Size of Optic Nerve in a Toddler

I took my 2 year old son to a Pediatric Opthalmologist to have his eyes checked and she stated that the optic nerve is larger in African-Americans, but that my son's was larger than mine. She said his eyes were fine, but wants to see him again in six months as a large optic nerve is a precursor to Glaucoma. She also mentioned something about a "disc or cup." Is that different from the optic nerve. My husband seems to think that a child's optic nerve would be larger than an adult's because it is still developing. Can someone shed some light on optic nerve (disc or cup) and the average size of the optic nerve for a child and for an adult?

Thank You Very Much

[Ray T Oyakawa, MD]

Cupping is one indication of glaucoma.  The normal vary a lot.  See you doctor as recommended.

Dr. O.