title: Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study.
abstract: OBJECTIVE
  Degenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST).
  
  
  METHODS
  Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field.
  
  
  RESULTS
  In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training condition.
  
  
  CONCLUSIONS
  We conclude that the exploratory saccade training was beneficial for RP patients and resulted in shorter fixation durations after the training. We also found a significant improvement in relative walking speed during navigation in a real-world like controlled environment.
authors.affiliation: Vision Rehabilitation Research Unit, Centre for Ophthalmology, University Eye Hospital, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.|ZEISS Vision Science Lab, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.
authors.forename: Iliya V
authors.initials: IV
authors.lastname: Ivanov
authors.affiliation: The Smith-Kettlewell Eye Research Institute, San Francisco, United States of America.
authors.forename: Manfred
authors.initials: M
authors.lastname: Mackeben
authors.affiliation: Vision Rehabilitation Research Unit, Centre for Ophthalmology, University Eye Hospital, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.|Low Vision Clinic, Centre for Ophthalmology, University Eye-Hospital, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Vollmer
authors.affiliation: Institute for Clinical Epidemiology and Applied Biometry, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Martus
authors.affiliation: Low Vision Clinic, Centre for Ophthalmology, University Eye-Hospital, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.
authors.forename: Nhung X
authors.initials: NX
authors.lastname: Nguyen
authors.affiliation: Vision Rehabilitation Research Unit, Centre for Ophthalmology, University Eye Hospital, Eberhard-Karls University of Tuebingen, Tuebingen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Trauzettel-Klosinski
mesh_terms: D000328:Adult; D000368:Aged; D004780:Environment, Controlled; D005081:Exercise Therapy; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011930:Reaction Time; D012174:Retinitis Pigmentosa / Q000503:physiopathology / Q000628:therapy*; D012438:Saccades; D014794:Visual Fields