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Published on: December 5, 2013
Comparison of fixation disparity curve parameters obtained with the Wesson and Saladin fixation disparity cards
Janice Ngan1, David A Goss, Joseph Despirito
1School of Optometry, Indiana University, Bloomington, Indiana 47405, USA.
Purpose:
This study compared fixation curve parameters with two commercially available fixation disparity cards, one that has been available for several years, the Wesson card, and a new one, the Saladin card.
Methods:
Fixation disparity curves were measured on 50 subjects with the Wesson fixation disparity card and the Saladin fixation disparity card.
Results:
The x intercepts were on average more in the base-in direction with the Wesson card than with the Saladin card. The y intercepts were shifted in the exo direction with the Wesson card compared with the Saladin card. The slope with the Wesson card was steeper than the slope obtained with the Saladin card. The distribution of curve types was also different with the two different instruments.
Conclusion:
Fixation disparity curves measured with these two instruments are different, and separate norms should be used for each fixation disparity measurement method.
