探討不同眼位與虛擬實境動暈症之關係

目的：虛擬實境動暈症（Cybersickness, CS），又稱網絡病，是在虛擬實境使用時常見之疾病，因視覺、前庭覺、本體覺之感覺交互衝突導致一系列不舒適之症狀，對虛擬實境之推廣形成了重大阻礙；先前研究及動暈症理論皆指出視覺對動暈症形成至關重要，並擁有對於減緩動暈症之應用潛力，更有研究指出其與雙眼視覺之交互影響。故本研究之目的為探討在使用虛擬實境遭遇動暈症時雙眼視覺功能之變化，並進一步以稜鏡改變眼位，觀察改變雙眼視覺功能對動暈症之影響。方法：本研究共收納40位健康之年輕成年人（22.03±1.78歲），男生與女生各20位，進行正常狀態下及後續三次配戴不同稜鏡改變眼位的虛擬實境視覺刺激，並於結束刺激後進行雙眼視功能測試、問卷調查，並以SPSS 22統計軟體加以統整數據並分析，觀察其症狀對於雙眼視覺功能，以及改變雙眼視覺狀態，即不同眼位狀態下對其症狀嚴重程度之影響。結果：研究結果顯示，在退出虛擬實境後，雙眼視覺在眼位上大多向外偏斜（more exophoria），並在遮蓋測試、馬篤氏鏡、DLP、NLP之數據上有顯著差異，近點調節與近點聚散能力也在刺激後有顯著下降；VRSQ問卷分數顯示不適感有顯著產生，並在退出虛擬實境後約25分鐘症狀才會回復至與使用前相近之水平。在稜鏡介入後，自VRSQ分數可看出CS之發生率與症狀嚴重程度有略微下降，恢復速度更快，並在結束使用後10分鐘之分數顯著更低；雙眼視覺功能則在稜鏡介入後，稜鏡適應使眼位變化趨勢更明顯，近點調節與聚散能力同在結束使用後顯著下降，其餘雙眼視覺功能變化未有顯著。而以性別分組觀察個體差異，發現僅在介入後之發生率及症狀嚴重程度女性接略高於男性，雙眼視覺功能則大多顯示與性別無交互作用。結論：短時間之含有誘發CS條件之虛擬實境刺激會使眼位改變、近點調節力及聚散力下降，眼位向外偏斜居多，而使用稜鏡介入後，透過改變影像位置減調節聚散衝突（Vergence-Accommodation Conflict, VAC）之發生，根據本研究結果，能夠一定程度上緩解CS之發生率及症狀嚴重程度，而稜鏡介入之效果可能在性別上會有個體差異之存在。

Purpose：Cybersickness , usually occurs during virtual reality (VR) use. It results from sensory conflicts among visual, vestibular, and proprioceptive senses, leading to series of discomforting symptoms and sets a significant barrier to the promotion of VR technique. Previous studies and motion sickness theories have highlighted the critical role of visual input in the emerge of motion sickness and potential for symptom alleviation. Research has also indicated an interaction between cybersickness and binocular vision. Therefore, this study aims to investigate changes in binocular vision function when experiencing cybersickness during VR use and to observe the effects of altering binocular vision conditions by using prisms on cybersickness symptoms severity.Methods：This study included 40 healthy young adults (22.03±1.78 years old), with an equal number of males and females. Participants experienced specific VR visual stimulation under normal conditions and subsequently with three different eye position changes by using different prism.Binocular vision function tests and questionnaires were then applied after VR stimulation. Data were analyzed using SPSS v.22 to observe the impact of cybersickness symptoms on binocular vision function and the effect of different eye alignment on cybersickness symptoms severity.Results：The results indicate that binocular vision show more exophoria after exiting virtual reality, with significant differences observed in the data from the Cover Test, Maddox Rod, DLP, and NLP. Both near point of accommodation and near point of convergence showed significant declines after VR. The VRSQ questionnaire scores revealed a significant increase in discomfort, with symptoms taking approximately 25 minutes post-exposure to return to near pre-exposure levels.Following prism intervention, the VRSQ scores indicated a slight decrease in the incidence and severity of CS symptoms, with a faster recovery rate. The scores were significantly lower 10 minutes after exiting VR. Binocular vision function, after prism intervention, showed a more apparent trend in phoria change due to prism adaptation, with significant declines in near point of accommodation and convergence. Other binocular vision function changes were not significant.When observing individual differences by gender, it was found that the incidence and severity of symptoms post-intervention were slightly higher in females compared to males. However, binocular vision functions changes mostly did not show difference with gender.Conclusions：Short-term virtual reality stimulation containing cues that induce cybersickness (CS) can cause exo shift in phoria, a decrease in near-point accommodation, and near-point convergence ability. After prism intervention, the occurrence of vergence-accommodation conflict (VAC) can be reduced by altering the eye alignment. According to the results of this study, prism intervention can alleviate the incidence and severity of CS to a certain extent. Additionally, the effects of prism intervention may vary between gender.