What are the Major Parts of the Eye?

@Mor - Yeah, I did a bit of research on it because I've been thinking about getting my short sightedness corrected. Apparently most of the surgery is done with lasers and is very quick and easy.

It's the after care where people often make mistakes. You have to be very careful to follow instructions to keep the area disinfected, because an eye infection on recent surgery can lead to blindness if you aren't careful.

I don't believe even that happens very often at all. But, at the moment it's mostly laser eye surgery cost that's stopping me from doing it. Once the price comes down it will be a different story.

@ddljohn - That kind of surgery on an eye problem is very common. They do it in order to fix myopia all the time now. From what I've heard the cornea heals itself in basically a few days.

It's scary, because often you'll be awake for it, even if they numb and immobilize your eye. And these fears are definitely something to talk to your doctor about, because really, any surgery has some risks. But, for a surgery, it's pretty safe.

@donasmrs - Something that scientists have found really fascinating is that animals like octopuses and squids actually evolved and developed eyes separately from animals with spines. Even though they are very similar, the octopus eye is also different, for example in that it doesn't have the blind spot caused by the optical nerve that most animals have.

With that said, all eyes, whether they be insect, human or cephalopod, have a common ancestry and probably developed from photo sensitive cells. Having the ability to see would have been such an advantage that it must have developed quite rapidly once they got past the initial steps.

@donasmrs-- That depends on which animal we're talking about but many animals have very similar eye structures as humans.

I don't know if eyelids are considered part of the eye but I know for example that cats have a second eyelid that they use to coat and protect their eyes in certain situations. It's visible sometimes when a cat is waking up from sleep, it looks like a white sheet that emerges from the sides.

This eyelid automatically closes when something is aimed at the eye. So if the cat is walking inside a bush with lots of poking branches, it will use this second eyelid to protect the cornea from being damaged.

Cool right?

I've been thinking about getting laser eye surgery to fix my eye sight but after I learned about what they actually do in the surgery, I've been very scared.

My doctor said that this surgery involves cutting a flap from the top of the cornea. After they remove this flap, they use laser to make changes in the cornea itself to fix eye sight and then they put the flap of cornea back.

Isn't this really dangerous? Does our cornea have the capacity to fix itself after it has been cut like that?

I had no idea that our eyes were so complex.

I'm curious, are the eyes of animals structured the same way as ours? Do they have the same parts?

Great article- I just want to add that a good way to protect the retina is to purchase polarized sunglasses.

Polarized sunglasses protect the eyes and especially the retina from the harmful UVA and UVB rays. It allows you to see objects clearly without any form of glare.

It is well known that prolonged exposure to UVB rays can lead to photokeratitis which is a sunburn in the eyes. This sun exposure burns the cornea. This is another reason why polarized glasses are so important.