Normal Vision Group Research Articles

Orbital decompression improves visual function and macular blood perfusion status in patients with thyroid-related eye disease.

Orbital decompression surgery is a treatment option for Thyroid-associated Ophthalmopathy (TAO). However, its effects on visual function and macular perfusion status remain unclear. This study examined how orbital decompression surgery affects visual acuity and macular blood flow in TAO patients and the variation between these two factors. This study involved cross-sectional and longitudinal analyses of 54 TAO patients, who were categorized into a normal vision group (n = 40) and an impaired vision group (n = 14) based on the presence of visual impairment before surgery (LogMAR BCVA >0.097). Among the participants, 20 underwent orbital decompression surgery (normal vision group: n = 13, impaired vision group: n = 7). BCVA and IOP were assessed at baseline in patients with TAO, and macular retinal blood perfusion indices were measured using OCTA. One month post-operatively, changes in these indices were compared between the two groups, and the correlation between visual acuity and macular perfusion indices was analyzed. The LogMar BCVA in the visual impairment group was significantly worse than that in the normal vision group (p < 0.001), while the W-MVD was significantly lower (p = 0.01). In the visual impairment group, post-operative LogMar BCVA improved significantly (p = 0.038), and W-MVD increased significantly (p = 0.008) compared to baseline. However, there were no significant changes in LogMar BCVA, S-MVD, D-MVD, or W-MVD in the normal vision group from preoperative to postoperative assessments. A strong negative correlation was found between the changes in W-MVD and changes in LogMar BCVA in the eyes of the visual impairment group treated with orbital decompression (Pearson correlation coefficient, R = -0.812, p = 0.05). This study found that TAO patients with visual impairment had lower macular blood flow perfusion than those with normal vision. Endoscopic orbital decompression surgery was found to improve both the best-corrected visual acuity and macular blood flow perfusion in TAO patients with visual impairment, and the improvement in visual acuity was correlated with the improvement in macular blood flow perfusion.

Vision Is Not Required to Elicit Balance Improvements From Beam Walking Practice.

Beam walking is a highly studied assessment of walking balance. Recent research has demonstrated that brief intermittent visual rotations and occlusions can increase the efficacy of beam walking practice on subsequent beam walking without visual perturbations. We sought to examine the influence of full vision removal during practice walking on a treadmill-mounted balance beam. Although visual disruptions improved performance of this task, we hypothesized that removing visual feedback completely would lead to less balance improvements than with normal vision due to the specificity of practice. Twenty healthy young adults trained to walk at a fixed speed on a treadmill-mounted balance beam for 30min, either with, or without, normal vision. We compared their balance pre-, during, and posttraining by calculating their step-offs per minute and the percentage change in step-offs per minute. Balance improved in both groups after training, with no significant difference in percentage change in step-offs between the normal vision and the no vision participants. On average, the no vision participants had twice as many step-offs per minute as the normal vision group during training. Although previous experiments show that intermittent visual perturbations led to large enhancements of the effectiveness of beam walking training, completely removing visual feedback did not alter training effectiveness compared with normal vision training. It is likely a result of sensory reweighting in the absence of vision, where a greater weight was placed on proprioceptive, cutaneous, and vestibular inputs.

Impact of color vision deficiency on the quality of life in a sample of Indian population: Application of the CVD-QoL tool

Purpose: To investigate the quality of life (QoL) in a sample of color vision deficit (CVD) patients in India and how color vision deficiency affects them psychologically, economically, and in productivity related to their work and occupation. Methods: A descriptive and case–control study design using a questionnaire was conducted on N = 120 participants, of whom 60 were patients of CVD (52 male and eight female) who visited two eye facilities in Hyderabad between 2020 and 2021 and 60 were age-matched normal color vision participants who served as controls. We validated English–Telugu adapted version of CVD-QoL, developed by Barry et al. in 2017 (CB-QoL). The CVD-QoL consists of 27 Likert-scale items with factors (lifestyle, emotions, and work). Color vision was assessed using the Ishihara and Cambridge Mollen color vision tests. A six-point Likert scale was used, with lower scores indicating poor QoL (from 1 = severe issue to 6 = no problem). Results: The CVD-QoL questionnaire’s reliability and internal consistency were measured, including Cronbach’s a (a =0.70–0.90). There was no significance between the group in age (t = −1.2, P = 0.67) whereas the Ishihara colour vision test, scores showed a significant difference (t = 4.50, P < 0.001). The QoL scores showed a significant difference towards lifestyle, emotions and work (P = 0.001). The CVD group had a poorer QoL score than the normal color vision group odds ratio [OR] =0.31, 95% confidence interval [CI], (P = 0.002, CI = 0.14–0.65, Z = 3.0) . In this analysis, a low CI indicated that the OR was more precise. Conclusion: Color vision deficiency affects Indians’ QoL, according to this study. The mean scores of lifestyle, emotions, and work were lower than the UK sample.Since CVD is underreported and possibly affects developing countries more, advocacy for a new health care plan on CVD is essential. Increasing public understanding and awareness could also help diagnosing the CVD population.

Association of n-3 polyunsaturated fatty acid intakeswith juvenile myopia: Across-sectional study based on the NHANES database.

Inflammation is involved in the development of myopia. n-3 polyunsaturated fatty acids (n-3 PUFAs) have vasodilating and anti-inflammatory effects, which may be involved in controlling myopia. It is of great significance to explore the relationship between n-3 PUFA intakes and juvenile myopia in order to control and alleviate myopia among teenagers through dietary intervention. Sociodemographic data, information of nutrient intakes, cotinine, PUFAs, and eye refractive status of 1,128 juveniles were extracted from the National Health and Nutrition Examination Survey (NHANES) database in this cross-sectional study. PUFAs contained total polyunsaturated fatty acid (TPFAs), alpha-linolenic acid, octadecatetraenoic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Covariates were screened by comparison among groups of normal vision, low myopia, and high myopia. The association between n-3 PUFA intakes and the risk of juvenile myopia was evaluated using univariate and multivariate logistic regression analyses with odds ratios (ORs) and 95% confidence intervals (CIs). Among the juveniles, 788 (70.68%) had normal vision, 299 (25.80%) had low myopia, and 41 (3.52%) had high myopia. There were significant differences in average EPA and DHA intakes among the three groups, and mean DPA and DHA intakes in the normal vision group were lower than those in the low myopia group (P < 0.05). After adjustment for age, gender, TPFAs, and cotinine, a high dietary intake of EPA (≥11 mg/1,000 kcal) in juveniles seemed to be associated with the risk of high myopia (OR = 0.39, 95% CI: 0.18-0.85), while no significant associations were identified between n-3 PUFA intakes and the risk of low myopia. A high dietary intake of EPA may be associated with a decreased risk of high myopia among juveniles. A further prospective study is needed to validate this observation.

Frequencies and patterns of symptoms in Chinese adults with accommodative and binocular dysfunctions.

Recent studies have found that children with convergence insufficiency experience higher frequencies of performance-related symptoms (e.g., losing concentration), but data on performance-related symptoms among adults with accommodative dysfunctions (ADs) and/or binocular dysfunctions (BDs) are lacking, which might cause misdiagnosis, diagnostic confusion, or exacerbation of attention deficits. We aimed to describe frequencies and symptom patterns in adults with ADs and/or BDs who were treated at optometric clinics and explore any correlations between visual symptoms and clinical findings. This cross-sectional study divided 235 participants (age: 23.7 ± 2.9years) into three groups: ADs, BDs, and normal binocular vision (NBV) groups. Convergence Insufficiency Symptom Survey (CISS), refractive examinations, and binocular tests were administered to all participants. After 1-to-1 propensity score matching, outcomes were assessed using Mann‒Whitney U test and Pearson's correlation analysis among three groups. In this sample, the number (frequency) of individuals with ADs and/or BDs was 117 (49.8%). ADs and BDs groups experienced significantly more performance-related symptoms (feeling sleepy, losing concentration, trouble remembering, reading slowly, losing place, and having to re-read; all P < 0.05) than the NBV group. Significant correlations were observed between performance-related symptoms and clinical findings, including accommodative amplitude (r = - 0.294), accommodative facility (r = - 0.452), near phoria (r = - 0.261), near point of convergence (r = 0.482), and positive fusional vergence (r = - 0.331) (all P < 0.001). ADs and/or BDs are commonly present in adults treated at optometric clinics, and adults diagnosed with ADs and/or BDs exhibit more performance-related symptoms than participants with NBV.

Comparison of Depression in Low Vision Patients and Normal Vision Patients

Objective: To compare the frequency of depression in low vision and normal vision patients.&#x0D; Study Design: Comparative cross-sectional study.&#x0D; Place and Duration of Study: Eye Department, Combined Military Hospital, Malir Cantt, Karachi Pakistan, from Dec 2017 to May 2019.&#x0D; Methodology: Patients with low vision and normal vision were evaluated for depression. Initially, each patient underwent a complete Outpatient ophthalmological workup. Then, the patients were assigned to the low vision and normal vision groups,and after informed consent, each patient was to complete Patient Health Questionnaire-9 (PHQ-9). &#x0D; Result: Two hundred and sixty-nine patients with low vision and 275 patients with normal vision were included in the study.One hundred and eighty-two (67.66%) patients with low vision and 71(25.82%) patients with normal vision were found to have significant depression (PHQ-9 score≥5). Depression was significantly more prevalent in the Low Vision-Group (p=&lt;0.01).&#x0D; Conclusion: Significantly high level of depression in the Low Vision-Group needs to be taken care of in ophthalmology departments. The ophthalmologist should not look into the eyes but treat the patients as human beings.

Theta burst stimulation in adults with symmetric and asymmetric visual acuity.

Theta Burst Stimulation can influence adult neuro-visual response in imbalanced visual pathways, possibly by influencing cortical excitability. Our objective was to compare suppressive imbalance (SI) and visual acuity (VA) after applying repetitive Transcranial Magnetic Stimulation between groups of subjects with normal binocular vision, visual asymmetry, and amblyopia. Thirty-five volunteers between 19 and 51years of age were split into three groups: 6 volunteers with asymmetric VA (group A); 19 amblyopes (group B); and 10 subjects with normal binocular vision (group C). VA and SI of all groups were evaluated before and after a single session of continuous Theta Burst Stimulation (cTBS) or placebo stimulation over the right occipital cortex. In both groups A and B, we found a significant VA improvement in the non-dominant eye after cTBS (p = 0.04 and p = 0.01, respectively). In SI evaluation, group A and group B also revealed a significant improvement after the cTBS session (p = 0.03 and p = 0.01, respectively). Finally, in the group of volunteers with normal binocular vision and for placebo groups A and B, there were no significant differences in VA and SI after cTBS. Amblyopic and visually asymmetric individuals improved VA and SI of the non-dominant eye after cTBS when compared to baseline and to placebo stimulation. These enhancements were not found in the group of volunteers with normal binocular vision. We can therefore reasonably assume that cTBS may interfere with the visual system of subjects that present some kind of asymmetry, possibly by improving neuronal imbalances.

Automatic compensation enhances the orientation perception in chronic astigmatism

Astigmatism is a prevalent optical problem in which two or more focal points blur the retinal image at a particular meridian. Although many features of astigmatic vision, including orientation perception, are impaired at the retinal image level, the visual system appears to partly restore perceptual impairment after an extended period of astigmatism. However, the mechanism of orientation perception restoration in chronic astigmatism has not yet been clarified. We investigated the notable reduction of perceptual error in chronic astigmatism by comparing the orientation perception of a chronic astigmatism group with the perception of a normal-vision group, in which astigmatism was transiently induced. We found that orientation perception in the chronic group was more accurate than in the normal vision group. Interestingly, the reduction of perceptual errors was automatic; it remained even after the optical refractive errors were fully corrected, and the orientation perception was much more stable across different orientations, despite the uneven noise levels of the retinal images across meridians. We provide here a mechanistic explanation for how the compensation of astigmatic orientation perception occurred, using neural adaptation to the biased distribution of orientations.

A Unified Rule for Binocular Contrast Summation Applies to Normal Vision and Common Eye Diseases.

PurposeBinocular summation refers to better visual performance with two eyes than with one eye. Little is known about the mechanism underlying binocular contrast summation in patients with common eye diseases who often exhibit binocularly asymmetric vision loss and structural changes along the visual pathway. Here we asked whether the mechanism of binocular contrast summation remains preserved in eye disease.MethodsThis study included 1035 subjects with normal ocular health, cataract, age-related macular degeneration, glaucoma, and retinitis pigmentosa. Monocular and binocular contrast sensitivity were measured by the Pelli-Robson contrast sensitivity chart. Interocular ratio (IOR) was quantified as the ratio between the poorer and better eye contrast sensitivity. Binocular summation ratio (BSR) was quantified as the ratio between binocular and better eye contrast sensitivity.ResultsAll groups showed statistically significant binocular summation, with the BSR ranging from 1.25 [1.20, 1.30] in the glaucoma group to 1.31 [1.27, 1.36] in the normal vision group. There was no significant group difference in the BSR, after accounting for IOR. By fitting a binocular summation model Binocular = (Leftm + Rightm)1/m to the contrast sensitivity data, we found that the same binocular summation rule, reflected by the parameter m, applies across the five groups.ConclusionsCortical binocular contrast summation appears to be preserved in spite of eye diseases that can affect the two eyes differently. This finding supports the importance of assessing both monocular and binocular functions, rather than relying on a monocular assessment in the better eye as a potentially inaccurate surrogate measure.

Incremental Visual Occlusion During Split-Belt Treadmill Walking Has No Gradient Effect on Adaptation or Retention.

Split-belt treadmills have become an increasingly popular means of quantifying ambulation adaptability. Multiple sensory feedback mechanisms, including vision, contribute to task execution and adaptation success. No studies have yet explored visual feedback effects on locomotor adaptability across a spectrum of available visual information. In this study, we sought to better understand the effects of visual information on locomotor adaptation and retention by directly comparing incremental levels of visual occlusion. Sixty healthy young adults completed a split-belt adaptation protocol, including a baseline, asymmetric walking condition (adapt), a symmetric walking condition (de-adapt), and another asymmetric walking condition (re-adapt). We randomly assigned participants into conditions with varied visual occlusion (i.e., complete and lower visual field occlusion, or normal vision). We captured kinematic data, and outcome measures included magnitude of asymmetry, spatial and temporal contributions to step length asymmetry, variability of the final adapted pattern, and magnitude of adaptation. We used repeated measures and four-way MANOVAs to examine the influence of visual occlusion and walking condition. Participants with complete, compared to lower visual field visual occlusion displayed less consistency in their walking pattern, evident via increased step length standard deviation (p = .007, d = 0.89), and compared to normal vision groups (p = .003 d = 0.81). We found no other group differences, indicating that varying levels of visual occlusion did not significantly affect locomotor adaptation or retention. This study offers insight into the role vision plays in locomotor adaptation and retention with clinical utility for improving variability in step control.

Introduction of a digital near-vision reading test for normal and low vision adults: development and validation

BackgroundMNREAD is an advanced near-vision acuity chart that has already been translated and validated in Greek language. Considering that no validated Greek digital near-vision test exists, our primary objective was to develop and validate a digital near-vision reading test based on the fundamental properties of the Greek printed MNREAD (MNREAD-GR).MethodsThis is a prospective, comparative study. A digital near-vision chart was developed (Democritus Digital Acuity Reading Test – DDART) with text size calibration, audio recording for automatic reading timing, as well as automatic calculation of reading acuity (RA), maximum reading speed (MRS), critical print size (CPS) and reading accessibility index (ACC). Normal and low vision subjects participated in the validation process, responding to MNREAD-GR and DDART at the same day, at a 40 cm viewing distance. Differences in all parameters between the charts were compared with t-test and intraclass correlation coefficients (ICCs). Within 15 days, all participants responded again to DDART in a different set of sentences to assess its test-retest reliability.ResultsOne hundred patients (normal vision group - NVG: 70 patients; low vision group - LVG: 30 patients) responded to both reading tests. Non-significant differences were detected for all parameters between DDART and MNREAD-GR except for MRS and ACC that were significantly higher in MNREAD-GR in NVG (p < 0.01). NVG participants demonstrated sufficient ICCs that ranged from 0.854 to 0.963, while LVG demonstrated ICCs for RA, ACC, MRS and CPS equal to 0.986, 0.894, 0.794 and 0.723, respectively. All parameters calculated with DDART demonstrated excellent test-retest reliability (ICCs: 0.903 – 0.956).ConclusionsThe proposed reading test presented comparable validity and repeatability to MNREAD-GR suggesting that it can be used both in normal and low vision Greek patients.Trial registrationClinicalTrials.gov, NCT04242836. Registered 24 January 2020 – Retrospectively registered.

Receiver operating characteristic curve analysis of clinical signs for screening of convergence insufficiency in young adults.

Convergence insufficiency (CI) is a dysfunction of binocular vision that is associated with various signs and symptoms in near work. However, CI screening is performed less frequently in adults than in children. We aimed to evaluate the ability of screening tests to discriminate CI from other binocular vision anomalies and normal binocular vision in young adults. One hundred eighty-four university students (age, 18-28 years) who underwent an eye examination due to ocular discomfort were included. Near point of convergence (NPC), phoria, accommodative amplitude, fusional vergence, the ratio of accommodative convergence to accommodation, relative accommodation, binocular accommodative facility, vergence facility, and the values corresponding to Sheard's and Percival's criteria were evaluated. Receiver operating characteristic (ROC) curve analysis for each test was also performed. The prevalence of CI ranged from 10.3% to 21.2%, depending on the signs and the presence of CI associated with accommodative disorders. Assessments based on NPC, Sheard's criterion, and Percival's criterion showed high discriminative ability, with the ability being higher between the CI and normal binocular vision groups than between the CI and non-CI groups. Sheard's criterion showed the highest diagnostic performance in discriminating CI with three signs from the non-CI group. The cut-off values were 7.2 cm for NPC, -0.23 to 1.00 for Sheard's criterion, and -4.00 to -2.33 for Percival's criterion. Our results suggest that the use of Sheard's criterion with NPC shows high performance for screening of CI.

Evaluation of Central Macula, Retinal Nerve Fiber Layer, and Ganglion Cell Complex Thickness in Congenital Color Vision Deficiency.

Objectives:This study was designed to evaluate the thickness of the central macula, the retinal nerve fiber layer (RNFL), and the ganglion cell complex (GCC) in individuals with congenital red-green color vision deficiency (CVD) using spectral-domain optical coherence tomography (SD-OCT).Methods:This study included 22 males with a red-green CVD (Group 1) and 22 males with normal color vision (Group 2). The Ishihara test was used to determine CVD. SD-OCT was used to evaluate the central macula, RNFL, and GCC measurements of all of the study participants. The quantitative data of the 2 groups were compared. The Kruskal-Wallis test was used for the statistical analysis and a p value <0.05 was considered significant.Results:The mean central macula thickness observed in Group 1 and 2 was 255.00±25.50 µm and 248.95±24.70 µm, respectively. The mean RNFL thickness of Group 1 and 2 was 110.66±14.70 µm and 109.49±9.90 µm, respectively, and the mean GCC thickness of Group 1 and 2 was 97.70±10.80 µm and 97.56±5.10 µm, respectively. There were no significant differences between the groups in the assessment of the central macula, RNFL, or GCC thickness (p=0.20, p=0.34, p=0.37).Conclusion:The results of this study suggested that congenital red-green CVD does not affect the thickness of the central macula, RNFL, or GCC. To the best of our knowledge, this is the first study to evaluate the thickness of the GCC in individuals with congenital red-green CVD.

The effects of temporal pressure on obstacle negotiation and gaze behaviour in young adults with simulated vision loss

Individuals with vision loss adapt their locomotion and gaze behaviour to safely negotiate objects in temporally unconstrained situations. However, everyday activities are often performed under time-pressure. We investigated the effects of blur on anxiety, movement kinematics and gaze behaviour during the negotiation of a floor-based obstacle under three amounts of pressure: 1) no-pressure; 2) tonal-pressure: an intermittent tone was played at a constant frequency; 3) tonal + time pressure: the intermittent tone increased in frequency and participants had to walk 20% faster to reach the end of the lab. Irrespective of the amount of pressure, the blurred vs. normal vision group reported 32% more anxiety, lifted the lead foot 43% higher and 10% slower over the obstacle, and looked 6% longer and 6% more frequently ahead of the obstacle. In the tonal + time pressure vs. no-pressure condition, both groups were more anxious, showed adaptations in movement kinematics related to walking faster, and adopted a ‘checking strategy’ by shortening their fixation durations at the obstacle. These results show that irrespective of temporal pressure, the blurred vision group remained more cautious as to how the lead foot negotiated the obstacle, in order to reduce the chance of tripping during crossing.

Opposing Effects of PPARα Agonism and Antagonism on Refractive Development and Form Deprivation Myopia in Guinea Pigs.

To determine if drug-induced peroxisome proliferator-activated receptor α (PPARα) signal pathway modulation affects refractive development and myopia in guinea pigs. Pigmented guinea pigs were randomly divided into normal vision (unoccluded) and form deprivation myopia (FDM) groups. Each group received daily peribulbar injections of either a vehicle or (1) PPARα agonist, GW7647, clofibrate, or bezafibrate or (2) PPARα antagonist, GW6471, for 4 weeks. Baseline and posttreatment refraction and ocular biometric parameters were measured. Immunofluorescent staining of PPARα and two of its downstream readouts, cytosolic malic enzyme 1 (ME1) and apolipoproteinA II (apoA-II), was undertaken in selected scleral sections. Western blot analysis determined collagen type I expression levels. GW6471 induced a myopic shift in unoccluded eyes, but had no effect on form-deprived eyes. Conversely, GW7647 inhibited FDM progression without altering unoccluded eyes. Bezafibrate and clofibrate had effects on refraction similar to those of GW7647 in unoccluded and form-deprived eyes. GW6471 downregulated collagen type I expression in unoccluded eyes whereas bezafibrate inhibited collagen type I decreases in form-deprived eyes. GW6471 also reduced the density of ME1- and apoA-II-stained cells in unoccluded eyes whereas bezafibrate increased apoA-II-positive cell numbers in form-deprived eyes. As GW7647 and GW6471 had opposing effects on myopia development, PPARα signaling modulation may be involved in this condition in guinea pigs. Fibrates are potential candidates for treating myopia since they reduced both FDM and the associated axial elongation. Bezafibrate also inhibited form deprivation-induced decreases in scleral collagen type I expression and the density of apoA-II expressing cells.

Measuring the Difficulty Watching Video With Hemianopia and an Initial Test of a Rehabilitation Approach.

PurposeIf you cannot follow the story when watching a video, then the viewing experience is degraded. We measured the difficulty of following the story, defined as the ability to acquire visual information, which is experienced by people with homonymous hemianopia (HH). Further, we proposed and tested a novel rehabilitation aid.MethodsParticipants watched 30-second directed video clips. Following each video clip, subjects described the visual content of the clip. An objective score of information acquisition (IA) was derived by comparing each new response to a control database of descriptions of the same clip using natural language processing. Study 1 compared 60 participants with normal vision (NV) to 24 participants with HH to test the hypothesis that participants with HH would score lower than NV participants, consistent with reports from people with HH that describe difficulties in video watching. In the second study, 21 participants with HH viewed clips with or without a superimposed dynamic cue that we called a content guide. We hypothesized that IA scores would increase using this content guide.ResultsThe HH group had a significantly lower IA score, with an average of 2.8, compared with 4.3 shared words of the NV group (mixed-effects regression, P < 0.001). Presence of the content guide significantly increased the IA score by 0.5 shared words (P = 0.03).ConclusionsParticipants with HH had more difficulty acquiring information from a video, which was objectively demonstrated (reduced IA score). The content guide improved information acquisition, but not to the level of people with NV.Translational RelevanceThe value as a possible rehabilitation aid of the content guide warrants further study that involves an extended period of content-guide use and a randomized controlled trial.

Stroboscopic Vision When Interacting With Multiple Moving Objects: Perturbation Is Not the Same as Elimination.

Motivated by recent findings of improved perceptual processing and perceptual-motor skill following stroboscopic vision training, the current study examined the performance and acquisition effects of stroboscopic vision methods that afford a different visual experience. In Experiment 1, we conducted a within-subject design study to examine performance of a multiple object tracking (MOT) task in different stroboscopic vision conditions (Nike Vapor Strobe®, PLATO visual occlusion, and intermittent display presentation) operating at 5.6, 3.2, or 1.8 Hz. We found that participants maintained MOT performance in the Vapor Strobe condition irrespective of strobe rate. However, MOT performance deteriorated as strobe rate was reduced in the other two stroboscopic vision conditions. Moreover, at the lowest strobe rate (1.8 Hz) there was an increase in probe reaction time, thus indicating an increased attentional demand due to the stroboscopic vision. In Experiment 2, we conducted a mixed design study to examine if practice in different stroboscopic vision conditions (Nike Vapor Strobe® and PLATO visual occlusion) influenced acquisition of a novel precision-aiming task [i.e., multiple object avoidance (MOA) task] compared to a normal vision group. Participants in the PLATO visual occlusion group exhibited worse performance during practice than the Vapor Strobe and normal vision groups. At post-test, the Vapor Strobe group demonstrated greater success and reduced end-point error than the normal vision and PLATO groups. We interpret these findings as showing that both an intermittent perturbation (Nike Vapor Strobe®) and elimination (PLATO visual occlusion and intermittent display presentation) of visual motion and form are more attention demanding (Experiment 1), however, the intermittent perturbation, but not elimination, of visual motion and form can facilitate acquisition of perceptual-motor skill (Experiment 2) in situations where it is necessary to maintain and update a spatio-temporal representation of multiple moving objects.

Prostaglandin F2α Receptor Modulation Affects Eye Development in Guinea Pigs.

Retinal arachidonic acid (ARA) levels in form-deprived eyes decline in guinea pigs. As prostaglandin F2α (PGF2α) is an ARA metabolite and endogenous agonist of prostaglandin F receptor (FP), we have been suggested that down-regulation of PGF2α-FP receptor signalling pathway contributes to myopia onset. To test this hypothesis, this study determines whether: (i) retinal PGF2α levels decline during the development of form deprivation myopia (FDM) in guinea pigs; (ii) FP receptor agonism and antagonism alter emmetropization and myopia development. Pigmented guinea pigs were randomly assigned to normal vision and form-deprived groups. Ultraperformance liquid chromatography coupled with a mass spectrometer (UPLC-MS) measured retinal PGF2α levels 2weeks after form deprivation (FD). The selective FP agonist, latanoprost acid (LAT) and its corresponding antagonist, AL8810, were peribulbarly injected into each group. An eccentric infrared photorefractor (EIR) monitored refraction. A-scan ultrasonography measured axial elongation (AL) and vitreous chamber depth (VCD). Tonometry measured the intraocular pressure (IOP). Retinal PGF2α levels declined in form-deprived eyes compared to those in normal eyes. Neither LAT nor AL8810 affected IOP with or without FD. On the other hand, after 4weeks of daily 0.5μg AL8810 treatment, a myopia of -1.99±0.34dioptre (D) developed, but LAT had no effect on emmetropization in a normal visual environment. Nevertheless, daily 30μg LAT treatment for 4weeks inhibited FDM development by 41% (vehicle control: -8.39±0.45D; LAT: -4.95±0.39D; two-way anova with repeated measures, p<0.05). Down-regulation of PGF2α-FP receptor signalling pathway may contribute to myopia onset as retinal PGF2α declined in myopic eyes and antagonism of FP receptor by AL8810 induced a myopic shift in normal vision environment. Meanwhile, up-regulation of this pathway by LAT inhibited FDM development. However, the mechanism underlying LAT-induced FDM inhibition needs further clarification. This uncertainty exists because its inhibition of FDM suggests that LAT strengthens the scleral framework which reduces axial elongation. On the other hand, its IOP-lowering effect is attributed to thinning and weakening the scleral framework in glaucoma treatment.

People with Hemianopia Report Difficulty with TV, Computer, Cinema Use, and Photography.

Our survey found that participants with hemianopia report more difficulties watching video in various formats, including television (TV), on computers, and in a movie theater, compared with participants with normal vision (NV). These reported difficulties were not as marked as those reported by people with central vision loss. The aim of this study was to survey the viewing experience (e.g., frequency, difficulty) of viewing video on TV, computers and portable visual display devices, and at the cinema of people with hemianopia and NV. This information may guide vision rehabilitation. We administered a cross-sectional survey to investigate the viewing habits of people with hemianopia (n = 91) or NV (n = 192). The survey, consisting of 22 items, was administered either in person or in a telephone interview. Descriptive statistics are reported. There were five major differences between the hemianopia and NV groups. Many participants with hemianopia reported (1) at least "some" difficulty watching TV (39/82); (2) at least "some" difficulty watching video on a computer (16/62); (3) never attending the cinema (30/87); (4) at least some difficulty watching movies in the cinema (20/56), among those who did attend the cinema; and (5) never taking photographs (24/80). Some people with hemianopia reported methods that they used to help them watch video, including video playback and head turn. Although people with hemianopia report more difficulty with viewing video on TV and at the cinema, we are not aware of any rehabilitation methods specifically designed to assist people with hemianopia to watch video. The results of this survey may guide future vision rehabilitation.

A comparative study of the perception of music emotion between adults with and without visual impairment

In music listening, limitations on visual experience affect a listener’s abstract information processing and conceptualization of the music. The aim of this study is to examine the differences in emotional responses to music between adults with visual impairment (VI) and adults with normal vision (NV). By using specific, emotion-inducing music reflecting happiness, sadness, anger, and fear, this study considers factors such as music emotion identification, emotional valence, arousal, intensity, and musical preference. A total of 120 participants (60 VI and 60 NV) listened to sixteen 15-second music excerpts and reported which emotion and to what extent they perceived it, using a self-reported music emotion evaluation scale. The results indicated that both of the groups showed high congruence in music emotion identification. However, the VI group showed significantly higher arousal, intensity and preference for sadness, while showing the lowest score for the intensity of fear. The main factor affecting emotion identification was preference for the VI group, and valence for the NV group.