Open-Angle Glaucoma

Definition

Open-angle glaucoma also called primary or chronic glaucoma is defined as glaucoma with wide and open angle between iris and cornea along with raised intraocular pressure. IOP rises due to slow clogging of drainage canals of eye.

Facts about Open-angle glaucoma

• It is the most common form of glaucoma, accounting for at least 90% of all glaucoma cases

• Leading cause of irreversible blindness
• Without any associated underlying disease
• Develops gradually and steals vision
• Is a lifelong condition
• Almost unnoticeable symptoms and eye damage for many years
• Initial loss of vision is of side or peripheral vision
• Vision loss means advanced stage of glaucoma

Risk factors of Open-angle glaucoma

Risk factors for primary open-angle glaucoma have been extensively described and include the following:

• Elevated intraocular pressure
• Advanced age
• Family history
• African American or Latino ancestry
• Myopia
• Thinner cornea
• Certain systemic diseases, such as diabetes, cardiovascular diseases and hypertension
• Previous eye disease, eye surgery, or eye/head trauma
• A sedentary lifestyle without regular exercise

Symptoms of Open-angle glaucoma

Most of the cases of open-angle glaucoma have typically no warning or painful signs and symptoms till there is significant vision loss. In the later stage of disease, patient complains of the following:

• Sudden vision loss
• Extreme headache
• Eye pain or redness
• Multi-coloured halos especially in light

Eye Screening for every individual with risk factors

Glaucoma is a serious eye condition that can take the vision all of a sudden without showing any warning signs or symptoms. It is very important for every individual (especially with risk factors) to screen themselves at regular intervals to save their vision and avoid any emergency condition. Regular eye examinations with an ophthalmologist are important to screen for primary open-angle glaucoma and other ocular conditions that are increasing the eye pressure.

Diagnosis of open-angle glaucoma

Early diagnosis plays a very crucial role in treatment as well as preservation of the vision. The late stage of disease can cause sudden and irreversible vision loss and that is why early screening of every individual at risk of developing open-angle glaucoma is very important. The diagnosis of open-angle glaucoma requires following tests and examination:

• Visual acuity to check peripheral (or side) vision
• Slit lamp examination of the anterior segment, cornea, iris, lens
• Fundoscopy
• Tonometry to measure the pressure inside the eye
• Gonioscopy to check the drainage angle of eye
• Pachymetry to evaluate corneal thickness

Treatment of open-angle glaucoma

Without proper and prompt treatment, open-angle glaucoma can lead to blindness. After proper evaluation of the patient, ophthalmologist may prescribe following line of treatment for the patient:

• Medication : The goal of medical treatment is to reduce the eye pressure before performing the surgery. Various eye medications may be required like:
  • Alpha-agonists
  • Beta-blockers
  • Carbonic anhydrase inhibitors
  • Miotics
  • Prostaglandin analogs
• Surgery : Surgery is required in cases of optic nerve damage and may be any of the following depending upon patient condition and disease severity:
  • Trabeculoplasty
  • Conventional incisional surgery (also known as filtering surgery)
  • Trabeculectomy
  • Drainage implant surgery
  • Ciliary body ablation