January 2025
Volume 66, Issue 1
Open Access
Visual Psychophysics and Physiological Optics  |   January 2025
Dynamic Accommodation Responses in Subjects Wearing Myopia Control Spectacles Modifying Peripheral Refraction
Author Affiliations & Notes
  • Zhenghua Lin
    Laboratorio de Óptica, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
    Aier Academy of Ophthalmology, Central South University, Changsha, China
    Hunan Province Optometry Engineering and Technology Research Center, Changsha, China
    Hunan Province International Cooperation Base for Optometry Science and Technology, Changsha, China
  • Dimitrios Christaras
    Diestia Systems, Athens, Greece
  • Raul Duarte-Toledo
    Laboratorio de Óptica, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
  • Zhikuan Yang
    Aier Academy of Ophthalmology, Central South University, Changsha, China
    Hunan Province Optometry Engineering and Technology Research Center, Changsha, China
    Hunan Province International Cooperation Base for Optometry Science and Technology, Changsha, China
    Aier School of Optometry and Vision Science, Hubei University of Science and Technology, Xianning, China
  • Augusto Arias
    ZEISS Vision Science Lab, University of Tübingen, Tübingen, Germany
  • Weizhong Lan
    Aier Academy of Ophthalmology, Central South University, Changsha, China
    Hunan Province Optometry Engineering and Technology Research Center, Changsha, China
    Hunan Province International Cooperation Base for Optometry Science and Technology, Changsha, China
    Aier School of Optometry and Vision Science, Hubei University of Science and Technology, Xianning, China
  • Pablo Artal
    Laboratorio de Óptica, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
    Aier Academy of Ophthalmology, Central South University, Changsha, China
    Hunan Province Optometry Engineering and Technology Research Center, Changsha, China
    Hunan Province International Cooperation Base for Optometry Science and Technology, Changsha, China
  • Correspondences: Pablo Artal, Universidad de Murcia, Murcia 30100, Spain; [email protected]
  • Weizhong Lan, Aier Academy of Ophthalmology, Central South University, Changsha 410000, China; [email protected]
  • Footnotes
     WL and PA contributed equally.
Investigative Ophthalmology & Visual Science January 2025, Vol.66, 55. doi:https://doi.org/10.1167/iovs.66.1.55
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      Zhenghua Lin, Dimitrios Christaras, Raul Duarte-Toledo, Zhikuan Yang, Augusto Arias, Weizhong Lan, Pablo Artal; Dynamic Accommodation Responses in Subjects Wearing Myopia Control Spectacles Modifying Peripheral Refraction. Invest. Ophthalmol. Vis. Sci. 2025;66(1):55. https://doi.org/10.1167/iovs.66.1.55.

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Abstract

Purpose: Peripheral optics have been suggested to play a role in myopia progression, with accommodation responses also considered a potential contributor. This study aimed to investigate whether modifications in peripheral optics through different spectacle lenses affect accommodation responses.

Methods: Dynamic accommodation responses were assessed using a double-pass instrument while switching the target from distance (3 m for 3 seconds) to near (0.22 m/4.5 D for adults, 0.18 m/5.5 D for children, 5 seconds) and then back to distance (3 m for 3 seconds). Three groups were studied. Group 1 included 13 adults (age = 28 ± 4.5 years). Participants wore one of three myopia control lenses (MiYOSMART [Hoya], Stellest [Essilor], or MyoCare [ZEISS]) randomly, along with their habitual glasses. The testing involved both central clear zones and peripheral side-vision zones, with habitual glasses served as reference. Group 2 underwent same procedure, but in children (age = 9.8 ± 1.7 years). Group 3 included 8 adults (age = 27.9 ± 5.3 years) wearing standard glasses partially excised with central holes (diameter = 12 mm). The lens refraction included plano, +3 D defocus, −3 D defocus, and −3 D oblique astigmatism.

Results: The accommodative lag was less than 0.5 D for all eyes under near stimulation. No significant differences in the amplitude of accommodation responses were observed among the myopia control lenses or the partially excised glasses.

Conclusions: No effect on accommodation responses was found in subjects wearing different types of myopia control lenses. This finding indicates that the induced changes in the ocular peripheral optics do not have an impact on accommodation.

Myopia is the leading cause of permanent visual impairment in the world.1 The prevalence of myopia has increased dramatically worldwide in the last decades, especially in east Asia.2 High myopia increases susceptibility to serious ocular diseases, like retinal detachment, retinal degeneration, myopic maculopathy, and glaucoma.3 Correcting the underlying high myopia does not prevent the onset of associated pathologies, making the prevention of myopia of utmost importance. 
The etiology of myopia is associated with multiple factors. Among them, accommodative dysfunction is of particular interest, with conflicting results from various studies. Longitudinal studies in children indicated that the accommodative lag does not affect myopia progression.4,5 However, in children wearing soft contact lenses, those with reduced accommodation responses exhibit greater myopia progression.6 In an orthokeratology study, a more accurate accommodation response was linked to a lower axial elongation.7 The mechanism by which accommodation influences myopia progression remains unclear. 
In contrast, it has been suggested that peripheral defocus may guide the direction of ocular growth.813 A lag of accommodation means the ocular response is less than the stimulation, resulting in hyperopic defocus across the whole retina, potentially causing myopia development. Interestingly, the theory is linked to the asymmetric feature of two-dimensional peripheral retinal refraction in the vertical direction.14,15 It suggests that near vision tasks could impose more relative hyperopic defocus on the superior retina owing to the minor but persistent accommodative lag over an extended period.1416 
In recent years, there are several commercial multifocal spectacles (MiyoSmart,17 Stellest,18 and MyoCare19) and contact lenses (MiSight20) designed to reduce hyperopic defocus as a protection against myopia progression. An accommodative lag was observed in the subjects wearing contact lenses.21,22 In contrast, a reduced accommodative lag was found in progressive addition lens.23,24 A previous study investigated peripheral refraction in near vision during accommodation or far vision with relaxed accommodation, and they found that emmetropes show more myopic change in peripheral field comparing with myopes.25 
In this study, our main objective was to use a double-pass, through-focus, image-based instrument to investigate the accommodation responses dynamically while viewing through the central and decentered optics of myopia control lenses. The research aims to provide insights into the mechanisms through which these lenses may influence visual behavior and potentially provide indications for myopia prevention. 
Methods
Subjects
Three groups of subjects participated in this study. The first group included 13 adults (mean age = 28 years) tested with myopia control lenses. One subject (age = 29) was excluded owing to the low accommodation response amplitude (amplitude of accommodation = 3.5 D). The second group included nine children (mean age = 9.8 years) who underwent the same procedure as group 1. The third group was derived from the first group and consisted of seven emmetropes and one myope corrected using contact lenses, and they were tested with four customized, partially excised spectacles. Demographic and other characteristics of the cohort used in our study are summarized in Table 1
Table 1.
 
The Demographics of the Subjects in Three Groups
Table 1.
 
The Demographics of the Subjects in Three Groups
The inclusion criteria were as follows: age 38 years or younger, astigmatism of less than 1.5 D, best-corrected visual acuity of 0.8 or greater (decimal), no history of eye disease or systemic disease, and no use of orthokeratology or any other myopia treatment solutions in the last 3 months. The amplitude of accommodation had to be greater than 5.0 D (adults) or 10.0 D (children). 
All subjects and their guardians (for children) were informed fully of the details of the experiment protocol, and consent was taken. All the tests is complied with the tenets of the Declaration of Helsinki. The ethical review was approved by the Institution Review Board of the University of Murcia (M10/2023/080). 
Double-Pass Instrument
An experimental prototype was used to evaluate dynamic accommodation response and retinal image quality. The device is capable of capturing double-pass through-focus images (TFIs) of the eye, computing the refractive error in less than 1 second. The instrument consist of a 780-nm infrared diode laser that produces a retinal point-like spot, a tunable lens capable of inducing −10 D to +10 D of defocus, and a CMOS camera for acquiring double-pass retinal images of the spot. The instrument uses an open-view configuration, allowing the subject to fixate at an external target, which can move freely on a 1-m (1 D) rail. A stepper motor was used to switch fixation between a distant target (3 m) and a near target (0.22 m for adults, 0.18 m for children). A Maltese cross with a size corresponding with a visual field of 0.8 (decimal) was placed on the far wall for distant vision or attached to a movable target for near vision. The target was printed on a white paper with black Maltese cross in 100% contrast. A photo that explains the testing room and the instrument was attached as Figure 1. The light intensity was around 200 lux at the eye's position with myopia control lenses (measured with Couclip; Glasson Technology, Hanzhou, China). A customized Matlab application was designed to control the experimental system and analyze the data. Additional details about the device can be found elsewhere.26 
Measurements of Dynamic Accommodation
The initial central refraction (ISER) for each subject was determined with myopia correction where necessary. The ISER value is the reference point for the double-pass instrument to generate a TFI during the dynamic accommodation test. The testing range for TFI was defined as ISER + [−6 D to +2 D] for adults and ISER + [−7 D to +2 D] for children. This variation in testing range accounts for the accommodative stimulus, which is 4.5 D (0.22 m) for adults and 5.5 D (0.18 m) for children. The chosen range ensured that the measured accommodative response stayed within the instrument's available TFI range. The TFI step size was set to 0.25 D, balancing the instrument's measurement speed with diopter accuracy. As a result, the instrument completed a full-range scan in approximately 0.65 seconds (33 captures, 0.02 seconds per image), measuring refraction at a frequency of 1.54 Hz. 
During the dynamic accommodation test, subjects were instructed to fixate on a distant target for 3 seconds; after that, a motorized near target appeared, inducing the subject to accommodation. The near target remained 5 seconds before disappearing, and then return to the far target for the final 3 seconds, inducing the subject to relax accommodation. 
Myopia Control Spectacles
Three commercially available myopia control glasses were used in the experiment: MiYOSMART (or DIMS; Hoya, Tokyo, Japan), Stellest (Essilor, Charenton-le-Pont, France), and MyoCare (ZEISS, Jena, Germany). MiYoSMART and Stellest have myopic defocus incorporated through micro lenslets in the periphery. Stellest uses lenslets of high asphericity. MyoCare consists of a concentric ring-like cylindrical refractive pattern on the lens surface, expanding from center to the periphery. All myopia control lenses had plano refraction. To investigate the accommodation behavior while subjects looking through the periphery of the lens, customized frames were designed and printed for each brand with a 3D printer (Form 3L, Formlabs, Somerville, MA) for a complete piece of myopia control lens. The customized frame allows displacement in horizontal direction to the nasal side of the subject for 15 mm. The vertex distance (the distance between the eye and myopia control lenses) were from 14 mm to 17 mm for subjects wearing spectacles, or 12 mm to 15 mm for subjects without spectacles. Some critical parameters of the lenses are summarized in Table 2
Table 2.
 
Critical Dimensions of the Myopia Control Lenses
Table 2.
 
Critical Dimensions of the Myopia Control Lenses
Table 3.
 
The Amplitude of Accommodation Response With Different Spectacles at the Beginning, Middle, and Late Stages of Dynamic Accommodation
Table 3.
 
The Amplitude of Accommodation Response With Different Spectacles at the Beginning, Middle, and Late Stages of Dynamic Accommodation
Table 4.
 
The Mean Accommodation Response in Adults at the Beginning, Middle, and Late Stages of Dynamic Accommodation for Regular Glasses With Central Hole
Table 4.
 
The Mean Accommodation Response in Adults at the Beginning, Middle, and Late Stages of Dynamic Accommodation for Regular Glasses With Central Hole
Myopic subjects were wearing their habitual glasses before the application of myopia control lenses to fully stimulate the accommodation. Therefore, during the experiment, myopes had both prescribed single-vision glasses and myopia control lenses in front of their eyes, whereas emmetropes only had myopia control lenses with plano refraction. 
In addition to the myopia control glasses, four regular single-vision glasses with central holes (SVH) were used for the third group of subjects. The lenses were positioned perpendicularly on a wooden board, and the central portion was removed using a 12-mm diameter drill bit designed for organic materials. This modification limited the optical effect to the peripheral visual field. The interpupillary distance of the SVH was set as 62 mm, and the same SVH was provided for all subjects throughout the study. Real-time video images from the pupil camera of the double-pass instrument confirmed all subjects maintained clear central vision during the study. Refraction of the four glasses is plano, +3 D defocus, −3 D defocus, and −3 D oblique astigmatism (OD: +3.0 DS/−3 DC × 45°; OS: +3.0 DS/−3 DC × 135°). The glasses ensured significant amount of blur appeared in peripheral retina by adding defocus or astigmatism.27 The appearance of SVH is demonstrated in Figure 2
Experimental Protocol
Autorefraction, best-corrected visual acuity, and accommodation amplitude (minus lens technique28 for adult and push up test22 for children) were initially assessed to determine the selected subjects, according to the inclusion criteria. To prevent potential fatigue effects from prolonged measurements, the sequence of examinations for different types of spectacles was randomized before the dynamic accommodation testing. Subjects were instructed to wear their habitual glasses or, without glasses if they were emmetropic, to perform the test. If an adult was emmetropic or myopic with a single-vision contact lens, they were required to continue the dynamic test for the four different single-vision lenses specialized for peripheral refraction. All measurements were performed three times, and the average values were used for analysis. Only the right eye was evaluated, with the fellow eye covered by an eyepatch. 
Data Processing and Statistical Analysis
The data were processed using Matlab (MathWorks, Natick, MA) and then analyzed with SPSS for statistical analysis (SPSS, Inc, Armonk, NY). Because subjects are likely to blink during the experiment, and lens reflections from glasses occasionally affect the accuracy of the image processing algorithm, a Matlab application was developed to manually check and select the best-focused images. See Figure 3 for an example of manually checking. The accommodation response was averaged over three periods: the beginning (0 to 1.5 seconds, for the distant target), the middle stage (5 to 6.5 seconds, for the near target), and the final stage (9.5 to 12.0 seconds, for the distant target again). These averages served as representative data for each period to compare differences among various spectacles. Data are presented as mean ± 1 SD in text descriptions and as mean ± 1 standard error in figure plots. A one-way ANOVA test was used to compare differences in accommodation response for different test lenses. A Bonferroni correction was applied to the post hoc comparison for the ANOVA test. 
Figure 1.
 
The instrument and testing room. (a) A front view from the operator's side. The subject was wearing his habitual glasses and fixating on a near target, with the myopia control lens positioned in front of his eye. (b) A side view of the instrument. (c) An example illustrating distant vision during a relaxed accommodation state. (d) A view showing the near target used for inducing accommodation. The light intensity at the subject's eye level was approximately 200 lux.
Figure 1.
 
The instrument and testing room. (a) A front view from the operator's side. The subject was wearing his habitual glasses and fixating on a near target, with the myopia control lens positioned in front of his eye. (b) A side view of the instrument. (c) An example illustrating distant vision during a relaxed accommodation state. (d) A view showing the near target used for inducing accommodation. The light intensity at the subject's eye level was approximately 200 lux.
Figure 2.
 
Regular spectacles with central holes used to modify peripheral refraction in experiment 3.
Figure 2.
 
Regular spectacles with central holes used to modify peripheral refraction in experiment 3.
Figure 3.
 
A screenshot illustrating an example of Matlab application for manually checking the best focus images. The red arrow indicates the misidentification of the best focus image caused by blinking. The red rectangular represents the masked TFI during the blink (approximately 0.25 seconds). The green arrow indicates the manual correction/estimation for the best focus image. The plot in the left window displays the accommodation curve before and after the manual correction.
Figure 3.
 
A screenshot illustrating an example of Matlab application for manually checking the best focus images. The red arrow indicates the misidentification of the best focus image caused by blinking. The red rectangular represents the masked TFI during the blink (approximately 0.25 seconds). The green arrow indicates the manual correction/estimation for the best focus image. The plot in the left window displays the accommodation curve before and after the manual correction.
Results
The dynamic accommodation responses with various myopia control spectacles are presented in Figure 4. The accommodation stimulation was 4.5 D (0.22 m) for adults or 5.5 D (0.18 m) for children. In general, we observed that the lag of accommodation is less than 0.5D for near targets for both groups, and no significant difference was found among different myopia control glasses both in adults and children. The refractive error was corrected in adults, and a stable refraction (approximately −0.25 D) was observed before the shifting of the target (from 0 to 3 seconds). All recruited children had good uncorrected visual acuity (>1.0); therefore, no correction was required for the children cohort. The accommodation response during the far stimulation for children was 0 ± 0.1, 0.1 ± 0.1, 0.3 ± 0.1, and 0.1 ± 0.1 for single-vision glasses, well-centered DIMS, Stellest, and MyoCare, respectively. 
Figure 4.
 
Dynamic accommodation response over time in adults (a) and children (b). The accommodation requirement for near target was 4.5 D or 5.5 D for adults or children. The instrument was programmed to present distant target, near target, and distant target for 3 seconds, 5 seconds, and 3 seconds, respectively. The legend single-vision glasses, DM0, DM1, ST0, ST1, MP0, and MP1 refer to single vision glasses, centered MiYOSMART, decentered MiYOSMART, centered Stellest, decentered Stellest, centered MyoCare, and decentered MyoCare, respectively. The data are presented as mean ± 1 standard error in the plots.
Figure 4.
 
Dynamic accommodation response over time in adults (a) and children (b). The accommodation requirement for near target was 4.5 D or 5.5 D for adults or children. The instrument was programmed to present distant target, near target, and distant target for 3 seconds, 5 seconds, and 3 seconds, respectively. The legend single-vision glasses, DM0, DM1, ST0, ST1, MP0, and MP1 refer to single vision glasses, centered MiYOSMART, decentered MiYOSMART, centered Stellest, decentered Stellest, centered MyoCare, and decentered MyoCare, respectively. The data are presented as mean ± 1 standard error in the plots.
Subjects took approximately 2 seconds (from the sixth time point [at 3.3 seconds] to the ninth time point [at 5.2 seconds]) back to a stable refraction status after shifting the target from far distance to near distance (Fig. 4a). For relaxed accommodation (from the 13th time point [at 8.1 seconds] to the 15th time point [at 9.7 seconds]), it takes approximately 1.6 seconds back to the stable refraction status again. It is important to note that these times were estimated roughly, because the interval between dynamic accommodation measurements was 0.65 seconds. During the near vision task, subjects have a subtle tendency to lose the ability to focus on the target, which is a known phenomenon in general. The moment for shifting the targets from near to far (at 8 seconds) persisting a relatively high variability, especially in children. For example, the standard error for adults at 9 seconds, the moment for relax accommodation, for single-vision glasses, DM0, DM1, ST0, ST1, MP0, MP1 were 0.3 D, 0.2 D, 0.3 D, 0.3 D, 0.3 D, 0.2 D, and 0.2 D, respectively; for children it was 0.6 D, 0.5 D, 0.6 D, 0.5 D, 0.4 D, 0.5 D, and 0.6 D, respectively. These differences could be related to a visual fatigue effect after long time fixating and lower compliance in children during the experiment. More details about the results and statistics can be found in Table 3
Similar visual behavior was found with the partially excised spectacles (Fig. 5). There was no clear difference in the amplitude of accommodation response among different spectacles at any stage of the dynamic accommodation test. For example, the mean and SD during near stimulation was −4.1 ± 0.6 D, −4.2 ± 0.6 D, −4.3 ± 0.7 D, and −4.2 ± 0.7 D for SVH with peripheral refraction as plano, +3 D defocus, −3 D defocus, and −3 D oblique astigmatism (F = 0.11, P = 0.95, one-way ANOVA), respectively. See more relevant details in Table 4
Figure 5.
 
Dynamic accommodation response over time with partially central excised regular spectacles in adults. The material in central circular region with diameter of 12 mm was removed. The legend PL, +3 D, −3 D, and −3 D Ast indicate the refraction in those spectacles are plano, +3 D spherical refraction, −3 D spherical refraction, and −3 D astigmatism (prescription: OD: +3.0 DS/−3 DC × 45°; OS: +3.0 DS/−3 DC × 135°), respectively.
Figure 5.
 
Dynamic accommodation response over time with partially central excised regular spectacles in adults. The material in central circular region with diameter of 12 mm was removed. The legend PL, +3 D, −3 D, and −3 D Ast indicate the refraction in those spectacles are plano, +3 D spherical refraction, −3 D spherical refraction, and −3 D astigmatism (prescription: OD: +3.0 DS/−3 DC × 45°; OS: +3.0 DS/−3 DC × 135°), respectively.
Discussion
In this study, we investigated the dynamic accommodation responses with three commercially available myopia control lenses. Testing was conducted with the lenses in both centered positions, providing vision through the central clear zone, and decentered positions, allowing vision through the peripheral defocus zone of the lenses. However, no significant differences in accommodation response were observed under the various experimental conditions. Additionally, the investigation using regular spectacles with central holes suggests that solely modifying peripheral optics does not influence the accommodation responses. These findings offer new insights into the mechanism of myopia prevention: the treatment effect of peripheral defocus-based lenses is unlikely to operate through the regulation of accommodation, such as by reducing accommodative lag or improving accommodative accuracy. 
To the best of our knowledge, this study is the first to investigate dynamic accommodation response through modification of peripheral optics via spectacles. There are a few studies that investigated the dynamic accommodation response with multifocal contact lens. For instance, Papadogiannis et al.29 investigated accommodation response in single-vision glasses, MiSight, and Acuvue Moist contact lenses designed for presbyopia. Their findings revealed that MiSight could increase the accommodation response and decrease the contrast of image in periphery compared with regular spectacles and Acuvue Moist, and this feature could be the mechanics of MiSight for myopia control. The myopia treatment efficacy in orthokeratology has been well documented. It is hypothesized that the enhanced accommodative accuracy after lens fitting is associated with the improved treatment efficacy of myopia.7 
To avoid the impact of visual fatigue on the experiment, the sequence for conducting the test was randomized for all the lenses and the lens positions (center or decentered). As the central clear zone of the spectacles was approximately 3.5 to 4.5 mm in radius for all the myopia control lenses, the degree of horizontal displacement was determined as 15.0 mm, ensuring the foveal vision can be fully exposed to the peripheral region of the spectacles. The selected distance for decentration could effectively simulate the visual behavior of the subject when looking through the periphery of the spectacles. However, no significant differences were observed among various myopia control lenses in either children or adults in terms of dynamic accommodation response. This finding is kind of interesting; the previous study30 found that the through-focus PSF image30 (more specifically, the retinal contrast) is significantly different among various myopia control lenses. Although the peripheral defocus-based myopia control lenses showed a lower contrast value compared with single-vision glasses,30 the accommodation pattern is the same across the lenses in current study. 
The accommodation stimulation was set at 4.5 D and 5.5 D for adults and children, respectively, corresponding to 64.2% (4.5 D/7.0 D) and 34.3% (5.5 D/16.0 D) of the average subjective amplitude of accommodation of the cohorts. The choice 4.5 D for adults was based on local population data, where the average amplitude of accommodation ranging from 6.0 D to 6.5 D among adults, aged from 28 to 30 years. The accommodation stimulation for children was set at 5.5 D. The dioptric distance was constrained by the appearance of the device in the upper part that is for placing the near target. This configuration aimed to ensure that all participants consistently maintained sufficient exertion during the accommodation test. 
In addition to the peripheral defocus-based spectacles, we conducted a parallel experiment using four conventional single-vision glasses with the central part of the material removed, focusing solely on peripheral refraction. The peripheral refraction of the spectacles is +3 D defocus, −3 D defocus, plano, and −3 D astigmatism. Although the peripheral refraction of the lenses is obviously varied, no differences in accommodation response were found across all time points (see Fig. 5). The optical design of the spectacles ensured that only peripheral refraction was modified in this study. Consequently, we can conclude that, for a 3-D amount of refraction, peripheral retinal refraction does not exert a discernible impact on accommodation response. 
Despite significant variations in retinal image quality among different experimental conditions, no differences were observed in dynamic accommodation response throughout the entire testing period. These findings suggest that the human eye possesses a certain degree of adaptability to blurred images when focusing on objects, no matter in near distance or far distance. It is worth noting that the maximum defocus from the peripheral lenslets of the spectacles is approximately +3.5 D, indicating the potential for further enhancing myopia control efficacy by introducing additional defocus. The current optical design has not yet reached the threshold of visual comfort for myopia treatment in clinics. For instance, the study by Lu et al.17 found that peripheral refraction modification with DIMS had a very slight impact on visual comfort. 
Another hypothesis for the nonsignificant differences in accommodation between centered optics and decentered optics could be related to competitive signals and fine vision. Although the peripheral zones had higher power, the defocus incorporated multiple segment designs (DIMS, Stellest, and MyoCare) simultaneously provides both high power and prescribed optical signals. We speculate that the focused optics from the competitive peripheral region had a stronger influence on the accommodation response than the peripheral defocus signals. Because accommodation is driven primarily by fine vision, the impact of the fine vision likely dominated the response, which explains why no significant differences were observed across the various experimental conditions. Further supporting this hypothesis is evidence from a Hartmann–Shack aberrometer, which was unable to measure the lenslet power in human subjects wearing these glasses.31 However, the refraction pattern of the myopia control lenses could be measured using a high-resolution single-pass Shack–Hartmann aberrometer,32 suggesting that the analyzed pupil region was much larger than the visual field projected by the micro lenslets in the periphery. This strategy is similar to how the eye seems to ignore the visual signal from the high-power micro lenslets. 
Our study seems to show different results compared with other studies on how modifications in peripheral refraction affect accommodation. These differences can be attributed to at least three factors: the approach to myopia correction, the instruments used, and the population studied. To our knowledge, this study is the first to compare dynamic accommodation using peripheral multiple segment defocus-based spectacles. Other studies have primarily used soft contact lenses21,22,29 or progressive spectacles.23 For instance, Vera et al.21 and Gong et al.22 found a similar increase in accommodative lag with MiSight lenses compared with single-vision contact lenses. However, Papadogiannis et al.29 found that MiSight reduced accommodative lag compared with both single-vision frame glasses and multifocal contact lenses designed for presbyopia. This highlights the importance of the control group in drawing conclusions. Varnas et al.23 compared accommodative lag in two types of progressive addition lenses with single-vision frame glasses, and both progressive addition lenses reduced accommodative lag. Interestingly, Varnas et al.23 used two instruments to measure accommodative response: the Grand Seiko autorefractor WAM-5500 (Grand Seiko Co. Ltd., Mahwah, NJ) and the COAS-HD aberrometer (WaveFront Sciences, Albuquerque, NM). They found that the accommodative lag measured by the WAM-5500 was higher than that measured by the COAS-HD (approximately 0.62 D vs. 0.37 D, respectively, for measurements taken at 25 cm with the progressive addition lenses-1 lens). They also measured accommodative lag at 20 cm using only the Grand Seiko, and the results were consistent with the 25-cm measurements. When comparing Varnas's findings for progressive addition lenses-1 with our results for peripheral-defocus lenses, the results are similar. The choice of instrument also plays a role in the outcome. Our instrument was carefully calibrated using an emmetropic artificial eye and standard trial lenses, with a 2-mm vertex distance between the back surface of the trial lens and the aperture of the artificial eye. Differences in calibration procedures between devices could also contribute to the discrepancies. Finally, the study population may have influenced the results. Our research included only stable myopes and emmetropes, as we were unable to include myopic children owing to limited recruitment resources. Previous studies have suggested that progressive myopes tend to exhibit larger accommodative lags, while stable myopes and emmetropes show smaller lags (<0.5 D).33,34 
There are several strengths of this current study. First, we used a prototype double-pass instrument to measure the dynamic accommodation response objectively. The retinal images captured by the device are generated from a point-like laser resource, providing a true representation of the retinal image that traditional wavefront sensors may inaccurately quantify.35 Second, the verification of best focus images during accommodation was manually performed using a custom Matlab application to ensure accurate preservation before data analysis (Fig. 3). This step was necessary because the instrument captured 33 TFI over 0.65 seconds, although the total testing duration was 11.0 seconds. As a result, there was a potential risk of subjects blinking during image acquisition. If a blink occurred or external reflections from glasses overlapped with the best focus PSF image, the instrument could produce inaccurate data. To mitigate this limitation, we manually reviewed the TFI using the application, either estimating the best focus image or discarding the measurement at that time point to maintain the accuracy of the dynamic results. Third, myopia control lenses were fixed in a moveable three-dimensional–printed frame, facilitating the straightforward evaluation of the peripheral region's impact on accommodation response. This design eliminates the need for subjects to rotate their eyes, reducing potential data variability. 
However, the study does have some limitations. The main limitation being the relatively small sample size, which also restricted the recruitment of progressive myopic subjects. Despite this factor, the variability of the accommodation data is small, maintaining a high reliability of the study. Second, the accommodation response was performed monocularly with the contralateral eye covered, potentially not fully reflecting the true visual behavior while wearing spectacles with binocular vision. Third, the study does not include the DOT lens, which is specialized for decreasing retinal contrast, preventing a direct comparison of image quality between peripheral micro lenslets–based technology and microscopic diffusers–based spectacle lenses. Fourth, we did not recruit children in the progressive stage of myopia. This group may exhibit different accommodative responses and show differences in comparisons of various myopia control lenses. Fifth, the increment of TFI was set as 0.25 D, as a compromise between the instrument's measurement speed and diopter accuracy. If the differences between the various experimental conditions are smaller than this value, the statistics may not be able to detect them. Last, the measuring speed of accommodation is relatively slow to allow a complete assessment of the dynamics of accommodation, with roughly 1.5 measurements per second. Despite this, the measurement principle ensures the trustworthiness of all collected data. 
In summary, our findings indicate that currently available commercial peripheral defocus-based spectacles do not induce changes in dynamic accommodation response over short-term observation periods. This finding suggests that the human eye may possess a higher threshold for adjusting accommodation to blurred images when fixating on an object. Therefore, the mechanisms underlying the myopia control effect of peripheral defocus-based spectacles are unlikely to involve adjustments in accommodation response, at least in adults and progressive emmetropes. 
Acknowledgments
Supported by grants from “Agencia Estatal de Investigacion,” Spain (PID2023-146439OB-I00); “The Science and Technology Innovation Program of Hunan Province,” China (2023RC1079); “Ministry of Science and Techniques,” China (2022YFE0124600). 
Disclosure: Z. Lin, None; D. Christaras, None; R. Duarte-Toledo, None; Z. Yang, None; A. Arias, None; W. Lan, None; P. Artal, None 
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Figure 1.
 
The instrument and testing room. (a) A front view from the operator's side. The subject was wearing his habitual glasses and fixating on a near target, with the myopia control lens positioned in front of his eye. (b) A side view of the instrument. (c) An example illustrating distant vision during a relaxed accommodation state. (d) A view showing the near target used for inducing accommodation. The light intensity at the subject's eye level was approximately 200 lux.
Figure 1.
 
The instrument and testing room. (a) A front view from the operator's side. The subject was wearing his habitual glasses and fixating on a near target, with the myopia control lens positioned in front of his eye. (b) A side view of the instrument. (c) An example illustrating distant vision during a relaxed accommodation state. (d) A view showing the near target used for inducing accommodation. The light intensity at the subject's eye level was approximately 200 lux.
Figure 2.
 
Regular spectacles with central holes used to modify peripheral refraction in experiment 3.
Figure 2.
 
Regular spectacles with central holes used to modify peripheral refraction in experiment 3.
Figure 3.
 
A screenshot illustrating an example of Matlab application for manually checking the best focus images. The red arrow indicates the misidentification of the best focus image caused by blinking. The red rectangular represents the masked TFI during the blink (approximately 0.25 seconds). The green arrow indicates the manual correction/estimation for the best focus image. The plot in the left window displays the accommodation curve before and after the manual correction.
Figure 3.
 
A screenshot illustrating an example of Matlab application for manually checking the best focus images. The red arrow indicates the misidentification of the best focus image caused by blinking. The red rectangular represents the masked TFI during the blink (approximately 0.25 seconds). The green arrow indicates the manual correction/estimation for the best focus image. The plot in the left window displays the accommodation curve before and after the manual correction.
Figure 4.
 
Dynamic accommodation response over time in adults (a) and children (b). The accommodation requirement for near target was 4.5 D or 5.5 D for adults or children. The instrument was programmed to present distant target, near target, and distant target for 3 seconds, 5 seconds, and 3 seconds, respectively. The legend single-vision glasses, DM0, DM1, ST0, ST1, MP0, and MP1 refer to single vision glasses, centered MiYOSMART, decentered MiYOSMART, centered Stellest, decentered Stellest, centered MyoCare, and decentered MyoCare, respectively. The data are presented as mean ± 1 standard error in the plots.
Figure 4.
 
Dynamic accommodation response over time in adults (a) and children (b). The accommodation requirement for near target was 4.5 D or 5.5 D for adults or children. The instrument was programmed to present distant target, near target, and distant target for 3 seconds, 5 seconds, and 3 seconds, respectively. The legend single-vision glasses, DM0, DM1, ST0, ST1, MP0, and MP1 refer to single vision glasses, centered MiYOSMART, decentered MiYOSMART, centered Stellest, decentered Stellest, centered MyoCare, and decentered MyoCare, respectively. The data are presented as mean ± 1 standard error in the plots.
Figure 5.
 
Dynamic accommodation response over time with partially central excised regular spectacles in adults. The material in central circular region with diameter of 12 mm was removed. The legend PL, +3 D, −3 D, and −3 D Ast indicate the refraction in those spectacles are plano, +3 D spherical refraction, −3 D spherical refraction, and −3 D astigmatism (prescription: OD: +3.0 DS/−3 DC × 45°; OS: +3.0 DS/−3 DC × 135°), respectively.
Figure 5.
 
Dynamic accommodation response over time with partially central excised regular spectacles in adults. The material in central circular region with diameter of 12 mm was removed. The legend PL, +3 D, −3 D, and −3 D Ast indicate the refraction in those spectacles are plano, +3 D spherical refraction, −3 D spherical refraction, and −3 D astigmatism (prescription: OD: +3.0 DS/−3 DC × 45°; OS: +3.0 DS/−3 DC × 135°), respectively.
Table 1.
 
The Demographics of the Subjects in Three Groups
Table 1.
 
The Demographics of the Subjects in Three Groups
Table 2.
 
Critical Dimensions of the Myopia Control Lenses
Table 2.
 
Critical Dimensions of the Myopia Control Lenses
Table 3.
 
The Amplitude of Accommodation Response With Different Spectacles at the Beginning, Middle, and Late Stages of Dynamic Accommodation
Table 3.
 
The Amplitude of Accommodation Response With Different Spectacles at the Beginning, Middle, and Late Stages of Dynamic Accommodation
Table 4.
 
The Mean Accommodation Response in Adults at the Beginning, Middle, and Late Stages of Dynamic Accommodation for Regular Glasses With Central Hole
Table 4.
 
The Mean Accommodation Response in Adults at the Beginning, Middle, and Late Stages of Dynamic Accommodation for Regular Glasses With Central Hole
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