Glaucoma Surgeries

Glaucoma is a disease caused by elevated pressure inside the eye. The eye constantly produces aqueous, the clear fluid that fills the anterior chamber (the space between the cornea and iris). The aqueous flows out of the anterior chamber through a complex drainage system. The delicate balance between the production and drainage of aqueous determines the eye’s intraocular pressure (IOP).  In patients with glaucoma, the outflow of fluid becomes restricted, causing the pressure inside the eye to rise. If left untreated, the elevated eye pressure can damage the optic nerve and retina.

Are  there different types of glaucoma ? 

Yes, there are many different types, but there are two major types: Chronic and Acute. Chronic open angle glaucoma (COAG) is the most common form glaucoma. In COAG the entrance to the drainage canals is open, but there is a clogging problem inside the drainage canals. The disease is slow, causes gradual loss of small patches of vision, it is a lifelong condition and responds well to medication and surgery.

Acute closed-angle glaucoma is rare. The eye pressure goes up quickly and high because the drainage canals are suddenly blocked. This causes severe headaches or eye pain, nausea, rainbows around light at night, severely blurred vision. This glaucoma demands immediate medical attention, day or night.

Medical Treatments

Prescribing eye drops is usually the first step in lowering the IOP. Most medications reduce the eye pressure by decreasing the production of aqueous. However, because the aqueous supplies nourishment to the front of the eye, the body has a built-in mechanism that limits the extent the eye’s pressure can be lowered with medication. Other medications work by improving the outflow of fluid from the eye. For the maximum benefit, these two types of drugs are often used together.

Surgical Treatments

When medications no longer control the eye pressure adequately, surgery may be needed. All types of surgeries are done here, namely Trabecultechtomy, Trabeculotomy, Argon Laser Trabeculoplasty, YAG Oridotomy, etc. Surgeries for glaucoma may be performed using a laser or conventional surgical instruments. Laser Surgeries use a concentrated beam of light to open the flow of aqueous out of the eye and thus decrease intraocular pressure.

The most common conventional surgical procedure is called a filtering surgery. Filtering surgery is usually done in a hospital or outpatient surgery center. A tiny piece of the white part of the eye (the sclera) is removed leaving a tiny hole. The aqueous can then drain through the hole and be reabsorbed into the bloodstream. This in turn decreases intraocular pressure.

Sometimes the placement of a small tube or valve in the eye through a tiny incision in the sclera is needed to control pressure. The valve is a regulator of aqueous within the eye. When the intraocular pressure reaches a certain level, the valve opens allowing the fluid to flow out and be reabsorbed by into the bloodstream. The healing process for incisional surgery is short and should be only a few days.


The most common glaucoma laser surgeries are:

Laser Peripheral Iridotomy (LPI):

Often used in people with narrow-angle glaucoma. Narrow-angle glaucoma occurs when the angle between the iris and the cornea in the eye is too small. This causes the iris to block fluid drainage, which makes the inner eye pressure increase. LPI makes a small hole in the iris, allowing it to fall back from the fluid channel and helping the fluid drain.

Argon Laser Trabeculoplasty (ALT):

Used in people with primary open angle glaucoma (POAG). The laser beam opens the fluid channels of the eye, helping the drainage system to work better. In many cases, medication will still be needed.

It has successfully lowered the eye pressure in up to 75% of patients treated.

Selective Laser Trabeculoplasty (SLT)

Uses a combination of frequencies.

Nd:YAG Laser Cyclophoto-coagulation (YAG CP):

Used in people with severe glaucoma damage that is not being managed by standard glaucoma surgery.

Glaucoma Surgery Breakthrough

Recent advancements in surgical technique have led to the development of a procedure called viscocanalostomy. This surgery involves removing an internal layer of scleral tissue. Thick viscoelastic fluid is then injected in the eye’s drainage canal to help maintain an open pathway for the aqueous to drain.

This technique allows the aqueous fluid to flow from the front of the eye at a much more controlled rate than with other glaucoma surgeries. Because of this, the eye pressure is much more likely to fall in the desired range after the operation, significantly reducing the risk of an extremely low pressure (hypotony).

Another advantage of viscocanalostomy is that it stimulates the body’s healing mechanism less than trabeculectomy, so there is a reduced tendency for scar tissue to form and the eye pressure to rise. 

Although viscocanalostomy takes longer for the doctor to perform and requires more skill, it is much simpler for the patient. This procedure can be performed alone or along with cataract surgery. Most patients enjoy a quick recovery following viscocanalostomy compared to other glaucoma surgeries, along with less dependence on medication, fewer postoperative visits, and reduced risk.


There are some instances where surgery alone does not completely work. Some patients may have to return to medication and some may have to have more surgery to prevent any further loss of vision.