The visual accommodation response during concurrent mental activity

Malmstrom, Frederick V.; Randle, Robert J.; Bendix, John S.; Weber, Robert J.

doi:10.3758/bf03204888

Cited by 38 publications

(23 citation statements)

References 20 publications

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“…Birnbaum [20] postulated that the conflicting results of Malmstrom et al [19] and Kruger [18] may be explained by optical factors. Kruger's concurrent mental task was centred on the visual stimulus for which accommodation was measured.…”

Section: Discussionmentioning

confidence: 99%

“…One area of contention that exists, however, is the effect of mental effort or cognitive demand on accommodation. Kruger [18] showed that when 20 subjects changed from passive reading of two-digit numbers at 40 cm to adding the numbers there was a significant increase in mean accommodative response of 0.28 D. Malmstrom [19] demonstrated, however, that a written backward-counting task could produce a decrease in accommodative response of 0.25-0.75 D for a 3.00 D target. Malmstrom and his co-workers have suggested that cognitive induced shifts in accommodation are caused by changes in the autonomic balance of the subject.…”

Section: Introductionmentioning

confidence: 99%

“…Certain authors have found that mental effort induces a decrease in accommodation [19] suggesting an increase in sympathetic innervation to the ciliary muscle [20]. Conversely, other studies have shown increases in accommodation associated with mental effort [17,18] and propose that this is due to an increase in parasympathetic innervation [17].…”

Section: Introductionmentioning

confidence: 99%

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The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

Bullimore

Gilmartin

1988

Doc Ophthalmol

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The accommodative response of 12 emmetropic subjects was measured for an array of numbers located at -1, -3 and -5 dioptres using an objective infra-red optometer. Responses were compared for passive (reading numbers) and active (adding numbers) conditions. The imposition of mental effort induced a significant increase in mean response for the -1 D stimulus, a response equivalent to the passive condition at -3 D and a reduction in response at -5 D. Mental effort induced similar responses for the -1 D and -3 D locations when sympathetic innervation to the ciliary muscle was blocked with the beta-receptor antagonist timolol maleate. Responses for the -5 D location were, however, significantly increased. It is proposed that sympathetic inhibition can modify the effect of mental effort on near accommodative responses.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

Bullimore

Gilmartin

1988

Doc Ophthalmol

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“…When the subjects added the numbers the mean accommodation to the screen during the 30 s treatment period was significantly greater by 0.28 D than when they only read the numbers. Malmstrom et al ( 1980) tested subjects who observed a fixation target at different viewing distances for a 30 s period and concurrently wrote down numbers as they counted backwards. When the target was at a 33 cm viewing distance accommodation was lower by about 0.25 D during the mental task compared with the condition where they simply observed the fixation target.…”

mentioning

confidence: 99%

“…Even in similar experimental conditions, e.g. viewing close targets, mental tasks may produce an increase in accommodation (Kruger, 1980), B decrease (Malmstrom et al, 1980), or no change (Gawron, Paap and Malmstrom, 1985). The type and the difficulty of the mental tasks may have differed between studies.…”

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confidence: 99%

Effect of a mental arithmetic task on dark focus of accommodation

Jaschinski

Toenies

1988

Ophthalmic Physiologic Optic

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Three subjective techniques for measuring accommodation (polarized vernier optometer, laser optometer, and a hand optometer based on the vernier principle) were used to measure subjects' dark focus while they performed a short-term mental arithmetic task. Compared with the initial values measured without the arithmetic task, significant changes in dark focus occurred when the task was performed. The effects depended on the initial dark focus of the subjects: in far-dark-focus subjects, inward shifts were generally observed; in near-dark-focus subjects, the dark focus shifted in different directions when different measuring techniques were used. The individual changes in dark focus due to the mental task were reproducible when the mean dark focus of the group shifted inward and when the same technique for measuring accommodation was used. The results have implications for the interpretation of dark focus shifts that are found following prolonged visual work at close distances, e.g. at visual display terminals.

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Vergence eye movements during fixations in reading

Hendriks

1996

Acta Psychologica

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The purpose of this explorative study was to examine vergence eye movements during fixations in reading. Eye movements of twelve normal adults were assessed during reading of different materials, that is, words within context (prose passages) and words without context (word lists), as well as during different tasks, that is, reading while attending to the meaning and reading while attending to the sound (words had to be pronounced subvocally). Results indicated that vergence velocity was higher during the reading of prose than during the reading of word lists as well as higher during reading for meaning than during reading while sub vocalizing. These findings were also true if only the initial 80 ms of each fixation were measured. Post-hoc analyses indicated that the effects of text type and reading objective were partially, but not entirely, attributable to differences in saccade sizes. Findings are taken to suggest that the increase in vergence velocity results from readers attending to larger units of the text.

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The visual accommodation response during concurrent mental activity

Cited by 38 publications

References 20 publications

The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

Effect of a mental arithmetic task on dark focus of accommodation

Vergence eye movements during fixations in reading

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