Usefulness of eye tracking systems in multiple sclerosis

Abstract

Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by inflammation and neurodegeneration. It represents the leading cause of nontraumatic disability in young adults in many places around the world.Currently, for the objective quantification of the damage of the visual pathway swept‐source OCT (SS‐OCT) is considered the most appropriate technique. Additionally, during the course of the disease multiple neurological deficiencies can appear, including eye motility disorders.Patients may develop various ocular motor disorders (OMDs) affecting visual function and significantly increasing disability. These alterations involve visual function and may decrease quality of life perceived by patients because they affect, among other functions, reading capability.OMDs, can be analysed by several recording systems, although they have not been incorporated into the practice routine clinic due to its complexity, high costs and also because the value of these alterations is probably not known.It is possible that an accurate examination of motility eye, may have a substantial impact on the diagnosis and management of those patients. OMDs has been suggested as potential biomarker of early neurological deterioration and its evaluation could contribute to obtaining progression and response to treatments, facilitating translational development of so‐called precision medicine.Eye trackers are state‐of‐the‐art tools that can obtain valuable information of OMDs in neurological degenerations. In MS, oculomotor alterations as saccadic dysmetria, saccadic intrusions, nystagmus, fixational deficits, smooth pursuit impairment, skew deviation, optokinetic and vestibulo‐ocular reflex impairments, may go unnoticed because systematic examination of the oculomotor systems do not use routinely these techniques.As mentioned, objective recordings of eye movements through eye‐tracking systems are not currently performed widely, despite that they have been described as an important adjunct in diagnosis, documentation, and management of different neurologic conditions.In addition, eye tracking is also a capable method to investigate the relationship between behaviour and neural mechanisms. Eye motion recordings provide a measure of functional preservation of the nervous system, which should be recognized to be of significant importance in assessing a disease in which disability is manifested by disruption of normal neuronal functions.In fact, it has been described that eye tracking tasks (especially saccadic tasks) are often used as an adjunct to traditional scales for cognitive assessment. In addition, eye tracking data confirmed that MS is characterized by attention deficits.In conclusion, there is a growing interest in the use of eye tracking systems as biomarkers for MS. Specifically in this work we have analysed a large series MS patients to detect if any of the anomalies that patients refer to, such as reading difficulties, are related to disorders of the ocular motor systems.