Glasses, or contact lenses: which are better for your eyes?

Eagle-eyed expert Roger Buckley had the answer to Korochkina's question... Roger - Well short-sighted people usually see better with contact lenses than with glasses and the reason is that there's no frame in the way. If you have an occupation which requires use of optical instruments like a microscope, in my case the operating microscope for example, it's much easier to get close to where you need to be if you're wearing contact lenses rather than glasses. And the other thing is, if you're short-sighted, the contact lenses will produce a slightly larger image on the retina so you will actually see better.

But against that, you have to bear in mind that glasses never did any eye any damage, whereas contact lenses can. The can cause infection, particularly if they're worn overnight. You're twenty times more likely to develop a corneal infection if you wear your lenses overnight than if you take them out every day.

Chris - Now if I go around struggling and I don't correct my vision because of vanity or whatever reason, are there any consequences apart from obviously walking into walls and having car accidents?

Roger - Yeah. Those are the main ones probably. We're talking about now in adults, in children it may be different. There may be reasons why children have got to wear glasses to correct their sight but in adults with their sight established, you're not going to damage your eyes if you don't wear your glasses. You could wear an out of date prescription, you could even wear someone else's glasses. You wouldn't see very well but it's not going to cause any damage.

Chris - Giles has just waved his hand. Are you wearing someone else's glasses?

Giles - I'm not wearing because of vanity. Because of how I look I don't wear glasses. But my question is: short-sightedness - is it reversible at all without laser surgery I mean? Does it go away or once you've established your eyesight, that's what it is?

Roger - Yes, in a word. It's all to do with the shape of the cornea but, more usually, with the total length of the eyeball. If the eyeball is too long you're short-sighted and there's nothing you can do to shorten it.

Chris - It's because the light is falling in front of the retina rather than on the retina and then it's passing through it's focal point and spreading out again, so you get a blurred image. You're not seeing spots of light you're seeing bigger blobs of light so things look blurry.

Roger - Exactly right.

Chris - Where do you stand on this whole idea of reading in the dark because people used to say to me when I was a kiddie - Oh don't read in the dark in poor light, you'll strain your eyes. Is that true?

Roger - I don't think there's any real evidence of that. The only thing I would say that the modern lifestyle which involves reading and using tablets, and telephones, and gadgets, is producing a race of short-sighted people. It's an epidemic. We don't go out and play games in the open air. We watch television, we work close too, if you see children walking in the street they're very often their nose is almost on the telephone or the pad, whatever it may be. And this is causing them to accommodate grossly, much more than is necessary.

Chris - Adapt their vision for close work?

Roger - Yes. Chris - Giles.

Giles - I didn't know this. In other words during development obviously you have brain plasticity, you know how everything is actually wiring themselves up, this is also true for your eyesight? You need to develop your eyesight to actually get to twenty-twenty, six-six vision? Roger - Yeah. The visual system when a child is born is really quite primitive, but also the eye is small, it's got to grow. What you don't want it to do is to grow too much, become too long and, therefore, short-sighted. So this is why it's better for children to be outside playing, kicking a football around, than it is to be concentrating on something just a few inches from their nose.

Chris - And last one Roger, very quickly. Laser surgery, where do you stand on that?

Roger - I think if the cases are very carefully chosen by experts, it can be very useful and it does have certain medical uses. For example, if one is very different from the other they can be evened out. But for purely cosmetic purposes, I have my doubts.