Yes wearing sleep eye masks can cause blurry vision which is normal.
The sleep eye mask can put pressure on your eyes and when you wake up in the morning and remove the sleep eye mask you can experience blurry vision for 3 to 40 minutes or so after you wake up which is normal.
The sleep eye mask causes blurry vision for some people and it's nothing to worry about.
Usually wearing the cheaper sleep eye masks is the cause of the blurry vision so trying a better quality sleep mask may stop the blurry vision.
Your sleep mask puts pressure on your eyes and after you remove the sleep eye mask it takes a bit of time to get the eyes to adjust back to normal and have the normal pressure return to your eyes.
If your blurry vision lasts longer than an hour or so then you might want to see your eye doctor about it but otherwise it's normal to experience blurry vision after wearing a sleep eye mask.