Glaucoma Surgery: The Risks, Benefits & More

This article explores the potential risks of glaucoma surgery and explains why the benefits outweigh the risks in most advanced cases.

Glaucoma treatments

Glaucoma is a chronic and progressive deterioration of the optic nerve. (The optic nerve is the bundle of nerve fibers at the back of the eye that carry visual messages from the retina to the brain.) Glaucoma is usually caused or worsened by pressure inside the eye (intraocular pressure or IOP) that is too high to maintain constant nerve health.

The only proven treatment for glaucoma is to reduce eye pressure to prevent or delay damage to the optic nerve.

Complications of glaucoma

According to the World Health Organization, glaucoma is the second leading cause of blindness in the world after cataracts.

In people with glaucoma, the risk of loss of visual function or unilateral blindness is 50% at 15 years if they are not receiving treatment and up to 20% if it is bilateral blindness.

Meanwhile, cataract is more frequent in patients with glaucoma or who are receiving treatment.

Glaucoma surgery

Glaucoma Surgery: The Risks, Benefits & More
Glaucoma Surgery

Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the nerve at the back of the eye, known as the optic nerve.

If glaucoma medications and laser treatment haven’t helped treat your glaucoma, your doctor might recommend surgery. Surgery can’t cure glaucoma or restore lost vision, but it can help protect your vision and keep it from getting worse.

There are a few different types of glaucoma surgery that can help lower the pressure in the eye:

  • Trabeculectomy
  • Implant surgery for glaucoma
  • Minimally Invasive Glaucoma Surgery (MIGS).

If you need glaucoma surgery in both eyes, the doctor will only operate on one eye at a time.

What is trabeculectomy?

This type of surgery is usually used to treat open-angle glaucoma. It is done in a hospital and usually takes less than an hour.

The surgeon will create a small opening in the upper part of the eye, under the lid, where no one will see it. This opening allows excess fluid in the eye to drain, reducing eye pressure. 

You will usually be awake during this surgery, but you will receive numbing medicine as well as medicine to help you relax. He can usually go home the same day, but he will need someone to drive him back. 

What is glaucoma implant surgery?

This type of surgery is used to treat several types of glaucoma, including congenital glaucoma, neovascular glaucoma, and glaucoma caused by injury. It is done in a hospital and usually takes one to two hours.

In this operation, the surgeon implants a tiny tube, or drainage tube (called a “shunt”), in the white part of the eye. The tube helps drain excess fluid from the eye, which lowers eye pressure.

In most cases, you will be awake during this surgery, but you will receive numbing medications as well as medications to help you relax. He can usually go home the same day, but he will need someone to drive him back.

What is minimally invasive glaucoma surgery (MIGS)?

If you have mild glaucoma, your doctor may recommend a new technique called minimally invasive glaucoma surgery (MIGS). This also lowers eye pressure, but is safer and helps you recover faster.

There are different types of MIGS. So check with your eye doctor to see if MIGS might be an option for you.

Benefits versus risks of surgical treatment

As with any operation, there are risks associated with glaucoma surgery. This article looks at different risks, that way you can have an open dialogue with your eye surgeon (ophthalmologist).

However, it is important to note that surgery has very high success rates in slowing or substantially delaying the progression of glaucoma. When it comes to surgery for advanced glaucoma, the benefits generally outweigh the risks. The following are (rare) glaucoma surgery risks or side effects to review with your doctor:

  • Sight loss
  • Bleeding in the eye
  • Infection
  • Low eye pressure (or hypotonia)
  • Scarring cataract formation.

Below, we discuss each of the risks and why we believe the benefits outweigh or outweigh them.

Sight loss

In the short term after your operation, glaucoma surgery temporarily alters your vision. It is important to understand that vision can be permanently reduced, or even, in very rare cases, lost entirely as a result of any of these glaucoma surgeries; however, permanent vision loss is not a common side effect. Therefore, surgery is more likely to benefit your vision in the long term.

Bleeding in the eye

With any of these surgeries, complications can occur even using the best surgical techniques. Complications that rarely or rarely occur include bleeding inside the eye, infection, and fluid buildup behind the retina due to very low eye pressures. Bleeding within the eye can be a very serious complication, so you should talk to your ophthalmologist if you are taking blood thinners and follow their instructions on whether to continue or stop taking the medication before surgery.


Ophthalmologists administer antibiotics before, during, and after surgery, and use meticulous sterile techniques to try to avoid any infection. However, very rarely, an infection can occur inside the eye, which can be very serious and can endanger vision. These infections can occur weeks, months, or even years after surgery. So, even if it’s years after surgery, if you have early signs of infection, such as redness, pain, or excessive tearing, you should call and see your ophthalmologist right away to treat the infection before it becomes more serious. Early detection, in most infections can be adequately treated with antibiotic drops.

Low eye pressure (or hypotonia)

Sometimes surgery can cause eye pressures that are too low, also known as hypotonia. This is more common soon after surgery. With hypotonia, fluid can build up behind the retina (choroidal detachment), which can cause a shadow in your peripheral or side vision. This is usually temporary as pressure returns to expected levels. However, sometimes hypotonia persists and surgery must be performed to fix this problem.

Scarring cataract formation

Much more common than eye pressure that is too low, these glaucoma surgeries can fail over time due to the natural healing tendencies of the eye, resulting in eye pressures that are higher than anticipated. Sometimes, the scarring is so intense that the operation does not achieve low pressure and you may need to restart your glaucoma medications or have check-ups in the clinic or repeat surgery in the operating room.


Cataract formation will likely be accelerated by glaucoma surgery, but fortunately cataracts are fairly easy to correct surgically. Glaucoma surgeries are sometimes combined with cataract surgery if your ophthalmologist feels that the cataracts are having a moderate to significant impact on your vision. However, for some glaucoma surgeries, it is better to perform it separately and eventually operate on the cataract later in a second surgery.

What happens after the surgery?

Your doctor will prescribe eye drops to help prevent inflammation and infection, and you will need to use them for several weeks. These eye drops are different from other glaucoma treatment drops you might be using. 

While you recover, you may need to avoid some activities for 2 to 4 weeks, such as heavy lifting. You will also need follow-up checkups with your doctor to make sure your eye is healing well.

Will I need a new surgery?

For some people, the benefits of surgery last a long time. For others, the opening of the eye begins to close and requires another surgery. You will need regular check-ups with your doctor to measure your eye pressure. That way, your doctor can act quickly if you need more treatment.

Research shows that trabeculectomy lowers eye pressure in 7 out of 10 people who have it. It may work best for people who have not had an eye injury or other eye surgery.

Safer procedures in the future

MIGS (minimally invasive glaucoma surgery) are a group of newer procedures that are usually combined with cataract surgery to lower eye pressure to the mid-range (approximately 15 mmHg). In most cases, the safety profile of these procedures is higher than the more traditional glaucoma surgeries described above. However, this improved safety profile, its effectiveness is offset by a very modest reduction in eye pressure. Therefore, these procedures are usually combined with cataract surgery for patients with early to moderate stage glaucoma. For patients with advanced glaucoma, MIGS procedures are less likely to produce the necessary low intraocular pressures.


Although glaucoma surgery can prevent further vision loss and, in rare cases, can even improve vision, the damage that has already occurred due to this condition is considered permanent and is not yet reversible through medications, laser surgery , ocular stents or MIGS. While it is important to understand the risks discussed above, many of which are rare to occur, it is also important to recognize that the vast majority of glaucoma surgeries are successful in slowing or substantially delaying glaucoma progression and in achieving target eye pressure. Therefore, we recommend that you work with your ophthalmologist to explore options when the time is right and not delay treatment unnecessarily.

Tips to prevent glaucoma

Not all risk factors for glaucoma are preventable since, as we have seen, genetics plays an important role in the development of this disease. However, a diet rich in antioxidants and vitamins and low in animal fat, together with the practice of age-appropriate physical exercise and not smoking, can help improve a person’s physical condition and reduce the risk of suffering from arteriosclerosis, a pathology that damages all the arteries of the body, including those of the optic nerve.

Likewise, a review by a specialist is an essential recommendation and the most effective measure to detect glaucoma in its early stages when there are no symptoms yet. Thus, from the age of 40 -or earlier if there is a family history-, we must go to an examination by an ophthalmologist once every 5 years. From the age of 65, we will do it once every two years.
In short, these are the keys to preventing glaucoma:

• 1. Check your vision regularly.

Early detection of ocular hypertension and glaucoma is essential in order to prevent or stop vision loss. To do this, regularly go to ophthalmological check-ups; at least once every five years starting at age 40 and every two years starting at age 65.

• 2. Follow a diet rich in antioxidants and vitamins.

Eat fruits and vegetables daily and consult with your doctor or pharmacist about the possibility of taking food supplements with blueberries and/or vitamins, minerals and antioxidants. If you are a person who is at risk of suffering from ocular hypertension or glaucoma, moderate or also eliminate the consumption of animal fats.

• 3. Drink plenty of water.

Especially if you have glaucoma with normal intraocular pressure. In this case, your doctor will also monitor your blood pressure and thyroid function.

• 4. Practice moderate and regular physical exercise.

Always according to your age and general state of health, perform physical activity daily, to help you avoid high eye pressure.

• 5. Don’t smoke.

It is confirmed that the risk of intraocular hypertension and glaucoma increases depending on the number of cigarettes consumed, so it is essential to give up this habit.

• 6. Control stress.

Stress can nullify or reduce the effect of medications and lead to an increase in intraocular pressure.

• 7. Take care of your posture when sleeping.

If you have intraocular hypertension, it is recommended that you raise the head of the bed a few centimeters and that you avoid sleeping on your stomach.

• 8. Moderate your coffee consumption.

If you suffer from high eye pressure or glaucoma, do not consume more than three to four cups of coffee a day. Its effect of increasing intraocular pressure is known.

• 9. Adapt your environment to your needs.

If you have glaucoma, you may need to adjust lighting to your visual needs and use color contrasts to better see objects, mark stairs, etc.

• 10. Faithfully follow the medication indicated by the specialist.

It is very important that you comply with the treatment correctly, even if you do not have any pain, in order to prevent ocular hypertension from continuing, as well as the risk of glaucoma appearing or advancing. In addition, people with high eye pressure should avoid corticosteroids -including topical ones- and vasoconstrictor drugs and change the dosage if there are drops in nocturnal pressure.

Dr. Ashwani Kumar is highly skilled and experienced in treating major and minor general medicine diseases.