First do a complete eye exam remembering to look for retinitis pigmentosa for Kearns-Sayre disease. Look for proptosis (thyroid eye disease) from behind. Then look for a doll’s eye equivalent movement in the vertical plane for supranuclear palsy (found in Steele-Richardson, Alzheimers, Lewy body disease and Parinauds syndrome). Then test CN V (you should have already done the cornela reflex)( in case there is a cavernous sinus thrombosis/ Tolosa-Hunt syndrome), VII and IX, X (oculopharyngeal dystrophy).
Now test for fatiguability (lift both hands up into the air and count backwards from 100 – Myasthenia Gravis). Now quickly feel for a goitre (Graves + thyroid eye diease). Now get them to walk looking for ataxia (Miller-Fischer or Wernickes) and then sit down looking for areflexia (Miller-Fischer). Now test cerebellar signs (Kearns-Sayer), look at the JVP and feel the apex (cardiomyopathy in Kearns-Sayre) and look for pretibial myxoedema. Ask for a U/A (K-S), examine the gentilia (K-S)