Is it okay to see an aura due to eye strain?

Possibly. Auras are usually flashing lights or lightning patterns seen either alone or as a precursor to a migraine. If alone, they are often called ocular migraines, and tend to resolve within an hour. Migraines can be triggered by may different stressors, so straining your eyes could do it. If you experience new auras, or visul symptoms that do not disappear, please see your eye doctor.
Aura. Not really. Aura is classically associated with migraine or a seizure. Eye strain refers to the tired feeling in one's eyes from prolonged use, such as from reading or computer. It may also result from using the eyes for long periods with the wrong glasses prescription.