본 구에서는 2D 및 VR HMD 영상 시청이 눈물의 안정성과 시력의 질에 미치는 영향, 그리고 자각적 피로도 및 건조감에 미치는 영향에 대해서 알아보았다. 안질환 및 시기능 이상이 없는 양안 교정 시력 0.8 이상인 성인 남녀 37명(22.33±1.84세)을 대상으로 하였 다. 2D 디스플레이와 VR HMD에서 동일한 영상을 각각 40분 동안 시청하게 한 뒤 비침 습적 눈물 막 파괴시간(Noninvasive break up time, NIBUT), 눈물띠 높이(Tear meniscus height, TMH), 각막 고위 수차(Corneal Higher-order of aberrations, HOA), 상의 집속률 (Strehl ratio)의 변화를 측정하였다. 또한 실험 전·후 피로도 설문(Virtual Reality Symptom Questionnaire, VRSQ), 안구표면질환지수(Ocular Surface Disease Index, OSDI)설문을 통해 피로도 및 건조감 변화를 확인하였다. NIBUT의 전·후 차이 값은 VR에서 증가하였고 2D 에서는 감소하였다. TMH의 전·후 차이 값은 VR에서 안정 또는 증가하였고 2D에서 감소하였다. Corneal HOA의 전·후 차이 값은 4 mm의 동공크기 VR에서 안정 또는 감소하였고, 2D에서 증가하였다. 6 mm의 동공크기 VR에서 안정 또는 감소하였고, 2D에서 증가하였다. Strehl ratio의 전·후 차이 값은 4 mm의 동공크기 VR에서 안정 또는 감소하였고, 2D에서 증가하였다. 6 mm의 동공크기 VR에서 안정 또는 감소하였고, 2D에서 증가하였다. 피로도 설문에서 전·후 차이 값은 VR HMD와 2D 모두 증가하였고 VR HMD에서 더 높았다. 또한 건조감 설문에서 전·후 차이 값은 VR HMD와 2D 모두 증가하였고 VR HMD에서 더 높았 다. 설문 결과에서 뚜렷한 개선이 관측되지 않은 것은, VRSQ 설문에서는 건조감 이외의 무게감, 멀미감 등 다른 항목들이 전신과 눈에 미치는 영향이 컸기 때문으로 생각된다.또한 안구건조와 관련된 NIBUT, TMH 증가와 OSDI 설문이 다른 경향을 보이는 것은 시력교정 수술을 한 피검자들은 OSDI 기본값이 중증인 경우가 많아 다른 피검자들에 비해 건조감을 더 심하게 느꼈기 때문으로 생각된다. 또한 VR HMD와 2D 모두 OSDI 점수와 항목별 전, 후차에서 서로 연관성을 보였다. OSDI 기본값과 NIBUT, TMH, Strehl ratio 전,후 차 값들은 음의 상관관계를 보였고 OSDI 기본값과 VRSQ, OSDI, Corneal HOA는 양의 상관관계를 보였다. 이는 간단한 OSDI 설문을 통해 VR HMD와 2D의 자각적, 타각적 불 편 정도를 사전에 파악할 수 있는 자료로 제시될 수 있다. 본 연구를 통하여 VR HMD 가상현실 영상과 2D 시청이 안구건조와 시력의 질과 관련된 매개변수에 영향을 미치는것을 확인하였다. 선행논문을 통해 VR HMD 착용이 순목횟수 저하로 안구건조에 영향을줄 수 있다고 보고 하였지만 본 연구에서는 안구건조와 시력의 질과 관련된 매개변수 기능 저하에 영향을 미치지 않는 것을 확인하였다. VR HMD가 다양한 분야에서 활용되고있는 만큼 장시간 사용시 안구건조와 시력의 질에 미치는 영향에 대한 다양한 관점의 향후 연구가 필요하고 생각된다.
Purpose: This study investigated the effect of watching 2D and VR movies on ocular dryness, optical quality, subjective fatigue, and dryness. Methods: thirty-seven adults withbinocular corrected visual acuity of 0.8 or higher and without eye disease or visual dysfunction, participated. This study measured changes in NIBUT, TMH and Corneal HOAbefore and after watching the same 40 min movie by 2D display and VR device. In addition, subjective changes of fatigue and dryness was measured by VRSQ, OSDI questionnaire. Results: NIBUT difference before and after watching movie were increase of 4.57±4.73 sec for VR and decrease of –6.3±2.98 sec for 2D. TMH difference was 0.03±0.05 mm for VR and –0.02±0.03 mm for 2D. In 4mm pupil size, HOA difference were decrease of –0.04±0.18 ㎛ for VR and increase of 0.1±0.12 ㎛ for 2D. In 6mm pupil size, HOA difference were decrease of –0.05±0.28 ㎛ for VR and increase of 0.15±0.17 ㎛ for 2D. NIBUT, TMH and Corneal HOA difference were statistically significantly different and showed different trends for VR and 2D. (p<0.05) For VRSQ, difference was 9.46±4.54 for VR and 7.32±3.39 for 2D. (p=0.009) For OSDI, difference was 12.3±7.36 in VR and 9.59±5.93 in 2D. (p=0.062)Conclusion: It was confirmed that NIBUT, TMH and Corneal HOA were stabilized and subjective symptoms were affected when watching VR movie. As VR use increases, continuous research on the quality of visual acuity and dry eyes seems necessary
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목 차국문 요약 ································ⅰ표 목차 ·································ⅵ그림 목차 ································viiI. 서 론 ································· 1II. 이론적 배경 ······························ 21.VR HMD ································ 22. 비침습적 눈물막 파괴시간(Non-invasive break up time, NIBUT) ······· 53. TMH(tear meniscus height) ························ 74. 고위 수차(Higher-order of aberrations) ·················· 85. 상의 집속률(Strehl ratio) ························106. 각막 지형도(Antares, Corneal Topographer, CSO, Italy)···········11III. 실험 대상 및 방법 ·························· 121. 실험 대상 ······························ 122. 실험 도구 ·······························132.1) VR HMD와 2D display ························132.2) 각막 지형도(Antares, Corneal Topographer, CSO, Italy) ·········152.3) 자각설문 ······························153. 실험 방법 ·······························163.1) NIBUT ·······························173.2) TMH ································183.3) Corneal HOA ····························193.4) Strehl ratio ·····························193.5) 자각 설문 ·····························204. 통계 처리 ·······························20IV. 결과 및 고찰 ···························· 211. 실험대상 ······························· 212. 시기능 검사 ······························272.1) NIBUT ·······························282.2) TMH ································302.3) Corneal HOA ····························312.4) Strehl ratio ·····························333. 자각 설문 ·······························353.1) VRSQ ·······························373.2) OSDI ································394. OSDI baseline 점수와 항목별 연관성···················424.1) OSDI baseline & NIBUT ·······················434.2) OSDI baseline & TMH ························464.3) OSDI baseline & Corneal HOA ····················494.4) OSDI baseline & Strehl ratio ·····················544.5) OSDI baseline & VRSQ························594.6) OSDI baseline & OSDI ························62V. 결론 ································· 65참고문헌 ·································67영어 초록(Abstract) ····························73감사의 글 ································75