Why do new glasses give me a headache?

Quite a few persons who wear glasses are very astonished: Why do I have a feeling of nausea, dizziness and headache when I wear my newly-purchased prescription glasses? As the glasses have problems, if they are not corrected in time, when our eyes adapt to the new defective glasses, it means that a harm has been done to our eyes. Then, why do I have a feeling of headache and nausea while wearing my new glasses? How to alleviate the headache caused by glasses?
Reason for headache caused by glasses and method for alleviating the headache:1. Adaption to new prescriptionWhen you buy new prescription glasses, the oculist may remind you that new glasses give you a headache, nausea even with correct prescription. The reason is that your eyes need a certain period to adapt to the new prescription. It means new glasses adjustment period called...