Purpose of Glaucoma Surgery

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Glaucoma surgery is performed to help lower your intraocular pressure when you have glaucoma. This can help to reduce your risk of losing vision. Glaucoma surgery also may be done to lower the number of eye drop medications you use.

When you have glaucoma, you may need one or more eye drops every day to help keep your intraocular pressure down. Keeping track of those different eye drops and using them properly can be challenging. Glaucoma surgery may eliminate the need for some of those eye drops.

Older male patient with eye doctor.
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Diagnosis Related to Glaucoma Surgery

A diagnosis of glaucoma is needed to have glaucoma surgery. Glaucoma causes a progressive problem in the optic nerve. Your optic nerve is a series of nerve fibers that carry visual messages from the back of the eye to the brain.

Glaucoma can become worse by a pressure inside the eye that’s called intraocular pressure. A normal eye pressure is 10 to 20 mm Hg (mm Hg is short for millimeters of mercury). Left untreated, glaucoma can cause vision loss and blindness.

There are more than 3 million people in the U.S. who have glaucoma and 80 million worldwide. Glaucoma becomes more common in your 40s, 50s, and 60s. The number of people expected to have glaucoma likely will increase in the future due to the aging of the population.

Your eye doctor may recommend glaucoma surgery if medications don’t effectively lower your intraocular pressure.

Another reason an eye doctor may advise surgery is if you are taking many eye drops and they are hard to manage, or if it’s a physical challenge for you to use eye drops (for example, due to arthritis in your hands). Patients often miss their recommended dose of drops when they don’t use the drops properly.

Glaucoma once had a limited number of surgical options, but that has changed in recent years. There is now a growing number of surgical options to help you if you have glaucoma. 

There are several different types of glaucoma surgery performed. They are typically described as laser glaucoma surgery or incisional glaucoma surgery. No matter what the approach, the goal is the same – to lower your intraocular pressure.

Laser glaucoma surgery uses a beam of light to treat the eye’s drainage system, which is also called the trabecular meshwork. Laser surgery helps to raise the fluid flow from the eye. Types of laser glaucoma surgery include:

  • Argon laser trabeculoplasty
  • Laser cyclophotocoagulation
  • Laser peripheral iridotomy
  • Selective laser trabeculoplasty

Laser surgery for glaucoma is effective for most patients, but its effects can wear off over time. That means the laser surgery may need to be repeated.

Incisional surgery for glaucoma allows the eye doctor to create a drainage hole that allows eye fluid to bypass the eye’s blocked drainage system and flow out of the newly-created drainage hole. Incisional surgery is also referred to as filtering surgery. Types of incisional surgery include:

  • Trabeculectomy involves the creation of a small opening in the eye, under your eyelid, allowing extra fluid to drain away.
  • Glaucoma implant surgery is a type of glaucoma surgery in which the eye doctor implants a small tube on the white of your eye to help drain extra fluid.
  • Minimally invasive glaucoma surgery (MIGS) uses microscopic-sized equipment and incisions to help lower the complications associated with traditional glaucoma surgery.

MIGS approaches often build on the types of surgeries already performed. For instance, there are MIGS approaches for trabeculectomies and for glaucoma implant surgery.

Some types of MIGS approaches can be combined with cataract surgery, helping a glaucoma patient who needs a cataract removed to take care of two necessary surgeries at one time.


Aside from having a diagnosis of glaucoma, the criteria to have glaucoma surgery often depends on the eye doctor’s discretion. Your eye doctor will consider the following when recommending if glaucoma surgery is right for you:

  • Glaucoma severity
  • The number of glaucoma eye drops you currently use: Glaucoma surgery may not eliminate the need for all of your eye drops, but it can reduce how many you use.
  • If the eye drops you are using cause certain side effects that you dislike
  • The cost involved with your glaucoma eye drops: Sometimes, surgery may be more cost effective than the continued use of drops.

Tests and Labs

Eye surgery generally doesn’t require a large battery of tests beforehand. The need for pre-surgery tests and labs also will depend on your individual medical history.

Before you have glaucoma surgery, you may need to have a pre-surgery exam by your primary care doctor. This is to help rule out any new medical problems. This is usually done within a month before glaucoma surgery.

Your eye doctor may require you to have a blood test called a complete metabolic panel, which includes your blood sugar. If you have had heart problems before, you also may need to have an electrocardiogram (EKG) within six months before surgery. If you are using a type of drug called a diuretic, you may need a potassium test.

A Word From Verywell

Glaucoma can be a sight-threatening condition. If you have glaucoma, make sure to:

  • Take all eye drops as prescribed by your eye doctor.
  • Ask for help if you have trouble using eye drops. There are videos and other aids to make the use of eye drops easier.
  • Keep all scheduled appointments with your eye doctor.

If these are not enough to control your glaucoma, then talk to your eye doctor about how glaucoma surgery can help you to lower your intraocular pressure and maintain your sight.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1.  American Academy of Ophthalmology. Eye pressure.

  2. BrightFocus Foundation. Glaucoma: Facts and figures.

  3. Glaucoma Research Foundation. Laser surgery.

  4. National Eye Institute. Glaucoma surgery.

  5. American Academy of Ophthalmology. Choosing wisely part 1: Preoperative testing.

By Vanessa Caceres
Vanessa Caceres is a nationally published health journalist with over 15 years of experience covering medical topics including eye health, cardiology, and more.