Why can't I see without glasses?

Why do I need glasses?

The need for glasses to help us out is very normal and is due to a number of different factors.

I'm going to try to keep this as simple as I can because it can get a little bit in-depth and confusing sometimes. The basic reason that people need glasses, and now I'm talking about just normal distance, everyday glasses. Like me, I wear my glasses all day, so I when I'm driving, when watching telly, I'll have them on when I'm reading, etc. So, that is basically down to the anatomy of your eyeball. Okay. So, it's all to do with the curves of your eye and the length of your eyeball. So, we'll ignore what else goes on. We'll ignore the lens and the focusing and all that sort of stuff, but it's the length of your eye and the curves of your eyeballs that is the main cause.

So for example, if your eyeball was a bit too long, the light, when it goes through your eye, isn't going to get focused on the back of your eye, it's going to fall short of that and therefore the image isn't going to be sharp. It's going to be blurred. The same thing happens if your eye is a bit too curved at the front where the light hits it. A very curved surface is going to bend the light more than a flatter surface. So, it's going to bend it too much, and again, it's going to put that focal point in front of the retina. It's not going to reach the bit that does the vision – the retina. This is would be a short sighted eye. Now, the opposite is also true. If an eyeball is too short and the light is focusing behind it as it were, so it's not getting to a focal point before it hits the retina. And, if the eye is too flat at the front, it's not going to bend the light enough to actually get that focus on the retina. It's almost like the focal point is going to fall behind the retina. This is basic long sighted eye.

The other thing to add into that is that there could be a difference in curves across the eye, and that's going to bend the light in different ways. That's going to cause problems too. So, the main reason for needing glasses is literally down to the anatomy of your eyeball and how that changes as we grow and changes over time, which is why eyesight does tend to change. The other big reason for needing glasses is one that affects, well, nearly every single human in the world and that is the natural loss of focus for near vision.

There's a natural loss of focus with age. You might be surprised to hear that an optician can look at your date of birth and already kind of knows what reading power they would need to give you because it is that strongly linked to age, and that's down to the lens inside your eye. It’s to do with how the lens functions and how the lens itself can move and therefore bend the light to help you focus things when they're closer to you. So, that is the other reason why we need glasses. Now, that affects people in their 40s usually. Some people make it closer to 50, some people come in on their 40th birthday, but generally it's round the time you're about 45 you're going to need some help with reading. So, you're looking at reading glasses for that kind of thing.

So there you go, those are the main reasons that we need glasses. So, it's down to anatomy of your eyeball, and how that changes over time. It's down to natural loss of focus in the eye, down to changes in the lens in your eye. Now, I will explain those in a bit more detail when we talk about short-sightedness, long sightedness, astigmatism, and needing reading glasses, which is actually called presbyopia. I'll explain those in their own little videos and pages in a bit more detail. So, if you want to find out more, find those videos and find out some more about each of those conditions.