+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Simulated torsional disparity disrupts horizontal fusion and stereopsis



Simulated torsional disparity disrupts horizontal fusion and stereopsis



Journal of Aapos 11(2): 120-124



To investigate how increasing torsional disparity affects clinical measures of the quality of binocular single vision. Synoptophore targets were adjusted to present varying degrees of torsional disparity (relative to the fusion-free rest position of the eyes) such as might be observed in a patient with excyclotropia. This disparity was increased in 2 degrees increments up to 10 degrees in 21 normal subjects. The fusional divergence and convergence amplitudes and random-dot stereoacuity were measured at each level of torsional disparity. Horizontal fusional vergence was not significantly altered from the baseline measures at 2 degrees and 4 degrees of torsional disparity. However, both the divergence and the convergence amplitudes declined and were significantly different than the baseline measures at 6 degrees . A similar decline in the random-dot stereoacuity measurements was evident. Fine levels of stereopsis were decidedly affected at greater than 4 degrees of torsional disparity, while more gross levels were similarly affected beyond 6 degrees . Although human binocular vision can demonstrate the sensory capacity for cyclofusion beyond 10 degrees , torsional disparity of 6 degrees or more significantly degrades horizontal fusional vergence and stereopsis. Torsion in excess of this degree might therefore be a barrier to asymptomatic and comfortable binocular single vision and may require appropriate attention in the planning of more successful surgery for superior oblique palsy and cyclovertical incomitant strabismus.

(PDF emailed within 0-6 h: $19.90)

Accession: 055783354

Download citation: RISBibTeXText

PMID: 17416321

DOI: 10.1016/j.jaapos.2006.09.022


Related references

Gain of human torsional optokinetic nystagmus depends on horizontal disparity. Investigative Ophthalmology & Visual Science 46(1): 133-136, 2004

Decreasing local stereopsis with increasing horizontal disparity indicating decreasing density of bin ocular cortical projection toward the limits of panums area. Albrecht Von Graefes Archiv fuer Klinische und Experimentelle Ophthalmologie 213(2): 109-114, 1980

Fixational disparity and the maintainence of fusion in the horizontal meridian. American Journal of Optometry and Archives of American Academy of Optometry 32(10): 520-534, 1955

Simulated disparity and peripheral blur interact during binocular fusion. Journal of Vision 14(8): 13-13, 2014

Induced size effect III A study of the phenomenon as influenced by horizontal disparity of the fusion contours. 1939

Projected disparity, not horizontal disparity, predicts stereo depth of 1-D patterns. Vision Research 49(17): 2209-2216, 2009

Correlation sensitivity for horizontal disparity, vertical disparity and glass patterns. IOVS 39(4): S615, March 15, 1998

Vertical binocular disparity is encoded implicitly within a model neuronal population tuned to horizontal disparity and orientation. Plos Computational Biology 6(4): E1000754-E1000754, 2010

Stereopsis from centroid disparity. Investigative Ophthalmology & Visual Science 36(4): S813, 1995

Stereopsis and vertical disparity. A.M.A. Archives of Ophthalmology 53(4): 495-504, 1954

Disparity and training in stereopsis. Japanese Psychological Research 13(3): 148-152, 1971

Fixation disparity and stereopsis. American Journal of Optometry and Physiological Optics 54(8): 550-555, 1977

Disparity limits of stereopsis. A.M.A. Archives of Ophthalmology 48(1): 50-60, 1952

Prismatic correction of vertical deviations with experimental study of the behavior of fusion amplitude in relation to horizontal and torsional vertical deviations. Annali di Ottalmologia E Clinica Oculistica 79(9): 431-444, 1953