Contrast coding and magno/parvo segregation revealed in reaction time studies

AbstractReaction times (RTs) are obtained for a wide range of contrasts of vertical sinusoidal gratings. The data are plotted as a function of the reciprocal of contrast. In some conditions, a single linear function accounts for the data. In others a clear bi-linear function is obtained. The low and high contrast regions of the function are interpreted as representing magno and parvo activity, respectively. RT-based supra-threshold sensitivity functions are obtained for different luminances, stimulus durations and eccentricities and these are compared with conventional threshold-based sensitivities to establish the extent to which RTs and contrast sensitivity are constrained by the same sensory processes

Summation characteristics of the detection of compound gratings

AbstractMany classical experiments have shown that two superimposed gratings are more easily detected than a single grating, in keeping with probability theory. Here we test the rules for the detection of 2-component compound gratings by extending the range of parameters used in previous experiments. Two complementary methods of deriving summation indices are described. Data are presented so that the conditions for the transition from probability to neural summation are easily identified. True probability summation occurs only when grating contrasts are carefully perceptually equalised and spatial frequency differs by more than a factor of 2. A wide range of contrast ratios of the component gratings were explored such that gratings were at different contrasts, relative to respective thresholds. We find clear evidence of suppressive interactions when the compound gratings are composed of a close to threshold low frequency component and a below-threshold higher spatial frequency component

Cinco años compartiendo la optometría con un público global y multidisciplinar

[Excerpt] The clinical and scientific activity in the field of optometry has experienced a rapid expansion in the last decades.1 In many places around the World, where this specialty was not developed in the middle of the 20th century, Optometry is now flourishing with new schools, training centers and other structures. This made possible to provide eye care to millions of people who otherwise would not be served. These strategies have been particularly important in Asia, Middle East, Africa and Latin America. Besides the publication of mainstream state of the art research results in the field of optometry and visual sciences,2, 3, 4 the Journal of Optometry has been committed to be a platform for sharing with a Global Audience the scientific and clinical information coming from or related with developing countries in those areas. The issue being published now is a good example, with a significant proportion of its information arising directly or indirectly from populations whose ocular characteristics and ocular morbidity are now better known. [...](undefined)info:eu-repo/semantics/publishedVersio

Self-reported visual symptoms and high visual demand activities in professional football players: a cross-sectional survey

Background: Vision is crucial for football players, impacting decision-making and athletic performance. Despite its global popularity, football lacks comprehensive evaluations of the impact of digital device use on ocular symptoms during high-demand activities. Purpose: To gain knowledge about the time spent by football players in high visual demand activities, the symptoms associated with binocular vision dysfunction, and their relationship with sports performance. Methods: A cross-sectional observational study was conducted in 2020 using an online survey targeting football players from Portugal, England, Spain, and Saudi Arabia. The survey, distributed over 5 weeks, aimed to collect data from approximately 5,000 football players. Information on player profiles, competitive levels, vision habits, and symptoms related to binocular vision dysfunctions was collected. The Convergence Insufficiency Symptom Survey (CISS) employed a 5-point Likert scale to indicate the average frequency of each symptom. Due to non-normality, non-parametric tests were used (p < 0.05). Specifically, Mann-Whitney U, Kruskal-Wallis, Chi-square, and Spearman's rank correlation tests were used as appropriate. Results: Analyzing male professional football players (mean age: 27.4 ± 5.0 years, 95% CI, 26.7–28.1), it was found that 38.1% of the players had been called up to the national team and 6.9% had played over 50 games. Self-rated last season's performance had a mean score of 6.5 ± 2.1 (95% CI, 6.2–6.8)(on a scale of 1 to 10). Smartphone use exceeded 1 h daily for all players, with 36.0% surpassing 4 h. Visual symptoms, notably associated with smartphone use (35.5%), were observed. Regarding the CISS score, the mean was 7.1 ± 7.7 (IC95%: 6.6 to 8.8). A weak negative correlation (rho = −0.215, p = 0.003) emerged between CISS scores and self-perceived sports performance. Football players using prescription lenses had significantly higher CISS scores (11.9 ± 10.4, 95% CI, 12.3–7.7) compared to non-users (6.2 ± 6.8, 95% CI, 7.8–5.7) (p < 0.001). Conclusion: This study reveals that professional football players engage in high visual demand tasks, notably on smartphones. One-third of the players link smartphone use to ocular symptoms. The Convergence Insufficiency Symptoms Survey indicates that 6.3% exhibit binocular vision dysfunction symptoms. Those with fewer ocular symptoms perceive that they have better sports performance than their counterparts.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/202

STRIDE LENGTH REGULATION AT THE APPROACH PHASE OF LONG JUMP IN VISUALLY IMPAIRED (F12 CLASS) ATHLETES

The present study examined whether long jumpers with visual impairment (class F12) demonstrate at the approach run the same pattern of footfall variability across trials as athletes without visual impairment. Five male and five female elite F12 class long jumpers were recorded during a competition. The athletes demonstrated an initial ascending footfall variability followed by a descending one, suggesting the existence of stride length regulation. This regulation emerged on the fourth and the third stride prior to take-off area and at a mean distance of 9.09 ± 0.26 m and 6.28 ± 0.26 m for the males and the females respectively from the take-off line. Results indicated that the stride pattern of F12 class long jumpers was similar to that reported in the literature for athletes without visual impairment, with stride regulation commencing one stride closer to the take-off board

Randomized crossover trial of silicone hydrogel presbyopic contact lenses

PURPOSE: To assess the performance of four commercially available silicone hydrogel multifocal monthly contact lens designs against monovision. METHODS: A double-masked randomized crossover trial of Air Optix Aqua multifocal, PureVision 2 for Presbyopia, Acuvue OASYS for Presbyopia, Biofinity multifocal, and monovision with Biofinity contact lenses was conducted on 35 presbyopes (54.3 ± 6.2 years). After 4 weeks of wear, visual performance was quantified by high- and low-contrast visual acuity under photopic and mesopic conditions, reading speed, defocus curves, stereopsis, halometry, aberrometry, Near Activity Visual Questionnaire rating, and subjective quality of vision scoring. Bulbar, limbal, and palpebral hyperemia and corneal staining were graded to monitor the impact of each contact lens on ocular physiology. RESULTS: High-contrast photopic visual acuity (p = 0.102), reading speed (F = 1.082, p = 0.368), and aberrometry (F = 0.855, p = 0.493) were not significantly different between presbyopic lens options. Defocus curve profiles (p <0.001), stereopsis (p <0.001), halometry (F = 4.101, p = 0.004), Near Activity Visual Questionnaire (F = 3.730, p = 0.007), quality of vision (p = 0.002), bulbar hyperemia (p = 0.020), and palpebral hyperemia (p = 0.012) differed significantly between lens types, with the Biofinity multifocal lens design principal (center-distance lens was fitted to the dominant eye and a center-near lens to the nondominant eye) typically outperforming the other lenses. CONCLUSIONS: Although ocular aberration variation between individuals largely masks the differences in optics between current multifocal contact lens designs, certain design strategies can outperform monovision, even in early presbyopes

Perfiles de potencia de las lentes de contacto medidas con NIMO TR1504

This study was supported by the Ministerio de Economía y Competitividad and FEDER (Grant DPI2015-71256-R) and by the Generalitat Valenciana (Grant PROMETEOII-2014-072), Spain.Rodríguez-Vallejo, M.; Montagud-Martínez, D.; Monsoriu Serra, JA.; Furlan, WD. (2017). On the power profiles of contact lenses measured with NIMO TR1504. Journal of Optometry. 10(4):265-266. https://doi.org/10.1016/j.optom.2016.10.002S26526610

Light disturbance with multifocal contact lens and monovision for presbyopia

Dysphotopsia affects a significant number of patients, particularly after visual correction with multifocal optical designs. Purpose Evaluate light distortion (LD) in two modalities of contact lens (CL) wear: multifocal (MF) and monofocal (MV). Methods This was a randomized, double-masked, crossover study involving 20 presbyopic patients. Patients were randomized first into either MF or MV for 15 days of use with a 1 week wash-out period between each lens type. The LD was evaluated with the Light Distortion Analyzer (LDA, University of Minho) under monocular and binocular conditions. The light distortion index (LDI, %), among other parameters were analyzed. Subjective quality of vision was assessed with the Quality of Vision (QoV). Results The LD showed an increase in all parameters in both CL modalities being significant for MV in the non-dominant eye (p < 0.030, for all LD parameters). For the MF, there was also a significant increase in LDI (p = 0.016) and in BFCrad (p = 0.022) in the non-dominant eye. After 15 days of MF lens wear, there was a significant decrease in all LD parameters (p < 0.002) in the dominant eye. Binocularly, a significant improvement from 1 to 15 days was observed for LDI (p = 0.009) and BFCrad (p = 0.0013) with MF. The QoV questionnaire showed no significant changes with neither CL. Conclusions. Adaptation to light disturbances induced by MF CL is more effective compared to MV. Practitioners will have greater success if they prepare their patients for the adaptation required as their vision will get better and have less of an issue with light disturbanceThis study has been funded in part by an individual research grant (FCT −SFRH/BPD/92365/2013 to Fernandes, P) and projects PTDC/SAU-BEB/098392/2008 and PTDC/SAU-BEB/098391/2008 funded by the Portuguese Foundation for Science and Technology through the European Social Fund and by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project UID/FIS/04650/2013info:eu-repo/semantics/publishedVersio

Assessing and managing concurrent hearing, vision and cognitive impairments in older people: an international perspective from healthcare professionals

Background: there is a significant gap in the understanding, assessment and management of people with dementia and concurrent hearing and vision impairments. / Objective: from the perspective of professionals in dementia, hearing and vision care, we aimed to: (1) explore the perceptions of gaps in assessment and service provision in ageing-related hearing, vision and cognitive impairment; (2) consider potential solutions regarding this overlap and (3) ascertain the attitudes, awareness and practice, with a view to implementing change. / Methods: our two-part investigation with hearing, vision, and dementia care professionals involved: (1) an in-depth, interdisciplinary, international Expert Reference Group (ERG; n = 17) and (2) a wide-scale knowledge, attitudes and practice survey (n = 653). The ERG involved consensus discussions around prototypic clinical vignettes drawn from a memory centre, an audiology clinic, and an optometry clinic, analysed using an applied content approach. / Results: the ERG revealed several gaps in assessment and service provision, including a lack of validated assessment tools for concurrent impairments, poor interdisciplinary communication and care pathways, and a lack of evidence-based interventions. Consensus centred on the need for flexible, individualised, patient-centred solutions, using an interdisciplinary approach. The survey data validated these findings, highlighting the need for clear guidelines for assessing and managing concurrent impairments. / Conclusions: this is the first international study exploring professionals’ views of the assessment and care of individuals with age-related hearing, vision and hearing impairment. The findings will inform the adaptation of assessments, the development of supportive interventions, and the new provision of services

Investigating the utility of clinical assessments to predict success with presbyopic contact lens correction

PURPOSE: To determine the utility of a range of clinical and non-clinical indicators to aid the initial selection of the optimum presbyopic contact lens. In addition, to assess whether lens preference was influenced by the visual performance compared to the other designs trialled (intra-subject) or compared to participants who preferred other designs (inter-subject). METHODS: A double-masked randomised crossover trial of Air Optix Aqua multifocal, PureVision 2 for Presbyopia, Acuvue OASYS for Presbyopia, Biofinity multifocal and monovision was conducted on 35 presbyopes (54.3±6.2years). Participant lifestyle, personality, pupil characteristics and aberrometry were assessed prior to lens fitting. After 4 weeks of wear, high and low contrast visual acuity (VA) under photopic and mesopic conditions, reading speed, Near Activity Visual Questionnaire (NAVQ) rating, subjective quality-of-vision scoring, defocus curves, stereopsis, halometry, aberrometry and ocular physiology were quantified. RESULTS: After trialling all the lenses, preference was mixed (n=12 Biofinity, n=10 monovision, n=7 Purevision, n=4 Air Optix Aqua, n=2 Oasys). Lens preference was not dependent on personality (F=1.182, p=0.323) or the hours spent working at near (p=0.535) or intermediate (p=0.759) distances. No intersubject or strong intrasubject relationships emerged between lens preference and reading speed, NAVQ rating, halo size, aberrometry or ocular physiology (p>0.05). CONCLUSIONS: Participant lifestyle and personality, ocular optics, contact lens visual performance and ocular physiology provided poor indicators of the preferred lens type after 4 weeks of wear. This is confounded by the wide range of task visual demands of presbyopes and the limited optical differences between current multifocal contact lens designs