title: A new method for accurate and fast measurement of 3D eye movements.
abstract: Videooculography (VOG) is an eye movement measurement method used in the objective evaluation of vestibulo-ocular reflexes (VOR). An important requirement of VOG is to accurately estimate pupil center and ocular torsion, irrespective of drooping eyelids, eyelashes, corneal reflection, and blinking. Finding the accurate center of the pupil is particularly important in three-dimensional VOG, since otherwise, significant errors can occur in measuring torsional eye movement. A fast algorithm was proposed to accurately ascertain the pupil center, in spite of the complicating factors mentioned above. In this study, real-time three-dimensional VOG, which can measure horizontal, vertical, and torsional eye movements and calculate the pupil radius, was implemented using the proposed method. When the pupil radius was determined, the vertical position was measured within an error margin of less than 3%, even though only 10% of the pupil was visible. The time required to measure both three-dimensional eye movements and the pupil radius was less than 16 ms. Thus, eye movements can be measured in real-time. The resolutions of horizontal, vertical, and torsional eye movement were 0.2 degrees, 0.2 degrees, and 0.1 degrees, respectively, with maximum ranges of +/- 35 degrees, +/- 25 degrees, and +/- 18 degrees.
authors.affiliation: Graduate School of Bio & Information Technology, Hankyong National University, Ansung, South Korea.
authors.forename: Soo Chan
authors.initials: SC
authors.lastname: Kim
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Nam
authors.forename: Won Sang
authors.initials: WS
authors.lastname: Lee
authors.forename: Deok Won
authors.initials: DW
authors.lastname: Kim
mesh_terms: D000465:Algorithms; D000818:Animals; D004585:Electrooculography / Q000379:methods*; D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009801:Oculomotor Muscles / Q000502:physiology; D011680:Pupil / Q000502:physiology; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D015203:Reproducibility of Results; D012107:Research Design; D013997:Time Factors; D014741:Video Recording