Glaucoma refers to a group of diseases that are characterized by an increase in intraocular pressure that damages the optic nerve, and subsequently causes visual impairment. The increase in the intraocular pressure is caused by the buildup of aqueous humor because of improper drainage from the eye. Glaucoma is one of the primary causes of blindness affecting 60 million people worldwide.

Most Common Forms of Glaucoma 

  1. Open-angle glaucoma occurs when there is a gradual increase in the resistance to the outflow of the aqueous humor through the trabecular meshwork. This decrease in drainage increases the intraocular pressure. Open-angle glaucoma is characterized by a slow progression of disease and the drainage angle between the iris and cornea remains open.

Open-angle glaucoma may be asymptomatic, especially at the beginning, or may present with worsening peripheral vision, headaches, and blurred vision

  1. Angle-closure glaucoma occurs in those whose iris is close to the drainage angle and the cornea and iris connect, closing the angle and subsequently blocking drainage through the trabecular meshwork completely. Angle-closure glaucoma is characterized by a sudden and painful onset, red eyes, blurry vision, headache, and nausea. Angle-closure glaucoma requires emergent treatment.

Risk Factors for Glaucoma

  • Advanced age
  • Ethnicity: African, Hispanic, or Asian
  • History of glaucoma in a first degree relative
  • Chronic medical conditions, such as diabetes, high blood pressure, and heart disease.
  • History of trauma to the eye or retinal detachment
  • Tumor of the eye
  • Protracted use of corticosteroids
  • Anatomical differences, such as thin corneas, myopia, and hyperopia.

Source: Dietze J, Blair K, Havens SJ. Glaucoma. [Updated 2022 Jan 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: