I don´t know of type 1 diabetes, but I know that when blood glucose goes down it doesn´t go down right away in one's eyes... but anyway maybe glucose is going down in your eyes by and by and maybe your brain which has been used to swimming in blood glucose also reacts a bit too rapid changes... I think you need to mention this to your diabetes team, but it might be that it is only a temporary problem, actually I believe it will be, but always communicate all troubles with your team, as one could overlook something very fatal... are you sure you are not too low in blood glucose during your sleep...?
having hypoes can cause headaches but also be dangerous .by the way when blood glucose going down it is not the right time to get new glasses not until it has been low and stable for a while/some month because blood glucose going down can also affect the strength of what level one's glasses need to be... and it will be a sad thing to get new glasses that are not of the right strength for one only one month later