Validity and Repeatability of a Novel Dynamic Visual Acuity System

Relationship between dynamic visual acuity and static visual acuity, refractive error, and binocular vision in elite soccer players

CLINICAL RELEVANCE

In many sports, dynamic visual acuity is used. In order to improve dynamic visual acuity, it is important to understand the aspects of the visual system that can cause compromise.

BACKGROUND

To investigate the parameters of the visual system that may influence dynamic visual acuity in professional soccer players.

METHODS

In 2022, 40 professional players were analysed. Screening consisted of a survey, the measurement refractive error, and static and dynamic visual acuity and the binocular vision parameters. All athletes were men with a mean age of 24.9 ± 4.8 years.

RESULTS

The mean refractive error was -0.29 ± 0.61D, and 22.5% of athletes are myopic only and 7.5% hyperopic. Static visual acuity was R: -0.037 ± 0.094 LogMAR , L: -0.036 ± 0.098 LogMAR. Dynamic visual acuity was 0.154 ± 0.118 LogMAR . There is a positive and moderate correlation between monocular static visual acuity and dynamic visual acuity, with r = 0.524 (r2 = 0.275 , p < 0.001) for the right eye and r = 0.553 (r2 = 0.306, p < 0.001) for the left eye. For the component of astigmatism (J = 0) and for stereopsis in distance vision, the correlation was, r = -0.472 (r2 = 0.223, p = 0.002) and r = -0.467 (r2 = 0.218, p = 0.002), respectively.

CONCLUSION

Athletes with lower static visual acuity in distance vision, or with worse stereopsis in distance vision or more myopic astigmatism, have lower dynamic visual acuity than other athletes.

The impact of patient-reported visual disturbance on dynamic visual acuity in myopic patients after corneal refractive surgery

Purpose

To investigate the impact of patient-reported visual disturbance on dynamic visual acuity in myopic patients after corneal refractive surgery.

Methods

This is a prospective nonrandomized study. Adult myopic patients receiving bilateral laser-assisted sub-epithelial keratomileusis (LASEK), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), or small incision lenticule extraction (SMILE) with Plano target were included. Eight types of patient-reported visual disturbance were evaluated regarding frequency, severity and bothersome and dynamic visual acuity (DVA) of 40 and 80 degrees per second (dps) was measured postoperatively at 3 months.

Results

The study enrolled 95 patients with an average age of 27.6 ± 6.4 years. The most frequently reported visual disturbance was the fluctuation in vision (70.5%), followed by glare (66.3%) and halo (57.4%). Postoperative DVA at 80 dps was significantly associated with the total score of haloes (p = 0.038) and difficulty in judging distance (p = 0.046). Significant worse postoperative DVA at 40 dps was observed in patients with haloes than those without (p = 0.024). The DVA at 80 dps for patients without haloes or difficulty in judging distance was significantly better than that with the symptoms (haloes, p = 0.047; difficulty in judging distance, p = 0.029). Subgroup analysis by surgical procedures demonstrated that the significant difference in DVA between patients with and without visual disturbance was only observed in patients receiving FS-LASIK.

Conclusion

Postoperatively, myopic patients undergoing corneal refractive surgery with haloes or difficulty in judging distance have significantly worse low and high-speed DVA than those without the symptoms. The present study provided the basis for postoperative guidance in daily tasks involving dynamic vision when patients have visual disturbances.

Advances in dynamic visual acuity test research

The dynamic visual acuity test (DVAT) is a functional evaluation tool for the impairment and compensation of the vestibular system, which could reflect the Vestibulo-ocular reflex (VOR) function. We present an overview of DVAT research, displaying recent advances in test methods, application, and influencing factors; and discussing the clinical value of DVAT to provide a reference for clinical application. There are two primary types of DVAT: dynamic-object DVAT and static-object DVAT. For the latter, in addition to the traditional bedside DVAT, there are numerous other approaches, including Computerized DVAT (cDVAT), DVAT on a treadmill, DVAT on a rotary, head thrust DVA (htDVA) and functional head impulse testing (fHIT), gaze shift dynamic visual acuity with walking (gsDVA), translational dynamic visual acuity test (tDVAT), pediatric DVAT. The results of DAVT are affected by subject [occupation, static visual acuity (SVA), age, eyeglass lenses], testing methods, caffeine, and alcohol. DVAT has numerous clinical applications, such as screening for vestibular impairment, assessing vestibular rehabilitation, predicting fall risk, and evaluating ophthalmology-related disorders, vestibular disorders, and central system disorders.

The impact of different corneal refractive surgeries on binocular dynamic visual acuity

Purpose

To investigate the influence of different corneal refractive surgeries on dynamic visual acuity (DVA), and explore its potential influence factors.

Methods

This was a prospective non-randomized study. Adult myopic patients undergoing bilateral laser-assisted sub-epithelial keratomileusis (LASEK), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), or small incision lenticule extraction (SMILE) with Plano refraction target were enrolled. Uncorrected and corrected distance visual acuity (UDVA/CDVA), manifest refraction and binocular optotype-moving DVA of 40 and 80 degrees per second (dps) were evaluated pre-operatively and post-operatively up to 3 months.

Results

The study included 264 eyes of 132 subjects, with an average age of 27.0 ± 6.7 years, and females accounted for 59% of the participants. Significant improvement was observed at the 3-month visit for 40 dps (SMILE, P = 0.001; LASEK, P = 0.006; FS-LASIK, P = 0.010) and 80 dps (SMILE, P = 0.011; LASEK, P = 0.025; FS-LASIK, P = 0.012) DVA. Adjusting for pre-operative DVA, there was no significant difference in DVA among groups at 3 months post-operatively (P > 0.05 for multiple comparisons). Overall, multiple linear models demonstrated that post-operative DVA at 3 months was correlated with pre-operative DVA (40 dps, β = 0.349, P = 0.001; 80 dps, β = 0.447, P < 0.001), pre-operative spherical equivalent (40 dps, β = 0.311, P = 0.003; 80 dps, β = 0.261, P = 0.009) and post-operative UDVA (40 dps, β = -0.224, P = 0.024; 80 dps, β = -0.188, P = 0.05).

Conclusion

Dynamic visual acuity at 3 months post-operatively of the three corneal refractive surgeries was better than that before the surgery in adult myopic patients, and there was no significant difference among different surgical techniques. Post-operative DVA at 3 months was found correlated with pre-operative DVA, pre-operative SE, and post-operative UDVA. With further improvement, DVA could be a promising functional visual indicator for myopic patients undergoing refractive surgeries.

Relationship between dynamic visual acuity and multiple object tracking performance

We assessed the association between measures of dynamic visual acuity and a multiple object tracking task in physically active young adults. Ninety-four young adults performed the dynamic visual acuity and multiple object tracking tasks. Dynamic visual acuity was measured for horizontal and random walk motion paths at four target speeds (5, 10, 20, and 30°/s). For the multiple object tracking task, participants had to track three out of eight balls for 10 s, and the object speed was adjusted by a staircase procedure. We found that multiple object tracking performance was associated with better identification of horizontally and randomly moving targets in the dynamic visual acuity test (p < .001, r = -.35 [-.52, -.16]; and p < .001, r = -.52 [-.65, -.35]; respectively). This effect was consistent across all target speeds (all p-values<0.05). However, static visual acuity did not correlate with any measure of dynamic visual acuity or multiple object tracking (p > 0.170 in all cases). This study provides novel insights into the association between the ability to identify horizontally and randomly moving targets and track multiple objects. Future studies are needed to determine the potential utility of dynamic visual acuity for talent identification and predicting sports performance in real-game situations.

Applications of dynamic visual acuity test in clinical ophthalmology

Dynamic visual acuity test (DVAT) plays a key role in the assessment of vestibular function, the visual function of athletes, as well as various ocular diseases. As the visual pathways conducting dynamic and static signals are different, DVATs may have potential advantages over the traditional visual acuity tests commonly used, such as static visual acuity, contrast sensitivity, and static perimetry. Here, we provide a review of commonly applied DVATs and their several uses in clinical ophthalmology. These data indicate that the DVAT has its unique clinical significance in the evaluation of several ocular disorders.

Athletes Demonstrate Superior Dynamic Visual Acuity

SIGNIFICANCE

Athletes exhibit better dynamic visual acuity (DVA) compared with nonathletes, whereas action video game players (VGPs) perform more similarly to controls despite having similar static visual acuity and refractive errors. The differences in DVA between groups were not related to differences in static visual acuity, refractive error, or smooth pursuit gain.

PURPOSE

The purpose of the study was to examine whether athletes and VGPs have superior DVA than controls (nonathletes, nongamers).

METHODS

Forty-six participants (15 athletes, 11 VGPs, 20 controls) aged 21.7 years (standard deviation, 2.8 years) were recruited. Participants were emmetropic with equivalent monocular and binocular static visual acuity between groups. Dynamic visual acuity was assessed using predictable (horizontal) and unpredictable (random) motion targets at velocities of 5, 10, 20, and 30°/s. Smooth pursuit eye movements were assessed using a horizontal motion step-ramp stimulus at the same speeds. This study was pre-registered with the Center for Open Science (https://osf.io/eu7qc).

RESULTS

At 30°/s, there were significant main effects of group (F = 4.762, P = .01) and motion type (F = 9.538, P = .004). Tukey post hoc analysis for groups indicated that athletes performed better than did the control group (t = -2.919, P < .02). An omnibus (group × motion type × speed) repeated measures ANOVA showed a main effect of speed (F = 110.137, P < .001) and a speed × motion-type interaction (F = 27.825, P < .001). Dynamic visual acuity decreased as speed increased, and the slope of the change was greater for random than for horizontal motion. Smooth pursuit gains were not significantly different between groups (P > .05).

CONCLUSIONS

Athletes have superior dynamic visual acuity performance compared with controls at 30°/s. This between-group difference cannot be fully explained by differences in smooth pursuit eye movements and therefore may reflect other differences between the groups.

Do Impairments in Visual Functions Affect Skiing Performance?

Nordic and alpine skiing-related visual tasks such as identifying hill contours, slope characteristics, and snow conditions increase demands on contrast processing and other visual functions. Prospective observational studies were conducted to assess the relationships between skiing performance and a broad range of visual functions in nordic and alpine skiers with vision impairments. The study hypothesized that contrast sensitivity (CS), visual acuity (VA), and visual field (VF) would be predictive of skiing performance. Binocular static VA, CS, light sensitivity, glare sensitivity, glare recovery, dynamic VA, translational and radial motion perception, and VF were assessed in elite Para nordic (n = 26) and Para alpine (n = 15) skiers. Skiing performance was assessed based on skiers’ raw race times. Performance on the visual function tests was compared with skiing performances using Kendall’s correlations (with and without Bonferroni–Holm corrections) and linear multivariable regressions (p < 0.05 considered significant). None of the vision variables were significantly correlated with performance in Para nordic or Para alpine skiing after Bonferroni–Holm corrections were applied. Before applying the corrections, VF extent (ρ = -0.37, p = 0.011), and static VA (ρ = 0.26, p = 0.066) demonstrated the strongest correlations with Para nordic skiing performance; in Para alpine skiing, static VA and CS demonstrated the strongest correlations with downhill (static VA: ρ = 0.54, p = 0.046, CS: ρ = -0.50, p = 0.06), super G (static VA: ρ = 0.50, p = 0.007, CS: ρ = -0.51, p = 0.017), and giant slalom (static VA: ρ = 0.57, p = 0.01, CS: ρ = -0.46, p = 0.017) performance. Dynamic VA and VF were significantly associated with downhill (ρ = 0.593, p = 0.04) and slalom (ρ = -0.49, p = 0.013) performances, respectively. Static VA was a significant predictor of giant slalom [(F(3,11) = 24.71, p < 0.001), and R of 0.87], super G [(F(3,9) = 17.34, p = 0.002), and R of 0.85], and slalom [(F(3,11) = 11.8, p = 0.002), and R of 0.80] performance, but CS and VF were not. Interestingly, static VA and CS were highly correlated in both Para nordic (ρ = -0.60, p < 0.001) and Para alpine (ρ = -0.80, p < 0.001) skiers. Of the vision variables, only static VA and VF were associated with skiing performance and should be included as the in Para nordic and Para alpine classifications. The strong correlations between static VA and CS in these skiers with vision impairment may have masked relationships between CS and skiing performance.

Effects of caffeine ingestion on dynamic visual acuity: a placebo-controlled, double-blind, balanced-crossover study in low caffeine consumers

BACKGROUND

Acute caffeine ingestion has been associated with improvements in cognitive performance and visual functioning. The main objective of this study was to determine the effects of caffeine intake on dynamic visual acuity (DVA).

METHODS

Twenty-one low caffeine consumers (22.5 ± 1.6 years) took part in this placebo-controlled, double-blind, and balanced crossover study. In two different days and following a random order, participants ingested either caffeine (4 mg/kg) or placebo, and DVA was measured after 60 min of ingesting the corresponding capsule. A recently developed and validated software (moV& test, V&mp Vision Suite, Waterloo, Canada) was used to assess DVA.

RESULTS

We found a greater accuracy for both the horizontal and random motion paths of DVA after caffeine ingestion (p < 0.001 and p = 0.002, respectively). In regard to the speed of the response, our data revealed that caffeine intake was associated with a faster reaction time for horizontally (p = 0.012) but not for randomly (p = 0.846) moving targets. Also, participants reported higher levels of perceived activation after consuming caffeine in comparison to placebo (p < 0.001).

CONCLUSIONS

Our data suggest that caffeine intake (i.e., a capsule containing 4 mg/kg) has an ergogenic effect on DVA, which may be of special relevance in real-word contexts that require to accurately and rapidly detect moving targets (e.g., sports, driving, or piloting).

Vision function of pseudophakic eyes with posterior capsular opacification under different speed and spatial frequency

PURPOSE

To investigate the characteristics of dynamic visual acuity (DVA) and contrast sensitivity (CS) in pseudophakic patients with posterior capsular opacification (PCO).

METHODS

Fifty-four eyes (36 patients) with PCO planned for laser capsulotomy were recruited. They underwent examinations of static visual acuity (SVA), DVA, CS and optical quality analysis (OQAS) before and one week after the laser treatment. Improvements in each index after laser treatment were analyzed. The visual quality of patients with good initial vision was studied separately.

RESULTS

SVA, DVA and CS all significantly increased after capsulotomy (P < 0.05). Postoperative improvements in DVA were higher than in SVA, but they decreased when the speed increased. DVA at 15 dps gained the most improvement after capsulotomy. DVA at all analyzed speeds was significantly lower than SVA (P = 0.000). There was a significant speed-dependent decrease in DVA at lower speeds compared with higher speeds. The postoperative improvements in CS decreased when the spatial frequency was increased. The CS at the lower frequencies of 3 cpd and 6 cpd was the most improved after capsulotomy. CS was much lower at high frequencies (p < 0.05). There was a significant decrease in CS at higher spatial frequencies compared with lower frequencies. DVA improvements were correlated with CS improvements at medium spatial frequencies and with objective scattering index and Strehl ratio. The CS at all frequencies significantly improved for patients with good initial vision.

CONCLUSION

PCO could impair dynamic vision function, but CS was a more sensitive indication of visual complaints in patients with slight PCO.

Relationship of Contrast Sensitivity Measured Using Quick Contrast Sensitivity Function With Other Visual Functions in a Low Vision Population

Purpose

Contrast sensitivity (CS) is predictive of various aspects of an individual's functional vision, such as recognizing faces and driving. Currently available CS charts are limited in terms of the spatial frequencies they can test and/or the contrast resolution of the targets they present. The traditional methods for measuring full CS functions (CSFs) are time consuming. The purpose of this study was to examine the feasibility of using the quick CSF method in a low vision population and to assess the relationships of CS with other visual functions, which can contribute to the understanding of the functional vision.

Methods

Static visual acuity, dynamic visual acuity, CS, global motion perception thresholds, and visual field were measured binocularly in 53 individuals with low vision. The number of participants who could complete each assessment was used to assess feasibility. The relationships between CS and other visual functions were assessed using linear regressions and multiple regressions.

Results

The quick CSF was quantifiable in 34 participants of the 42 with quantifiable visual acuities. The area under the log CSF—the summary statistic of CSF—was significantly correlated with static visual acuity and dynamic visual acuity (r = −0.79 and r = −0.63, respectively; P < 0.001).

Conclusions

The qCSF is capable of measuring CS in a wide range of visual impairment severities. area under the log CSF only correlates with measures of visual acuity.

A novel standardized test system to evaluate dynamic visual acuity post trifocal or monofocal intraocular lens implantation: a multicenter study

OBJECTIVES

To compare the dynamic visual acuity (DVA) following implantation of trifocal with monofocal intraocular lenses (IOL) and using a novel test system.

METHODS

The present research was a retrospective, multicenter clinical study. Two hundred and ten eyes of 149 patients that underwent cataract phacoemulsification and IOL implantation were enrolled. One hundred and ten eyes of patients received trifocal (AT LISA tri839MP, Carl Zeiss Meditec, Germany) and 100 eyes received monofocal (Tecnis ZCB00, Abbott, United States) lenses and were evaluated 3 months after implantation. Outcome measures included monocular uncorrected distance (UDVA), intermediate (UIVA) and near (UNVA) visual acuity and best corrected distance visual acuity (BCDVA; logMAR units); contrast sensitivity under photopic, mesopic, with glare conditions; and dynamic visual acuity using a self-developed system.

RESULTS

There was no statistically significant difference in baseline characteristics between groups. Monocular UDVA, UIVA, and UNVA were significantly better (all p < 0.001) in the trifocal IOL group, but not BCDVA. The trifocal IOL group showed better contrast sensitivity under photopic, mesopic, with or without glare conditions (p < 0.05) and statistically significantly better dynamic vision at 15, 30, 60, and 90 degrees per second (dps) compared with the monofocal group (all p < 0.001). The strength of positive association only between UIVA and dynamic visual acuity increased as the velocity increased, but not UDVA or UNVA.

CONCLUSIONS

Diffractive trifocal IOL provides better postoperative full range vision acuity, contrast sensitivity, and dynamic vision compared with monofocal IOLs. And intermediate visual acuity is increasingly associated with DVA as the velocity increasing.

A Review of the Use of Confidence Intervals for Bland-Altman Limits of Agreement in Optometry and Vision Science

SIGNIFICANCE

Confidence intervals are still seldom reported for Bland-Altman 95% limits of agreement. When they are reported, 50% of articles use approximate methods and 50% use exact methods.

PURPOSE

Bland-Altman limits of agreement can be unreliable estimates, especially for small sample sizes. However, authors seldom use confidence intervals for limits of agreement. This article reviews their use in Optometry and Vision Science.

METHODS

A keyword search for "Bland," "Altman," "Bland-Altman," "LoA," and "limits of agreement" was conducted on the Optometry and Vision Science website within a time range from January 2016 to December 2018.

RESULTS

Fifty articles were reported or were judged to use Bland-Altman analysis; sample sizes ranged from 3 to 2072. Eight of these article reported confidence limits for limits of agreement, four of which used exact methods and four used Bland and Altman's approximate method.

CONCLUSIONS

Use of confidence intervals for limits of agreement has increased in Optometry and Vision Science but is far from universal. To assist researchers in calculating exact confidence limits for Bland-Altman limits of agreement, spreadsheets are included for performing the calculations and generating Bland-Altman plots with the confidence intervals included.

Static and dynamic visual acuity and refractive errors in elite football players

BACKGROUND

The aim of this study was to investigate static and dynamic visual acuity, refractive error, and the use of visual compensation of elite football players.

METHODS

From 2015 to 2017, 147 professional players from five teams were analysed. Screening consisted of a survey about the use of visual correction, and measurement refractive error, static visual acuity and dynamic visual acuity. Refractive error was assessed using an autorefractor. Distance static visual acuity was evaluated using a Snellen chart. Dynamic visual acuity was measured at five metres using the software COI-SV. All athletes were male with a mean age of 24.6 ± 4.1 years.

RESULTS

The mean refractive error of the athletes was -0.04 ± 0.83 D, and 16.4 per cent were myopic. Statistically significant differences were found for dynamic visual acuity (p = 0.033), based on the position occupied. Goalkeepers displayed the best dynamic visual acuity and forwards had the lowest values (0.82 ± 0.14 and 0.62 ± 0.17, respectively). The forwards presented with the highest prevalence of myopia and goalkeepers the lowest, at 22.5 per cent and 12.5 per cent, respectively. All goalkeepers who needed to use a correction for play used it, whereas only 16 per cent of the forwards who needed a correction used it.

CONCLUSION

Dynamic visual acuity of forwards is lower than that of other players. Twenty-five per cent of players who need to use visual correction to practice sports actually use it.