Types Of Glaucoma

Did you know there’s more than one type of glaucoma? Each type affects your eyes a little differently. Explore the main types and learn how they can impact your vision, so you’re better prepared to understand your condition or help a loved one. 

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Open Angle Glaucoma1,2,3

What is it?

Open-angle glaucoma, which accounts for over 90% of all glaucoma cases, typically has no early symptoms and often goes unnoticed until vision loss begins. Peripheral vision loss (tunnel vision) typically progresses slowly over time which causes difficulty reading, driving and walking. 

Causes

It is caused by increased intraocular pressure exceeding the normal range (10 to 21 mm Hg) due to improper drainage of fluid. Increased fluids in the eye causes pressure on the optic nerves. 

Who is at risk?

It is caused by increased intraocular pressure exceeding the normal range (10 to 21 mm Hg) due to improper drainage of fluid. Increased fluids in the eye causes pressure on the optic nerves. 

  • Patients with higher age (more than 40)
  • Patient with Myopia
  • Family History of Glaucoma
  • Patient with High blood pressure or Diabetes

Symptoms

Open angle glaucoma doesn’t have any early symptoms hence it is important to have regular eye check-ups.

There are two types of OAGS:

Primary Open Angle Glaucoma

Primary open-angle glaucoma is a chronic, progressive condition where the eye’s drainage angle remains open, leading to increased intraocular pressure and optic nerve damage.

Secondary Open Angle Glaucoma

Reference:

  1. Wang SY, Singh K, Lin SC. Association of glaucoma with cognitive function, neurodegenerative disease, and brain imaging abnormalities: a systematic review. 2024;331(4):355 -65. doi: 10.1001/jama.2023.26739.
  • GGupta D, Chen Glaucoma. Am Fam Physician. 2016 Apr 15;93(8):668–74. PMID: 27175838.
  • Machiele R, Motlagh M, Zeppieri M, Patel BC. Intraocular pressure. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Feb 27 [updated 2025 Jan]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532237/.

Angle Closure Glaucoma1,2,3.4

What is it?

Angle closure Glaucoma is also known as narrow angle glaucoma which is usually more severe compared to open angle glaucoma. 

Causes

This is caused by a damaged iris, the coloured part of our eye which leads to the blocking of the outlet. Due to blocked outlets the fluid inside the eye increases again leading to an increase in the intraocular pressure which gradually affects the vision and may cause blindness.

Who is at risk?

  • Increasing Age
  • Genetic Factor
  • East Asian Ethnicity
  • Female Gender
  • Shallow anterior chamber

Symptoms

Like open-angle glaucoma, closed-angle glaucoma is also an asymptomatic disease which remains unnoticed until vision loss.

Reference:

  1. Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a review. JAMA. 2014 May 14;311(18):1901 -11. doi: 1001/jama.2014.3192.
  2. National Eye Types of glaucoma [Internet]. Bethesda (MD): National Eye Institute; [cited 2025 Sep 1]. Available from: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma/types-glaucoma
  3. GGupta D, Chen Glaucoma. Am Fam Physician. 2016 Apr 15;93(8):668–74. PMID: 27175838.
  4. Amerasinghe N, Aung Angle-closure: risk factors, diagnosis and treatment. Progress in brain research. 2008 Jan 1;173:31-45. doi: https://doi.org/10.1016/S0079-6123(08)01104-7

CONGENITAL GLAUCOMA1,2,3.4

What is it?

Congenital glaucoma is rare but serious eye condition present at birth where the eye’s drainage system does not develop properly. Primary congenital glaucoma (PCG) affects roughly 1 in 10,000 to 18,000 live births. Approximately 18% of children in blind facilities and 5% of pediatric blindness globally are caused by glaucoma.

Causes

This is caused due to poor fluid outflow, causing a buildup of intraocular pressure. Over time, the elevated pressure can damage the optic nerve and affect vision in children.

Who is at risk?

  • Age less than 3 years
  • Family history
  • Developmental abnormalities

Symptoms and signs

  • Having cloudy eyes
  • Are sensitive to light
  • Make extra tears
  • May have eyes that are larger than normal

Reference:

  1. Mandal AK, Chakrabarti Update on congenital glaucoma. Indian J Ophthalmol. 2011;59(Suppl 1):S148–57. doi: 10.4103/0301-4738.73683
  2. National Eye Types of glaucoma [Internet]. Bethesda (MD): National Eye Institute; [cited 2025 Sep 1]. Available from: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma/types-glaucoma
  3. American Academy of Congenital glaucoma – Europe [Internet]. San Francisco: AAO; [cited 2025 Sep 1]. Available from: https://www.aao.org/education/topic-detail/congenital-glaucoma-europe
  4. Gilbert CE, Canovas R, Kocksch de Canovas R, Foster Causes of blindness and severe visual impairment in children in Chile. Dev Med Child Neurol. 1994 Apr;36(4):326-33. doi: 10.1111/j.1469-8749.1994.tb11853.x. PMID: 8157155.

SECONDARY GLAUCOMA 1,2,3

What is it?

Secondary Glaucoma is caused due to underlying medical conditions or eye injuries which increase eye pressure leading damage of optic nerve.

Causes

Secondary Glaucoma is caused due to different factors based upon its types:

  • Neovascular: Happens when the eye makes extra blood vessels that cover the part of your eye where fluid would normally drain. This can be caused due to Hypertension or Diabetes
  • Trauma: It is due to any injury to eye
  • Uveitic: occurs when a part of the eye called the uvea becomes swollen and inflamed.
  • Pigmentary: This is caused when the pigment granules clogs the eyeball drain system the drain hence increasing the intraocular pressure
  • Steroid Induced: Due to increased use of steroidal medicines like corticosteroids.
  • Other Conditions like Cataract and Tumors can also cause Glaucoma but not very common

Symptoms

  • Patchy Blind Spot
  • Headache
  • Pain in the eyes
  • Redness of eyes
  • Visible Halos around lights

Reference:

  1. Glaucoma Secondary glaucomas [Internet]. London: Glaucoma UK; [cited 2025 Sep 1]. Available from: https://glaucoma.uk/about-glaucoma/ what-is-glaucoma/secondary-glaucomas/
  2. Glaucoma Research Secondary glaucoma [Internet]. San Francisco: Glaucoma Research Foundation; [cited 2025 Sep 1]. Available from: https://glaucoma.org/types/secondary-glaucoma
  3. National Eye Types of glaucoma [Internet]. Bethesda (MD): National Eye Institute; [cited 2025 Sep 1]. Available from: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma/types-glaucoma