Saccadic abnormalities, changes in optokinetic nystagmus, slow eye movements, and weakness in the pupillary constrictor muscle can be useful diagnostic markers for myasthenia gravis, according to a new review article published in the Journal of Neuro-Ophthalmology.

Eye-tracking technologies like video-oculography could, therefore, help diagnose the disease in a noninvasive, time-effective manner with minimal technical expertise.

“Our review identified several potentially useful variables that derive from oculography and pupillometry,” the authors wrote.

However, they stressed that the heterogeneity of the studies they reviewed in terms of sample size and quality was a limitation that could affect their findings. They added that larger studies evaluating measures of eye-tracking to diagnose myasthenia gravis are needed, “especially for patients presenting with purely ocular symptoms.”

Read more about the diagnosis of myasthenia gravis

The comprehensive literature review explored the efficacy of quantitative eye and pupil tracking as a potential approach to diagnosing myasthenia gravis. The authors, led by Sashank Prasad, MD, from the Department of Neurosciences at Monash University and the Departments of Neurology and Neuro-Ophthalmology at Alfred Health, both in Melbourne, Australia, evaluated 32 articles that used oculography and 6 that used pupillometry to diagnose the disease.

The variables identified that could have diagnostic value included intersaccadic, intrasaccadic, and postsaccadic abnormalities, optokinetic nystagmus changes, slow eye movements, disconjugate saccades, and pupillary constrictor muscle weakness.

Myasthenia gravis is a rare autoimmune disease characterized by the immune system mistakenly attacking the neuromuscular junction. It is difficult to diagnose the disease, especially in its early stages.

The majority of patients (around 60% to 75%) have initial ocular symptoms that are nonspecific. Being able to recognize these symptoms early could ensure that timely interventions are put in place to reduce morbidity and mortality.

The sensitivity of currently available diagnostic tools is limited, especially for patients who have only ocular symptoms. The tests are also generally time-consuming, invasive, and difficult to obtain, and necessitate a high level of technical expertise.

Reference

Nguyen MNL, van der Walt A, Fielding J, et al. Tracking eye movements for diagnosis in myasthenia gravis: a comprehensive review. J Neuroophthalmol. Published online August 2, 2022. doi:10.1097/WNO.0000000000001668