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Vergence and Accommodation: I Can Change in Size Induce Vergence Movements?

Vergence and Accommodation: I Can Change in Size Induce Vergence Movements? Abstract Of the many factors which influence vergence movements (tonicity of the extraocular muscles, distance of the fixated object,1 concave lenses and accommodation,2 prisms,3 and disparity,4 among others) target size has perhaps been given the least experimental attention. In an important analysis of this problem Ittelson and Ames found that an increase in both vergence and accommodation was associated with an increase of the image of a playing card projected (with a Clason projector) on a screen 40 cm. in front of the observer's eyes.5 It was soon pointed out, however, that the measured changes in vergence might only be pure accommodative vergence associated with the changes in accommodation.6 Are changes in target size associated with changes in vergence when all other relevant variables (including the accommodation posture of the eyes) are held fixed? Method The experiment was essentially a modification of the original Ittelson-Ames References 1. It should be pointed out that the Ittelson-Ames procedure of using a Clason projector has the inherent difficulty that changes in size are associated with changes in luminance. Since it seemed important to repeat their experiment as carefully as possible, this is also true in the present experiment. In the present experiment the smallest target size was 215 foot-lamberts; the medium target size was 163 foot-lamberts, and the largest target size was 133 foot-lamberts. Experiments in our laboratory indicate that there does not seem to be any marked effect of luminance on vergence over the very small range of luminance variation of the present experiment. 2. Alpern, M., and Ellen, P.: A Quantitative Analysis of the Horizontal Movements of the Eyes in the Experiment of Johannes Mueller , Am. J. Ophth. 42:289-302 (Oct., (Pt. 2) ) 1956. 3. Alpern, M.: Testing Distance Effect on Phoria Measurement at Various Accommodation Levels , A. M. A. Arch. Ophth. 54:906-915, 1955.Crossref 4. Alpern, M.: The Position of the Eyes During Prism Vergence , A. M. A. Arch. Ophth. 57: 345-353, 1957.Crossref 5. Westheimer, G., and Mitchell, A. M.: Eye Movement Responses to Convergent Stimuli , A.M. A. Arch. Ophth. 55:848-856, 1956.Crossref 6. Ittelson, W. H., and Ames, A.: Accommodation, Convergence and Their Relation to Apparent Distance , J. Psychol. 30:43-62, 1950.Crossref 7. Hof stetter, H. W.: Accommodation, Convergence and Their Relation to Apparent Distance: A Criticism , J. Psychol. 30:393-394, 1950.Crossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png A.M.A. Archives of Ophthalmology American Medical Association

Vergence and Accommodation: I Can Change in Size Induce Vergence Movements?

A.M.A. Archives of Ophthalmology , Volume 60 (3) – Sep 1, 1958

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References (6)

Publisher
American Medical Association
Copyright
Copyright © 1958 American Medical Association. All Rights Reserved.
ISSN
0096-6339
DOI
10.1001/archopht.1958.00940080371001
Publisher site
See Article on Publisher Site

Abstract

Abstract Of the many factors which influence vergence movements (tonicity of the extraocular muscles, distance of the fixated object,1 concave lenses and accommodation,2 prisms,3 and disparity,4 among others) target size has perhaps been given the least experimental attention. In an important analysis of this problem Ittelson and Ames found that an increase in both vergence and accommodation was associated with an increase of the image of a playing card projected (with a Clason projector) on a screen 40 cm. in front of the observer's eyes.5 It was soon pointed out, however, that the measured changes in vergence might only be pure accommodative vergence associated with the changes in accommodation.6 Are changes in target size associated with changes in vergence when all other relevant variables (including the accommodation posture of the eyes) are held fixed? Method The experiment was essentially a modification of the original Ittelson-Ames References 1. It should be pointed out that the Ittelson-Ames procedure of using a Clason projector has the inherent difficulty that changes in size are associated with changes in luminance. Since it seemed important to repeat their experiment as carefully as possible, this is also true in the present experiment. In the present experiment the smallest target size was 215 foot-lamberts; the medium target size was 163 foot-lamberts, and the largest target size was 133 foot-lamberts. Experiments in our laboratory indicate that there does not seem to be any marked effect of luminance on vergence over the very small range of luminance variation of the present experiment. 2. Alpern, M., and Ellen, P.: A Quantitative Analysis of the Horizontal Movements of the Eyes in the Experiment of Johannes Mueller , Am. J. Ophth. 42:289-302 (Oct., (Pt. 2) ) 1956. 3. Alpern, M.: Testing Distance Effect on Phoria Measurement at Various Accommodation Levels , A. M. A. Arch. Ophth. 54:906-915, 1955.Crossref 4. Alpern, M.: The Position of the Eyes During Prism Vergence , A. M. A. Arch. Ophth. 57: 345-353, 1957.Crossref 5. Westheimer, G., and Mitchell, A. M.: Eye Movement Responses to Convergent Stimuli , A.M. A. Arch. Ophth. 55:848-856, 1956.Crossref 6. Ittelson, W. H., and Ames, A.: Accommodation, Convergence and Their Relation to Apparent Distance , J. Psychol. 30:43-62, 1950.Crossref 7. Hof stetter, H. W.: Accommodation, Convergence and Their Relation to Apparent Distance: A Criticism , J. Psychol. 30:393-394, 1950.Crossref

Journal

A.M.A. Archives of OphthalmologyAmerican Medical Association

Published: Sep 1, 1958

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