Glaucoma is a common eye problem that is characterized by failure to maintain the balance in eye fluid production and drainage, resulting in an increase in intraocular pressure (pressure inside the eye). Glaucoma causes loss of vision and it is best to avoid this complication by seeking immediate medical attention when signs of increased intraocular pressure occur.

There are mainly five types of glaucoma: open-angle glaucoma, angle-closure glaucoma, normal-tension glaucoma, developmental glaucoma and pigmentary glaucoma. To understand this condition and identify causes of glaucoma, we will first discuss how glaucoma develops.

Eye Anatomy and Glaucoma

To understand how glaucoma leads to vision loss, you first must understand more about intraocular fluid movement in the eye:

1. A small structure (ciliary body) found behind the colored portion of your eye (iris) produces a clear fluid (aqueous humor).
2. Aqueous humor circulates in the front (anterior) chamber of the eye and is drained through a drainage angle formed between the iris and the surface of the eye (cornea).
3. The aqueous passes through the angle and the white part (sclera) of your eye and drains to the vein network outside your eye.
4. Disruption in this fluid outflow can result in an increase in intraocular pressure (IOP) or glaucoma.

Glaucoma Causes

The common causes of glaucoma include:

• Intraocular pressure (IOP). The eye is a globe-like structure that depends on its internal pressure to retain its shape. This pressure is influenced by its fluid content, which is not static but dynamic. When the eye loses its ability to regulate the balance between fluid production and drainage, intraocular pressure can rise dangerously, leading to glaucoma. The high pressure, if sustained, affects the nerve fibers that comprise the optic nerve, causing damage and permanent loss of vision.
• Eye injury. An increase in IOP may be caused by eye injuries that result in failure to drain fluid buildup inside the eye.
• Poor intraocular blood flow. This is associated with scotomas (blind spots) that develop within your visual field. These are similar to those occurring in glaucoma.
• Protein buildup. Accumulation of beta-amyloid, a protein in the retina, is associated with glaucoma. It has also been found to be associated with Alzheimer’s disease.

The most common cause of glaucoma is an increase in internal eye pressure but the disease can also occur when the intraocular pressure is normal. This condition is called normal-tension glaucoma, which occurs in people who have optic nerves that are highly sensitive to pressure even with normal IOP. The exact cause is unknown, but research suggests that narrowing (vasospasm) of blood vessels and decreased blood flow to the optic nerve may be one of the glaucoma causes.

Diagnosis and Treatments

Conventional methods used in testing for glaucoma involves screening for high intraocular pressure. However, glaucoma can occur even with normal IOP, so direct examination (fundoscopic exam) of the optic nerve as well as testing the visual field are important to diagnose glaucoma.

Immediate glaucoma treatment is necessary to protect the nerve cells of the eye from being damaged, which can lead to blindness. Common treatment include eye drops, laser surgery and microsurgery for glaucoma. And for different kinds of glaucoma, the surgery may vary. For example, Argon Laser Trabeculoplasty (ALT) is usually for open-angle glaucoma; Laser Peripheral Iridotomy (LPI) is for angle-closure glaucoma. Doctors will take the proper surgery for specific condition. 

You can watch the following video for knowing more about glaucoma causes, symptoms, prevention and treatment options.