Dark vergence in relation to fixation disparity at different luminance and blur levels

Fixation disparity was measured psychophysically when subjects viewed a central fusion stimulus at 50 cm distance. Reducing luminance and increasing target blur resulted in an exophoric shift of fixation disparity. Fixation disparity was significantly more exophoric in subjects with distant dark vergence, i.e. the resting position of vergence. This was true for the bright and sharp target, as well as for targets impaired by blurring or dimming. These results are interpreted as a bias of fixation disparity towards the individual resting position of vergence not only for degraded stimuli but also for strong central fusion stimuli.

[1]  Effect of Reading in Low Illumination on Fixation Disparity , 1987, American journal of optometry and physiological optics.

[2]  W Jaschinski-Kruza,et al.  Effects of stimulus distance on measurements of dark convergence , 1990, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[3]  G. Heath,et al.  The influence of visual acuity on accommodative responses of the eye. , 1956, American journal of optometry and archives of American Academy of Optometry.

[4]  Kenneth N. Ogle,et al.  Oculomotor imbalance in binocular vision and fixation disparity , 1968 .

[5]  H. Heuer,et al.  [Rest position of the eyes and its effect on viewing distance and visual fatigue in computer display work]. , 1989, Zeitschrift fur experimentelle und angewandte Psychologie.

[6]  E Schubert-Alshuth,et al.  Variability of fixation disparity and accommodation when viewing a CRT visual display unit , 1992, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[7]  W Jaschinski-Kruza,et al.  Eyestrain in VDU Users: Viewing Distance and the Resting Position of Ocular Muscles , 1991, Human factors.

[8]  THE CLINICAL ASSESSMENT OF BINOCULAR VISION BEFORE AND AFTER A WORKING DAY * , 1987, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[9]  D. A. Owens,et al.  The accuracy of binocular vergence for peripheral stimuli , 1983, Vision Research.

[10]  E F FINCHAM,et al.  The reciprocal actions of accommodation and convergence , 1957, The Journal of physiology.

[11]  W Jaschinski-Kruza.  Fixation disparity at different viewing distances of a visual display unit , 1993, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[12]  D A Owens,et al.  Near work, visual fatigue, and variations of oculomotor tonus. , 1987, Investigative ophthalmology & visual science.

[13]  A. Ivanoff,et al.  Night binocular convergence and night myopia. , 1955, Journal of the Optical Society of America.

[14]  H. Leibowitz,et al.  The Relation of Vergence Effort to Reports of Visual Fatigue Following Prolonged Near Work , 1990, Human factors.

[15]  A JAMPOLSKY,et al.  Fixation disparity in relation to heterophoria. , 1957, American journal of ophthalmology.

[16]  Alex Pentland,et al.  Microcomputer-based estimation of psychophysical thresholds: The Best PEST , 1982 .

[17]  K. Ciuffreda,et al.  Relation between Distance Heterophoria and Tonic Vergence , 1988, American journal of optometry and physiological optics.

[18]  C. Johnson,et al.  Effects of luminance and stimulus distance on accommodation and visual resolution. , 1976, Journal of the Optical Society of America.

[19]  H Heuer.  [Computer display work and rest position of the vergence system]. , 1993, Zeitschrift fur experimentelle und angewandte Psychologie.

[20]  R A Tyrrell,et al.  Lateral phoria at distance: contributions of accommodation. , 1992, Investigative ophthalmology & visual science.

[21]  Miller Rj.  Nonius alignment apparatus for measuring vergence. , 1987 .

[22]  C. Wildsoet,et al.  THE EFFECT OF ILLUMINATION AND FOVEAL FUSION LOCK ON CLINICAL FIXATION DISPARITY MEASUREMENTS WITH THE SHEEDY DISPAROMETER , 1985, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[23]  K. Ciuffreda,et al.  Contrast and accommodation in amblyopia , 1985, Vision Research.

[24]  M Millodot,et al.  Clinical evaluation of the Canon Autoref R-1. , 1985, American journal of optometry and physiological optics.

[25]  D. Pickwell.  Binocular Vision Anomalies: Investigation and Treatment , 1984 .

[26]  I. Matsumura,et al.  The Design of an Open View Autorefractometer , 1983 .