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Pupil size primarily changes to regulate the amount of light entering the retina, optimizing the balance between visual acuity and sensitivity for effective visual processing. However, research directly examining the relationship between pupil size and visual processing has been limited. While a few studies have recorded pupil size and EEG signals to investigate the role of pupil size in visual processing, these studies have predominantly focused on the domain of visual sensitivity. Causal effects of pupil size on visual acuity, therefore, remain poorly understood. By manipulating peripheral background luminance levels and target stimulus contrast while simultaneously recording pupillometry and EEG signals, we examined how absolute pupil size affects visual discrimination and visually evoked potentials (VEP) in a task using optotype mimicking the Snellen eye chart, the most common assessment of visual acuity. Our findings indicate that both higher background luminance levels and higher target contrast were associated with improved target discrimination and faster correct reaction times. Moreover, while higher contrast visual stimuli evoked larger VEPs, the effects of pupil size on VEPs were not significant. Additionally, we did not observe inter-individual correlations between absolute pupil size and discrimination performance or VEP amplitude. Together, our results demonstrate that absolute pupil size, regulated by global luminance level, played a functional role in enhancing visual discrimination performance in an optotype discrimination task. The differential VEP effects of pupil size compared to those of stimulus contrast further suggested distinct neural mechanisms involved in facilitating visual acuity under small pupils. [ABSTRACT FROM AUTHOR]

Purpose: Spectacle lenses with arrays of lenslets have gained popularity in myopia control due to their high efficacy, low impact on visual performance, and non-invasiveness. One of the questions regarding their impact on visual performance that still remain is that: do the lenslets impact visual field sensitivity? The current study aims to investigate the impact of wearing spectacle lenses with highly aspherical lenslets (HAL) on the visual field sensitivity. Methods: An automated static perimetry test (Goldman perimeter target III) was employed to measure the detection sensitivity in the visual field. Targets were white light dots of various luminance levels and size 0.43°, randomly appearing at 76 locations within 30° eccentricity. Twenty-one adult subjects (age 23-61, spherical equivalent refractive error (SER) -8.75 D to +0.88 D) participated in the study. Sensitivities through two lenses, HAL and a single vision lens (SVL) as the control condition, were measured in random order. Results: The mean sensitivity differences between HAL and SVL across the 76 tested locations ranged between -1.14 decibels (dB) and 1.28 dB. Only one location at 30° in the temporal visual field reached statistical significance (p < 0.00065) whereby the sensitivity increased by 1.1 dB with HAL. No significant correlation was found between the difference in sensitivity and age or SER. Such a difference is unlikely to be clinically relevant. Conclusion: Compared to the SVL, the HAL did not change detection sensitivity to static targets in the whole visual field within 30° eccentricity. [ABSTRACT FROM AUTHOR]

Pupil size primarily changes to regulate the amount of light entering the retina, optimizing the balance between visual acuity and sensitivity for effective visual processing. However, research directly examining the relationship between pupil size and visual processing has been limited. While a few studies have recorded pupil size and EEG signals to investigate the role of pupil size in visual processing, these studies have predominantly focused on the domain of visual sensitivity. Causal effects of pupil size on visual acuity, therefore, remain poorly understood. By manipulating peripheral background luminance levels and target stimulus contrast while simultaneously recording pupillometry and EEG signals, we examined how absolute pupil size affects visual discrimination and visually evoked potentials (VEP) in a task using optotype mimicking the Snellen eye chart, the most common assessment of visual acuity. Our findings indicate that both higher background luminance levels and higher target contrast were associated with improved target discrimination and faster correct reaction times. Moreover, while higher contrast visual stimuli evoked larger VEPs, the effects of pupil size on VEPs were not significant. Additionally, we did not observe inter-individual correlations between absolute pupil size and discrimination performance or VEP amplitude. Together, our results demonstrate that absolute pupil size, regulated by global luminance level, played a functional role in enhancing visual discrimination performance in an optotype discrimination task. The differential VEP effects of pupil size compared to those of stimulus contrast further suggested distinct neural mechanisms involved in facilitating visual acuity under small pupils., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chin, Tai, Yep, Chang, Hsu and Wang.)

Purpose: Spectacle lenses with arrays of lenslets have gained popularity in myopia control due to their high efficacy, low impact on visual performance, and non-invasiveness. One of the questions regarding their impact on visual performance that still remain is that: do the lenslets impact visual field sensitivity? The current study aims to investigate the impact of wearing spectacle lenses with highly aspherical lenslets (HAL) on the visual field sensitivity., Methods: An automated static perimetry test (Goldman perimeter target III) was employed to measure the detection sensitivity in the visual field. Targets were white light dots of various luminance levels and size 0.43°, randomly appearing at 76 locations within 30° eccentricity. Twenty-one adult subjects (age 23-61, spherical equivalent refractive error (SER) -8.75 D to +0.88 D) participated in the study. Sensitivities through two lenses, HAL and a single vision lens (SVL) as the control condition, were measured in random order., Results: The mean sensitivity differences between HAL and SVL across the 76 tested locations ranged between -1.14 decibels (dB) and 1.28 dB. Only one location at 30° in the temporal visual field reached statistical significance ( p < 0.00065) whereby the sensitivity increased by 1.1 dB with HAL. No significant correlation was found between the difference in sensitivity and age or SER. Such a difference is unlikely to be clinically relevant., Conclusion: Compared to the SVL, the HAL did not change detection sensitivity to static targets in the whole visual field within 30° eccentricity., Competing Interests: All authors were employed by Essilor International. The authors declare that this study received funding from Essilor International. The funders were not involved in the study design, collection, analysis, interpretation of data, or the writing of this article. The funders were involved in the decision to submit it for publication., (Copyright © 2022 Gao, Spiegel, Muzahid, Lim and Drobe.)