Effect of Experimental Conditions in the Accommodation Response in Myopia

Otero, Carles; Aldaba, Mikel; Vera-Díaz, Fuensanta A; Pujol, Jaume

doi:10.1097/opx.0000000000001140

Cited by 13 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is important to note that all these studies were each limited in sample size and difficult to reproduce due to the lack of information about the participants' age, refractive error, or the explicit task instructions. As shown in previous studies, the accommodative response and some parameters of its dynamics (e.g., latency) are significantly affected by age, 8,9 refractive error, 10,11 and the instructions given to participants. 12 When these factors are not controlled, they could mask or bias the findings.…”

Section: Introductionmentioning

confidence: 52%

“…After a thorough review of previous studies that found an effect of stimulus predictability on accommodation, [1][2][3] it came to light that their results were obtained using limited sample sizes (4 subjects 2 or 1 subject 1,3 ), they did not report whether participants were naïve or not, and did not describe the specific task observers were instructed to perform. It is therefore difficult to compare our results with these studies since accommodation dynamics are affected by age, 8,9 refractive error 10,11 and instructions. 12 We speculate that we did not find an effect of predictability in our study because: 1) every observer was instructed to "clear the target" naturally, and 2) none of the participants were trained to perform voluntary accommodation and all of them were naïve to the purpose of the study.…”

Section: Discussionmentioning

confidence: 87%

See 1 more Smart Citation

Stimulus Unpredictability in Time, Magnitude, and Direction on Accommodation

et al. 2019

Self Cite

View full text Add to dashboard Cite

SIGNIFICANCE The effect of predictability in changes of time, magnitude, and direction of the accommodation demand on the accommodation response latency and its magnitude are insignificant, which suggests that repetitive accommodative tasks such as the clinical accommodative facility test may not be influenced by potential anticipation effects. PURPOSE The purpose of this study was to investigate the effect of stimulus' time, magnitude, and direction predictability, as well as their interactions, on accommodation latency and response magnitude. METHODS Monocular accommodative response and latency were measured in 12 young subjects for nine different conditions where the stimulus accommodative demand changed several times in a steplike fashion for a period of 120 seconds. Each change in accommodative demand could have different time duration (i.e., 1, 2, or 3 seconds), magnitude (1, 2, or 3 diopters), and/or direction (i.e., accommodation or disaccommodation). All conditions were created permuting the factors of time, magnitude, and direction with two levels each: random and not random. The baseline condition was a step signal from 0 to 2 diopters persisting for 2 seconds in both accommodative demands. After each condition, subjects were asked to provide a score from 1 to 5 in their perceived predictability. RESULTS Friedman test conducted on the perceived predictability of each condition resulted in statistically significant differences between the nine conditions (χ2 = 56.57, P < .01). However, repeated-measures analysis of variance applied to latency and accommodative response magnitude did not show significant differences (P > .05). In addition, no correlation was found between the perceived predictability scores and both latency and accommodative response magnitudes between the most predictable and the most unpredictable conditions. CONCLUSIONS Subjects were able to perceptually notice whether the stimulus was predictable or not, although our results indicate no significant effect of stimuli predictability on either the accommodation latency or its magnitude.

show abstract

Section: Introductionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 87%

Stimulus Unpredictability in Time, Magnitude, and Direction on Accommodation

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…These findings are expected; the subjective refraction of VAO mimics the gold standard method and includes visual acuity measurements. It is not surprising that VAO subjective refractions were on average left slightly myopic compared with the gold standard measurements as instrument accommodation artefacts could have been induced, 33 owing to the closed and small field of view of the VAO system; however, if VAO subjective refractions had used the same starting point of refraction as the clinician refraction (i.e., autorefraction instead of Hartmann–Shack measures), the agreement between both methods would have likely been better as the autorefractor provided—on average—overplus refractions, whereas the Hartmann–Shack overminused them.…”

Section: Discussionmentioning

confidence: 99%

A Comparison Between Refraction From an Adaptive Optics Visual Simulator and Clinical Refractions

Tabernero

Otero

Pardhan

2020

Trans. Vis. Sci. Tech.

Self Cite

View full text Add to dashboard Cite

Purpose The Visual Adaptive Optics (VAO) is an adaptive optics visual simulator with an embedded Hartmann–Shack aberrometer that can give objective and subjective refraction measures. The aim of the present study was to compare the findings of the objective and subjective refractions from the VAO with a commercial autorefractometer (Topcon Corp., Tokyo, Japan) and a subjective refraction by an optometrist. The influence of age, refractive error type, and presence of ocular diseases was ascertained. Methods The refractive error was obtained in 469 participants using the four techniques mentioned. Data were analyzed with power vectors mean spherical equivalent, the vertical Jackson-Cross-Cylinder, and the oblique Jackson-Cross-Cylinder. Age, refractive error type (myopia, emmetropia, hyperopia) and presence of ocular diseases (yes, no) were included as covariates. Agreement was assessed using the 95% interval of agreement. Results The median spherical equivalent difference and the interval of agreement for all the participants with the VAO subjective, VAO objective, and autorefraction with the clinical subjective refraction were (+0.13, 1.80 diopters [D]), (+0.38, 1.80 D), and (−0.38, 2.10 D), respectively. When considering only healthy participants, the results were (+0.06, 1.70 D), (+0.38, 1.60 D) and (−0.25, 1.80 D), respectively. When considering only those participants with any ocular condition, the results with VAO subjective, VAO objective and autorefraction were (+0.13, 2.50 D), (+0.31, 2.70 D), and (−0.50, 4.80 D), respectively. Conclusions The VAO subjective refraction is more accurate than VAO objective refraction and autorefraction, regardless of refractive error, age, or the presence of ocular conditions. The presence of ocular conditions significantly deteriorates the accuracy of all refraction methods. Translational Relevance Reported clinical comparisons between different types of standard refraction methods and a new adaptive optics refraction instrument (VAO) are in good agreement and support the further development of this method to increase refraction accuracy and to refract quicker than standard procedures.

show abstract

“…This latter point is especially relevant because it has been shown that the steady-state accommodative response stimulated with lens-based systems is affected by many factors such as the refractive error or the field of view when compared to free-space stimulation. [11][12][13] Finally, a better understanding of the dynamics of accommodation under optical stimulation would provide insight into the visual discomfort that some individuals may experience in virtual reality systems. 14 Visual fatigue has been associated with factors such as fast motion in depth, insufficient depth information, and unnatural types of blur.…”

Section: Q5mentioning

confidence: 99%

“…Thus, it may be possible that the differences found in our study are also larger due to the number of subjects with myopia in our sample (65% of the sample). Indeed, the accommodative response is affected not only by experimental conditions, 11 but also by the observer's refractive error. 13 In conclusion, our results show that a hybrid unpredictable approach is able to provide a more comprehensive examination of the accommodative capability to change focus over time than the conventional accommodative facility test.…”

Section: Repeatability and Agreement Between Manual Flippers And The mentioning

confidence: 99%

Random Changes of Accommodation Stimuli: An Automated Extension of the Flippers Accommodative Facility Test

Otero

Aldaba

López

et al. 2018

Current Eye Research

Self Cite

View full text Add to dashboard Cite

The automated accommodative facility test does not agree with the manual flipper test results. Operator delays in flipping the lens may account for these differences. This novel test, using unpredictable stimuli, provides a more comprehensive examination of accommodative dynamics than conventional manual accommodative facility tests. Unexpectedly, the unpredictability of the stimulus did not to affect accommodation dynamics. Further studies are needed to evaluate the sensitivity of this novel hybrid technique on individuals with accommodative anomalies.

show abstract

Effect of Experimental Conditions in the Accommodation Response in Myopia

Abstract: Previously reported differences in AR when using lens-based methods compared with free space viewing may be explained by the effect of other factors such as the FOV or the depth of the stimulus. Targets with an FOV of 8 or 10° may be optimal for accurate ARs.

Cited by 13 publications

References 31 publications

Stimulus Unpredictability in Time, Magnitude, and Direction on Accommodation

Stimulus Unpredictability in Time, Magnitude, and Direction on Accommodation

A Comparison Between Refraction From an Adaptive Optics Visual Simulator and Clinical Refractions

Random Changes of Accommodation Stimuli: An Automated Extension of the Flippers Accommodative Facility Test

Contact Info

Product

Resources

About