Why Does Glaucoma Cause Irreversible Vision Loss?

Glaucoma is one of the most common age-related eye conditions that you can develop. It’s also a leading cause of blindness in people over 60.

Glaucoma is often referred to as the “silent thief of sight” because it’s hard to detect in the early stages. When most people notice vision loss from glaucoma, irreversible vision loss has already occurred.

If you’ve suffered any damage to your eyes from glaucoma, it’s permanent. The same is true for any vision you’ve lost. The reason for this is the part of your eye that’s damaged and how it’s damaged.

The good news is that you can save your remaining vision with early diagnosis. But the only way to do that is to schedule regular eye exams with your eye doctor. Keep reading to learn more about glaucoma and why it causes irreversible vision loss.

What is Glaucoma?

Glaucoma refers to a group of eye diseases that all have one thing in common: they cause damage to the optic nerve. The optic nerve is what connects your eye to the rest of your nervous system and your brain.

Without the optic nerve, your eye wouldn’t be able to send the information about what it sees to your brain. Glaucoma is most often caused by a buildup of IOP or intraocular pressure.

Your eyes are naturally filled with fluid that flows through them to keep everything in your eyes healthy. But when something blocks off the natural drainage channels in your eye, the fluid can get stuck, leading to pressure build-up. The increased pressure puts strain on your optic nerve and eventually damages it.

There are two main types of glaucoma: open-angle and angle-closure. Open-angle glaucoma is by far the most common form of glaucoma.

Open-Angle Glaucoma

The angle referred to is the channel between the iris and cornea. In open-angle glaucoma, this channel is open, but the trabecular meshwork, the semi-porous tissue that surrounds your eye, becomes blocked somehow.

When the trabecular meshwork is blocked, IOP builds very slowly but will eventually put too much strain on the optic nerve and damage it permanently.

Angle-Closure Glaucoma

Angle-closure glaucoma occurs when the channel between the iris and cornea becomes blocked, usually because the iris bulges out. This often happens suddenly, in which case it’s called acute angle-closure glaucoma. Acute angle-closure glaucoma is a medical emergency that requires immediate treatment to relieve pressure.


The symptoms of acute angle-closure glaucoma are immediately apparent and include:

  • Nausea
  • Eye pain
  • Intense headache
  • Blurred vision

If you experience the sudden onset of these symptoms, immediately seek emergency medical care. You may be able to save your vision by undergoing emergency treatment to relieve the pressure.

The symptoms of open-angle glaucoma, on the other hand, are more complex. There are no noticeable symptoms in the early stages of the disease.

You can’t feel your intraocular pressure increasing. You also won’t experience any noticeable symptoms that affect your vision until damage to the optic nerve has already occurred. When the damage is done, you may experience symptoms that can include:

  • Blind/patchy spots in your vision
  • Decreased peripheral vision
  • Tunnel vision

Tunnel vision occurs in the late stages of having open-angle glaucoma. It can eventually completely overtake your ability to see, leaving you with only minimal central vision or even none at all.

But even with treatment, it’s not possible to restore vision that’s already been lost. Treatment only slows further deterioration, meaning it cannot restore any lost vision.

Vision Loss

Glaucoma is called a “silent thief of sight” because the damage has already been done when you present symptoms. The optic nerve is delicate and cannot be repaired.

But vision loss doesn’t have to be inevitable. The only way to prevent vision loss from glaucoma is by catching it in the early stages of the disease before you experience any symptoms. But to do that, you need to have regular eye exams.

Glaucoma Management

There is no cure for glaucoma, but it is possible to manage it after diagnosis. Treatment is geared towards lowering IOP and slowing the progression of the disease.

To do this, however, you need to be diagnosed with glaucoma before you experience significant vision loss. The only way to do that is to have regular eye exams.

Comprehensive eye exams almost always include taking your IOP. For some patients that have increased eye pressure but haven’t received a diagnosis of glaucoma, a comprehensive eye exam will also include examining the optic nerve for signs of damage. Assessing both these factors are required before diagnosing a patient with glaucoma.

Adults over 50 are at an increased risk for glaucoma and should have eye exams annually, if not more often. Your eye doctor will tell you how often you need to schedule eye exams based on your family history and other glaucoma risk factors.

Ideally, you should have eye exams at least every other year by the time you’re 40. If you have diabetes or a family history of glaucoma, you may also be at higher risk and require more frequent exams. Talk to your eye doctor to assess your risk and determine the best eye exam schedule for keeping your eyes healthy.

Taking Medication to Lower IOP

If you’re diagnosed with high IOP but haven’t experienced any optic nerve damage yet, the first step may involve taking medication to lower your intraocular pressure. These medications come in the form of eye drops that you need to take daily.

In more advanced stages of glaucoma, your eye doctor may recommend surgery to relieve eye pressure by creating a hole in your trabecular meshwork or inserting a drainage device. You may require a combination of surgery and medication.

The most important thing to know is that you cannot gain any vision lost to glaucoma even after diagnosis and treatment, making regular eye exams extremely important. As long as you stay vigilant about your eye health, you can keep your vision for years to come, even if you do develop glaucoma.

Are you concerned about glaucoma? Learn more about treating the condition by scheduling an appointment at New England Eye Center in Boston, MA, today.

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