Some people need glasses because they cannot see clearly without them. Three of the most common eye problems are being nearsighted, being farsighted, and having an astigmatism.

If you are nearsighted, you can see things clearly only if they are very near. If you are farsighted, you can see things clearly only if they are far away. If you have an astigmatism, things look blurry whether they are near or far.

All three problems can be corrected with eyeglasses. Glasses help to focus the light properly so that you can see clearly all the time.