Revolutionizing optometric tests with eye tracking

The University of Zaragoza in Spain is home to a pioneering research group led by Dr. Ana Sanchez-Cano and Dr. Elvira Orduna-Hospital, specializing in binocular vision, vision therapy, and rehabilitation. These scientists fuse physics concepts with optics and optometric approaches while applying their findings practically in clinical settings. Their latest research focuses on eye tracking applications in the field of optometry and ophthalmology. Using Tobii Pro Fusion, the team validated two eye tracking-based optometric tests.

Over the last 50 years, optometric tests have been carried out by human examiners, often yielding unreliable results due to errors and varying interaction quality between the examiner and the patient. The research group led by Dr. Ana Sanchez-Cano and Dr. Orduna-Hospital challenged the traditional optometry methods by introducing eye tracking as an objective means of performing optometric tests. Their goal is to standardize the optometric test measurements and increase the data reproducibility when performed by different examiners.

Researchers at the University of Zaragoza built a custom-made setup where they use Tobii Pro Fusion to perform optometric measurements and Tobii Pro Lab to record the data. The results of their work and their custom-made eye tracking setups have been featured in two scientific publications.

In the first research study, the scientists explore how Tobii Pro Fusion evaluates ocular motility when performing the Developmental Eye Movements (DEM) test in their custom laboratory setup. The DEM test measures visual-verbal ability and can help identify reading and academic learning difficulties. The study showed that eye tracking performs the DEM test objectively and quantifies ocular motility parameters that are not achievable by traditional subjective methods.

In the second study, the researchers measured conjugate eye movements and gaze direction while performing the Hess Lancaster Screen Test (HLST) with Tobii Pro Fusion. The HLST is used in clinical settings and allows the estimation of heterophoria and heterotropia (strabismus). In this study, the researchers compared the results obtained with an eye tracker to those of traditional subjective HLST performance. They concluded that eye tracking offered more accurate results than the traditional method. The authors also noted that the eye tracking-based test is complementary and would add to the complete binocular vision examination.  

Dr. Ana Sanchez-Cano and Dr. Elvira Orduna-Hospital talk about the advantages of using eye tracking in the optometric examination:

The next step is to apply these optometric tests to patients with binocular dysfunctions and intellectual disabilities, where the measurements with traditional methods yield unreliable results. The researchers note that many more optometric tests could be performed with an eye tracker, including the Visual Tracing Test, the King Devick, and the Worth Test.

In addition, for use in optometric tests, the group at the University of Zaragoza uses eye tracking in two other research areas in their laboratory. One aims to evaluate ocular motility from various eye movements (e.g., fixations, saccades, vergence). The second one aims to integrate eye tracking into visual fatigue studies, evaluating the changes in speed and length of the saccades over time depending on the lighting or the reading device. Read their latest publication on this topic.

Publications

Orduna-Hospital E, Navarro-Marqués A, López-de-la-Fuente C, Sanchez-Cano A. Eye-Tracker Study of the Developmental Eye Movement Test in Young People without Binocular Dysfunctions. Life. 2023; 13(3):773.

Orduna-Hospital E, Maurain-Orera L, Lopez-de-la-Fuente C, Sanchez-Cano A. Hess Lancaster Screen Test with Eye Tracker: An Objective Method for the Measurement of Binocular Gaze Direction. Life. 2023; 13(3):668.

Orduna-Hospital, E., Safarian Baloujeh , E., Navarro, R., & Sanchez-Cano, A. (2023). Optical and motor changes associated with lighting and near vision tasks in electronic devices. Journal of Eye Movement Research, 16(2).