t(22) = 0.54, P = 0.60), suggesting that inherent visual snow does not act like external noise in controls. Conclusions: Our quantitative estimates of visual snow constrain its likely neural origins, may aid differential diagnosis, and inform future investigations of how it affects vision. Methods to quantify visual snow are needed for evaluation of potential treatments.


Subject(s)
Visual Acuity , Humans , Male , Female , Adult , Middle Aged , Visual Acuity/physiology , Young Adult , Sensory Thresholds/physiology , Vision Disorders/physiopathology , Vision Disorders/diagnosis , Aged , Visual Perception/physiology , Observer Variation , Pattern Recognition, Visual/physiology , Perceptual Disorders
19.
Cereb Cortex ; 34(5)2024 May 02.
Article in English | MEDLINE | ID: mdl-38795357

ABSTRACT

Visuospatial processing impairments are prevalent in individuals with cerebral visual impairment (CVI) and are typically ascribed to "dorsal stream dysfunction" (DSD). However, the contribution of other cortical regions, including early visual cortex (EVC), frontal cortex, or the ventral visual stream, to such impairments remains unknown. Thus, here, we examined fMRI activity in these regions, while individuals with CVI (and neurotypicals) performed a visual search task within a dynamic naturalistic scene. First, behavioral performance was measured with eye tracking. Participants were instructed to search and follow a walking human target. CVI participants took significantly longer to find the target, and their eye gaze patterns were less accurate and less precise. Second, we used the same task in the MRI scanner. Along the dorsal stream, activation was reduced in CVI participants, consistent with the proposed DSD in CVI. Intriguingly, however, visual areas along the ventral stream showed the complete opposite pattern, with greater activation in CVI participants. In contrast, we found no differences in either EVC or frontal cortex between groups. These results suggest that the impaired visuospatial processing abilities in CVI are associated with differential recruitment of the dorsal and ventral visual streams, likely resulting from impaired selective attention.


Subject(s)
Magnetic Resonance Imaging , Space Perception , Visual Cortex , Humans , Male , Female , Adult , Space Perception/physiology , Visual Cortex/diagnostic imaging , Visual Cortex/physiopathology , Visual Cortex/physiology , Visual Pathways/diagnostic imaging , Visual Pathways/physiology , Visual Pathways/physiopathology , Young Adult , Vision Disorders/physiopathology , Brain Mapping , Middle Aged , Visual Perception/physiology , Photic Stimulation/methods
20.
J Glaucoma ; 33(7): 505-515, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38595156

ABSTRACT

PRCIS: Online circular contrast perimetry provides visual field assessment on any computer or tablet with no extra hardware. It has good test repeatability and reliability that is comparable with standard automated perimetry. It holds promise for use in disease screening and surveillance to expand the provision of glaucoma care. PURPOSE: To evaluate the repeatability of online circular contrast perimetry (OCCP) compared to standard automated perimetry (SAP) in normal participants and patients with stable glaucoma over 18 weeks. METHODS: Thirty-six participants (13 normal controls and 23 patients with open angle glaucoma) were recruited. OCCP and SAP perimetry tests were performed twice at baseline, then at 6, 12, and 18 weeks. Global perimetric indices were compared between perimetry types and analyzed for short-term and intermediate-term repeatability. RESULTS: There were no statistically significant changes over time for both OCCP and SAP across all groups for mean deviation (MD), pattern standard deviation, and visual index/visual field index ( P >0.05). Test-retest intraclass correlation coefficients (ICCs) for OCCP MD were excellent at baseline (0.98, 95% CI: 0.89-0.99) and good at 18 weeks (0.88, 95% CI: 0.51-0.98). SAP test-retest ICCs were excellent at baseline (0.94, 95% CI: 0.70-0.99) and 18 weeks (0.97, 95% CI: 0.84-0.99). Inter-test ICCs were good, ranging from 0.84 to 0.87. OCCP testing time was shorter than SAP (5:29 ± 1:24 vs. 6:00 ± 1:05, P <0.001). OCCP had similar false-positive (3.84 ± 3.32 vs. 3.66 ± 4.53, P =0.48) but lower false-negative (0.73 ± 1.52 vs. 4.48 ± 5.00, P <0.001) and fixation loss responses (0.91 ± 1.32 vs. 2.02 ± 2.17, P <0.001). CONCLUSIONS: OCCP allows visual field assessment on any computer screen with no additional hardware. It demonstrated good repeatability and reliability with similar performance indices to SAP in both the short term and intermediate term. OCCP has the potential to be utilized as a glaucoma screening and surveillance tool for in-clinic and at-home testing, expanding the provision of care.


Subject(s)
Glaucoma, Open-Angle , Intraocular Pressure , Vision Disorders , Visual Field Tests , Visual Fields , Humans , Visual Field Tests/methods , Reproducibility of Results , Visual Fields/physiology , Glaucoma, Open-Angle/diagnosis , Glaucoma, Open-Angle/physiopathology , Female , Male , Middle Aged , Aged , Vision Disorders/diagnosis , Vision Disorders/physiopathology , Intraocular Pressure/physiology , Adult
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