Experimental evidence for separate mechanisms mediating accommodative vergence and vergence accommodation

Semmlow, John L.; Hung, George K.

doi:10.1007/bf00143885

Cited by 12 publications

(12 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, no evidence of a reciprocal relationship between the response AC/A and CA/C ratios was demonstrated, similar to the findings of Rosenfield (Rosenfield, Ciuffreda, & Chen, 1995). This inverse relationship adds to the body of evidence which suggests two separate neural mechanisms control the accommodative vergence cross-link and the vergence accommodation cross-link Owens, 1980;Rosenfield, Ciuffreda, & Chen, 1995;Semmlow & Hung, 1981;Wolf, Ciuffreda, & Jacobs, 1987). The lack of a reciprocal relationship between the AC/A and CA/C ratios means that measuring only the AC/A ratio, which is common in current clinical practice, does not give a true representation of both cross-link interactions.…”

Section: Discussionsupporting

confidence: 66%

“…Some models have found the cross-links are reciprocally related (i.e. the AC/A is equal to 1/CA/C) (Schor & Kotulak, 1986;Schor, 1992), although other studies have been unable to replicate this finding Owens, 1980;Owens & Wolf-Kelly, 1987;Rosenfield, Ciuffreda, & Chen, 1995;Semmlow & Hung, 1981). Other models suggest the cross-links are inversely related (i.e.…”

Section: Introductionmentioning

confidence: 87%

“…Other models suggest the cross-links are inversely related (i.e. as the AC/A increases in value the CA/C ratio decreases) (Semmlow & Hung, 1981).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantifying interactions between accommodation and vergence in a binocularly normal population

et al. 2014

View full text Add to dashboard Cite

Stimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (mean ± SD age 21.0 ± 1.9 years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r² = 0.96, p < 0.001) and CA/C ratios (r² = 0.40, p < 0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI -0.06 to 0.24 MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI -0.46 to 0.42 D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement.

show abstract

Section: Discussionsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 87%

See 1 more Smart Citation

Quantifying interactions between accommodation and vergence in a binocularly normal population

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Blur occurs when this compensation is no longer adequate. Further experimental evidence to support the "lens overdrive" hypothesis comes from Semmlow and Hung (1981) the associated vergence accommodation tends to increase the lens accommodation. If the accommodative stimulus is held constant, the accommodative system operating through feedback will compensate for this increase in disparity induced lens drive by decreasing the blurdriven accommodation and thereby reducing the accommodative convergence (Semmlow & Hung., 1981).…”

Section: Introductionmentioning

confidence: 99%

Effect of Vergence Adaptation and Positive Fusional Vergence Training on Oculomotor Parameters

Thiagarajan

Lakshminarayanan²,

Bobier³

2010

Optometry and Vision Science

View full text Add to dashboard Cite

“…cues to drive vergence. The so-called near triad motor response is driven by three cues that activate vergence including the accommodative response to image blur, fusional or disparity-induced vergence, and proximity vergence (Maddox, 1893;Semmlow & Hung, 1981). Research has attempted to separate out these individual cues to assess their relative contributions during oculomotor development, especially as the accommodation and vergence response systems are linked.…”

Section: Introductionmentioning

confidence: 99%

Convergence and divergence to radial optic flow in infancy

Nawrot

2019

Journal of Vision

View full text Add to dashboard Cite

Research finds a relationship between the development of depth perception and ocular motion functions including smooth pursuit and ocular following response. Infants' reactions to looming stimuli also suggest sensitivity to optic flow information that specifies relative distance. With radial optic flow, an expanding flow field elicits involuntary convergent eye movements while a contracting one elicits involuntary divergent eye movements. This response suggests the visual system is interpreting the radial flow as a change in relative depth. We measured the oculomotor response to radial optic flow in infants aged two to five months. The stimulus comprised a radial optic flow pattern that expanded or contracted across eight 400 ms trials while eye position was monitored with a Tobii X120 eye tracker. A subset of infants also viewed trials of a static version of the stimulus. On average, most infants in each age group demonstrated convergence to the expanding pattern and divergence to the contracting one. Moreover, the difference in gain between the convergence and divergence eye movements was significant. The presence of correct-direction vergence eye movements in response to expansion and contraction provides further evidence that infants are sensitive to information that specifies relative motion in depth.

show abstract

Experimental evidence for separate mechanisms mediating accommodative vergence and vergence accommodation

Cited by 12 publications

References 28 publications

Quantifying interactions between accommodation and vergence in a binocularly normal population

Quantifying interactions between accommodation and vergence in a binocularly normal population

Effect of Vergence Adaptation and Positive Fusional Vergence Training on Oculomotor Parameters

Convergence and divergence to radial optic flow in infancy

Contact Info

Product

Resources

About