Effect of heterophoria type and myopia on accommodative and vergence responses during sustained near activity in children

Sreenivasan, Vidhyapriya; Irving, Elizabeth L.; Bobier, William R.

doi:10.1016/j.visres.2012.01.011

Cited by 41 publications

(37 citation statements)

References 70 publications

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“…In the Tassinari study, mean lags with MEM retinoscopy were 0.23 D for exophoria, 0.32 D for orthophoria and 0.49 D for esophoria. The results of the present study are also consistent with the findings of Sreenivasan, Irving and Bobier that the accommodative response increases from monocular to binocular conditions in persons with higher than normal exophoria and that accommodative response decreases from monocular to binocular viewing in esophoria.…”

Section: Discussionsupporting

confidence: 92%

“…In contrast, participants with exophoria at near‐point may have a higher accommodative response binocularly than monocularly because they accommodate more when they converge to fuse. Such findings were reported by Sreenivasan, Irving and Bobier . They found that participants with more than six prism dioptres of exophoria at near‐point had an increase in accommodative response going from monocular to binocular conditions and participants with more than two prism dioptres of esophoria at near‐point had a decrease in accommodative response going from monocular to binocular conditions.…”

supporting

confidence: 79%

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Accommodative response under monocular and binocular conditions as a function of phoria in symptomatic and asymptomatic subjects

Momeni‐Moghaddam

Goss

Sobhani

2014

Clinical and Experimental Optometry

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Background:The neurological linkage of vergence and accommodation is a factor which can affect accuracy of accommodation, is in turn associated with symptoms of near-related visual discomfort. The purpose of this study was to compare the accommodative response under monocular and binocular conditions in symptomatic and asymptomatic participants with different near phorias. Methods: Seventy students at Zahedan University of Medical Sciences, Iran (mean age: 21.2 Ϯ 1.7 years; age range: 18 to 25 years) participated. The participants were divided into symptomatic and asymptomatic groups according to the convergence insufficiency symptom survey questionnaire score. The type and magnitude of the near dissociated phoria were determined using the prism neutralised cover test. The accommodative lag was measured by the 'monocular estimate method' (MEM) retinoscopy, at first under binocular and then monocular conditions. Testing distance was 40 cm. Results: The accommodative lag in exophoric participants was lower under binocular conditions compared to monocular and in esophoric participants greater under binocular than under monocular conditions. The binocular accommodative response (AR) was greatest in participants with high exophoria at near vision and least in participants with esophoria at near vision (p < 0.001; one-way analysis of variance). The difference between binocular lag and monocular lag was significantly greater in symptomatic participants than in asymptomatic participants in both exophoria (p < 0.001) and esophoria (p = 0.009) (independent samples t-test). Conclusion:The near binocular accommodative response was related to near heterophoria. Higher levels of vergence accommodation, resulting in differences in lag under monocular and binocular conditions, may be a factor in near point asthenopia.

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Section: Discussionsupporting

confidence: 92%

supporting

confidence: 79%

Accommodative response under monocular and binocular conditions as a function of phoria in symptomatic and asymptomatic subjects

Momeni‐Moghaddam

Goss

Sobhani

2014

Clinical and Experimental Optometry

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“…Several studies agreed that the onset and progression of myopia is associated esophoria at near12132728 and with a higher degree of myopia 29. In Leone et al’s11 study, more 6-year-old children presented with lower myopia than those aged 12 years, and they found the significant association between myopia and near heterophoria.…”

Section: Discussionmentioning

confidence: 94%

The distribution of near point of convergence, near horizontal heterophoria, and near vergence among myopic children in South Korea

Jang

Park

Jang³

2016

Taiwan Journal of Ophthalmology

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Background/Purpose:To assess the distribution of near point of convergence (NPC), near heterophoria, and near vergence among myopic school children in South Korea.Methods:One hundred and thirty-six elementary school children, aged 8–13 years, were each given a thorough eye examination including binocular vision testing, NPC using standard push-up technique, horizontal heterophoria measurement by Von Graefe, distance, and near negative and positive vergence with a phoropter and phoropter replacement card.Results:NPC break and recovery points were highest in the age 9 years group, but the mean values of NPC were within the normal range. Of 136 individuals, 52 presented with esophoria, 53 presented with 0 –6-Δ exophoria, and 31 presented with ≥7-Δ exophoria. In the younger age groups (8 years and 10 years) 0–6-Δ exophoria was prevalent, whereas in the older age groups (11 years, 12 years, and 13 years) esophoria was prevalent. Near positive fusional vergence (break and recovery point) presented with statistically significant correlations with the participants’ ages. Esophoria showed higher correlations with high myopia (8.00 ± 0.000) rather than with low myopia (3.36 ± 2.499) or medium myopia (3.42 ± 2.149). The mean value of 0–6Δ exophoria was highest in medium myopia (4.04 ± 1.517), and of ≥7-Δ exophoria was the highest in high myopia (12.66 ± 1.154).Conclusion:There were no statistically significant correlations between the school childrens’ ages and NPC, near horizontal heterophoria, and near fusional vergence, except near positive fusional vergence. Also, unlike many studies, myopic magnitude did not present a significant correlation with near phoria and fusional vergence.

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“…Calibration procedures followed for the PowerRefractor were similar to those described in 114 previous studies (Sreenivasan, Irving, & Bobier, 2012, 2014. Gradient response AC/A 115 (Accommodative convergence per diopter of accommodative response) was quantified as the 116 change in the phoria with negative lenses.…”

Section: Accommodative Parameters 111mentioning

confidence: 99%

Are high lags of accommodation in myopic children due to motor deficits?

Labhishetty

Bobier

2017

Vision Research

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Phone: +12269783740The final publication is available at Elsevier via http://doi.org/10.1016Elsevier via http://doi.org/10. /j.visres.2016Elsevier via http://doi.org/10. .11.001 © 2017. This manuscript version is made available under the .0/ Highlights 1. Blur accommodation but not convergence accommodation (CA/C) is reduced in myopes. 2. Myopes show a similar rate of change in the response dynamics like the emmetropes. 3. Atypical response patterns exist with blur accommodation but decrease with age. 4. Pure sensory or motor deficit doesn't predict the abnormal behavior in myopes. 5. Model simulation with altered sensory and motor gain predicts the myopic behavior.Children with a progressing myopia exhibit an abnormal pattern of high accommodative lags coupled with high accommodative convergence (AC/A) and high accommodative adaptation. This is not predicted by the current models of accommodation and vergence. Reduced accommodative plant gain and reduced sensitivity to blur have been suggested as potential causes for this abnormal behavior. These etiologies were tested by altering parameters (sensory, controller and plant gains) in the Simulink model of accommodation. Predictions were then compared to the static and dynamic blur accommodation (BA) measures taken using a Badal optical system on 12 children (6 emmetropes and 6 myopes, 8-13 years) and 6 adults (20-35 years). Other critical parameters such as CA/C, AC/A, and accommodative adaptation were also measured. Usable BA responses were classified as either typical or atypical. Typical accommodation data confirmed the abnormal pattern of myopia along with an unchanged CA/C. Main sequence relationship remained invariant between myopic and non-myopic children. An overall reduction was noted in the response dynamics such as peak velocity and acceleration with age. Neither a reduced plant gain nor reduced blur sensitivity could predict the abnormal accommodative behavior. A model adjustment reflecting a reduced accommodative sensory gain (ASG) coupled with an increased AC cross-link gain and reduced vergence adaptive gain does predict the empirical findings. Empirical measures also showed a greater frequency of errors in accommodative response generation (atypical responses) in both myopic and control children compared to adults.

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Effect of heterophoria type and myopia on accommodative and vergence responses during sustained near activity in children

Cited by 41 publications

References 70 publications

Accommodative response under monocular and binocular conditions as a function of phoria in symptomatic and asymptomatic subjects

Accommodative response under monocular and binocular conditions as a function of phoria in symptomatic and asymptomatic subjects

The distribution of near point of convergence, near horizontal heterophoria, and near vergence among myopic children in South Korea

Are high lags of accommodation in myopic children due to motor deficits?

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