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Raising children's myopia prevention awareness and behaviour tends to exhibits a protective effect against myopia among schoolchildren. To investigate the effect of an original myopia song in raising school children's awareness of healthier eye use behaviour and on myopia prevention. In this prospective randomised control study, two groups of students from one primary schools in Jiangxi, China, were enrolled and monitored from grade 3 to grade 6 (2016–2019). The primary outcome was the change in axial length (AL) after the intervention. Secondary outcomes included changes in spherical equivalent refraction (SER), near work and outdoor time, corrected near and distant visual acuity, visual discomfort score (VDS) and accommodative lag. Four hundred students (193 females, 48.25%) aged 9.3 (range 8–10) years with emmetropia to moderate myopia were enrolled. Children in the myopia song group had a significantly shorter AL and less myopic refractive change than those in the control group (p = 0.04 and 0.02, respectively). Compared with the control group, children in the myopia song group spent less time on near work and more time outdoors (p = 0.04 and 0.04, respectively). At the final follow-up, the proportion of children with myopia was significantly lower in the myopia song group (30.5%) than in the control group (41%) (p = 0.03). No significant differences were found for the secondary outcomes, including corrected near and distant visual acuity, VDS and accommodative lag. An original myopia song performed twice daily in primary schools appeared to have a modest effect on myopia control among school-aged children by changing their lifestyles in the long term. [ABSTRACT FROM AUTHOR]

Ocular accommodation refers to the process by which the ciliary muscle creates a clear image of the object in the retina by changing the refractive power of the lens. When the accommodation ability of the eye is insufficient, the imaging focus falls on the region behind the retina and hyperopic defocus is easily formed, resulting in axial growth and leading to the development of myopia, and it is found that most myopic patients usually have some accommodation dysfunction. Myopia has become a public health problem in China, and the prevalence of adolescents has increased dramatically. How to prevent and stop the occurrence and development of myopia is a major challenge. Previous studies have found that ocular accommodation dysfunction is associated with the occurrence and development of myopia, and the measurement of parameters related to accommodation function has certain guiding significance for the prevention and control of myopia. The purpose of this paper is to review the correlation between myopia and ocular accommodation function, with a view to providing new ideas for the prevention, control and treatment of myopia.

Introduction: This study evaluated novel automatic dual rotational Risley prisms (ADRRPs) as a vergence exercise tool for patients with myopia to improve accommodative lag and accommodative facility. Methods: Participants with myopia aged 20–24 years were recruited. After vergence exercises with prisms (treatment group) or plano lenses (control group) using ADRRPs for 10 min, measurements were taken using an open-field autorefractor (Grand Seiko WAM-5500) at viewing distances of 0.4 m and 6.0 m. We measured accommodative facility using a ± 2.00 D accommodative flipper. Results: A total of 56 participants (treatment group, 39; control group, 17) performed vergence exercises using ADRRPs. Participants in the treatment group showed improvements in accommodative lag at a 0.4 m viewing distance, with measurements of 0.57 D (right eye; OD) and 0.53 D (left eye; OS) and 0.21 D (OD) and 0.27 D (OS) before and after the exercises, respectively (p < 0.001). Over-refractions using an open-field autorefractor with spherical equivalent contact lenses at a 6.0 m viewing distance were − 0.01 ± 0.30 D (OD) and 0.03 ± 0.34 D (OS) and 0.15 ± 0.32 D (OD) and 0.19 ± 0.28 D (OS) before and after the exercises, respectively (difference + 0.16 D; p < 0.001). Accommodative facility values before and after exercises were 14.88 ± 3.36 and 15.59 ± 3.60 cpm, respectively (p < 0.01). No significant differences in accommodative lag, relaxation, and accommodative facility before and after exercise were observed in the control group. Conclusions: Using ADRRPs in vergence exercises can improve accommodative lag, accommodative facility, and accommodative relaxation in adults with myopia. Further research to evaluate persistent and long-term effects is needed. [ABSTRACT FROM AUTHOR]

Abstract Introduction This study evaluated novel automatic dual rotational Risley prisms (ADRRPs) as a vergence exercise tool for patients with myopia to improve accommodative lag and accommodative facility. Methods Participants with myopia aged 20–24 years were recruited. After vergence exercises with prisms (treatment group) or plano lenses (control group) using ADRRPs for 10 min, measurements were taken using an open-field autorefractor (Grand Seiko WAM-5500) at viewing distances of 0.4 m and 6.0 m. We measured accommodative facility using a ± 2.00 D accommodative flipper. Results A total of 56 participants (treatment group, 39; control group, 17) performed vergence exercises using ADRRPs. Participants in the treatment group showed improvements in accommodative lag at a 0.4 m viewing distance, with measurements of 0.57 D (right eye; OD) and 0.53 D (left eye; OS) and 0.21 D (OD) and 0.27 D (OS) before and after the exercises, respectively (p

Purpose: To assess and compare the changes produced by the two most commonly used substances, alcohol and cannabis, on accommodation dynamics. Methods: A total of 38 young participants (19 females) were enrolled in the study. They were assigned to two groups: a cannabis group (N = 19) and an alcohol group. Participants in the cannabis group underwent two randomized sessions: a baseline session and a session after smoking a cigarette. Participants in the alcohol group underwent three randomized sessions: a baseline session, a session after the intake of 300 ml of red wine (Alcohol 1), and other after the ingestion of 450 ml of wine (Alcohol 2). For the accommodation assessment, the open-field autorefractor WAM-5500 was used. Results: The decrease of the mean velocity of the accommodative response produced by Alcohol 2 condition was significantly greater than that observed for Alcohol 1 and Cannabis (p = 0.046). The direction of the accommodation (near-distance and distance-near) had no effect on the deterioration of the accommodation dynamics following substance use. The target distance had a significant effect on the decrease of the mean velocity following substance use (p = 0.002). The decrease of the amplitude of the accommodative response was associated with a decrease of the peak velocity (p = 0.004) and the increase of the accommodative lag (p < 0.001). Conclusions: A moderate-high dose of alcohol impairs accommodation dynamics to a greater extent that lower dose of alcohol or smoked cannabis. The deterioration of the accommodation mean speed was higher for a shorter target distance. [ABSTRACT FROM AUTHOR]

The progression of myopia in young adults due to inadequate accommodation is currently one of the global research challenges. Studies have demonstrated that multifocal contact lenses have a different effect on accommodative response. The aim of this study was to assess the accommodative lag using various design multifocal contact lenses at different working distances. The study was conducted on 10 emmetropic subjects aged 22â28 years. An open-field autorefractor PowerRef 3 was used to assess the response of eye accommodation to stimuli placed at a distance of 25 cm and 40 cm for subjects wearing monofocal and multifocal contact lenses. To determine the effectiveness of contact lens design for accommodative lag compensation, the results of the accommodative lag with and without contact lenses were compared. The measured accommodative lag for stimuli at 40 cm was 1.05 ± 0.11 D and for stimuli at 25 cm 1.53 ± 0.11 D. Regarding the effect of multifocal contact lenses, it was determined that the near vision power zone in the centre of the lens reduces the accommodative lag, while the respective distance vision power zone does not produce a statistically significant change. The near power zone in the centre of the multifocal contact lens effectively affects the accommodative lag by reducing accommodation inaccuracy as effectively as spherical contact lenses with positive power. The addition design for multifocal lenses (Med or Hi) does not significantly affect the accommodative lag. The results of centre-distance multifocal contact lenses depend on the strength of the addition used.

The progression of myopia in young adults due to inadequate accommodation is currently one of the global research challenges. Studies have demonstrated that multifocal contact lenses have a different effect on accommodative response. The aim of this study was to assess the accommodative lag using various design multifocal contact lenses at different working distances. The study was conducted on 10 emmetropic subjects aged 22-28 years. An openfield autorefractor PowerRef 3 was used to assess the response of eye accommodation to stimuli placed at a distance of 25 cm and 40 cm for subjects wearing monofocal and multifocal contact lenses. To determine the effectiveness of contact lens design for accommodative lag compensation, the results of the accommodative lag with and without contact lenses were compared. The measured accommodative lag for stimuli at 40 cm was 1.05 ± 0.11 D and for stimuli at 25 cm 1.53 ± 0.11 D. Regarding the effect of multifocal contact lenses, it was determined that the near vision power zone in the centre of the lens reduces the accommodative lag, while the respective distance vision power zone does not produce a statistically significant change. The near power zone in the centre of the multifocal contact lens effectively affects the accommodative lag by reducing accommodation inaccuracy as effectively as spherical contact lenses with positive power. The addition design for multifocal lenses (Med or Hi) does not significantly affect the accommodative lag. The results of centredistance multifocal contact lenses depend on the strength of the addition used. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the cross-sectional area (CSA) and thickness of the ciliary muscle and their correlation with accommodative lag in hyperopic anisometropic children. Methods: Forty children aged between 6 and 10 years with hyperopic anisometropia were recruited. The more hyperopic eye (mean refractive power of 3.51 ± 1.70 D) was compared with the less hyperopic eye (mean refractive power of 0.78 ± 1.41 D). The thickness and CSA of the ciliary muscle were measured with anterior segment optical coherence tomography (OCT) images at four meridians. The differences between the eyes and the correlations between CSA, thickness, axial length and accommodative lag were accessed. Results: There was no statistically significant difference in CSA between the two groups at any meridian, except at the inferior meridian (P < 0.05). There was no statistically significant difference in ciliary muscle thickness between eyes at any meridian, except on the temporal and the nasal meridians (P < 0.05). There was a significant difference in the ratio of CSA to axial length at all meridians between the two groups (all P < 0.05). Accommodative lag was 1.65 ± 0.55 D and 0.93 ± 0.45 D in the more and less hyperopic eyes, respectively, which was a statistically significant difference (P < 0.05). There was no significant correlation between the CSA with the axial length and the accommodative lag. Conclusions: This study demonstrated a greater degree of accommodative lag in the more hyperopic eye of anisometropic children. There was no correlation among accommodative lag, axial length and CSA of the ciliary muscle with the degree of hyperopia. [ABSTRACT FROM AUTHOR]

Background and Objectives: With the pervasive use of digital devices, especially smartphones, concerns about their harmful effects on vision has increased. The aim of the present study was to evaluate the effect of long-term activity with a smartphone on the accuracy of lag of accommodation of two eyes. Methods: In this cross-sectional study, 27(16 females and 11 males) students and staff (23 students and 4 staff) of the Iran University of Medical Science with a Mean±SD age of 25.29±4.72 years, with a visual acuity of 10/10, and emmetropic refraction with the available sampling method were selected. At first, the participants used a smartphone for an hour, and then, the lag of accommodation of two eyes was assessed with the monocular estimate method. Results: lag of accommodation of the right eye (P=0.001) and left eye (P=0.001) both statically increased significantly after one hour of smartphone use. However, no significant difference was found between the lag of accommodation of two eyes after near work with a smartphone (P=0.265). Conclusion: The present study confirmed the relationship between long-term near work with a smartphone and increased lag of accommodation.

Background: To assess agreement between accommodative lag by monocular estimation method (MEM) retinoscopy and Nott retinoscopy compared to open-field autorefraction using spherical equivalent versus power in the 180 meridian for both children and adults.Methods: Twenty-six children aged 7-16 years (mean: 9.9 ± 2.3) and 27 adults aged 22-29 years (mean: 24.2 ± 1.7) participated. Accommodative lag was measured by examiners with autorefraction and separate examiners using MEM and Nott retinoscopy while subjects viewed 6/18 letters at 33 cm. Five measures of autorefraction were averaged with vector analysis and both power in the 180 meridian and spherical equivalent was determined. Two-factor repeated measures analysis of variance and the mean difference and 95 per cent limits of agreement were calculated.Results: Mean (standard deviation) lag for each technique was: MEM = 0.69 (0.52) D, Nott = 0.62 (0.51) D, autorefraction in 180 = 0.66 (0.50) D and autorefraction spherical equivalent = 0.60 (0.46) D. Lag did not vary across techniques (p = 0.48), but children did have smaller lags than adults (p < 0.001) and greater amounts of uncorrected astigmatism (0.61 ± 0.09 D versus 0.42 ± 0.08 D, p = 0.02). There was no significant interaction between age group and technique (p = 0.74). Mean differences between techniques were small, ranging from -0.14 to +0.06 D. Ninety-five per cent limits of agreement ranged from ±0.80 to ±1.33 around the mean with the narrowest ranges found for comparisons made to autorefraction in 180. Limits of agreement were also narrowest in children as compared to adults with similar mean differences between age groups.Conclusions: This study demonstrates the mean agreement between autorefraction and retinoscopic techniques is centred on zero (no bias) in both children and adults. The range of agreement becomes narrower when autorefraction power in the 180 is calculated, even for a sample of subjects with moderately small amounts of uncorrected astigmatism. [ABSTRACT FROM AUTHOR]

Aim: Myopia is one of the most common eye conditions and often has a progressive nature. With higher degrees come greater risks of visual disability; however, typically no treatment is offered clinically to tackle myopic progression. This review aims to determine whether it is possible to predict future high myopia, review the available treatments to slow myopic progression and consider their role in clinical practice. Methods: A literature search was undertaken using the Web of Knowledge and PubMed databases. Results: Progressive addition lenses (PALs) are effective in slowing myopic progression in those with larger accommodative lag, and bifocals with base-in prisms have been found effective in progressing myopia with both high and low accommodative lag. However, the reduced progression gained from these treatments is small (treatment effects: 0.28–0.33D/3 years, 0.61D/18 months and 0.85D/2 years). Atropine and pirenzepine instillation are consistent in slowing myopic progression in most cases (treatment effect 0.14–1.25D/year); however, accelerated myopic progression in treated eyes has been observed after atropine treatment. Conclusions: None of the discussed treatments warrant widespread use. Atropine and pirenzepine appear to be the most effective options at present for slowing myopic progression. However, there is doubt as to whether their effects are maintained post-treatment. As it stands PALs have little effect clinically, though they may be beneficial for susceptible groups. Further research is required before clinicians can create evidence-based guidleines for these treatments, if their use is recommended at all.

Background: To investigate accommodative response and accommodative lag changes after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction. Methods: A total of 32 eyes of 32 patients with no strabismus who underwent SMILE were enrolled in this prospective clinical study. The accommodative response was obtained viewing monocularly with spherical equivalent refractive error corrected, using an open-field autorefractor at different stimulus levels (2.00D, 2.50D, 3. 00D, 4.00D and 5.00D) for the right eye before a standard SMILE surgery and at 1-month follow-up after surgery. Results: The mean age of the patients were 23.34 ± 2.90 years and the mean preoperative manifest refraction spherical equivalent was -5.74 ± 1.98 diopters. Significant differences were detected in both preoperative and postoperative accommodative responses to different stimulus levels (P < 0.001). Multiple linear regression model analysis revealed preoperative manifest refractive spherical equivalent (P = 0.006) and preoperative accommodative lag (P = 0.04) showed a significant impact on postoperative accommodative lag. Conclusions: This is the first report of accommodative changes after SMILE. Our preliminary results showed that a decrease in postoperative accommodative lag that might be related to the relief of the visual discomfort symptom. [ABSTRACT FROM AUTHOR]

Introduction: Previous studies suggest that monocular estimate method (MEM) and Nott retinoscopy yield identical results in the assessment of the accommodative lag. However, two recent studies suggested that the accommodative lag measured with MEM retinoscopy is twice that with Nott. This study was designed to re-evaluate the agreement of MEM and Nott retinoscopy techniques. Material and methods: One hundred and thirty (130) subjects aged between 18 and 30 years (22±3 years – mean ±SD), with no history of contact lens wear, ocular and systemic disease or ocular surgery, participated in the study. Nott and MEM Retinoscopy were used to assess the lag of accommodation through the Corrected Ametropia Most Plus (CAMP) subjective refraction at 40 cm. Results: The mean difference between both sessions for Nott retinoscopy was 0.01±0.1 D (mean ±SD). The mean difference between both sessions for MEM retinoscopy was – 0.002±0.11 D (mean ±SD). The mean difference between Nott and MEM dynamic retinoscopy was 0.01±0.13 D (mean ±SD) with 95% limits of agreement ranging between +0.26 and -0.25 D. For both Nott and MEM, there was no significant difference (P>0.05) of the measured lag between the four measurement sessions and no significant difference (P>0.05) was found between both methods. Conclusions: We conclude that in normal healthy subjects with normal accommodative and binocular function, MEM and Nott dynamic retinoscopy techniques may be used, interchangeably, to assess the lag of accommodation at 40 cm.

The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median = 24 years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between -2.00 and -5.00 diopters (D) (median = -3.41 D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C04 ) and secondary (C06 ) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C04 (r = -0.49, p < 0.05) and a very strong correlation with C06 (r = 0.78, p < 0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye's positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye. [ABSTRACT FROM AUTHOR]

Background: Diabetes has been associated with decline in accommodative function in some ethnic groups. This outcome, however, could differ since ethnic variations in accommodation have been noted. This study investigated the relationship between plasma sugar level on subjective accommodative amplitude and accommodative lag in black Africans with type-1 diabetes. Methods: An examiner-blind study of subjective accommodative amplitude and accommodative lag between 45 diabetic subjects (15 males, 30 females) aged 12–39 years and 45 age- and sex-matched healthy non-diabetic controls was conducted. Accommodative amplitude was measured by the push-up to blur/push-down to clear methods using a RAF rule, the accommodative lag by the MEM retinoscopy, and the fasting plasma sugar (FPS) by a glucose meter. Results: Comparatively, the diabetic subjects had significantly lower accommodative amplitude (10.1 ± 2.7 D versus 11.5 ± 2.4 D, respectively;p = 0.010) and greater accommodative lag (1.1 ± 0.4 D versus 0.7 ± 0.2 D;p < 0.001, respectively) than the controls. Multiple regression analyses showed that after adjusting for age, FPS concentration significantly predicted accommodative amplitude (R2 = 0.05,p = 0.022) and accommodative lag (R2 = 0.30,p < 0.001) in diabetes. Duration of diabetes was not significantly related to accommodative amplitude and accommodative lag. Conclusion: Diabetes mellitus in black Africans was associated with lower accommodative amplitude and greater accommodative lag. An adequate control of the plasma sugar concentration may be vital to maintain proper accommodative function. [ABSTRACT FROM PUBLISHER]

Background: Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common disorders diagnosed in children. Researchers have found links between tracking deficits, convergence insufficiency, and a diagnosis of ADHD, but little research exists on the relationship between accommodation and ADHD. This study investigates whether there is a correlation between ADHD and accommodation dysfunction. Methods: Patients aged 7-18 in the Pediatrics and Binocular Vision Service at the Ferris State University Eye Center presenting for a comprehensive eye examination were invited to participate in the study using an anonymous ADHD symptom survey produced and accredited by the American Pediatric Association or a stated previous diagnosis of ADHD. The student clinician or faculty member recorded the patient's amplitude of accommodation and accommodative lag at the conclusion of the eye examination in order to correlate the diagnosis. Results: Using t-test and chi-square analyses, a statistically significant link between lower- than-average lag of accommodation and ADHD was demonstrated (p=0.04 and p<0.1%, respectively). A link between amplitude of accommodation and attention disorders was not significant. Conclusions: While lower-than-average accommodative lag was shown to correlate with ADHD (established or symptom-based diagnosis), further investigation is necessary to determine whether accommodative amplitude correlates with ADHD. [ABSTRACT FROM AUTHOR]

Purpose To give a summary of the original paper 'The effect of refractive error on the accommodative response gradient' published in 1986 and to present a brief overview of the most salient, subsequent findings which have appeared since then. Recent findings Intensive and prolonged near work as a precursor to myopia has been substantiated since the original paper and is thought to contribute to the remarkable increase in the prevalence of myopia in the world which has occurred in the last 30 years, consistent with the emergence of compulsory education, computers and urbanisation. Increased accommodation has not been found to be essential in the development of myopia, but inaccurate accommodation during near work in the form of accommodative lag with its consequent hyperopic defocus has been confirmed as an association with myopia, although it is not clear whether that association is causal or merely a consequence of myopia. Summary The premise of the original paper that near work engenders lower accommodation in myopes compared to emmetropes and hyperopes has been corroborated over the years, particularly in progressing myopes as distinct from stable adult myopes. Inaccurate accommodation resulting in accommodative lag has been amply confirmed in subsequent studies. [ABSTRACT FROM AUTHOR]

Background: To compare the accommodative amplitude (AA), facility (AF), and lag between dominant and non-dominant eyes. Methods: Seventy students [mean (SD) age: 21.2 (1.7) years, range 18-25] from Zahedan University of Medical Sciences were selected. Retinoscopy and subjective refraction was used to determine the refractive error. The hole-in-the card method was used to determine eye dominance. The accommodative amplitude (AA) was measured in the dominant and non-dominant eye using the push-up method, and accommodative facility (AF) using ±2.00 dioptre flipper lenses at 40 cm. Accommodative lag was determined using monocular estimate method (MEM) retinoscopy at 40 cm. Results: The right eye was dominant in 53 subjects (75.7 %). There was no significant difference in refractive error (sphere, cylinder, and spherical equivalent) between dominant and non-dominant eyes. The mean (SD) for the AA, AF, and lag in dominant eyes was 12.48 (2.56) dioptres, 12.45 (4.83) cycles per minute, and 0.80 (0.27) dioptres respectively. The mean (SD) for the AA, AF, and lag in non-dominant eyes was 12.16 (2.37) dioptres, 12.20 (4.88) cycles per minute, and 0.83 (0.28) dioptres respectively. The mean (SD) difference in AA, AF, and lag between dominant and non dominant eyes was 0.32 (0.75) dioptres ( P = 0.001), 0.25 (1.05) cycles per minute ( P = 0.04), and −0.02 (0.11) dioptres ( P = 0.10) respectively. The AA and AF was statistically better ( P < 0.05) in the dominant eye group than in the non-dominant eye group. These data provided little evidence of any difference in the accommodative lag between dominant and non-dominant eyes ( P > 0.05). Conclusion: The right eye was dominant in 76 % of subjects. Superior AA and AF was found in the dominant eye as determined by hole-in-the card method in young healthy adults, although these differences are perhaps not of clinical significance (<0.50 dioptres and <2 cycles per minute). [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy of multifocal soft contact lenses to reduce asthenopic symptoms in myopes with accommodative lag.Methods: Twenty-four myopic participants, aged 18-35 years, with mean spherical equivalent (MSE) of ≤ -0.75D, were recruited in a randomised, double-blind crossover study. All participants were existing contact lens wearer with near orthophoria or esophoria, presenting with subjective asthenopic symptoms at baseline [Convergence Insufficiency Symptom Survey (CISS) score ≥ 21] and a lag of accommodation ≥ +0.75 D. All participants were initially fitted with single vision contact lenses for a one month period. Participants were then randomly assigned 1:1 to wear low add or high add multifocal soft contact lenses for a further month. After this period, the groups were reversed. Data were collected at baseline and following one month's wear of each lens. Change in CISS score was evaluated as the primary outcome measure, while secondary outcome measures were changes in accommodative lag and heterophoria status.Results: Baseline CISS score was (mean ± SD) 25.04 ± 4.58. Post-intervention scores were as follows: single vision: 24.46 ± 4.59, low add: 12.17 ± 6.89, high add: 13.71 ± 7.23. Both low add and high add multifocal soft contact lens wear was associated with an improvement in CISS score compared to baseline CISS and single vision (all p < 0.01). No significant difference was found between the CISS score for the baseline CISS and single vision (p = 1.00). No significant difference was found in lag of accommodation between lens conditions (all p > 0.05), however, there was an exophoric shift in near heterophoria between single vision and both multifocal contact lenses (low add: (mean difference 1.33 Δ, p = 0.02; high add: mean difference 1.23 Δ, p = 0.02) but not between habitual spectacle or any other modality (all p > 0.05).Conclusions: The use of multifocal soft contact lenses for a one-month period was associated with reduced severity of asthenopic symptoms in pre-presbyopic myopes with accommodative lag. Whilst improvement of symptoms does not appear to be mediated by a significant reduction in accommodative lag, changes in heterophoria may play a role in reducing asthenopic symptoms. [ABSTRACT FROM AUTHOR]

Purpose: Previous studies have reported variation in stimulus accommodative convergence to accommodation (AC/A) ratio across differing accommodative stimuli. Response AC/A ratio was assessed across 4 accommodative demands to determine if these differences could be due to accommodative inaccuracies to stimuli. Methods: Twenty-three student participants aged 18 to 26 years (mean age 20.3 ± 1.7 years) successfully completed all testing conditions. The modified Thorington technique was used at 4 m to measure heterophoria. The Shin Nippon SRW 5000 infrared autorefractor was used to determine accommodative change to −1.50, −3.00, −4.50, and −6.00D lens stimuli. Results: Significant differences were found in response AC/A ratio between different minus lens stimulated accommodative demands ( p < 0.001). Mean AC/A ratio values were 3.11 ± 1.29 with the −1.50D lens stimulus; 4.03 ± 2.11 with −3.00D; 4.14 ± 1.40 with −4.50D; and 4.48 ± 1.56 with −6.00D. No differences in linearity were noted between myopes and non-myopic participants, but myopes tended to have higher response AC/A ratios than non-myopes, mean 4.88 ± 1.89 for myopes vs 3.61 ± 1.47 for non-myopes ( p = 0.045). Conclusions: Response AC/A ratio did not display linearity across 4 minus lens accommodative stimuli, but tended to increase with accommodative demand. Significant variability in response AC/A ratio was found, both within individuals to different accommodative demands, and between individuals across the data set. [ABSTRACT FROM AUTHOR]

Purpose: To determine if there is a difference between the response AC/A ratios when measured using the gradient method at near and distance fixation with plus and minus lenses respectively in young adults with normal binocular single vision. Methods: A repeated measures design was used. The accommodative response of the right eye was measured objectively using the Shin-Nippon SRW-5000 autorefractor (Grand Seiko Company, Fukuyama, Japan) (open view) at 33 cm with and without plus lenses (2DS or 3DS) and at 3.8 m with and without minus lenses (2DS or 3DS) dependent on the participants'' ability to obtain subjectively ''clear'' vision. The angle of deviation was measured using the alternate prism cover test at 33cm and 3.8m fixing with the right eye with the participant sat at the autorefractor. LogMAR 0.0 (6/6) was used for fixation. Response AC/A ratios were calculated. Results: Twenty-five participants were examined; mean and standard deviation of their ages were 21.2 ±± 4.04 years. The mean and standard deviation of the near response AC/A ratios was 4.73 ±± 2.34/1 and at distance was 3.05 ±± 1.71/1. Pearson''s Product Moment Correlation Coefficient showed no correlation between the 2 sets of data. Paired t-test showed that there was a statistically significant difference between the near and distance response AC/A ratios ( t == 3.30, p == 0.003). The difference was found to be greater in participants who were non-orthoptic students. Conclusion: The response AC/A ratio was found to be slightly higher at 33 cm with plus lenses than at 3.8 m with minus lenses. No reason was identified for this difference but adaptation and perceptual effects could be further explored. [ABSTRACT FROM AUTHOR]

Abstract: The relationship between accommodative lag and annual myopia progression was investigated using linear models in 592 myopic children wearing a full refractive correction in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study. The mean (±SD) age and spherical equivalent refractive error at baseline were 10.4±1.8years and −2.13±1.24 D, respectively. The mean annual progression of myopia was −0.45±0.32 D, and the mean accommodative lag (for a 4-D Badal stimulus) was 1.59±0.63 D. Neither lag at the beginning nor at the end of a yearly progression interval was associated with annual myopia progression (all p ⩾0.12). These data suggest that foveal hyperopic retinal blur during near viewing may not drive juvenile-onset myopia progression. [Copyright &y& Elsevier]

Purpose: To assess the effect of bifocal soft contact lenses on the accommodative errors (lags) of young adults. Recent studies suggest that bifocal soft contact lenses are an effective myopia control treatment although the underlying mechanism is not understood. Methods: Accommodation responses were measured for four target distances: 100, 50, 33 and 25 cm in 35 young adult subjects (10 emmetropes and 25 myopes; mean age, 22.8 ± 2.5 years). Measurements were made under both monocular and binocular conditions with three types of lenses: single vision distance soft contact lenses (SVD), single vision near soft contact lenses (SVN; +1.50 D added to the distance prescription) and bifocal soft contact lenses (BF; +1.50 D add). Results: For the SVD lenses, all subjects exhibited lags of accommodation, with myopes accommodating significantly less than emmetropes for the 100 and 50 cm target distances ( p < 0.05). With the SVN lenses, there was no significant difference in accommodative responses between emmetropes and myopes. With the BF lenses, both emmetropic and myopic groups exhibited leads in accommodation for all target distances, with emmetropes showing significantly greater leads for all distances ( p < 0.005). Conclusions: Overall, myopes tended to accommodate less than emmetropes, irrespective of the contact lens type, which significantly affected accommodation for both groups. The apparent over-accommodation of myopes when wearing the BF contact lenses may explain the reported efficacy as a myopia control treatment, although further studies are required to elucidate the mechanism underlying this accommodative effect. [ABSTRACT FROM AUTHOR]

A model of the cross-link interactions between accommodation and convergence predicted that heterophoria can induce large accommodation errors (Schor, Ophthalmic Physiol. Opt. 1999;19:134–150). In 99 consecutive patients with intermittent tropia or decompensated phoria, we tested these interactions by comparing their accommodative responses to a 2.50-D target under binocular fused conditions (BFC) and monocular occluded conditions (MOC). The accommodative response in BFC frequently differed from that in MOC. The magnitude of the accommodative errors in BFC, ranging from an accommodative lag of 1.80 D (in an esophoric patient) to an accommodative lead of 1.56 D (in an exophoric patient), was correlated with distance heterophoria and uncorrected refractive errors. These results indicate that heterophoria affects the accuracy of accommodation to various degrees, as the model predicted, and that an accommodative error larger than the depth of focus of the eye occurs in exchange for binocular single vision in some heterophoric patients. [ABSTRACT FROM AUTHOR]

Abstract: Accommodative lags, induced by a target at 33cm (distance-induced condition) and by a −3.0D lens (lens-induced condition), and wavefront aberrations were measured in 27 young myopic eyes. The accommodative lags and Strehl ratios derived from the wavefront aberrations in myopes were compared with those from 57 emmetropes. Accommodation was measured using a Canon R-1 autorefractor, while aberrations were measured using a psychophysical ray-tracing technique. In accord with previous results, larger accommodative lags were found for the myopes than the emmetropes in both the lens-induced and distance-induced conditions. The mean Strehl ratio was smaller in the myopes (0.079) than the emmetropes (0.091); this difference approached significance (p=0.055). In addition, for myopes the accommodative lag was significantly correlated with the Strehl ratio in the lens-induced condition (r=−0.45, p<0.02) and approached significance in the distance-induced condition (r=−0.35, p=0.07). No significant correlations were found for emmetropes. Possible reasons to account for these results are discussed. [Copyright &y& Elsevier]

The accommodative response in 34 patients with accommodative and binocular disorders was assessed with two different techniques of dynamic retinoscopy used in clinical practice: monocular estimate method (MEM) and Nott retinoscopy. The data obtained by both techniques were compared, evaluating the correlation and agreement between them. Results showed that there were statistically significant differences between the techniques with MEM values being more plus than Nott ones. There was a high correlation between the two techniques (0.90) and the regression analysis indicated that a linear relationship existed between MEM and Nott dynamic retinoscopy, so that accommodative lag value for Nott dynamic retinoscopy would be calculated by dividing the MEM result by 2. However, although both retinoscopies were related, there was a lack of agreement between them (±0.53 D) indicating that the two methods are not interchangeable for clinical purposes. [ABSTRACT FROM AUTHOR]