04.10.2023
The Use of Eye Tracking Technology in Clinical and Medical Research
by Mirta Mikac, Product Manager
Eye tracking technology has become an increasingly important tool in clinical and medical research since it provides valuable insights into various conditions and disorders. It has a wide range of use, including:
1. Assessing cognitive functions
Eye tracking devices aid in evaluating cognitive function in patients with conditions like dementia, Alzheimer’s disease, and attention hyperactivity disorder (ADHD) due to their higher temporal resolution and granularity than conventional cognitive assessments1. By observing eye movements and response times, researchers can learn more about cognitive functions like attention, memory, and decision-making. Such oculomotor data can also provide insight into biological processes1.
2. Diagnosing and monitoring neurological disorders
It can additionally be utilized to identify and monitor a variety of neurological disorders, including traumatic brain injury, stroke, Parkinson’s disease, and an autism spectrum disorder. Analyzing eye movement patterns enables doctors and researchers to comprehend better how the brain functions and, as a result, detect abnormalities through studying eye movement patterns.
Eye tracking devices enable direct observation of visual exploration patterns as a nonverbal and less cognitively taxing method of recording disease progression in cognitively impaired individuals2. They can show visual exploration, illustrating how attention is dispersed throughout space. Eye tracking studies have utilized various stimulus types, such as random letter arrays, geometric forms, ordinary still images, moving images, or paradigms3. Karnath claims that during free visual exploration, patients with neglect turn their focus approximately 15° to the ipsilesional side4. In addition to being biased toward the ipsilesional side, visual neglect is characterized by frequent refixations, repeated visits to previously explored areas, shorter saccades amplitudes, and prolonged fixation times5.
3. Evaluating visual impairments
Visual impairments such as amblyopia (lazy eye), strabismus (crossed eyes), and nystagmus (involuntary eye movements) can be evaluated with eye tracking devices. The underlying causes of these conditions can be detected, and more effective treatments can be developed.
Instead of relying on conventional diagnosis and measurement methods ophthalmologists use, often influenced by their professional experiences and visual inspection, eye tracking devices provide objective and non-invasive diagnostical testing6.
4. Improving surgical procedures and serving as a didactic tool
Nowadays, eye tracking devices are also utilized as a didactic and evaluation tool to improve the learning experience of medical novices7. In the case of surgical procedures, eye trackers offer real-time data about a patient’s eye movements and gaze patterns. This enables surgeons to make more precise incisions and prevents damage to crucial ocular structures.
Numerous studies have also compared the gaze patterns of experts and novices and demonstrated differences in both pupillometry and gaze patterns8,9,10. Those differences are often used as a didactic tool to enhance novices’ learning and as a way to assess them since medical newbies can follow the expert’s gaze pattern and observe the exact point at which he stopped his gaze11. In addition, research has shown that the metrics of the gaze – speed, and entropy of the gaze, are reliable indices for assessing the workload in surgery12.
Moreover, eye tracking was used by O’Meara et al. to enhance student training in emergency simulations to prepare nursing and paramedicine students for emergency use cases13.
5. Developing assistive technologies
Another important field of use is the creation of assistive technology for individuals with disabilities. Since it acts as an autonomous form of assistive device that tracks the pupil of the eye to control a computer mouse or keyboard, it allows individuals with disabilities and incapable of regular movement to maintain effective interactions with both family members and the medical team without assistance from a caregiver14.
In conclusion, measuring eye movements with eye tracking technology has a variety of applications in clinical and medical research. Additionally, eye tracking offers tremendous new insights that complement conventional approaches. In combination, these methods enable more objective and complete insights.
1
Tao, L., Wang, Q., Liu, D., Wang, J., Zhu, Z., & Feng, L. (2020). Eye tracking metrics to screen and assess cognitive impairment in patients with neurological disorders. Neurological Sciences, 41, 1697-1704.
2
Delazer, M., Sojer, M., Ellmerer, P., Boehme, C., & Benke, T. (2018). Eye-Tracking Provides Sensitive Measure of Exploration Deficits After Acute Right MCA Stroke. Front. Neurol., 9.
3
Müri, R.M., Cazzoli, D., Nyffeler, T., & Pflugshaupt, T. (2009). Visual exploration pattern in hemineglect. Psychol Res, 73, 147-57.
4
Karnath, H.O. (2015). Spatial attention systems in spatial neglect. Neuropsychologia, 75, 61-73.
5
Mort, D.J., & Kennard, C. (2003). Visual search and its disorders. Curr Opin Neurol, 16, 51-7.
6
Chen, Z.H., Fu, H., Lo, W.L., Chi, Z., & Xu, B. (2018). Eye-tracking aided digital system for strabismus diagnosis. Healthcare Technology Letters, 5, 1-6.
7
Marin-Conesa, E., Sanchez-Ferrer, F., Grima-Murcia, M.D., & Sanchez-Ferrer, M.L. (2021). The Application of a System of Eye Tracking in Laparoscopic Surgery: A New Didactic Tool to Visual Instructions. Front. Surg., 8.
8
Zheng, B., Jiang, X., & Atkins, M.S. (2015). Detection of changes in surgical difficulty: evidence from pupil responses. Surg Innov., 22, 629-35.
9
Szulewski, A., Roth, N., & Howes, D. (2015). The use of task-evoked pupillary response as an objective measure of cognitive load in novices and trained physicians: a new tool for the assessment of expertise. Acad Med., 90, 981-7.
10
Atkins, M.S., Tien, G., Khan, R.S.A., Meneghetti, A., & Zheng, B. (2013). What do surgeons see: capturing and synchronizing eye gaze for surgery applications. Surg Innov, 20, 241-8.
11
Dempere-Marco, L., Hu, X.-P., MacDonald, S.L.S., Ellis, S.M., Hansell, D.M., & Yang, G.-Z. (2002). The use of visual search for knowledge gathering in image decision support. IEEE Trans Med Imaging, 21, 741-54.
12
Di Stasi, L.L., Diaz-Piedra, C., Rieiro, H., Sanchez Carrion, J.M., Martin Berrido, M., Olivares, G., et al. (2016). Gaze entropy reflects surgical task load. Surg Endoc., 30, 5034-43.
13
O’Meara, P., Munro, G., Williams, B., Cooper, S., Bogossian, F., Ross, L., et al. (2015). Developing situation awareness amongst nursing and paramedicine students utilizing eye tracking technology and video debriefing techniques: a proof of concept paper. Int Emerg Nurs., 23, 94-9.
14
Hwang, C.-S., Weng, H.-H., Wang, L.-F., Tsai, C.-H., & Chang, H.-T. (2014). An Eye-Tracking Assistive Device Improves the Quality of Life for ALS Patients and Reduces the Caregivers’ Burden. Journal of Motor Behavior, 46.