Mike - Is the double vision horizontal or vertical? If its vertical this narrows down the possibilities dramatically for a doctor. I have the vertical and so it is definitely Myasthenia Gravis. Look online for causes of vertical vs horizontal double vision and you will find alot of info. Good luck. The urgency -since there was no problem with your thymos on chest ct scan -would be a possible brain tumor -thus need for urgency. Take care, dont panic, its just time to go treasure hunting! Treasure being the diagnosis!