Computer vision syndrome (CVS) is a complex of symptoms experienced by up to 90% of computer users. Questions remain regarding its etiology. Changes in accommodation or vergence have been suggested as causative factors. This study sought to determine if subjects with CVS had abnormal accommodative or vergence facility findings and to identify if sustained computer use produces a change in these parameters. Twenty two subjects read text from a computer screen for a continuous 25 min period. Vergence facility and both monocular and binocular accommodative facility were measured. Following the computer task, subjects completed a questionnaire regarding their level of discomfort during the task. No significant change in monocular accommodative or vergence facility was observed following the computer task, although a small increase in post-task binocular accommodative facility was noted. The highest ocular symptoms reported were tired eyes, eyestrain and dry eye. These were not correlated significantly with the accommodative or vergence facility findings.The symptoms reported appeared to be related to dry eye, and not to either accommodative or vergence abnormalities.
The prism flipper test is a simple and commonly used test to assess vergence facility. In previous studies, prism flippers of various powers have been employed, but those tests have not been compared with each other, either as to facility responses or in relation to predicting ocular symptoms. Vergence facility was assessed in this study using prism flippers of 8BI/8BO and 5BI/5BO. Optometry students served as subjects and were tested after completing a questionnaire addressing symptoms experienced with nearpoint activities. There appears to be no significant difference between the results of the two tests nor between either test and ocular symptoms. Either test, however, is recommended as an important adjunct in clinical assessment of binocular status. Suggestions for future research are given.
Accommodative facility, vergence facility and random dot stereopsis were evaluated in a sample of 43 university baseball and softball players. All had previously passed a modified clinical vision screening. Seventeen subjects were categorized with low accommodative or vergence facility, but only three were low in both. Three of the subjects, including one with low accommodative facility failed the Random Dot E test.
Visual standards currently utilized for pilot qualification in the United States Air Force need to be updated as our knowledge of visual science expands. Vergence facility was selected as a test of dynamic visual function. A group of pilots was matched to a group of normal, non-pilot controls. The pilot group did not differ significantly from the control group in the test of vergence facility. This may be an appropriate test for inclusion in the current United States Air Force visual diagnostic battery but other approaches need to be evaluated.