VR-HMD型高速視線計測機器によるアクティブ視野検査の開発


視野欠損と呼ばれる眼疾患は,欠けた視野範囲を自覚することが難しいという特徴があり,自動車の運転や日常生活に大きな影響を及ぼす恐れがあります.現在,視野の異常を自覚するためには視野検査を行う必要があります.これまで,視野検査には主観的な評価方法が用いられており検査結果の信頼性が問題視されていました.しかし近年,視線移動の変化から欠損範囲を推定するアクティブ視野検査が提案されました.しかし,この検査方法は頭部を固定する必要があったために被験者の身体的負担が伴う,課題が残されていました.本研究では,VR-HMD型高速視線計測機器を提案・開発し,課題の解決を試みました.健常者による性能評価実験の結果,1分以内の短い検査時間で姿勢の違いに影響されずに検査が可能であることが確認されました.今後,本研究の視線計測技術は医療分野のみならず中心窩レンダリング(foveated rendering)などのVR技術への応用が期待されます.

Visual Field is the visual area that is perceived simultaneously by a fixating eye. If eye, optic nerve and brain gets disease, “visual field defect” that visual acuity reduces partially within the visual field may occur. It has a characteristic that it is difficult for us to perceive defect range. In the worst case scenario, it could affect daily lives like as traffic accident. Threrefore, it is assumed that early visual field test is very important in visual field defect. Until recently, subjective evaluation method has been used in visual field test. So, a new test by using gaze movement was proposed. It’s active visual field test that improved credibility of inspection result. But, measurement hardware for active visual field test had two problem that measurable visual field is narrow and physical burden is heavy. In this study, we proposed using high speed vr-hmd eye tracker for these problems. It is possible to display images in more wide-viewing-angle than on a LCD monitor. So, in order to verify the inspection performance of the device, we made experiments on healthy subjects for inspection time and pose. Consequently, it became clear that inspection time has less than about 1 minute, and influence of posture was very small on inspection result. In the future, we will measurement experiment for visual field defective patients, and compare usual visual field test and high speed vr-hmd eye tracker about inspection result. Also, we will verify usefulness this hardware.It is hoped that the gaze tracking technology cultivated in this study will be applied to VR technology like as fovea rendering in high demand lately.

VR-HMD型視線計測機器

視線変化