Question about glaucoma and high eye pressure?

I am a 16 year old male and I was just at my eye doctor. I've been wearing gles that are -3.25 (i am nearsighted), for about 8 months. I went for an eye check and my eye pressure is 23. The doctor said that it was high, and that the normal amount is lower than 21. I took the glaucoma test and the doctor said that i have no damaged nerves, and that i ped the test with no glaucoma. I am wondering what i can do to lower my eye pressure, and reduce my chance of glaucoma.