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1.
J. optom. (Internet) ; 17(3): [100510], jul.-sept2024. tab
Article En | IBECS | ID: ibc-231872

Purpose: To evaluate the association between visual symptoms and use of digital devices considering the presence of visual dysfunctions. Methods: An optometric examination was conducted in a clinical sample of 346 patients to diagnose any type of visual anomaly. Visual symptoms were collected using the validated SQVD questionnaire. A threshold of 6 hours per day was used to quantify the effects of digital device usage and patients were divided into two groups: under and above of 35 years old. A multivariate logistic regression was employed to investigate the association between digital device use and symptoms, with visual dysfunctions considered as a confounding variable. Crude and the adjusted odds ratio (OR) were calculated for each variable. Results: 57.02 % of the subjects reported visual symptoms, and 65.02% exhibited some form of visual dysfunction. For patients under 35 years old, an association was found between having visual symptoms and digital device use (OR = 2.10, p = 0.01). However, after adjusting for visual dysfunctions, this association disappeared (OR = 1.44, p = 0.27) and the association was instead between symptoms and refractive dysfunction (OR = 6.52, p < 0.001), accommodative (OR = 10.47, p < 0.001), binocular (OR = 6.68, p < 0.001) and accommodative plus binocular dysfunctions (OR = 46.84, p < 0.001). Among patients over 35 years old, no association was found between symptoms and the use of digital devices (OR = 1.27, p = 0.49) but there was an association between symptoms and refractive dysfunction (OR = 3.54, p = 0.001). Conclusions: Visual symptoms are not dependent on the duration of digital device use but rather on the presence of any type of visual dysfunction: refractive, accommodative and/or binocular one, which should be diagnosed.(AU)


Humans , Male , Female , Vision, Ocular , Vision Tests , Visual Fields , Visually Impaired Persons , Vision, Binocular , Surveys and Questionnaires , Optometry
2.
BMJ Open ; 14(6): e084068, 2024 Jun 05.
Article En | MEDLINE | ID: mdl-38839388

BACKGROUND: In adult patients with high myopia (HM), progressive axial elongation poses a significant risk for the development of subsequent ocular complications that may lead to visual impairment. Effective strategies to reduce or prevent further axial elongation in highly myopic adult patients have not been available so far. Recent studies suggested that medically lowering intraocular pressure (IOP) may reduce axial elongation. OBJECTIVE: This clinical randomised controlled trial (RCT) aims to evaluate the efficacy of medical IOP reduction in adult patients with progressive HM (PHM). TRIAL DESIGN: Single-centre, open-label, prospective RCT. METHODS: This RCT will recruit 152 participants with PHM at the Zhongshan Ophthalmic Center (ZOC). Randomised in a ratio of 1:1, participants will receive IOP-lowering eyedrops (intervention group) or will be followed without treatment (control group) for 12 months. Follow-up visits will be conducted at 1, 6 and 12 months after baseline. Only one eye per eligible participant will be included for analysis. The primary outcome is the change in axial length (AL) within the study period of 12 months. Secondary outcomes include the incidence and progression of visual field (VF) defects, changes in optic disc morphology and incidence and progression of myopic maculopathy. Difference in AL changes between the two groups will be analysed using linear regression analysis. For the secondary outcomes, a multifactor Poisson regression within a generalised linear model will be used to estimate the relative risk of progression in VF defects and myopic maculopathy, and the rate of thinning in retinal nerve fibre layer and ganglion cell-inner plexiform will be assessed through Kaplan-Meier curves and log-rank tests. ETHICS AND DISSEMINATION: Full ethics approval for this trial has been obtained from the Ethics Committee of ZOC, Sun Yat-sen University, China (ID: 2023KYPJ110). Results of this trial will be disseminated through peer-reviewed journals and conference presentations. TRIAL REGISTRATION NUMBER: NCT05850936.


Intraocular Pressure , Myopia, Degenerative , Humans , Prospective Studies , Adult , Disease Progression , Randomized Controlled Trials as Topic , Ophthalmic Solutions , Male , Female , Axial Length, Eye , Middle Aged , Visual Fields
3.
J Vis ; 24(6): 3, 2024 Jun 03.
Article En | MEDLINE | ID: mdl-38837169

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.


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
4.
BMC Ophthalmol ; 24(1): 209, 2024 May 10.
Article En | MEDLINE | ID: mdl-38724962

BACKGROUD: The aim of this study was to investigate the associations between fluctuation in blood pressure (BP), ocular perfusion pressure (OPP) and visual field (VF) progression in normal-tension glaucoma (NTG). METHODS: This prospective, longitudinal study included 44 patients with NTG. Only newly diagnosed NTG patients who had not been treated with a glaucoma medication were included. Patients were examined every year for 7 years. Intraocular pressure (IOP), heart rate (HR), systolic BP (SBP), diastolic BP (DBP), ocular perfusion pressure (OPP), and diastolic ocular perfusion pressure (DOPP) were measured at the same time. Ophthalmic examinations, including perimetry, were performed also. Initial VF were compared with follow-up data after 7 years. RESULTS: After 7 years of follow-up, 9 of the 44 patients showed VF progression. The standard deviation (SD) of SBP and OPP were significantly associated with VF progression (P = 0.007, < 0.001, respectively). Multiple regression analysis showed that VF progression was significantly associated with SD of OPP (odds ratio, OR = 2.012, 95% CI = 1.016-3.985; P = 0.045). CONCLUSIONS: Fluctuation in OPP was associated with VF progression in patients with NTG.


Blood Pressure , Disease Progression , Intraocular Pressure , Low Tension Glaucoma , Visual Fields , Humans , Low Tension Glaucoma/physiopathology , Visual Fields/physiology , Male , Female , Intraocular Pressure/physiology , Prospective Studies , Middle Aged , Blood Pressure/physiology , Follow-Up Studies , Aged , Visual Field Tests , Adult
5.
Am J Ophthalmol ; 259: 7-14, 2024 Mar.
Article En | MEDLINE | ID: mdl-38708401

Purpose: To evaluate the diagnostic accuracy of retinal nerve fiber layer thickness (RNFLT) by spectral-domain optical coherence tomography (OCT) in primary open-angle glaucoma (POAG) in eyes of African (AD) and European descent (ED). Design: Comparative diagnostic accuracy analysis by race. Participants: 379 healthy eyes (125 AD and 254 ED) and 442 glaucomatous eyes (226 AD and 216 ED) from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Methods: Spectralis (Heidelberg Engineering GmbH) and Cirrus (Carl Zeiss Meditec) OCT scans were taken within one year from each other. Main Outcome Measures: Diagnostic accuracy of RNFLT measurements. Results: Diagnostic accuracy for Spectralis-RNFLT was significantly lower in eyes of AD compared to those of ED (area under the receiver operating curve [AUROC]: 0.85 and 0.91, respectively, P=0.04). Results for Cirrus-RNFLT were similar but did not reach statistical significance (AUROC: 0.86 and 0.90 in AD and ED, respectively, P =0.33). Adjustments for age, central corneal thickness, axial length, disc area, visual field mean deviation, and intraocular pressure yielded similar results. Conclusions: OCT-RNFLT has lower diagnostic accuracy in eyes of AD compared to those of ED. This finding was generally robust across two OCT instruments and remained after adjustment for many potential confounders. Further studies are needed to explore the potential sources of this difference.


Glaucoma, Open-Angle , Intraocular Pressure , Nerve Fibers , Optic Disk , ROC Curve , Retinal Ganglion Cells , Tomography, Optical Coherence , Visual Fields , White People , Humans , Glaucoma, Open-Angle/ethnology , Glaucoma, Open-Angle/diagnosis , Tomography, Optical Coherence/methods , Nerve Fibers/pathology , Retinal Ganglion Cells/pathology , Female , Male , Middle Aged , Intraocular Pressure/physiology , Visual Fields/physiology , White People/ethnology , Reproducibility of Results , Aged , Optic Disk/pathology , Optic Disk/diagnostic imaging , Optic Nerve Diseases/diagnosis , Optic Nerve Diseases/ethnology , Black or African American/ethnology , Area Under Curve , Sensitivity and Specificity
6.
Sci Rep ; 14(1): 10261, 2024 05 04.
Article En | MEDLINE | ID: mdl-38704441

Previous studies have suggested behavioral patterns, such as visual attention and eye movements, relate to individual personality traits. However, these studies mainly focused on free visual tasks, and the impact of visual field restriction remains inadequately understood. The primary objective of this study is to elucidate the patterns of conscious eye movements induced by visual field restriction and to examine how these patterns relate to individual personality traits. Building on previous research, we aim to gain new insights through two behavioral experiments, unraveling the intricate relationship between visual behaviors and individual personality traits. As a result, both Experiment 1 and Experiment 2 revealed differences in eye movements during free observation and visual field restriction. Particularly, simulation results based on the analyzed data showed clear distinctions in eye movements between free observation and visual field restriction conditions. This suggests that eye movements during free observation involve a mixture of conscious and unconscious eye movements. Furthermore, we observed significant correlations between conscious eye movements and personality traits, with more pronounced effects in the visual field restriction condition used in Experiment 2 compared to Experiment 1. These analytical findings provide a novel perspective on human cognitive processes through visual perception.


Eye Movements , Personality , Visual Fields , Humans , Visual Fields/physiology , Eye Movements/physiology , Male , Personality/physiology , Female , Adult , Young Adult , Attention/physiology , Visual Perception/physiology
7.
Zhonghua Yan Ke Za Zhi ; 60(5): 423-429, 2024 May 11.
Article Zh | MEDLINE | ID: mdl-38706080

Objective: To investigate the effect of virtual reality visual training on remodeling optic nerve structures of glaucoma patients and analyze the influencing factors of visual training effect. Methods: A prospective non-randomized controlled trial was conducted. Glaucoma patients who presented to the Department of Ophthalmology, Beijing Shijitan Hospital between October 2021 and October 2022 were collected and divided into the training group or the control group according to their intentions. The training group accepted 3 months of visual training, while the control group did not. Optical coherence tomography was used to examine the disc edge area, cup volume, disc area, cup-to-disc ratio, and other parameters of the optic disc of both eyes of the patients at enrollment and after 3 months, and the changes of each parameter in the two groups were analyzed. Multivariate analysis was performed in the training group to investigate the effects of sex, age, visual field index, and mean defect on visual disc structure changes during visual training. Results: A total of 53 glaucoma patients (101 eyes) were included in the final analysis, among which the training group consisted of 27 cases (51 eyes), with 19 males and 8 females, and the age range was 48.0 (40.0, 61.0) years old. The control group comprised 26 cases (50 eyes), with 26 males and 11 females, and the age range was 54.0 (38.0, 63.0) years old. Compared with the control group, the deviation of cup volume was -0.006(-0.050, 0.015)mm3 (P<0.05), and the deviation of disc edge area was 0.00(-0.04, 0.05)mm2 (P<0. 05)in the visual training group after 3 months of visual training. The gender (OR=4.217, 95%CI=1.188-14.966) may be the influence factor of rim area. While,the mean defect (OR=1.526, 95%CI=0.245-9.491) was not that influential on rim area change. Conclusions: Visual training can increase the disc area and decrease the optic cup volume of the optic nerve in glaucoma patients. The rim area may be increased more easily after visual training in male glaucoma patients.


Glaucoma , Optic Disk , Tomography, Optical Coherence , Humans , Male , Female , Middle Aged , Prospective Studies , Adult , Visual Fields
8.
Harefuah ; 163(5): 298-304, 2024 May.
Article He | MEDLINE | ID: mdl-38734943

INTRODUCTION: Glaucoma is a progressive optic neuropathy and is the leading cause of preventable irreversible blindness worldwide. Glaucoma causes progressive visual field loss and can have significant implications on the patient's quality of life. Lowering intraocular pressure (IOP) is the only treatment proven to prevent vision loss from glaucoma. It is achieved using medication, laser treatment and surgery. The treatment paradigm of glaucoma has been one whereby surgical intervention has been left for advanced cases due to a variety of reasons, mainly concerning safety and long term success. The past two decades have seen a paradigm shift towards earlier IOP lowering interventions using a wide array of different technologies in the laser and surgical spaces. This review aims to understand the background to this paradigm shift, its necessity, and its potential impact on the vision and life of glaucoma patients.


Glaucoma , Intraocular Pressure , Laser Therapy , Quality of Life , Humans , Glaucoma/therapy , Glaucoma/surgery , Intraocular Pressure/physiology , Laser Therapy/methods , Blindness/etiology , Blindness/prevention & control , Visual Fields/physiology , Disease Progression , Optic Nerve Diseases/etiology , Optic Nerve Diseases/therapy
9.
Ophthalmol Retina ; 8(4): 331-339, 2024 Apr.
Article En | MEDLINE | ID: mdl-38752998

OBJECTIVE: To describe and quantify the structural and functional consequences of retinal vasculopathy with cerebral leukoencephalopathy (RVCL) on the neurosensory retina. DESIGN: Cross sectional descriptive study from December 2021 to December 2022. PARTICIPANTS: Retinal vasculopathy with cerebral leukoencephalopathy patients (n = 9, 18 eyes) recruited from the RVCL Research Center at Washington University in St. Louis. METHODS: Retinal vasculopathy with cerebral leukoencephalopathy patients underwent comprehensive ophthalmological evaluation including OCT, OCT angiography (OCTA), ultrawidefield fundus imaging, retinal autofluorescence, dark adaptation, electroretinography (ERG), Goldmann kinetic perimetry, and fluorescein angiography (FA). MAIN OUTCOME MEASURES: Comprehensive characterization from various modalities including best-corrected visual acuity, central subfield thickness (µm) from OCT, foveal avascular zone (mm2) from OCTA, dark adaptation rod intercept (seconds), cone response in ERG, and presence or absence of vascular abnormalities, leakage, neovascularization, and nonperfusion on FA. RESULTS: A total of 18 eyes from 9 individuals were included in this study. The best-corrected visual acuity ranged from 20/15 to 20/70. The mean central subfield thickness from OCT was 275.8 µm (range, 217-488 µm). The mean foveal avascular zone (FAZ) from OCTA was 0.65 (range, 0.18-1.76) mm2. On dark adaptometry, the mean time was 5.02 (range, 2.9-6.5) minutes, and 1 individual had impaired dark adaptation. Electroretinography demonstrated mild cone response impairment in 4 eyes. On FA, there was evidence of macular and peripheral capillary nonperfusion in 16 of 18 eyes and notable areas of vascular leakage and retinal edema in 5 of the 18 eyes. CONCLUSIONS: This study illustrates the phenotypic spectrum of disease and may be clinically valuable for aiding diagnosis, monitoring disease progression, and further elucidating the pathophysiology of RVCL to aid in the development of therapies. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.


Electroretinography , Fluorescein Angiography , Leukoencephalopathies , Multimodal Imaging , Tomography, Optical Coherence , Visual Acuity , Humans , Male , Female , Cross-Sectional Studies , Tomography, Optical Coherence/methods , Adult , Fluorescein Angiography/methods , Electroretinography/methods , Middle Aged , Leukoencephalopathies/diagnosis , Leukoencephalopathies/physiopathology , Visual Fields/physiology , Retinal Diseases/diagnosis , Retinal Diseases/physiopathology , Retinal Diseases/etiology , Retinal Vessels/diagnostic imaging , Retinal Vessels/physiopathology , Retinal Vessels/pathology , Young Adult , Fundus Oculi , Adolescent
10.
Retina ; 44(6): 982-990, 2024 Jun 01.
Article En | MEDLINE | ID: mdl-38767849

PURPOSE: To evaluate macular sensitivity using microperimetry in patients with proliferate diabetic retinopathy following vitrectomy and to investigate the relationship between the sensitivity and foveal microstructures with optical coherence tomography/angiography. METHODS: Eighty-four eyes of 84 patients with proliferative diabetic retinopathy, who were indicated for vitrectomy, had no intraocular surgery history 3 months preoperatively, and were able to ensure fundus examination after the vitrectomy, were included. A logMAR best-corrected visual acuity, macular sensitivity of microperimetry, macular retinal thickness, and macular vessel perfusion using optical coherence tomography/angiography were examined at 1 week, 1 month, and 3 months postoperatively. RESULTS: The logMAR best-corrected visual acuity and mean macular sensitivity of patients with proliferative diabetic retinopathy improved postoperatively (P < 0.05). There was a significant correlation between best-corrected visual acuity and mean sensitivity (P < 0.05). Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness in the 0 to 6 mm macular area (P < 0.05) and also significantly correlated with deep capillary plexus perfusion (P < 0.05). Fixation stability and mean macular sensitivity did not show any correlation with glycated hemoglobin, triglyceride, serum total cholesterol, carbamide, and creatinine and duration of diabetes mellitus (P > 0.05). CONCLUSION: Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness and deep capillary plexus perfusion for patients with proliferative diabetic retinopathy. The authors found that the visual performance of patients can be evaluated by the outer retinal thickness and deep capillary plexus perfusion, so optical coherence tomography/angiography examination can be an important prognostic factor for visual performance in patients.Clinical Trial Registration: This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn; Registration No.: ChiCTR2100043399).


Diabetic Retinopathy , Fluorescein Angiography , Macula Lutea , Tomography, Optical Coherence , Visual Acuity , Visual Field Tests , Vitrectomy , Humans , Diabetic Retinopathy/physiopathology , Diabetic Retinopathy/surgery , Diabetic Retinopathy/diagnosis , Vitrectomy/methods , Male , Female , Tomography, Optical Coherence/methods , Visual Acuity/physiology , Middle Aged , Visual Field Tests/methods , Fluorescein Angiography/methods , Macula Lutea/blood supply , Macula Lutea/diagnostic imaging , Aged , Adult , Visual Fields/physiology , Retinal Vessels/physiopathology , Retinal Vessels/diagnostic imaging , Postoperative Period
11.
PLoS One ; 19(5): e0303849, 2024.
Article En | MEDLINE | ID: mdl-38768185

PURPOSE: Random noise-moving images (noises) can make glaucoma patients with no subjective symptoms aware of visual field abnormalities. To explore this concept, we developed a noise using computer graphics (CG) and investigated the difference in the subjective perception of visual field abnormalities between CG and conventional analog noises. METHODS: We enrolled individuals with glaucoma (205 eyes), preperimetric glaucoma (PPG; 19 eyes), and normal eyes (35 eyes). For a CG noise, a series of still images was made by randomly selecting five monochromatic tones on 2-mm square dots, and these images were drawn at 60 frames per second (fps) to create a noise-moving image. The participants were asked to describe their perceived shadows on a paper. The results were categorized as follows based on the pattern deviation probability map of the Humphrey field analyzer (HFA): "agreement," "partial agreement," "disagreement," and "no response." The glaucoma stage was classified into four stages, from M1 to M4, based on the HFA's mean deviation. RESULT: The detection rates (agreement and partial agreement) were 80.5% and 65.4% for the CG and analog noises, respectively, with CG noise showing a significantly higher detection rate in all glaucoma eyes (P < 0.001). The detection rates tended to increase as the glaucoma stage progressed, and in Stage M3, these were 93.9% and 78.8% for the CG and analog noises, respectively. The PPG eyes did not exhibit subjective abnormalities for both noises. The specificity values were 97.1% and 100% for the CG and analog noises, respectively. CONCLUSION: The CG noise is more effective than the analog noise in evaluating the subjective perception of visual field abnormalities in patients with glaucoma.


Computer Graphics , Glaucoma , Visual Fields , Humans , Glaucoma/physiopathology , Visual Fields/physiology , Female , Male , Middle Aged , Aged , Visual Field Tests/methods , Adult , Visual Perception/physiology
12.
Invest Ophthalmol Vis Sci ; 65(5): 33, 2024 May 01.
Article En | MEDLINE | ID: mdl-38771569

Purpose: This study explored early (contrast discrimination) and intermediate (global form perception) visual processing in primary subtypes of glaucoma: primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). We aimed to understand early and intermediate visual processing in POAG and PACG, matched for similar visual field defect severity. Methods: Early visual processing was measured using a contrast discrimination task described by Porkorny and Smith (1997), and intermediate processing using a global form perception task using glass pattern coherence thresholds. Thresholds were determined centrally and at a single midperipheral location (12.5°) in a quadrant without visual field defects. Controls were tested in corresponding quadrants to individuals with glaucoma. Results: Sixty participants (20 POAG, 20 PACG, and 20 age-matched controls), aged 50 to 77 years, were included. Visual field defects were matched between POAG and PACG, with mean deviation values of -6.53 ± 4.46 (range: -1.5 to -16.85) dB and -6.2 ± 4.24 (range: -1.37 to -16.42) dB, respectively. Two-Way ANOVA revealed significant differences in thresholds between the glaucoma groups and the control group for both contrast discrimination and global form perception tasks, with higher thresholds in the glaucoma groups. Post hoc analyses showed no significant contrast discrimination difference between POAG and PACG, but POAG had significantly higher thresholds than PACG for form perception. Conclusions: In form perception, POAG showed slightly worse performance than PACG, suggesting that individuals with POAG may experience more severe functional damage than PACG of similar visual field severity.


Contrast Sensitivity , Form Perception , Glaucoma, Angle-Closure , Glaucoma, Open-Angle , Visual Fields , Humans , Glaucoma, Open-Angle/physiopathology , Glaucoma, Angle-Closure/physiopathology , Middle Aged , Aged , Male , Female , Visual Fields/physiology , Contrast Sensitivity/physiology , Form Perception/physiology , Intraocular Pressure/physiology , Sensory Thresholds/physiology , Visual Field Tests
13.
J Vis ; 24(5): 7, 2024 May 01.
Article En | MEDLINE | ID: mdl-38771584

This study aimed to investigate the impact of eccentric-vision training on population receptive field (pRF) estimates to provide insights into brain plasticity processes driven by practice. Fifteen participants underwent functional magnetic resonance imaging (fMRI) measurements before and after behavioral training on a visual crowding task, where the relative orientation of the opening (gap position: up/down, left/right) in a Landolt C optotype had to be discriminated in the presence of flanking ring stimuli. Drifting checkerboard bar stimuli were used for pRF size estimation in multiple regions of interest (ROIs): dorsal-V1 (dV1), dorsal-V2 (dV2), ventral-V1 (vV1), and ventral-V2 (vV2), including the visual cortex region corresponding to the trained retinal location. pRF estimates in V1 and V2 were obtained along eccentricities from 0.5° to 9°. Statistical analyses revealed a significant decrease of the crowding anisotropy index (p = 0.009) after training, indicating improvement on crowding task performance following training. Notably, pRF sizes at and near the trained location decreased significantly (p = 0.005). Dorsal and ventral V2 exhibited significant pRF size reductions, especially at eccentricities where the training stimuli were presented (p < 0.001). In contrast, no significant changes in pRF estimates were found in either vV1 (p = 0.181) or dV1 (p = 0.055) voxels. These findings suggest that practice on a crowding task can lead to a reduction of pRF sizes in trained visual cortex, particularly in V2, highlighting the plasticity and adaptability of the adult visual system induced by prolonged training.


Magnetic Resonance Imaging , Neuronal Plasticity , Visual Cortex , Visual Fields , Humans , Male , Female , Visual Cortex/physiology , Adult , Visual Fields/physiology , Magnetic Resonance Imaging/methods , Young Adult , Neuronal Plasticity/physiology , Photic Stimulation/methods
14.
Proc Biol Sci ; 291(2023): 20240239, 2024 May.
Article En | MEDLINE | ID: mdl-38808445

The ocean's midwater is a uniquely challenging yet predictable and simple visual environment. The need to see without being seen in this dim, open habitat has led to extraordinary visual adaptations. To understand these adaptations, we compared the morphological and functional differences between the eyes of three hyperiid amphipods-Hyperia galba, Streetsia challengeri and Phronima sedentaria. Combining micro-CT data with computational modelling, we mapped visual field topography and predicted detection distances for visual targets viewed in different directions through mesopelagic depths. Hyperia's eyes provide a wide visual field optimized for spatial vision over short distances, while Phronima's and Streetsia's eyes have the potential to achieve greater sensitivity and longer detection distances using spatial summation. These improvements come at the cost of smaller visual fields, but this loss is compensated for by a second pair of eyes in Phronima and by behaviour in Streetsia. The need to improve sensitivity while minimizing visible eye size to maintain crypsis has likely driven the evolution of hyperiid eye diversity. Our results provide an integrative look at how these elusive animals have adapted to the unique visual challenges of the mesopelagic.


Amphipoda , Animals , Amphipoda/physiology , Amphipoda/anatomy & histology , Ecosystem , Visual Fields , Eye/anatomy & histology , Vision, Ocular , X-Ray Microtomography
15.
PLoS One ; 19(5): e0302459, 2024.
Article En | MEDLINE | ID: mdl-38809939

Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the peripheral target to the very centre of the fovea. This mechanism extends the use of the superior image processing performance of the fovea over a large visual field. We know that visual information is processed quickly at the end of each saccade but estimates of the times involved remain controversial. This study aims to investigate the processing of visual information during post fixation oscillations of the eyeball. A new psychophysical test measures the combined eye movement response latencies, including fixation duration and visual processing times. When the test is used in conjunction with an eye tracker, each component that makes up the 'integrated saccade latency' time, from the onset of the peripheral stimulus to the correct interpretation of the information carried by the stimulus, can be measured and the discrete components delineated. The results show that the time required to process and encode the stimulus attribute of interest at the end of a saccade is longer than the time needed to carry out the same task in the absence of an eye movement. We propose two principal hypotheses, each of which can account for this finding. 1. The known inhibition of afferent retinal signals during fast eye movements extends beyond the end point of the saccade. 2. The extended visual processing times measured when saccades are involved are caused by the transient loss of spatial resolution due to eyeball instability during post-saccadic oscillations. The latter can best be described as retinal image smear with greater loss of spatial resolution expected for stimuli of low luminance contrast.


Fixation, Ocular , Reaction Time , Saccades , Visual Perception , Humans , Saccades/physiology , Adult , Male , Female , Reaction Time/physiology , Visual Perception/physiology , Fixation, Ocular/physiology , Young Adult , Photic Stimulation , Visual Fields/physiology , Time Factors
16.
Neuropsychologia ; 199: 108907, 2024 Jul 04.
Article En | MEDLINE | ID: mdl-38734179

Studies of letter transposition effects in alphabetic scripts provide compelling evidence that letter position is encoded flexibly during reading, potentially during an early, perceptual stage of visual word recognition. Recent studies additionally suggest similar flexibility in the spatial encoding of syllabic information in the Korean Hangul script. With the present research, we conducted two experiments to investigate the locus of this syllabic transposition effect. In Experiment 1, lexical decisions for foveal stimulus presentations were less accurate and slower for four-syllable nonwords created by transposing two syllables in a base word as compared to control nonwords, replicating prior evidence for a transposed syllable effect in Korean word recognition. In Experiment 2, the same stimuli were presented to the right and left visual hemifields (i.e., RVF and LVF), which project both unilaterally and contralaterally to each participant's left and right cerebral hemisphere (i.e., LH and RH) respectively, using lateralized stimulus displays. Lexical decisions revealed a syllable transposition effect in the accuracy and latency of lexical decisions for both RVF and LVF presentations. However, response times for correct responses were longer in the LVF, and therefore the RH, as compared to the RVF/LH. As the LVF/RH appears to be selectively sensitive to the visual-perceptual attributes of words, the findings suggest that this syllable transposition effect partly finds its locus within a perceptual stage of processing. We discuss these findings in relation to current models of the spatial encoding of orthographic information during visual word recognition and accounts of visual word recognition in Korean.


Reaction Time , Reading , Humans , Female , Male , Young Adult , Reaction Time/physiology , Functional Laterality/physiology , Pattern Recognition, Visual/physiology , Photic Stimulation , Adult , Visual Fields/physiology , Language
17.
Curr Biol ; 34(11): 2474-2486.e5, 2024 Jun 03.
Article En | MEDLINE | ID: mdl-38772362

ON and OFF thalamic afferents from the two eyes converge in the primary visual cortex to form binocular receptive fields. The receptive fields need to be diverse to sample our visual world but also similar across eyes to achieve binocular fusion. It is currently unknown how the cortex balances these competing needs between receptive-field diversity and similarity. Our results demonstrate that receptive fields in the cat visual cortex are binocularly matched with exquisite precision for retinotopy, orientation/direction preference, orientation/direction selectivity, response latency, and ON-OFF polarity/structure. Specifically, the average binocular mismatches in retinotopy and ON-OFF structure are tightly restricted to 1/20 and 1/5 of the average receptive-field size but are still large enough to generate all types of binocular disparity tuning. Based on these results, we conclude that cortical receptive fields are binocularly matched with the high precision needed to facilitate binocular fusion while allowing restricted mismatches to process visual depth.


Primary Visual Cortex , Vision, Binocular , Animals , Cats/physiology , Vision, Binocular/physiology , Primary Visual Cortex/physiology , Visual Fields/physiology , Visual Cortex/physiology , Vision Disparity/physiology
18.
J AAPOS ; 28(3): 103933, 2024 Jun.
Article En | MEDLINE | ID: mdl-38729256

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.


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
19.
Brain Behav ; 14(5): e3525, 2024 May.
Article En | MEDLINE | ID: mdl-38773793

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.


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
20.
J Glaucoma ; 33(6): 381-386, 2024 Jun 01.
Article En | MEDLINE | ID: mdl-38722193

PRCIS: A review of the literature found that certain types of exercise and physical activity result in transient reductions in intraocular pressure and may have a beneficial effect on glaucoma severity and progression. INTRODUCTION: Glaucoma is the most common cause of irreversible vision loss worldwide. Raised intraocular pressure (IOP) is the most important risk factor for the disease. Exercise is known to result in changes in IOP. The purpose of this review was to investigate the effect of exercise on IOP and glaucoma. METHODS: A comprehensive search of multiple literature databases was performed. Medline, EMBASE, and Cochrane libraries were used to search for the relevant terms. 16 original studies were selected for the review. RESULTS: Exercise of varying intensity and type has differing effects on IOP. Moderate-intensity aerobic exercise results in transient reductions in IOP, while high-intensity resistance exercise and weight-lifting lead to transient elevations in IOP. There is evidence to suggest that exercise and higher levels of fitness may be protective against the development of glaucoma. In addition, increased daily physical activity may be associated with less visual field progression in patients with glaucoma. While secondary causes of glaucoma are included in some of the studies discussed in this review, the findings are largely applicable to primary open angle glaucoma. CONCLUSION: Exercise may be a beneficial lifestyle modification in the management of glaucoma; however, further longitudinal studies are required to validate this.


Exercise , Glaucoma , Intraocular Pressure , Humans , Intraocular Pressure/physiology , Exercise/physiology , Glaucoma/physiopathology , Visual Fields/physiology , Glaucoma, Open-Angle/physiopathology , Tonometry, Ocular
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