How do i know if my 21 yr old sister has glaucoma?

Get tested : The only way to know if you have glaucoma is to get tested at an ophthalmologists office. Glaucoma has no real signs that a patient can see. By the time you notice loss of vision, you are almost permanently legally blind.

Diagnosis: Yu would need to ask if she was diagnosed with the disease by an ophthalmologist or optometrist. You cannot tell by looking at her eyes.