Nevus of the eye that is 32 years old

When I was 12 years old I noticed something had happened to my left eye. I thought maybe a blood vessel had burst in my eye or something. What did I know? I was only 12 years old. What I did know is that something was not quite right with my eye thereafter.
In a couple of weeks I will be 44 years old. The same 'blotch' is in the white part of my left eye - except now it is much larger, much more 'spidery' looking, and I would swear sometimes I think I can actually 'feel' this thing rub agains the inside of my eyelid when I blink.
I have heard this growth  referred to as a 'nevus'.  
Should I have this looked-at by an Opthomologist (sp?) or should I just 'get over it' and realise that it's more like a 'birthmark in my eye' than any kind of issue to be concerned about.
Can someone help me out here?
Thank you!

[Ray T Oyakawa, MD]

You need to see an ophthalmologist.  A nevus can become a melanoma, especially if it starts to grow.

Dr. O.