Myasthenia gravis (MG) is a disorder of signalling between nerves and muscles at the neuromuscular junction, resulting in fluctuating weakness. It is caused by specific antibodies that reduce the signal from the nerve to the muscle. The initial symptoms in about half of all patients with myasthenia are confined to the eyes (double vision, droopy eyelids), with other patients having additional problems with breathing, chewing, swallowing or limb weakness (generalised MG). However, over time, often within the first two years, many of the patients with pure eye symptoms at presentation develop generalised MG. Currently, there are no reliable tests or clinical evaluation features to help us determine which patients will develop generalisation of their myasthenia over time, and may require more aggressive treatment. In this study we intend to develop and validate robust clinical scores and blood tests in two large cohorts of MG patients that will enable us to predict which patients who initially present with pure eye symptoms will develop generalised MG and which patients won’t. By identifying patients at risk of generalisation, we would hope that, in future, specific MG therapies (for example, early thymectomy in patients with pure eye symptoms at presentation) can be better tailored to the individual patient.