What is Astigmatism?


 What is Astigmatism?

Astigmatism confuses an awful lot of people, it's difficult to actually explain and to get your head around what exactly it is. So we'll of go right back to the basics. Now, a lot of people think that astigmatism is a rugby ball shaped eye – but no, the eye is not rugby ball shaped in astigmatism.  I'll explain that in a moment.

Everyone understands or has some grasp of what long-sightedness and short-sightedness is, but astigmatism, is a little bit more complicated. So, the cornea, which is the little transparent window at the front of the eye so you can see the pupil and the iris behind there, is sort of sitting on the front of your eye. So your eyeball is a sphere like a ball the cornea kind of sits onto it, think of it like a football with half a tennis ball stuck onto it.

The cornea is the main surface that bends the light going into your eye. That's the main thing that's going to try to focus the light into the back of your eye. And if you are long-sighted it's a bit too flat and doesn't bend the light enough, if you're short-sighted it's a bit too curved and bends the light too much.

Astigmatism is almost like a little mix of the two. Astigmatism can be described as almost like having a little bit of a rugby ball shaped cornea. Not the whole eye, just the cornea. That means there's a difference in curves across that. So, if you think about that, if you took a football, a sphere, chopped it in half and stuck it on the wall, every curve around that is going to be the same curve. So if light was to hit that, with it being the same curve no matter where the light hits it, it's going to bend it to one nice neat focal point. That's no astigmatism.

If you took a rugby ball and chopped it in half and stuck it on the wall you've got quite a steep curve and then a longer, flatter curve. So, the longer, flatter curve isn't going to bend the light as much as the steep curve is. That means you don't get one neat focal point, you get two focal points. And your eye will try its best to put those points together, but it can't do that. That's why you need glasses for astigmatism.

People think it's something that's very rare, but it's not. It's there in the majority of people. We don't tend to find people who don't have astigmatism at all, but most people's astigmatism is just a little bit. So that's the simplest way to explain it, it's a difference in the curves on the front of your eye so you're not getting one nice neat focal point.

Now, astigmatism in small amounts is notorious, well any amount of astigmatism, but even in small amounts is notorious for giving people eye strain headaches because you're trying your best to get that focus onto the back of your eye and you just can't put the two focal points together.

Anyway, I hope that helps explain! If you have any more questions about astigmatism, please do get in touch with us and we'll try and answer those. 


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