Will wearing my glasses all the time worsen my eyesight?!

This is kind of a long explanation, but it'll help you understand what's going on.

If he told you to wear the glasses for driving and while reading from the board at school, then you are near-sighted (aka myopic). Glasses for myopic eyes are negative prescriptions (because your eyes are too powerful). The negative prescription in your glasses cancel out some of the positive power of your eye. Think of it like this...

All eyeballs have a "positive" power (positive powered lenses focus light together, negative powered lenses spread light apart). A normal and relaxed eye sees perfectly at any distance MORE than 20 feet. When an object becomes closer than 20 feet, your ciliary muscles in your eyes contract and cause the lens inside your eye to become more positive, which allows you to focus on things that are closer than 20 feet. We call this action "accomodation." This muscle can get tired and is the reason people get a headache if they read up close for too long - you probably don't have as much of a problem with this as people with normal eyes or people with hyperopia (far-sightedness). Your myopic eyes have a lens that already has too much plus power, so you're stuck focusing closer than 20 feet even when your ciliary muscle is completely relaxed. This means you can't see things clearly if they're far away. The glasses you have are a negative prescription, which takes some of the power away from your eyes. If your eye doctor did a good job finding the right prescription for you, the glasses should take away exactly enough power so that when your eyes are relaxed, you are focusing at 20 feet and beyond. So when you look at the board at school, or are driving, or looking up at the stars, your eyes are relaxed and not working hard. If your eye doctor was lazy or had a hard time figuring out your prescription (probably what happened), he may have given you too much negative prescription, meaning that in order to see ANYTHING (even the stars), your eyes would have to accomodate (become more positive by using your ciliary muscles) to cancel out the extra negative prescription. The further your eye doctor went past the perfect prescription for you, the more your eyes will have to accommodate to cancel out the extra negative prescription. And this is just to see things at infinity or more than 20 feet. To see closer than that, you will have to accommodate EVEN MORE. So if you're reading a book, your eyes are killing themselves trying to give you enough focusing power to see that close because your glasses are taking so much power away. This can lead to eyestrain and give you a headache. It does not cause any permanent damage to your eyes, just like lifting weights at the gym does not cause permanent damage to your biceps - it just hurts for a while. But you might as well take the glasses off and let your eyes natural overpoweredness help you out when you're looking at things close up.

If you're not getting headaches, don't take the glasses off. If you are, then take them off. Maybe take the glasses to another eye doctor and see what he thinks. If he's telling you not to wear them all the time, something is wrong with them. Sometimes, especially with people under 20, its pretty hard to find the perfect prescription. Kids have really squishy lenses in their eyes and its really easy for them to change where their eyes are focusing. So you can give them a negative 5 diopter lens when they only need a negative 2, but their eyes add the 3 diopters needed to get them back to negative 2 without the kid even thinking about it or realizing he/she is doing it. So you can end up giving them a way too strong of a negative prescription and they can get eye strain. This is why you can buy positive prescription glasses at the pharmacy without a prescription, but you need a doctor to get a negative lens. Everyone would be giving themselves VERY negative prescriptions because their eyes can accommodate to see everything clearly, but they'd be using their eye muscles too much and would have headaches all the time.

Yes, you should only wear your glasses when absolutely necessary.

The optometrist fitted your glasses to the refractive state of your eyes within the time you were tested in his/her office. Therefore, if your eyes want to see clearly through the glasses, they must remain at that exact same refractive state they were when you were tested; the glasses won't help if your eyes become stronger or weaker. So, the glasses can at best maintain your vision.

One way to think about this is to imagine someone using crutches for a broken ankle. As their ankle is healing, it will only get strong enough to support the person's weight as they are using the crutches. If the person wants to be able to walk on only their two legs again, then they will eventually need to start walking without crutches. After this change, the healing ankle will experience the person's full weight again and will strengthen to reach that task.

If you want some scientific evidence in support that glasses can worsen your eyesight, here is the name of a study that demonstrated that idea on chickens: "Accommodation, Refractive Error and Eye Growth in Chickens," Vision Research., Vol 28, No. 5 pp 639-657, 1988, Pergamon Press, Frank Schaeffel, Adrian Glasser and Howard C. Howland

personal experience and research

Use them when you only need it. What I am trying to say is to not wear them all the time because your eyes will rely on the glasses and your prescription will likely tend to increase. But at the same time you should wear them for certain purposes, like what you said for example, the board for school, if its hard to read on the board, and you strain them, most likely, that too will make them get worse. So you want to balance it out.

Scientific studies show there is no evidence that wearing /not wearing glasses damages your eyesight. If you feel you need them more and its quite natural to do this once you get used to decent eyesight I would do so.

I find it odd that your optometrist said not to , and if I were you I'd ask why and/or get another opinion. If you search answers you'll find that a lot of people ask this question and all the optiicans who come on say there is no damage to your eyes.

If it was possible for glasses to change your underlying eyesight, they would be used as therapy. People would wear them for a while, their eyes would improve, and they could quit.

no, not wearing them will worsen it

No

no, i wear my glasses all the time nothing happnes

Do you really expect an eye doctor/optometrist to just make a fool of him/herself by saying that not buying glasses and pursuing other avenues will help your eyesight? Judging by the opticians/eyecare practitioners commenting on this site some of them border on shocking for their lack of knowledge/ ignorance of the world outside their small dark hole.
However they know the importance of backing the product they sell and the importance company profit has on the viability of their monthly salary.

Nobody can give one simple answer to cover every single person out there. There are extremes. One person could have lived all their life with poor vision and not notice how bad their eyesight had got. Some people may know they have an eyesight issue but not care about it and will not wear glasses (or care about it getting worse). Some people when first shown glasses are impressed with them and will wear them all the time (however it doesnt mean that the person cares about their vision or is taking every precaution to avoid it deteriorating.)

Ok, if you put effort to look online for evidence of people who improved their eyesight or restored it you will find it.
This site for example posted new drivers licences as proof that natural vision restoration works:

http://naturalvisioncenter.com/Success.h…

There is a book written by someone certified as having 20/10 in vision by an independent eyetest.
'the secret of perfect vision' by David de Angelis.

In fact most authors of books on natural vision restoration have improved or restored their vision. It wouldn't make sense if they hadn't.


Popular books on natural vision restoration:

"Natural Vision Improvement" by Janet Goodrich
"Relearning to See" by Tom Quackenbush
"The Bates Method for Better Eyesight Without Glasses" by William H Bates


And some websites that may be of interest to you:

http://www.natural-vision.co.uk/
http://visionsofjoy.org/
http://www.youtube.com/watch?v=ub1LYoDiA… (eye relaxation techniques)
http://www.youtube.com/watch?v=9jhqZO18f… (eye exercises)
http://www.youtube.com/watch?v=IjaQKYnx1… (pinhole theory)
http://www.youtube.com/watch?v=gDBrn6Bo3… (clinic using pinhole glasses)



Scientific research actually shows myopia is not caused by parents/genetics.
Sources:

(Inuit Eskimo Eyesight Research)
http://www.google.co.uk/m/url?ei=TSUCTbj…

(Comparison of ethnic chinese children living in singapore and australia)
http://www.google.co.uk/m/url?ei=mSUCTbi…