You should choose morning to see your eye doctor and get your glasses prescription. The eyes after a night of full rest, get total relaxation, if you see your optometry in the morning you will getmore accurate glasses prescription. If you see your eye doctor, say, in the afternoon, your eyes feel very tired at that time, so you can not get more accurate prescription.
This is because the eyes look at the different objects far away or nearby, mainly by ciliary muscle contraction and relaxation, to adjust the thickness of the lens focal length. If you use eye long time, your ciliary muscle will be fatigue, then you can not get accurate glasses prescription. Wearing such glasses, you probably not feel any discomfort, buy may occur dizziness, dry eyes, and so on after a period of time.