Hello there, You have stumbled on to something which means you know your body very well and are very aware of how it functions. Timoptic-xe contains timolol maleate which works normally in most individuals but for certain people who have a predisposition for asthma we try to avoid it as it may cause you to have breathlessness and phlegm. So your connection is right. You can ask your doctor to change to a different medication if you feel the breathlessness is unmanageable. Thank you for your query, Dr Arun A