Accommodative Response Research Articles

Do myopia control spectacle lenses with defocus incorporated multiple segments technology alter visual parameters and cortical activity?

This study evaluated visual parameters and cortical activity after wearing myopia control spectacle lenses with defocus incorporated multiple segments (DIMS). Myopic adults between 20 and 30 years of age were enrolled. The study consisted of(1) examination of visual parameters and (2) measurement of cortical responses, while wearing single vision lenses (SVL) and MiYOSMART (MS) lenses in counterbalanced order after a two-week adaptation period. Visual parameters tested were: high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), contrast sensitivity, heterophoria, near point of convergence (NPC), stereopsis, accommodative facility and the accommodative response. Cortical responses were assessed by visual evoked potentials (VEPs), recorded from 10 electrodes placed over the parieto-occipital area. MiYOSMART lenses produced slightly better HCVA than SVL (-0.25 vs. -0.21 logMAR, p = 0.02) and a larger accommodative response (MS 1.68 D; SVL 1.53 D, p < 0.001). No significant differences in LCVA, heterophoria, NPC, stereopsis or contrast sensitivity were observed. The latencies and amplitudes of the early and late components of the VEPs (C1, N1, P1, P2) did not differ significantly between lenses. This study found no clinically significant differences in visual parameters or visual cortex responses between SVL and MS lenses after 2 weeks of adaptation. These results confirm the absence of adverse visual effects from DIMS lenses for myopia control.

Maintaining a young self-concept: Feeling young or shifting age thresholds?

In the face of prevailing negative views on old age, aging individuals try to maintain the self-concept of a young person. They may do so by feeling younger than they are or by shifting the threshold of old age. According to the dual-process theory of developmental regulation, the former represents an assimilative coping process, whereas the latter represents an accommodative coping process. In the present work, we investigated the usage of those two processes across various life domains (e.g., family, work, and leisure). We hypothesized that individuals try to maintain a young self-concept particularly in those domains they view as important for themselves. We furthermore expected older adults to rely more strongly on shifting the threshold of old age in personally important domains (= accommodative response) and younger adults to rely more strongly on feeling young in personally important domains (= assimilative response). We investigated these hypotheses in a cross-sectional sample of 768 individuals aged 30 to 80 years. Analyses were conducted in a multilevel framework with the life domains nested within individuals. Our hypotheses were confirmed. Participants protected a young self-concept selectively in domains that were important to them. Younger adults felt particularly young in self-relevant domains, whereas older adults selectively chose higher old age thresholds in self-relevant domains. Both processes may allow individuals to protect their self-concept and to dissociate themselves from the stigmatized identity of an old person. Results also shed light on the idealization of being young in our society.

Analysis of Accommodation and Optical Quality After Myopia Surgery With Phakic Intraocular Lens Implantation.

To characterize the accommodative function and optical quality in high and moderate myopia after the implantation of a phakic intraocular lens implantable collamer lens (ICL). This was a prospective observational study of 20 myopic patients undergoing bilateral ICL implantation with a mean spherical equivalent (SE) of -7.44 diopters (D) (range: -4.37 to -12.00 D). Amplitude of accommodation, subjective accommodative response, optical quality parameters including modulation transfer function cut-off, Objective Scatter Index, and Strehl ratio, and objective accommodative response with a double-pass system (HD Analyzer; Visiometrics SL) were assessed before surgery and 1 month postoperatively. Mean residual refractive error improved to 0.20 ± 0.19 D (P < .001) at 1 month postoperatively compared to preoperatively. Amplitude of accommodation decreased significantly by 1.65 D (P < .001) from 7.65 ± 1.33 D at baseline to 6.00 ± 0.95 D at 1 month after ICL implantation. However, no significant changes were found in accommodative response or in the optical quality parameters of modulation transfer function cut-off, Objective Scatter Index, Strehl ratio, and objective accommodative response with HD Analyzer between preoperatively and 1-month postoperative follow-up (P > .05). ICL implantation in healthy patients with moderate to high myopia does not significantly alter accommodative function, as measured by subjective or objective methods, or optical quality parameters, except for a non-clinically relevant decrease in amplitude of accommodation. [J Refract Surg. 2025;41(4):e325-e332.].

Performing a task in an augmented reality head-mounted display can change accommodation responses

Performing a task in an augmented reality head-mounted display can change accommodation responses

Analyzing display photometric features through time-dependent dynamics of accommodative responses and ocular imaging quality

To optimize screen quality for a better and healthier visual experience, it is essential to understand how photometric parameters impact ocular physiological parameters. However, the relationship between these photometric and physiological parameters has still not been clearly defined. In this study, time series data of accommodative response and ocular imaging quality at various time points during screen viewing were analyzed, examining different screen photometric parameters. The concept of “tolerance duration” based on these time series curves was introduced. The findings indicate that accommodative response is sensitive to screen brightness, while ocular imaging quality is affected by spectral power distribution. The mathematic models of time-dependent dynamics for both accommodative response and ocular imaging quality were developed, consisting of positive and negative forces. The accommodative response displayed an exponential decay and linear increase pattern, whereas the ocular imaging quality corresponded more closely to sigmoid functions. This innovative model could broaden the understanding of ocular physiological changes during screen use. Additionally, it may offer useful insights for optimizing screen photometric parameters and assist in monitoring ocular responses in clinical research.

Accommodative Response to Asymmetrical Accommodative Stimuli.

Recent advancements in head-up-displays have increased the number of instances where the visual system may face a different accommodative demand for each eye. A limited number of studies on aniso-accommodation exist, reporting contradictory results. We tested the natural capacity of observers to aniso-accommodate anisometropic stimuli. A dichoptic task allowed us to account for certain confounds, including high-level accommodation control. A 2AFC visual task was used, where participants judged if two overlapping sinusoidal gratings, presented dichoptically, had the same orientation. The gratings' spatial frequency could be 1, 4 or 10 c/deg. The accommodative demand for each eye could be independently set to 2D or 4D. The accommodative response for each eye was recorded using an autorefractometer. Higher spatial frequencies and anisometropy had a negative impact on task accuracy. Contrary to expectations, spatial frequencies had no significant impact on accommodation response. The accommodation response to anisometropic stimuli was equal in the two eyes and leaned toward the lower of two demands. Our results confirm that when presented with asymmetrical accommodation demand, the two eyes tend to keep the same refractive power even in a dichoptic-requiring task. They also contradict the guidance of accommodation by spatial frequency in sinusoidal gratings. The visual task provided an objective measure of subjects' performance, allowing for these conclusions to be drawn.

Effect of 0.025% atropine on ocular biometry changes during accommodation.

Low concentration atropine is an effective treatment to slow myopia progression and axial elongation and also reduces accommodation. On-axis ocular dimensions of the eye change during accommodation; hence, this study aimed to quantify the effect of 0.025% atropine eye drops on accommodation-induced changes in ocular biometry. Twenty-eight myopic participants with a mean (SD) age of 17.0 (6.0) years (range: 8.0-25.5 years) and spherical equivalent refraction (SER) of -2.03 (1.05) D (range: -0.75 to -4.38 D) were enrolled. Baseline ocular biometry measurements of the left eye were captured using an optical biometer (Zeiss IOLMaster 700) for 0, 2, 4 and 6 D accommodation stimuli, presented via a Badal optometer. The accommodation response (AR) was determined using wavefront aberrometry (Imagine Eyes irx3) for the same accommodation stimuli and following cycloplegia using 1% tropicamide. Participants instilled 0.025% atropine eye drops nightly for 1 week in both eyes, and ocular biometry measurements were repeated on the day after the final atropine dose. Anterior chamber depth (ACD) and corrected vitreous chamber depth (cVCD) decreased, and crystalline lens thickness (LT), anterior segment length (ASL), crystalline lens centre position (LCP) and the AR increased significantly during accommodation (all p ≤ 0.009). Accommodation-induced changes in ACD and LT were reduced following 0.025% atropine use (both p ≤ 0.01), with significant pre- and post-atropine differences for the 4 and 6 D stimuli (all pairwise comparisons, p ≤ 0.004). On average, ACD, ASL and LCP increased, while cVCD, corrected axial length (cAL), and the AR decreased following 1 week of 0.025% atropine use (all p ≤ 0.002). The AR and on-axis ocular biometric changes during accommodation were reduced following 1 week of 0.025% atropine use. These findings may have implications for the association between near work and myopia, and atropine's mechanism of action in humans.

Wavefront sensing: A breakthrough for objective evaluation of dynamic accommodation in accommodative dysfunctions.

Wavefront sensing: A breakthrough for objective evaluation of dynamic accommodation in accommodative dysfunctions.

Additional accommodative controls in near heterophoria targets do not improve accommodative responses in young adults.

This study evaluated newly designed tests to measure near heterophoria, comparing them to the Maddox Wing and Howell card, and assessed whether accommodative responses differed between the different heterophoria test targets. Near horizontal heterophoria of 20 visually normal young adults was measured using the Maddox Wing, Howell Card and two versions of a newly designed Huddersfield Heterophoria Test (HHT) card. The HHT cards are based on the Prentice method, either with or without an additional spatially defined grating superimposed on the scale. The addition of a spatially defined grating has been suggested to control accommodation better. A single examiner was used to take measurements on two separate occasions, presenting each test in a random order. Monocular accommodative responses to each heterophoria target were also obtained in a separate session by another examiner. Heterophoria measurements between the four tests were not significantly different, neither clinically nor statistically. Differences in test-retest measurements between test and retest conditions were small and not significantly different. Mean accommodative responses were also not significantly different between the test targets. Differences in target configurations in the Maddox Wing, Howell card or new HHT cards did not influence accommodative responses in a sample of young adults. The newly designed HHT cards (or other variations of the Prentice method) may be used to measure near horizontal heterophoria in a young adult population either with or without additional horizontal lines superimposed on the scale.

Fast and Slow Response of the Accommodation System in Young and Incipient-Presbyope Adults During Sustained Reading Task.

Objectives: To investigate the dynamics of accommodation during and immediately after a sustained reading task on a digital device across various age groups under monocular and binocular conditions. Methods: Seventeen subjects were selected and divided into three age groups: young adults (n = 4, age: 21.3 ± 3.2 years), adults (n = 4, age: 34 ± 3.56 years), and incipient presbyopes (n = 9, age: 45 ± 3.61 years). Dynamic accommodation and disaccommodation were objectively measured using the WAM-5500 open-view autorefractor during 2 min of distance fixation (Maltese cross at 6 m), 5 min of sustained near reading on a teleprompter app at the nearest readable distance, and 2 min of distance vision. Six sequential temporal landmarks were identified. Quantitative metrics for accommodation lag (AL), slope of slow accommodation (SSA), slope of slow disaccommodation (SSD), peak velocity of accommodation (PVA) and peak velocity of disaccommodation (PVD) were obtained as absolute values of spherical equivalent refractive (SER) change. Results: SSA, SSD, and AL were significantly and positively correlated with age (ρ = 0.75, 0.73, 0.51, respectively; p ≤ 0.038). For subjects under 45 years of age SSA and SSD increased quadratically with age, while for those above 45 years, both SSA and SSD decreased linearly. Linear regression of PVA and PVD with age indicated that the disaccommodation mechanism is faster than accommodation (slope = -0.15 and -0.23, respectively). PVA was significantly faster under monocular than binocular conditions (p = 0.124). Conclusions: Incipient presbyopes demonstrate a complex response in both accommodation and disaccommodation. The accommodation system responds quickly, but there is also a slower response that can provide up to an additional 1D of accommodative response during sustained near reading tasks. It is hypothesized that the crystalline lens exhibits hysteresis in returning to its unaccommodated state, due to its viscoelastic properties, which means it takes time to relax.

A tightly regulated auxin signaling landscape is required for spatial accommodation of lateral roots in Arabidopsis.

In Arabidopsis thaliana, lateral root (LR) development requires spatial accommodation responses in overlying endodermal cells. This includes loss of cell volume whilst maintaining membrane integrity to allow the expansion of the underlying LR primordia (LRPs). These accommodation responses are regulated by auxin-mediated signaling, specifically through Aux/IAA proteins, involving IAA3/SHY2. Plants that express a stabilized version of SHY2 (shy2-2) in differentiated endodermal cells, CASP1pro::shy2-2 plants, fail to make LRs. Exogenous treatment with 1-naphthaleneacetic acid (NAA) was reported to partially restore LR formation in this spatial accommodation mutant. Using treatments with auxins having different transport properties, such as NAA, indole-3-acetic acid (IAA), and 2,4-dichlorophenoxyacetic acid (2,4-D), we assessed the ability of each auxin to rescue LR formation in CASP1pro::shy2-2 roots. This revealed that IAA is the most effective in partially restoring LR development, NAA is effective in inducing LRPs but cannot maintain their canonical phenotype, whereas 2,4-D induces non-controlled cell divisions. In addition, we show that in CASP1pro::shy2-2 roots, AUX1 appears to be repressed in the zone where oscillation of the auxin response has been described. Our study advances the understanding of auxin-regulated spatial accommodation mechanisms during LRP formation and highlights the complex interplay of auxin transport and signaling in bypassing the endodermal constraints.

Accommodation microfluctuation in individuals with mTBI and the potential effect of chromatic filter on this parameter.

Accommodation microfluctuation in individuals with mTBI and the potential effect of chromatic filter on this parameter.

Temporal impacts of diverse concentrations of pilocarpine ophthalmic solution on human accommodation

ABSTRACT Clinical relevance Accommodation is crucial for clear near vision and is predominantly affected by presbyopia. The ability to modulate accommodative function with eye drops could offer a pharmacological approach to manage presbyopia. Background To investigate the effects of different concentrations of pilocarpine eye drops on ocular accommodation in young volunteers. Methods In this prospective study, healthy volunteers with mild or moderate myopia with corrected visual acuity of no less than 20/20 were recruited. Participants underwent four visits for baselining and administration of low (0.75%), medium (1.00%), and high (1.25%) concentrations of pilocarpine eye drops respectively. One eye of each participant was chosen and analysed. Ophthalmologic examinations included objective and subjective refraction, corrected distance visual acuity, intraocular pressure, and pupil size. Accommodation was assessed using the WAM-5500 binocular autorefractor. Accommodation facility and the defocus curve were measured. Results Volunteers (n = 24, mean age 23.7 ± 1.5 years) with a mean spherical equivalent of −2.91 ± 1.54 dioptres (D) were recruited. No serious adverse events occurred. All pilocarpine concentrations showed similar pupil constriction without significant intraocular pressure changes (p > 0.05). Pilocarpine induced greater objective refraction changes with higher concentrations (−1.12 ± 1.07D, −1.56 ± 1.38D, −1.68 ± 1.60D for low, medium, and high concentrations, respectively; p < 0.01). Subjective refraction showed a similar dose-response. Accommodative response decreased significantly at the 20 cm stimulus for medium and high concentrations (p < 0.05). Corrected distance visual acuity improved beyond −1.00D to + 0.50D defocus after all three pilocarpines. Accommodative facility improved more by 1.25% than 0.75% (p = 0.04). Conclusions Pilocarpine eye drops are effective in improving ocular accommodation, with higher concentrations leading to greater accommodative changes. Pilocarpine has potential for managing presbyopia.

Improving Complaint Handling: The Rhetorical Turn in Defensive and Accommodative Strategies

This article examines how Aristotelian rhetorical principles— ethos, pathos, and logos—can help manage social media outrage in complaint handling by translating them into defensive and accommodative response strategies commonly used in service recovery. Two online experiments evaluated four strategies for their effects on complainants’ moods: (a) blame-shifting; (b) promising action; (c) apologizing; and (d) a combination of empathy, apology, and promise. The results showed that accommodative strategies were more effective than defensive ones, with the combination of empathy, apology, and promise as the most effective. The findings suggest incorporating rhetorical training in business communication to enhance response efficacy.

Dynamic Accommodation Responses in Subjects Wearing Myopia Control Spectacles Modifying Peripheral Refraction.

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. 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 ± 4.5years). 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 ± 1.7years). Group 3 included 8 adults (age = 27.9 ± 5.3years) 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. 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. 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.

Ophthalmological and Orthoptic Findings in Down Syndrome: Is Genotype-Phenotype Correlation Possible?

Introduction: This is a preliminary study to investigate a feasible genotype-phenotype correlation by defining ophthalmological findings in different genotypes of Down syndrome (DS). Methods: The study included 62 eyes of 31 DS patients. Patients were further subgrouped according to cytogenetic forms of DS. A comprehensive ophthalmological examination was performed and, biometric, keratometric, and pachymetric parameters were evaluated. Results: The mean best-corrected visual acuity (BCVA) of trisomy 21 was 0.41 ± 0.14 (0.1–0.6) and was 0.6 ± 0.09 (0.5–0.7) for both mosaic and translocation trisomy 21 (p = 0.004). While 6 of the trisomy 21 patients (24%), 2 of the mosaic patients (66.7%), and all of the three translocation type patients had a normal accommodation response, the remaining patients had accommodation lags (p = 0.013). Conclusions: Lens opacities and fundus abnormalities were more common in trisomy 21 (p < 0.001). The angle kappa was larger in trisomy 21 and smallest in the translocation trisomy 21 (p = 0.014). K2 and corneal apex curvature were highest in trisomy 21 (p = 0.05 and p = 0.006, respectively). BCVA and accommodation response were reduced whereas lenticular opacities and fundus abnormalities were more common in trisomy 21. In addition, central cornea was steeper and angle kappa was larger. Further studies with larger cohorts would display differences among subgroups of cytogenetic abnormality.

Retinal image quality with myopia control lenses, in the synthetic accommodative wavefront model

Aims/Purpose: Current myopia control contact lenses (CLs) are based on multifocality designs that affect decrease retinal image quality (RIQ). This study aimed to evaluate the changes in RIQ and accommodative response (AR) with two myopia control CLs.Methods: 100 synthetic eyes were generated using anc accommodative wavefront model to simulate the changes in RIQ with accommodation. The synthetic eyes were “fitted”, using direct wavefront summation, with two myopia control CLs: the MiSight with +2.00D treatment zones and the Mylo with an EDOF design. Peak image quality was calculated for the naked eye and with CLs, in the relaxed state and a target vergence of 40 cm, with an entrance pupil diameter of 4.28 mm. Additionally, the AR that maximizes RIQ was calculated.Results: The mean RIQ [ranged from 0 to 1] for the relaxed eye was 0.42 ± 0.10 without a CLs. It halved to 0.26 ± 0.05 with the Misight and reduced by threefold to 0.15 ± 0.04 with the Mylo. For 40cm the RIQ was 0.34 ± 0.09 without a CL, 0.24 ± 0.07 with the Misight and 0.19 ± 0.03 with the Mylo.For target vergences with demands close the effective add power of the CL, the accommodative RIQ through‐focus produced a second peak prior to the maximum peak, correspondent to the focusing power of the treatment zones1, yielding a RIQ of 0.08 ± 0.03 and 0.12 ± 0.04 for the Misight and Mylo, respectively. The AR without CL was 2.33 ± 0.20 D, 1.75 ± 0.22 D and 1.75 ± 0.22 D with the Misight and the Mylo, respectively.Conclusions: Both myopia control CLs reduced the RIQ in the relaxed and accommodated states. For 40 cm, both CLs induce a secondary peak in the RIQ through‐focus. With Mylo, the secondary peak appeared less than 0.1D from the maximum peak, possibly due to its EDOF design. The AR was reduced with both CLs 0.58 D (lag) compared to the naked eye condition. These results indicate that, both lenses impose significant limitations RIQ and AR.

Retinal image quality with myopia control lenses, in the synthetic accommodative wavefront model

Aims/Purpose: Current myopia control contact lenses (CLs) are based on multifocality designs that affect decrease retinal image quality (RIQ). This study aimed to evaluate the changes in RIQ and accommodative response (AR) with two myopia control CLs.Methods: 100 synthetic eyes were generated using anc accommodative wavefront model to simulate the changes in RIQ with accommodation. The synthetic eyes were “fitted”, using direct wavefront summation, with two myopia control CLs: the MiSight with +2.00D treatment zones and the Mylo with an EDOF design. Peak image quality was calculated for the naked eye and with CLs, in the relaxed state and a target vergence of 40 cm, with an entrance pupil diameter of 4.28 mm. Additionally, the AR that maximizes RIQ was calculated.Results: The mean RIQ [ranged from 0 to 1] for the relaxed eye was 0.42 ± 0.10 without a CLs. It halved to 0.26 ± 0.05 with the Misight and reduced by threefold to 0.15 ± 0.04 with the Mylo. For 40cm the RIQ was 0.34 ± 0.09 without a CL, 0.24 ± 0.07 with the Misight and 0.19 ± 0.03 with the Mylo.For target vergences with demands close the effective add power of the CL, the accommodative RIQ through‐focus produced a second peak prior to the maximum peak, correspondent to the focusing power of the treatment zones1, yielding a RIQ of 0.08 ± 0.03 and 0.12 ± 0.04 for the Misight and Mylo, respectively. The AR without CL was 2.33 ± 0.20 D, 1.75 ± 0.22 D and 1.75 ± 0.22 D with the Misight and the Mylo, respectively.Conclusions: Both myopia control CLs reduced the RIQ in the relaxed and accommodated states. For 40 cm, both CLs induce a secondary peak in the RIQ through‐focus. With Mylo, the secondary peak appeared less than 0.1D from the maximum peak, possibly due to its EDOF design. The AR was reduced with both CLs 0.58 D (lag) compared to the naked eye condition. These results indicate that, both lenses impose significant limitations RIQ and AR.References Faria‐Ribeiro M, Amorim‐de‐Sousa A, González‐Méijome JM. Predicted accommodative response from image quality in young eyes fitted with different dual‐focus designs. Ophthalmic Physiol Opt. 2018;38(3):309‐16.

The effect of aging on the ciliary muscle and its potential relationship with presbyopia: a literature review.

The ciliary muscle is known to play a part in presbyopia, but the mechanism has not received a comprehensive review, which this study aims to achieve. We examined relevant articles published from 1975 through 2022 that explored various properties of the muscle and related tissues in humans and rhesus monkeys. These properties include geometry, elasticity, rigidity, and composition, and were studied using a range of imaging technologies, computer models, and surgical methods. We identified a notable age-related displacement of the ciliary muscle apex that is characterized by anterior and medial shifts, and hypothesized to be primarily attributed to the accrual of connective tissue and tension exerted by the thickening lens. Other factors could also contribute to the movement, particularly the "inward bowing" of the sclera. Another noteworthy observation is that while the ciliary muscle experiences increasing constraint with advancing age due to adjacent anatomical structures, its contractile capacity remains unaltered, alongside the sustained constancy in both the concentration of muscarinic receptors and their binding affinity. Overall, more studies on human ciliary muscle are needed, as it ages differently from that of monkeys' ciliary muscle. These studies should explore other perspectives, including those regarding changes in the physical properties of the tissue and its relationship with other connected tissues. This literature review utilized a systematic methodology to identify and analyze pertinent studies of the presbyopia and ciliary muscles. The approach encompassed a thorough examination of available literature across different academic databases, such as PubMed, Embase, and Cochrane Library. Many studies have identified age-related thickening in the ciliary muscle and its potential causes, including the heightened deposition of connective tissues and traction exerted by the thickening lens. Notably, these inquiries culminated in the formulation of a geometric theory positing that the morphology of the ciliary muscle and its spatial relationship with adjacent structures exert pivotal influence over the tension exerted on zonular fibers. The decline in the accommodative response of the muscle is prevalent in advanced age, with reduced mobility likely attributable to the increased stiffness of the Bruch's Membrane-Choroid Complex (BMCC), where the tendons of the ciliary muscle insert, as well as the thickening and stiffening of the lens. Importantly, the ciliary muscle forces do not change with age.

Individual Variations in Vergence and Accommodation Responses Following Virtual Reality Gameplay.

Virtual reality (VR) can challenge the visual system, leading to temporary oculomotor changes, though the degree of change varies among individuals. While the vergence and accommodation system plays a crucial role in VR perception, it remains unclear whether individuals whose visual functions fall outside clinical norms experience larger changes. Thus, our study aimed to investigate whether changes in vergence and accommodation responses following VR gameplay differ between individuals with and without non-strabismic binocular and accommodative disorders. To assess this, both subjective and objective measurements were conducted before and after 20 min of playing Beat Saber. Results revealed significant alterations across both subjective measurements-near point of convergence and near point of accommodation-and objective measurements, including eye refraction, accommodation lag, and accommodative microfluctuations at far. Moreover, individuals with non-strabismic binocular and accommodative disorders exhibited larger accommodative microfluctuations at far compared to the control group. Overall, these findings indicate that considering individual differences in vergence and accommodation responses is important when evaluating the impact of VR on the visual system and can be helpful in the design and use of VR systems, particularly for individuals with binocular and accommodative disorders.