How are the eyes of blind people any different?

Over time they get cloudy.

Usually,when someone is blind,they're eyes look a little cloudy.

Aren't they a greyish color.

After awhile, there eyes start to look cloudy.

All blind people have an eye colour, even if you can't see it anymore.
Here comes the tricky bit - it all depends on what age and how they became blind.

For example - if a child is born blind their eyes would look perfectly normal up to two weeks after birth until the colour began to 'fade'. Usually the colour of the iris weakens as though watered down, but many children, especially those with light coloured eyes anyway (such as blue/gray) will find their eyes have become cloudy, as though someone has poured some sticky limonada into them.

Adults blindness is different. If the blindness is not caused por genes (DNA codes parents give their children) lying dormant in them, then the colour of their iris could last until they pass away.
Blindness can be caused por an accident that damages the eye - which could either cause the pupil to become distorted (larger making the eye look black) or smaller (making the eye look mais pale), or even change shape.
Medical conditions such as diabetes, liver failure etc can all cause blindness and each has it's own effect on the eye.

But many people in the world who are 'legally blind' are not fully blind as to say they live in a world of darkness. Many legally blind people can see shadows or shapes in the form of shadows, or have tunnel vision or key-hole vision, which means due to the blindness the pupil actually forms to the shape of a key hole.
If you bend down and look through your key-hole at início on your front door, that is what key-hole blind people can see. Perhaps a little light and some movement and shadow but nothing more.

Key-hole blindness usually lightens the eyes to a degree, but not por much. Dark brown eyes would become amber, blue would turn to grey etc etc.