Eye movement behaviour of patients with visual field defects

People with a visual field defect suffer from reduced sensitivity or even complete blindness in parts of the visual field. Two common causes of visual field defects are glaucoma: a neurodegenerative disease in which peripheral vision slowly declines due to damage to the optic nerve, and homonymous hemianopia (HH): blindness in one half of the visual field, which is caused by damage to the visual pathways after the optic chiasm. In this dissertation, Gestefeld explored two questions. The first question was whether visual field defects can be detected based on eye movements. In her research, Gestefeld found that based on the eye movements, she could determine whether a video clip had been viewed by someone with a (simulated) visual field defect or with normal vision. This indicates that the eye movements contain sufficient information to diagnose visual field defects.Her second question was whether virtual reality and eye-tracking can be used to support people with a visual field defect during their rehabilitation. People with a visual field defect learn in rehabilitation to compensate for their visual field defect by making a certain viewing rhythm. Participants who tried a VR headset or a mobile (head-mounted) eye tracker during various mobility exercises had a positive experience and saw benefits from using these technologies. The same was true for the occupational therapists. So it makes sense to further explore how Virtual reality and eye-tracking can be used to improve rehabilitation.In summary, Gestefeld has found that eye movements can be used to determine the presence of a visual field defect in a very simple way. Thus, this could potentially lead to simpler methods of performing visual field measurements, for example in people for whom the current standard methods do not work well. In addition, they can also be used to compensate for a visual field defect

Eye tracking and virtual reality in the rehabilitation of mobility of hemianopia patients:A user experience study

Purpose: To test the usability of eye tracking and virtual reality during vision rehabilitation training of hemianopia patients.Methods: Individuals with hemianopia (n = 13) and normal-sighted controls (n = 4) performed various exercises that are commonly used in vision rehabilitation for mobility, while wearing a head-mounted eye tracker or a head-mounted virtual reality (VR) display. Occupational therapists (n = 4) guided them through the exercises. All participants (including therapists) filled out a questionnaire, assessing their experience with the used device. Individuals with hemianopia were split into three groups according to their stage in vision rehabilitation therapy and performed 1 (beginner), 2 (intermediate) or 3 (advanced) different exercises.Results: Individuals with hemianopia rated the mobile eye tracker with a score of 3.97 ± 0.5 points (beginner), 3.8 ± 0.5 points (intermediate) and 4 ± 0 points (advanced) the corresponding occupational therapists with a score of 3.6 ± 0.6, 3.4 ± 0.9 and 3.87 ± 0.6 points (out of a maximum of 4 points). The VR headset was rated with 3.9 ± 0.5 points by individuals with hemianopia, 3.8 ± 0.5 points by normal-sighted controls and 2.5 ± 1.4 points by the occupational therapist in a virtual hallway scenario. In a street-crossing scenario, it was rated with 3.7 ± 0.5 points by individuals with hemianopia, 3.7 ± 0.8 points by controls and 2.8 ± 1.2 by occupational therapists. In a walking along a pavement scenario the individual with hemianopia gave 4 ± 0 points and the controls 3.8 ± 0.4 points on average.Conclusions: Both devices were seen as useful additions to vision rehabilitation therapy, as they enable better feedback to patients and the opportunity to do different exercises at different levels of difficulty

Using natural viewing behavior to screen for and reconstruct visual field defects

There is a need for simple and effective ways to screen for visual field defects (VFD). Watching a movie is a simple task most humans are familiar with. Therefore we assessed whether it is possible to detect and reconstruct visual field defects based on free viewing eye movements, recorded while watching movie clips. Participants watched 90 movie clips of one minute, with and without simulated visual field defects (sVFD), while their eye movements were tracked. We simulated homonymous hemianopia (HH) (left and right sided) and glaucoma (small nasal arc, large nasal arc, and tunnel vision). We generated fixation density maps of the visual field and trained a linear support vector machine to predict the viewing conditions of each trial of each participant based on these maps. To reconstruct the visual field defect, we computed "viewing priority" maps and maps of differences in fixation density of the visual field of each participant. We were able to classify the simulated visual field condition with more than 85% accuracy. In simulated HH, the viewing priority distribution over the visual field indicated the location of the sVFD in the simulated HH condition. In simulated glaucoma the difference in fixation density to the control condition indicated the location of the sVFD. It is feasible to use natural viewing behavior to screen for and reconstruct (simulated) visual field defects. Movie clip viewing in combination with eye tracking may thus provide an alternative to or supplement standard automated perimetry, in particular in patients who cannot perform the latter technique

How Free-Viewing Eye Movements Can Be Used to Detect the Presence of Visual Field Defects in Glaucoma Patients

Gestefeld B, Marsman J-B, Cornelissen FW. How Free-Viewing Eye Movements Can Be Used to Detect the Presence of Visual Field Defects in Glaucoma Patients. Frontiers in Medicine. 2021;8: 689910.Purpose: There is a need for more intuitive perimetric screening methods, which can also be performed by elderly people and children currently unable to perform standard automated perimetry (SAP). Ideally, these methods should also be easier to administer, such that they may be used outside of a regular clinical environment. We evaluated the suitability of various methodological and analytical approaches for detecting and localizing VFD in glaucoma patients, based on eye movement recordings. Methods: The present study consisted of two experiments. In experiment 1, we collected data from 20 glaucoma patients and 20 age-matched controls, who monocularly viewed 28 1-min video clips while their eyes were being tracked. In experiment 2, we re-analyzed a published dataset, that contained data of 44 glaucoma patients and 32 age-matched controls who had binocularly viewed three longer-duration (3, 5, and 7 min) video clips. For both experiments, we first examined if the two groups differed in the basic properties of their fixations and saccades. In addition, we computed the viewing priority (VP) of each participant. Following a previously reported approach, for each participant, we mapped their fixation locations and used kernel Principal Component Analysis (kPCA) to distinguish patients from controls. Finally, we attempted to reconstruct the location of a patient's VFD by mapping the relative fixation frequency and the VP across their visual field. Results:We found direction dependent saccade amplitudes in glaucoma patients that often differed from those of the controls. Moreover, the kPCA indicated that the fixation maps of the two groups separated into two clusters based on the first two principal components. On average, glaucoma patients had a significantly lower VP than the controls, with this decrease depending on the specific video viewed. Conclusions: It is possible to detect the presence of VFD in glaucoma patients based on their gaze behavior made during video viewing. While this corroborates earlier conclusions, we show that it requires participants to view the videos monocularly. Nevertheless, we could not reconstruct the VFD with any of the evaluated methods, possibly due to compensatory eye movements made by the glaucoma patients

How Free-Viewing Eye Movements Can Be Used to Detect the Presence of Visual Field Defects in Glaucoma Patients

There is a need for more intuitive perimetric screening methods, which can also be performed by elderly people and children currently unable to perform standard automated perimetry (SAP). Ideally, these methods should also be easier to administer, such that they may be used outside of a regular clinical environment. We evaluated the suitability of various methodological and analytical approaches for detecting and localizing VFD in glaucoma patients, based on eye movement recordings

Using natural viewing behavior to screen for and reconstruct visual field defects

There is a need for simple and effective ways to screen for visual field defects (VFD). Watching a movie is a simple task most humans are familiar with. Therefore we assessed whether it is possible to detect and reconstruct visual field defects based on free viewing eye movements, recorded while watching movie clips. Participants watched 90 movie clips of one minute, with and without simulated visual field defects (sVFD), while their eye movements were tracked. We simulated homonymous hemianopia (HH) (left and right sided) and glaucoma (small nasal arc, large nasal arc, and tunnel vision). We generated fixation density maps of the visual field and trained a linear support vector machine to predict the viewing conditions of each trial of each participant based on these maps. To reconstruct the visual field defect, we computed "viewing priority" maps and maps of differences in fixation density of the visual field of each participant. We were able to classify the simulated visual field condition with more than 85% accuracy. In simulated HH, the viewing priority distribution over the visual field indicated the location of the sVFD in the simulated HH condition. In simulated glaucoma the difference in fixation density to the control condition indicated the location of the sVFD. It is feasible to use natural viewing behavior to screen for and reconstruct (simulated) visual field defects. Movie clip viewing in combination with eye tracking may thus provide an alternative to or supplement standard automated perimetry, in particular in patients who cannot perform the latter technique