Your health is so important, and there are so many different aspects of it that you need to think about. Your vision, for instance, is highly important, but it is something that you likely do not think about much unless you have a vision problem. If it is has been awhile since your last appointment with an optometrist, you should go in for an eye exam, even if you had 20/20 vision last time you went in. A lot can change in a few years, so it is good to go to an eye doctor every so often. Of course, if you are noticing that your vision is not as good as it used to be, or you simply have trouble reading things that other people can make out, you should go to an optometrist right away.
There are many different issues that your eyes can have, but you will never know which one you have, if you do have any, without going to your eye doctor. The primary way that they test for vision problems is by way o an eye exam. Eye exams do not typically take longer than ten minutes, although if you do have an issue, they make take a little bit longer, in order to zero in on your exact vision problem. The way eye exams work is very simple. The eye doctor shows you a series of symbols. They usually get smaller and smaller, and then different lenses are applied to see if they improve your vision at all. After they test this out a few times, they can figure out exactly what type of lens you need, in order to correct your vision problem and get you seeing at 20/20 again. After that, they will recommend lenses to you, so you can decide whether you want to get glasses or contacts.
Glasses and contacts are slightly different, but they work in essentially the same way. The way that they correct your vision is by reversing the effects of the misshapen lens. Most vision problems are caused by the lens being misshapen to some degree. When a lens that is specifically crafted to reverse this effect is placed in front of it, though, any distortion is cancelled out. This is how glasses and contacts enable people with vision problems to see as well as anyone else, as long as the lenses are in place. The only difference between glasses and contacts is how the lenses are applied. In the case of glasses, the lenses are attached to frames which are put in front of the eyes, sort of like a magnifying glass. Contact lenses, on the other hand, are not used in this way. Contacts are placed under the eyelid, directly on the cornea. Contacts are ultra thin and pretty much impossible to see, which is why some people choose them over glasses. Nonetheless, it is important to keep them as clean as possible, or else you could risk infection or other serious vision related problems.