Relations between Accommodation and Vergence in Darkness

Wolf, Karen S.; Bedell, Harold E.; Pedersen, Stig B.

doi:10.1097/00006324-199002000-00005

Cited by 17 publications

(5 citation statements)

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“…Subject Ju seems to overconverge compared to the dark focus, and subjects Je, Ml, and Ju underconverge. We found a moderate correlation of R 2 ¼ 0.43 between dark vergence and dark accommodation with high intersubject variability in agreement with previous studies (Fincham, 1962;Jiang et al, 1991;Kotulak & Schor, 1986;Owens & Leibowitz, 1976b;Wolf et al, 1990). The right panel in Figure 7 shows a high correlation (R 2 ¼ 0.90) between dark focus of DE and NDE.…”

Section: Dark Focus and Dark Vergencesupporting

confidence: 91%

“…Finally, the resting state of accommodation of the eyes could play a role in the onset of night myopia in the absence of visual stimuli (Owens & Leibowitz, 1980). Although dark vergence and dark accommodation seem to be independent from each other (Kotulak & Schor, 1986), vergence and accommodation are cross-coupled (Fincham, 1962;Jiang, Gish, & Leibowitz, 1991;Wolf, Bedell, & Pedersen, 1990). Accommodativeinduced vergence and vergence-induced accommodation are only weakly correlated but differ widely across subjects.…”

Section: Introductionmentioning

confidence: 99%

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Night myopia is reduced in binocular vision

et al. 2016

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Night myopia, which is a shift in refraction with light level, has been widely studied but still lacks a complete understanding. We used a new infrared open-view binocular Hartmann-Shack wave front sensor to quantify night myopia under monocular and natural binocular viewing conditions. Both eyes' accommodative response, aberrations, pupil diameter, and convergence were simultaneously measured at light levels ranging from photopic to scotopic conditions to total darkness. For monocular vision, reducing the stimulus luminance resulted in a progression of the accommodative state that tends toward the subject's dark focus or tonic accommodation and a change in convergence following the induced accommodative error. Most subjects presented a myopic shift of accommodation that was mitigated in binocular vision. The impact of spherical aberration on the focus shift was relatively small. Our results in monocular conditions support the hypothesis that night myopia has an accommodative origin as the eye progressively changes its accommodation state with decreasing luminance toward its resting state in total darkness. On the other hand, binocularity restrains night myopia, possibly by using fusional convergence as an additional accommodative cue, thus reducing the potential impact of night myopia on vision at low light levels.

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Section: Dark Focus and Dark Vergencesupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Night myopia is reduced in binocular vision

et al. 2016

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“…During the assessment, the subject was first dark-adapted for 5 min to uncouple accommodation and vergence and relax both systems (Wolf et al, 1990 ; Kotulak & Schor, 1986 ). Then, the subject was given a randomized sequence of four types of 2° symmetrical vergence step movements presented on a haploscope ( Figure 1A ) to keep accommodative cues constant (Kotulak & Schor, 1986 ).…”

Section: Methodsmentioning

confidence: 99%

Disparity vergence responses before versus after repetitive vergence therapy in binocularly normal controls

Talasan

Scheiman

et al. 2016

Journal of Vision

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This study sought to determine whether significant changes would be observed between vergence eye movements before and after 12 hr of repetitive vergence therapy (1 hr per day on different days) in subjects with normal binocular vision compared to controls. Disparity vergence responses from 23 subjects were studied. An assessment protocol that minimized the influence of the near dissociated phoria on the disparity vergence system was designed. The following parameters were quantified for the responses: latency, time to peak velocity, settling time, peak velocity, and accuracy (difference between the response and stimulus amplitudes). The following outcomes were observed when comparing the results after vergence therapy to the baseline measurements: (a) near point of convergence and near dissociated phoria did not significantly change (p > 0.15); (b) latency, time to peak velocity, and settling time significantly decreased (p ≤ 0.01); and (c) accuracy significantly improved (p < 0.01). Results support that vergence peak velocity is dependent on the subject's near dissociated phoria. The accuracy and temporal properties of vergence eye movement responses from subjects with normal binocular vision can be improved after vergence therapy. These methods can be utilized within future studies to quantitatively assess vergence therapy techniques for patients with binocular dysfunction.

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“…Previous investigations failed to show a strong relationship between dark focus of accommodation and dark vergence (Owens & Leibowitz 1983;Schor 1991).Kotulak& Schor(1986)found that accommodation and vergence approached the resting state at different rates and, in some subjects, in different directions. Although Wolf et al (1990) also failed to find.a strong relationship between dark focus of accommodation and dark vergence, they found that the restingvergence posture could be predicted from measurements of distant phoria and the resting state of accommodation when subjects' ACIA ratios were considered, suggesting that the dark focus of accommodation affects the ocular position in darkness.…”

Section: Discussionmentioning

confidence: 92%

Dark focus of accommodation in children with accommodative esotropia and hyperopic anisometropia

Miwa

Tokoro

1993

Acta Ophthalmologica

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We evaluated the dark focus of accommodation, referred to as tonic accommodation, in 60 young hyperopic subjects, 20 with and 20 without accommodative esotropia, and 20 with hyperopic anisometropia. We measured the distance, dark, and cycloplegic refractive errors by the Nidek Autorefractometer AR1600. The difference between dark and cycloplegic refractive errors was defined as the dark focus. The dark focus was significantly larger in esotropic eyes than in non-esotropic eyes, despite similar cycloplegic refractive errors in both types of eyes, suggesting that tonic accommodation may be associated with ocular position. The dark focus was similar in eyes of the same subjects with hyperopic anisometropia and also in normal and amblyopic eyes, suggesting that tonic accommodation is similar in both eyes in subjects with anisometropia and amblyopia.

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Relations between Accommodation and Vergence in Darkness

Cited by 17 publications

References 0 publications

Night myopia is reduced in binocular vision

Night myopia is reduced in binocular vision

Disparity vergence responses before versus after repetitive vergence therapy in binocularly normal controls

Dark focus of accommodation in children with accommodative esotropia and hyperopic anisometropia

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