Impairment to the optic nerve is thought to be triggered by augmented pressure in the eye (intraocular pressure, or IOP). This might result from excess fluid, called aqueous humor, building up in the eye for the eye produces too much or drains too little of the fluid. However, numerous cases of glaucoma develop without increased IOP. In these cases, decreased blood flow to the optic nerve may cause the damage. Glaucoma might develop after an eye injury, after eye surgery, from the growth of an eye tumor, or as a complication of a medical ailment such as diabetes. Certain medicines (corticosteroids) might cause glaucoma when they are used to treat eye inflammation or other ailments. Glaucoma that develops because of another condition is called secondary glaucoma.