Dynamics of Cover Test Eye Movements

Peli, Eli; McCormack, Glen

doi:10.1097/00006324-198308000-00010

Cited by 26 publications

(25 citation statements)

References 8 publications

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“…Similarly, corrective saccades occur to return the fixating eye onto target. These newly-observed fixating eye movements, also recently documented by Peli and McCormack (1983), can thus be put in line with those of the Mueller experiment.…”

Section: Binocular Vergence During the Cover Testsupporting

confidence: 87%

Accommodative Disfacility Presenting as Intermittent Exotropia

Stark¹,

Ciuffreda

Grisham³

et al. 1984

Ophthalmic Physiologic Optic

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Accommodative disfacility and intermittent exotropia are two common clinically-observed ocular abnormalities. However, records of individual system dynamics are rare and mechanisms for possible interactive effects between the accommodation and the vergence system remain obscure in cases of system dysfunction. We present objective, quantitative, static and dynamic records of accommodation, vergence and related system responses in a symptomatic patient having accommodation disfacility and intermittent exotropia and propose that these two conditions worked in a pathogenic symbiotic manner.

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Section: Binocular Vergence During the Cover Testsupporting

confidence: 87%

Accommodative Disfacility Presenting as Intermittent Exotropia

Stark¹,

Ciuffreda

Grisham³

et al. 1984

Ophthalmic Physiologic Optic

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“…The velocity of the vergence eye movement that occurs following the occlusion of one eye is typically slower (Barnard & Thomson, 1995; Kim, Granger-Donetti, Vicci & Alvarez, 2010; Ludvigh, McKinnon, & Zaitzeff, 1964; Park & Shebilske, 1991; Peli & McCormack, 1983) than vergence eye movements in response to horizontal image disparity during binocular viewing (Maxwell, Tong & Schor, 2010; Semmlow, Hung & Ciuffreda, 1986). It is therefore possible that the low velocity of the eye movement that occurs following the occlusion of one eye, compared to the higher velocity of vergence during binocular viewing is responsible for the decreased eye-position-signal weight for the occluded eye in Experiment 3.…”

Section: Experiments 4: Perceived Evd and Asymmetric Vergence Velocitymentioning

confidence: 99%

“…To assess whether the velocity of asymmetric vergence influences estimates of perceived EVD, nine observers viewed identical unblurred crosses (without suppression checks) in the two eyes that either (1) appeared with one of several asymmetric vergence demands with respect to the monitor, or (2) appeared initially with no vergence demand, after which the target seen by the varying eye moved at a velocity of either 0.75 or 1.5 deg/s to produce the same final amplitudes of asymmetric vergence. The velocities of 0.75 and 1.5 deg/s were chosen to approximately match the range of eye velocities reported previously after the occlusion of one eye (Barnard & Thomson, 1995; Kim, Granger-Donetti, Vicci & Alvarez, 2010; Ludvigh, McKinnon, & Zaitzeff, 1964; Park & Shebilske, 1991; Peli & McCormack, 1983). …”

Section: Experiments 4: Perceived Evd and Asymmetric Vergence Velocitymentioning

confidence: 99%

Binocular retinal image differences influence eye-position signals for perceived visual direction

Sridhar

Bedell

2012

Vision Research

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Correctly perceiving the direction of a visible object with respect to one’s self (egocentric visual direction) requires that information about the location of the image on the retina (oculocentric visual direction) be combined with signals about the position of the eyes in the head. The Wells-Hering laws that govern the perception of visual direction and modern restatements of these laws assume implicitly that retinal and eye-position information are independent of one another. By measuring observers’ manual pointing responses to targets in different horizontal locations, we show that retinal and eye-position information are not treated independently in the brain. In particular, decreasing the relative visibility of one eye’s retinal image reduces the strength of the eye-position signal associated with that eye. The results can be accounted for by interactions between eye-specific retinal and eye-position signals at a common neural location.

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“…This pattern occurs even when the binocularly visible stimuli are positioned collinear with one eye (Alpern and Ellen, 1956; Ono andNakamizo,, 1977, 1978; Ono and Tam, 1981), and has also been observed under monocular viewing, albeit with a greatly reduced amplitude (Kenyon et al, 1978). Furthermore, this pattern of vergence and fast movement has been observed when the vergence change was induced by prism (Alpern, 1957) and by phoria (Peli and McCormack, 1983). For descriptive simplicity, this fast movement will be referred to as a "saccade"; use of this term, however, is not intended to imply that only the saccadic system is involved.…”

Section: Introductionmentioning

confidence: 80%

Two factors affecting saccadic amplitude during vergence: The location of the cyclopean eye and a left - right bias

Barbeito¹

1986

Ophthalmic and Physiological Optics

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Saccades occurring during vergence have been reported to differ in amplitude depending on whether the saccade drives the eyes leftward or rightward. Furthermore, this difference varies in degree and direction among individuals. We examined two explanations of the variation--that it is the result of the cyclopean eye being nearer to one eye, and that it is the result of a pervasive bias, within an individual, to make larger saccades either leftward or rightward. Examination of the saccades of 14 subjects, recorded during both divergent and convergent movements that required leftward or rightward saccades, shows that neither explanation alone provides an adequate account of the differences observed. However, statistical analysis (ANOVA) indicates that almost 60% of the total variation in the observed saccadic amplitudes is related to the two explanations taken together. We speculate that both influences act on the saccade in a given individual, and that the amplitude manifested depends on the relative magnitudes of the two influences within that individual.

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Dynamics of Cover Test Eye Movements

Cited by 26 publications

References 8 publications

Accommodative Disfacility Presenting as Intermittent Exotropia

Accommodative Disfacility Presenting as Intermittent Exotropia

Binocular retinal image differences influence eye-position signals for perceived visual direction

Two factors affecting saccadic amplitude during vergence: The location of the cyclopean eye and a left - right bias

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