After a 3 hour eve flight the next day i woke up with severe blurred vision for about 30 minutes.but was fine coming home.due to fly again.wt was it?

Blurred vision: Transient visual blurring can result from a number of different conditions including migraine & vascular ischemic events (TIAs). Details of the history are important in deciding what was the likely cause - - for example whether there were flashing lights or wavy lines, headache, whether all or part of the visual field, & one or both eyes were affected. See a doctor , perhaps an ophthalmologist.