Accommodative Response Research Articles

Visual Dysfunctions in Mild Traumatic Brain Injury: A Focus on Accommodative System Impairments

Background: Mild traumatic brain injury (mTBI) is a prevalent neurological condition that results in various physical, emotional, and cognitive impairments. The most common are visual impairments, which affect vision’s perceptual, motor, and sensory aspects. Objective: This paper analyzes the pathophysiology of mild traumatic brain injury (mTBI) and its effects on visual and oculomotor functions, focusing on the deficits of the accommodative system and their underlying mechanism. Findings: mTBI frequently causes diffuse axonal injury, resulting in abnormalities of the neurometabolic cascade that impact the brain’s visual regions. Accommodative anomalies, including insufficiency, infacility, and spasm, are markedly more common in mTBI patients than in the general population. These deficiencies present as a notable delay in accommodation response, diminished peak velocity, and compromised dynamic responses, possibly due to sensory and motor disturbances. Conclusions: Accommodation disorder is a significant but under-examined component of visual sequelae related to mTBI. Future research should concentrate on the sensory and motor factors contributing to these deficiencies to enhance diagnostic precision and customize rehabilitative strategies.

Color vision-associated environmental and biological factors in the development of myopia.

Color vision-associated environmental and biological factors in the development of myopia.

Visual performance of single-vision contact lenses utilizing opaque, nonrefractive features for potential myopia management.

Contact lenses (CLs) utilizing opaque, nonrefractive features may purposefully modulate retinal ganglion cell activity away from the baseline activity. This is a nonrefractive mechanism that may reduce myopia progression. However, the visual performance of CLs with opaque features is unknown. This study aimed to compare the visual performance and binocular/accommodative function of CLs with opaque features (test) against MiSight (control-1) and single-vision (control-2) CLs. This was a prospective, randomized, unmasked, cross-over study where 35 myopic CL wearers (18 to 39 years) wore each design for at least 5 days. Visual performance was subjectively assessed using 1 to 10 numeric ratings comprising clarity of vision, lack of ghosting, vision when driving, overall vision satisfaction, and willingness to purchase (yes/no: based on vision and myopia efficacy). Visual acuity measurements comprised monocular and binocular high and low contrast visual acuity at 6 m, and binocular high contrast visual acuity at 70 and 40 cm. Binocular function was assessed using heterophorias at 3 m and 40 cm. Accommodative function was assessed using monocular accommodative facility (MAF) at 40 cm and dynamic monocular accommodative response (AR: 6 m, 70 cm, and 40 cm). Test was rated higher than control-1 (p<0.001) and control-2 was rated higher than test (p≤0.0052) for all subjective ratings. More participants were willing to purchase test compared with control-1 for vision and myopia efficacy (p<0.001), while there was no difference between test and control-2 for either question (p>0.7). Both controls were better than test for all acuity-based measurements (p≤0.0013). MAF at 40 cm was better with test compared with control-1 (p=0.010) and not different to control-2 (p>0.99). AR was higher with test than both controls at 70 cm (p<0.0001), higher than control-1 at 40 cm (p<0.0001), and not different to control-2 at 40 cm (p=0.12). There were no differences between CLs for AR at 6 m or heterophorias at 3 m or 40 cm (p>0.1). Compared with control-1, the test offered better visual performance, a higher proportion of participants willing to purchase, and better MAF. Compared with control-2, the test offered worse visual performance, but the proportion of participants willing to purchase was not different, and accommodative function was comparable.

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

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

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.

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

Accommodative and binocular characteristics in myopes with age-related accommodation deficiency

BackgroundTo investigate accommodative and binocular characteristics in myopic patients with age-related accommodation deficiency, and to investigate the relationship of accommodation amplitude (AA) with other accommodative and binocular parameters.MethodsMyopic patients between 40 and 50 years old to undergo refractive surgery were enrolled. Accommodative function, including AA, positive and negative relative accommodation (PRA and NRA), accommodative response (binocular cross cylinder, BCC), and binocular accommodative facility (BAF) were examined. Binocular vision measurements including simultaneous perception, fusional vergence, and stereovision assessed with a synoptophore. Near point of convergence (NPC) and the gradient accommodative convergence/accommodation (AC/A) ratio were also measured. A questionnaire was used to assess subjective visual discomfort experienced after prolonged near work.ResultsA total of 145 subjects were evaluated, with a mean age of 42.59 ± 2.89 (SD) years. In the full data set, 96(66.21%) of patients had PRA (>-1.50 D), 21(14.48%) of patients had NRA (< 1.50 D), and 113(77.93%) of patients had BCC (< 0.25 D). Out of 97 patients, 17(17.53%) had AC/A (< 2), 54(55.67%) had NPC (> 7.5 cm), 51(52.58%) had BAF (< 5 cpm). As for the simultaneous perception, 59(60.82%) had values greater than 0 prism dioptres. Adjusting for associated factors, participants with lower AA were more likely to be older (odds ratio [OR], 2.080; 95% confidence interval [CI], 1.523–2.841) and with milder myopia (OR, 1.280; 95% CI, 1.029–1.594). Lower BAF (OR, 4.990; 95% CI, 1.731–14.386) was more likely to be found in individuals with lower AA. The three most commonly reported visual discomforts were eye strain or soreness, ocular pain or headache, and blurred text.ConclusionFor myopes at the early stage of presbyopia, the continuous tension in the vergence system was also worthy of our attention, in addition to the well-known AA insufficiency. Comprehensive assessment of the binocular status and appropriate management is recommended before and after corneal refractive surgery.

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.

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.

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.