Evaluation of fixation disparity curve parameters with the modified near mallett unit in symptomatic and asymptomatic university students.
BACKGROUND
Research suggests that fixation disparity data are extremely useful in the assessment of the binocular and accommodative systems.


OBJECTIVE
The purpose of this study was to evaluate fixation disparity curve (FDC) parameters with a modified near Mallett unit in symptomatic and asymptomatic students of Paramedical Sciences School of Mashhad University of Medical Sciences in 2007.


METHODS
In this analytical-descriptive study, 100 students were selected randomly and divided into symptomatic and asymptomatic groups. Fixation disparity curve parameters were determined for each subject and compared in symptomatic and asymptomatic groups.


RESULTS
There were more subjects with exo fixation disparity than eso fixation disparity in the study sample. The means for fixation disparity, fixation disparity curve x-intercept, and slope with the modified Mallett unit were each significantly different by Mann-Whitney U test in the symptomatic and asymptomatic groups. Also there was a significant difference in the distributions of fixation disparity curve types in the two symptom groups by Chi-square test.


CONCLUSIONS
The X-intercepts (point at which the FDC crosses the X-axis) were on average more in the base-in direction, Y-intercepts (point at which the FDC crosses the Y-axis) were shifted in the exo direction, and slopes were steeper in the symptomatic group.
Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, IR Iran.
Hamed
H
Momeni Moghadam
School of Optometry, Indiana University, Bloomington, Indiana, USA.
David
D
A Goss
School of Paramedical Sciences, Mashad University of Medical Sciences, Mashhad, IR Iran.
Abbas A
AA
Yekta
School of Rehabilitation Sciences, Zahedan University of Medical Sciences, Zahedan, IR Iran.
Marzieh
M
Ehsani
Binocular Vision; Fixation Disparity; Visual Symptoms