Fatigue in plain sight: diagnosing myasthenia gravis based on eye movements

Myasthenia gravis (MG) is a rare condition in which the signals between nerves and muscles weaken with use (referred to clinically as ‘fatiguability'), so symptoms such as drooping eyelids and double vision come and go. Because patients can appear normal during the doctor's examination, the road to diagnosis is often long: international studies show the average patient waits around a year for an answer, sees four or more clinicians along the way, and is frequently given a different diagnosis first. This is important because MG is a treatable condition that can potentially be life threatening in some patients.

VRF Project Grant recipient, Dr Matthew McDonald, was a speaker at the Neuro-Ophthalmology Society of Australia (NOSA) 2026 meeting. He presented his research showing how this 'hidden fatigue' can be measured using an infrared camera that records eye movements at 500 times per second.

The study compared 15 people with MG to 40 healthy volunteers of similar age. 21 automated eye tracking measurements separated the two groups: eye movements in people with myasthenia were slower and smaller in every direction, became weaker within a single short recording, and showed distinctive changes in the steadiness between movements. Combining just two of these measurements identified myasthenia with high accuracy in this early group. These are first results from a small cohort, and larger studies will improve the detection even further with the aim of producing a quick, non-invasive diagnostic test which can spot MG earlier and objectively monitor whether they are responding well enough to treatment.