[header] How to know if you need new glasses [title] See your optometrist about frequent headaches. [step] Many people's vision slowly changes over time. Essentially, your eyes and brain will be straining to correct your vision if they need more assistance than your glasses provide, leading to fatigue and discomfort. 
As such, even slight changes in your vision can lead to headaches if you don't keep your prescription up to date. [substeps] If you notice a gradual increase in the frequency of headaches you experience, schedule an eye exam with your optometrist to determine whether your vision is the cause.