Hi my dad has glocoma for more than 10years now his optic never has been completely damaged over time th last doctor he saw in the past told him that ?

Likely: If your dad is being closely followed by a good ophthalmologist ( never use an optometrist for this potentially serious problem) then he is being regularly monitored and given the proper treatment to protect his eyes from any damage from glaucoma. The goal is to prevent the optic nerve from damage and this seems to be working.

Glaucoma is sneaky: Glaucoma is a tricky disease. Your father may not have had any symptoms but if the eye pressure was too high, he probably suffered progressive irreversible nerve damage. There is no way to get that back. It is important to keep the eye pressure down to prevent any further damage--especially in the "good" eye.