Glaucoma is a condition that harms the optic nerve of your eye. It generally occurs when fluid accumulates in the front section of the eye, which raises eye pressure and damages the optic nerve. Glaucoma is one of the leading causes of blindness in people over 60 years old. However, early treatment often prevents vision loss.
What Is the Main Cause of Glaucoma?
The eye constantly produces a fluid called aqueous humor. For eye pressure to remain stable, the fluid that enters the eye should drain out at the same rate. Drainage occurs through the drainage angle. When the drainage angle is blocked, fluid cannot exit the eye, causing pressure to rise and damaging the optic nerve. This pressure is called the intraocular pressure (IOP).
The optic nerve contains over a million small nerve fibers, functioning like an electric cable made of numerous wires. As these fibers die, blind spots appear in your vision. These blind spots often go unnoticed until nerve fibers responsible for central vision are damaged. Complete loss of fibers results in blindness.
How Do You Get Glaucoma?
There are two major types of glaucoma.
Open-angle glaucoma is the most common type. Even though the angle is open, the eye’s drainage system does not let fluid out efficiently, causing fluid buildup and increased eye pressure, similar to a clogged sink. As fluid accumulates, pressure increases, and the optic nerve begins to suffer damage. This type is gradual, painless, and does not affect vision in the early stages. Some people have optic nerves that are particularly sensitive to normal eye pressure, putting them at higher risk for glaucoma. Regular eye exams are essential for detecting early nerve damage before vision is affected.
Angle-closure glaucoma (also called “closed-angle” or “narrow-angle” glaucoma) occurs when the iris is positioned very close to the drainage angle, which can block fluid from exiting the eye. When the drainage angle is completely blocked, eye pressure rises rapidly, causing an acute attack. This is a medical emergency, and emergency ophthalmological care is necessary to prevent blindness.
The signs of an acute angle-closure glaucoma attack may include:
- Sudden blurry vision
- Severe eye pain
- Headache
- Nausea
- Vomiting
- Rainbow-colored rings or halos around lights
Some people develop angle-closure glaucoma slowly over time, which is referred to as chronic angle-closure glaucoma. Early on, there are no symptoms, and individuals may not realize they have the condition until significant damage occurs or an acute attack happens. Untreated angle-closure glaucoma can lead to permanent blindness.
What Happens if You Have Glaucoma?
Open-angle glaucoma symptoms
- Early stages show no warning signs.
- Blind spots develop in peripheral vision as the disease progresses.
- Vision changes may go unnoticed until severe damage occurs, earning it the nickname “silent thief of sight.”
- Regular eye exams are essential for early detection.
Angle-closure glaucoma symptoms
- Often symptomless until an attack.
- Early signs can include blurred vision, halos, mild headaches, or eye pain.
- An attack includes severe eye/forehead pain, eye redness, blurred vision, halos, headache, nausea, and vomiting.
Normal tension glaucoma symptoms
- Eye pressure is normal, but blind spots and optic nerve damage occur.
Glaucoma suspects
- Some have elevated eye pressure (ocular hypertension) but no damage.
- Others may have normal pressure but unusual optic nerve characteristics.
- Most glaucoma suspects are symptom-free and require careful monitoring for potential treatment initiation.
Pigment dispersion syndrome (PDS) and pigmentary glaucoma symptoms
- PDS occurs when pigment flakes from the back of the iris, raising eye pressure and causing pigmentary glaucoma.
- Symptoms may include halos or blurry vision after physical activities like jogging or basketball.
Seek an evaluation by an ophthalmologist if these or other symptoms occur.
Who Is at Risk for Glaucoma?
Individuals with higher risk factors include those who:
- Have high eye pressure
- Are farsighted or nearsighted
- Have experienced eye injury
- Use long-term steroid medications
- Have thin central corneas
- Have thinning optic nerves
- Have diabetes, migraines, high blood pressure, poor circulation, or other systemic health issues
- Are over 40 years old
- Have family members with glaucoma
Multiple risk factors increase the likelihood of developing glaucoma. Consult an ophthalmologist regarding your risk.
Glaucoma Diagnosis
A definitive glaucoma diagnosis requires a comprehensive eye exam. Eye pressure screening alone is insufficient.
During an exam, an ophthalmologist:
- Measures eye pressure
- Checks the drainage angle
- Examines the optic nerve
The following investigations are also performed:
- Testing peripheral (side) vision
- Imaging of the optic nerve, using Optical Coherence Tomography (OCT)
- Measurement of corneal thickness
Because early stages are symptom-free, half of those with glaucoma may not know they have it. Regular eye exams help detect disease early. Your ophthalmologist can advise on exam frequency.
Can Glaucoma Be Stopped?
Damage from glaucoma is permanent and cannot be reversed, but medications and surgical treatments can help prevent further damage.
Treatment Options
Medication
Eye drops are usually the first approach. Eye drops used daily can lower eye pressure either by reducing aqueous humor production or improving drainage.
Because medications can interact with other drugs, it is important to provide your ophthalmologist with a complete list of the medicines you take. Never stop or change glaucoma medication without consulting your ophthalmologist, and ensure timely prescription refills.
Laser Procedures
Two main laser procedures improve drainage:
- Trabeculoplasty: For open-angle glaucoma, a laser is used on the angle to improve drainage. It can be done as a replacement or an addition to medications.
- Iridotomy: For angle-closure glaucoma, a laser is used to create a tiny hole in the iris. This hole helps fluid flow to the drainage angle.
Surgery
- Trabeculectomy: the surgeon creates a small pathway that allows fluid inside the eye to drain more easily.
- Glaucoma drainage devices: Small tubes drain fluid to a reservoir beneath the conjunctiva for absorption.
- Cataract surgery/Clear lens extraction: Removing the natural lens in narrow-angle eyes increases space for fluid drainage and reduces eye pressure.
- Minimally Invasive Glaucoma Surgery (MIGS): For mild or moderate glaucoma, these surgeries use tiny openings or small devices to make drainage easier, and they are often done at the same time as cataract surgery.
Your Role in Glaucoma Treatment
Successfully managing glaucoma requires cooperation between you and your ophthalmologist.
Follow all instructions and take medications as prescribed. Once treatment begins, regular follow-up visits are essential, typically every 3-6 months, though your ophthalmologist may adjust this schedule depending on your needs.
Always discuss any concerns or questions about your eyes or treatment with your ophthalmologist.