Is that a cataract I can see growing over my eye?

Probably not.  Cataract refers to cloudiness or opacitiy in the lens of the eye.  The lens of the eye sits in behind the pupil, well inside the eye.   Most of the time cataracts are not visible looking at the eye.  In very advanced cases you might notice the pupil is greyish rather than black, but that's all you'd see. 

If you're look at your eye and seeing something growing over it, chances are you're looking at a pterygium.  Connective tissue growths, they are typically seen in people who spend lots of time outdoors, appearing white, but easily become inflamed in dry or dusty conditions.  They can be removed surgically if they encroach too far across the eye.  

If you're watching anything growing across your eye, it's best to get it checked out.