Is it permissible to perform the prayer while sitting if a doctor advises it due to an eye condition that prevents bowing, even if temporarily?

The obligation of prayer does not fall away from a Muslim as long as he is of sound mind. A Muslim prays according to his ability. If he is unable to stand, he prays sitting. If he is unable to do so, he prays on his side. If he is unable to prostrate, he indicates it by nodding, making the prostration lower than the bowing.