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

Thiagarajan, Preethi; Lakshminarayanan, Vasudevan; Bobier, William R.

doi:10.1097/opx.0b013e3181e19ec2

Cited by 18 publications

(19 citation statements)

References 86 publications

(160 reference statements)

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“…This value would be expected to change only if the cross-link ratio (response accommodative convergence/accommodation) changed [71]. However, past studies have reported constancy of this cross-link following vergence training in both visually nondisabled subjects [64,72] and in symptomatic individuals manifesting binocular vision dysfunction [73].…”

Section: Training Effect On Static Measures Of Vergencementioning

confidence: 94%

“…The fused percept was then maintained for 15 to 20 s. This sustained viewing trained the slow vergence mechanism that maintained the vergence response [63]. Such response maintenance reflects the vergence adaptation mechanism [63][64]. BO training was terminated at the point at which subjects could no longer fuse (and/or focus) with their maximum effort.…”

Section: Treatment Protocolmentioning

confidence: 99%

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Effect of oculomotor rehabilitation on vergence responsivity in mild traumatic brain injury

Thiagarajan¹,

Ciuffreda²

2013

J Rehabil Res Dev

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Abstract-A range of dynamic and static vergence responses were evaluated in 12 individuals with mild traumatic brain injury (age: 29 +/-3 yr) having near vision symptoms. All measures were performed in a crossover design before and after oculomotor training (OMT) and placebo (P) training. Following OMT, peak velocity for both convergence and divergence increased significantly. Increased peak velocity was significantly correlated with increased clinically based vergence prism flipper rate. Steady-state response variability for convergence reduced significantly following OMT. The maximum amplitude of convergence, relative fusional amplitudes, and near stereoacuity improved significantly. In addition, symptoms reduced significantly, and visual attention improved markedly. None of the measures were found to change significantly following P training. The significant improvement in most aspects of vergence eye movements following OMT demonstrates considerable residual brain plasticity via oculomotor learning. The improved vergence affected positively on nearwork-related symptoms and visual attention.

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Section: Training Effect On Static Measures Of Vergencementioning

confidence: 94%

Section: Treatment Protocolmentioning

confidence: 99%

Effect of oculomotor rehabilitation on vergence responsivity in mild traumatic brain injury

Thiagarajan¹,

Ciuffreda²

2013

J Rehabil Res Dev

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“…With regards to the time required for adaptation, Thiagarajan et al 12 investigated the effects of vergence adaptation and positive fusional vergence training on oculomotor parameters. They found that following introduction of 12D BO prism, most adaptation took place within the first in 3 to 6 min.…”

Section: Discussionmentioning

confidence: 99%

Stereoacuity as an Indicator of Prism Adaptation

Momeni‐Moghaddam

Eperjesi

Kundart

et al. 2014

Current Eye Research

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The time required for stereoacuity to return to baseline level was more than 3 min for BO, and more than 6 min for BI prism. In addition, the time required to return to baseline values was not similar for the stereoacuity and heterophoria. The recovery of stereoacuity is slower when adapting to divergence, as when looking from near to far. This implies that stereopsis responds faster to near targets than to distant one, and may precede complete phoria adaptation.

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“…In this ''noncongruent'' design, a much stronger SV response is required to prevent blur that would be generated via the PV driven vergence accommodation cross-link. Because of this, SV function has typically been characterized using base-in or base-out optical prism to create noncongruent disparity (Rosenfield, 1997;Thiagarajan, Lakshminarayanan, & Bobier, 2010); however, monocular optical prism creates a condition where fusion can be gained theoretically by a monocular movement and yet experimentally both eyes move, which invokes a complex vergence and saccadic interaction (Alpern & Ellen, 1956;Kenyon, Ciuffreda, & Stark, 1978). In contrast, symmetric disparities, created dichoptically, have typically been used to study PV.…”

Section: Dichoptic Stimuli and Test Distancementioning

confidence: 99%

Asymmetries between convergence and divergence reveal tonic vergence is dependent upon phasic vergence function

Erkelens

Bobier

2017

Journal of Vision

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Horizontal vergence eye movements are controlled by two processes, phasic and slow-tonic. Slow-tonic responses are hypothesized to be stimulated by the faster, pulse-step neural output of the phasic system. This suggests that the general behavior of each system should be similar; however, this relationship has yet to be investigated directly. We characterize the relationship between phasic and tonic vergence by quantifying directional asymmetries in the response properties of each mechanism to the same disparity amplitudes. Four subjects viewed symmetric steps in disparity dichoptically at 40 cm while eye movements were recorded with infrared oculography. First- and second-order phasic and slow-tonic convergence response properties increased linearly with disparity demand (p < 0.01), whereas divergence responses did not (p > 0.05). Phasic divergence responses were slower than convergence (p = 0.012) and were associated with a higher frequency of saccades (p < 0.001). The average rate of slow-tonic change was correlated to the average peak velocity of phasic vergence at the same vergence demand in both directions, r = 0.78, p < 0.0001. Clear directional asymmetries were observed in phasic and tonic vergence responses. The response properties of the slow-tonic mechanism varied directly with the peak velocity of the complementary phasic system. These results provide empirical evidence of the relationship between phasic and slow-tonic vergence, suggesting that the latter depends on the motor function of the former, specifically the peak velocity. The recruitment of additional oculomotor mechanisms, such as saccades, improved the phasic response properties of the slower divergence mechanism but did not directly influence the response behavior of the slow-tonic mechanism.

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

Cited by 18 publications

References 86 publications

Effect of oculomotor rehabilitation on vergence responsivity in mild traumatic brain injury

Effect of oculomotor rehabilitation on vergence responsivity in mild traumatic brain injury

Stereoacuity as an Indicator of Prism Adaptation

Asymmetries between convergence and divergence reveal tonic vergence is dependent upon phasic vergence function

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