| Objective:To research the change of visual function after viewing polarized 3D images thirty minutes and an hour for subjects with different phorias and explore the relationship between the visual function parameters' changes and visual fatigue.According to the cause of visual fatigue, put forward corresponding measures of relieving visual fatigue.Methods:1.Randomly selected 51 students, 15 boys and 36 girls, ages ranging from19 to 26,average(21.04±1.36)years old. According to near phorias, 51 volunteers were divied into three groups:normal phoria(-6??NP?0)20 cases, exophoria(NP<-6?)16cases, esophoria(NP > 0)15 cases. 2.The subjects were corrected using computer optometry and phoropter.3.Visual function parameters were measured before viewing polarized 3D images, after viewing half an hour and an hour later. The degree of visual fatigue was measured by visual fatigue questionnaire.4.Using SPSS 16 statistical software to process data. Repeated measures analysis of variance and Spearman correlation analysis were used to analyze the results, with P < 0.05 as the difference was statistically significant.Results:According to phorias:1.After viewing the 3D images for thirty minutes and an hour, the changes of accommodation response had statistically significant difference( P=0.004 ? P <0.001,P<0.001?P=0.001).The accommodation response of the subjects with normal phoria and esophoria, increases.2.After viewing the 3D images for thirty minutes and an hour, in normal phoria group,the changes of AC/A had statistically significant difference(P=0.003?P=0.003).3.In esophoria group, after half an hour and an hour, the changes of stereoacuity had statistically significant difference(P=0.02?P=0.03).4.After viewing the 3D images for thirty minutes and an hour,in normal phoria group,the changes of visual fatigue score had statistically significant difference(P=0.0032?P=0.0031).Before viewing 3D images, the visual fatigue score was the minimum5.The visual fatigue score in normal phoria and esophoria increased with the increase of the time of viewing 3D image.According to the time point:1.For the subjects with normal phoria,the accommodation response increased after viewing an hour than exophoria which change had statistically significant difference(P=0.017).2.For the subjects with esophoria, the positive fusional vergence bigger than exophoria before viewing 3D imange which had statistically significant difference(P=0.048).After thirty minutes and an hour, the changes of positive fusional vergence had statistically significant difference(P=0.019?P=0.024,P=0.006?P=0.037).The positive fusional vergence of the subjects with normal phoria and esophoria bigger than exophoria.3.The increase of AC / A breaks the original binocular balance in normal phoria group which leads to the desynchrony of accommodation and vergence function.4.After thirty minutes and an hour, the changes of fixation disparity had statistically significant difference(P=0.03?P<0.001,P=0.02?P=0.007).The fixation disparity of the subjects with normal phoria and esophoria, increases.5.After an hour, the absolute value of the slope of fixation disparity had statistically significant difference(P=0.007?P=0.013).The subjects with normal phoria and esophoria was lower than exophoria.6.For the subjects with exophoria,the visual fatigue score increased after viewing half an hour than normal phoria and esophoria which change had statistically significant difference(P=0.034?P=0.015).Conclusions:1.The visual fatigue in normal phoria and esophoria caused by excessive of accommodation.2.As seen near?too much negative parallax?the own design features of 3D imanges and other factors are all increasing the brain's fusion load which need more positive fusional vergence, it is easy to cause visual fatigue.3.AC/A increased in normal phoria group which brock the original binocular visual balance which caused the accommodation and vergence to become out of syn,so this could be a risk factor for 3D visual fatigue.4.Stereoacuity test should be used in combination with a variety of methods,for those whose stereo visual function poorer could do some stereo visual function training by watching 3D images.5.After watching 3D images the fixation disparity changes in all the three groups,exophoria group has the largest, then the normal phoria and esophoria group has the least fixation disparity.6.After an hour, the absolute value of the slope of fixation disparity had statistically significant difference.The subjects with exophoria was bigger than normal phoria and esophoria. The greater the slop, the more likely to appear as visual fatigue.7.For viewing 3D movies caused visual fatigue, we can give a correct refractive prescription,an ADD, prism or early visual training, strengthen the binocular visual function in order to reduce the visual fatigue while watching a 3D movie and improve the subject's eye comfort. |
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