Is having grey marks on your eyeball bad?

Not necessarily: See an eye doctor to be sure, but there are normal areas of pigmentation on the eye and sometimes areas can look red, yellow, brown or gray. There are rarer conditions where the white part can even be blue! sometimes these pigmentations are chronic and generally safer and sometimes these are new and need to be monitored closely.

Most likely benign : The white part of your eye is called the sclera. The sclera can accumulate pigmentation: blue, grey or brown discoloration due to melanin, a natural occurring pigment. Some rare cases are a form of "pre-cancer" - so you should let your eye md check you out. Rarely, certain silver containing medications can turn the sclera blue. Most cases are benign aging changes.

Usually normal: Grey marks over the white of the eye is usually a nevus at a deeper level or around the opening that lets a blood vessel come to the surface. Over the cornea it can be a scar. You can go see your specialist eye md to be sure.