[2] In myasthenia gravis, there is a variable weakness of skeletal muscles, which is exacerbated by repeated contraction.
To cause sustained contraction of levator palpebrae superioris muscle, the patient is asked to gaze upward for an extended period of time, without lifting the head.
[3] Thus, this test can be used to clinically differentiate between ocular myasthenia gravis and normal individuals.
It is sometimes done in conjunction with tensilon test, where edrophonium is injected to look for reversibility of eyelid drooping.
In myaesthenia gravis, eyelid drooping is no longer detectable after tensilon test.