I had my eyes checked last year - ophthalmologist said they're fine, and encouraged me to keep doing things like hand stitching while I watch tv. He said having my eyes focus on something at a distance (such as the tv), then focus on something close-up (such as my handwork) keeps the "lens" and eye muscles flexible, and is good for keeping my healthy vision. Maybe you could set a timer for 5 or 10 minutes, and when it goes off, stop looking at your applique and focus on something across the room for a few minutes. If your headaches and blurred vision continue, I would recommend seeing an ophthalmologist.