A class of eye diseases known as glaucoma harms the optic nerve, which is essential for sending visual data from the eye to the brain. Although glaucoma can develop with normal or low intraocular pressure (IOP), this damage is frequently linked to elevated IOP. Glaucoma can cause irreversible vision loss and perhaps blindness if treatment is not received. Although glaucoma comes in many forms, the two primary kinds are as follows: The most prevalent type of glaucoma is open-angle glaucoma. The trabecular meshwork, which drains the aqueous humour, becomes less effective as it steadily develops and the drainage angle of the eye stays open. The intraocular pressure rises as a result. Angle-closure glaucoma: This kind develops when the eye's drainage angle is obstructed, which causes an abrupt rise in intraocular pressure. It can be a medical emergency that needs to be attended to right now. In its early stages, glaucoma is often asymptomatic, which is why it is called "the silent thief of sight." Peripheral vision is usually impaired first as the optic nerve is destroyed, and symptoms may not become apparent until the condition has advanced. Age, family history, high intraocular pressure, certain medical problems (including diabetes), and ethnic background (those of African, Hispanic, and Asian descent are at higher risk) are risk factors for glaucoma.