Open Angle Glaucoma: types, risk factors and symptoms

What is open angle glaucoma?

Open angle glaucoma is the most common form of glaucoma, accounting for over 90% of cases. It is often linked to a gradual rise in eye pressure due to an imbalance in the production and drainage of aqueous fluid—the fluid that maintains the eye’s shape. Unlike closed angle glaucoma, open angle glaucoma usually develops slowly and does not present with noticeable symptoms in its early stages.

Types of open angle glaucoma

Open angle glaucoma is categorized into two main types:

1. Primary open angle glaucoma
   • This occurs when eye pressure is elevated without a specific underlying cause. The high pressure results from an imbalance between the production and drainage of aqueous fluid. The exact reason why some individuals develop this condition while others do not is not fully understood. Various risk factors, which can be found in the “Risk Factors” section below, may contribute to its development.
     
     
2. Secondary open angle glaucoma
   • This type of glaucoma arises because of other conditions while the drainage angle of the eye remains open. Possible secondary causes include:
     • Pigment dispersion syndrome: Pigment from the iris may obstruct the drainage angle.
     • Pseudoexfoliation: Flaky material from the lens can block the drainage angle.
     • Neovascularisation: Abnormal blood vessels may grow and obstruct the drainage angle.
     • Uveitis: Inflammation can obstruct the drainage angle.
     • Latrogenic Factors: Medical interventions, such as the use of tamponade gas during retinal surgery, can affect eye pressure.
     • Trauma: Injury to the eye may damage and block the drainage angle.
     • Steroid Response: Some individuals experience increased eye pressure as a reaction to steroid use.

Risk factors for open angle glaucoma

Several factors can increase the likelihood of developing open angle glaucoma:

• Family History: If a close relative has glaucoma, you may be at higher risk due to genetic factors.
• Age: The risk increases with age, particularly in individuals over 40.
• Race: People of African or Afro-Caribbean descent are more prone to developing open angle glaucoma.
• Gender: Men are more likely to develop this type of glaucoma.

Symptoms of open angle glaucoma

In the early stages, open angle glaucoma often does not present with noticeable symptoms. This gradual progression means that the individual may not be aware of vision changes until significant damage has occurred. The condition typically results in peripheral vision loss, which can go unnoticed until it becomes more severe. Untreated, open angle glaucoma is a leading cause of irreversible blindness worldwide.

Because symptoms are not apparent early on, open angle glaucoma is commonly detected during routine eye exams. Tests such as the “air puff” test can measure eye pressure, but additional diagnostic procedures are usually needed to confirm the presence of glaucoma.

If you want to read more about closed angle glaucoma, please visit here.

Open angle glaucoma treatment

Treatment for open angle glaucoma focuses on reducing intraocular pressure to prevent further damage. Options include:

• Eye drops: Typically the first line of treatment, these can help decrease the production of aqueous fluid or improve its drainage.
• Oral medications: Used for more severe cases or as a temporary measure, these can affect the liver and kidneys if used long-term.
• Laser treatment: Selective Laser Trabeculoplasty (SLT) is a common choice. It can lower eye pressure for up to five years in 75-80% of cases and can be repeated as needed. The procedure is quick, taking 10-15 minutes per eye, and has minimal side effects.
• Surgical treatment: Options include trabeculectomy or tube shunt surgery to create a new drainage pathway for the aqueous fluid, or newer methods like iStent insertion to improve fluid outflow.

Each treatment approach aims to either reduce fluid production or enhance drainage to lower eye pressure effectively. Your eye specialist will recommend the most suitable option based on the severity of your condition and overall health.

For more information on glaucoma treatments, please visit our treatment page here.