Glaucoma is associated with higher-than-normal pressure inside the eye (ocular hypertension). If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.
Globally, glaucoma is the second leading cause of blindness (behind cataracts), according to the World Health Organization (WHO). The two main types are open-angle and acute angle-closure. Distinguishing both types is important as their management is different.