What causes not being able to focus your eyes for a minute or so upon waking up?

Difficulty focusing your eyes upon waking can be caused by several factors, including sleep inertia, which is the grogginess that occurs after waking. During sleep, your eyes may not have been used, leading to temporary visual blurriness. Additionally, dry eyes or a build-up of sleep crust (rheum) can contribute to this issue. If it persists or is accompanied by other symptoms, it's advisable to consult a healthcare professional.