What Causes Elevation Of Optic Nerves?

My 23 year old daughter went to see a new Optometrist and was told she has elevated optic nerves. Her vision is -12.5 and -13.0 slightly worse than the last time. Her old records stated the optic nerves are thin. She has a follow-up next week with a Neuro- ophthalmologist. We have a strong history of glaucoma in our family. She is fine, an occ headache that has been relieved with OTC medications, She is scared. Any information would be helpful.