Glaucoma Surgery

A surgical procedure done to reduce the eye pressure to stabilize vision and prevent vision loss in the future due to glaucoma is known as glaucoma surgery.

A group of eye conditions that cause damage to the optic nerve, where it leaves the eye called glaucoma. The condition may lead to loss of vision.

Optic nerve is the nerve that sends signals from the retina (the neural tissue in the back of the eye) to the brain. The brain relies on these signals for creating various images and providing vision.

The different types of glaucoma include:
1. Open-angle glaucoma:

• This is the most common type of glaucoma.
• The condition occurs due to the gradual fluid buildup and pressure in the eye, known as intraocular pressure or eye pressure.
• The canals carrying the fluid away from the eye fail to drain well.
• There may be deposit formation, which may hinder drainage further.

2. Normal-tension glaucoma:

• This is a less common form of open-angle glaucoma. 
• It is also called normal-pressure and low-tension glaucoma.
• The eye pressure in this condition is considered to be normal for the general public but is considered to be too high for that particular eye, causing damage to the optic nerve.

3. Closed-angle glaucoma:

• This is a less common form of glaucoma.
• It is also called narrow-angle glaucoma, angle-closure glaucoma, or acute glaucoma.
• The condition takes place due to the narrowing of the iris (the part of the eye that is responsible for the eye color of a person) or blockage of the drainage angle (the point where the iris and the sclera, which is the white covering of the eye meet).
• This leads to an abrupt and rapid increase in eye pressure causing sudden symptoms.
• This condition is a medical emergency and may cause loss of vision in a short time.

4. Congenital glaucoma:

• This condition is present at birth.
• The condition occurs when the eye's drainage system fails to develop properly during fetal development.

The exact cause of glaucoma is not known but may occur due to several factors.
Intraocular eye pressure is the most important factor that may lead to glaucoma.
A fluid known as aqueous humor is produced by the eye. This fluid helps in the nourishment of the eyes.
This fluid flows through the pupil (the dark-colored openings present at the center of the eyes that lets light in) to the eye’s front portion.
The fluid leaves through a drainage canal that is located between the iris and cornea (the outer clear layer present at the front of the eye) in case of a healthy eye.
The drainage canals get clogged with microscopic deposits in case of glaucoma.
This fluid has no other place to go and so it starts building up in the eye. 
This excess fluid starts putting pressure on the eye.
The increase in eye pressure eventually leads to damage of the optic nerve, causing glaucoma.

Certain factors may increase the chances of developing glaucoma and may include:

• Increase in age
• African, Americans, Asians, and Latinos race
• Diabetes
• Family history of glaucoma
• Hyperopia or farsightedness (more commonly associated with closed-angle glaucoma) 
• Hypertension or high blood pressure
• Long-term use of corticosteroids
• Myopia or nearsightedness (more commonly associated with open-angle glaucoma)
• Previous eye surgery or eye injury

The symptoms of glaucoma vary depending on the stage and type of glaucoma present. 
The symptoms of open-angle glaucoma may include:
Patchy blind spots on the side (peripheral) or central vision, which is commonly seen in both the eyes
Tunnel vision (loss of peripheral vision) in the advanced stages
The symptoms of acute angle closure glaucoma may include:

• Eye pain
• Severe headache
• Nausea
• Vomiting
• Blurred vision 
• Halos around lights
• Eye redness
• When left untreated, glaucoma may cause blindness.

Glaucoma surgery can be performed by an ophthalmologist.

The following regular eye exams are performed to diagnose glaucoma or other eye problems:

1. Dilated eye exam: This exam is performed for widening the pupils and for the doctor to view the optic nerve present at the back of the eyes.
2. Gonioscopy: This test is done to examine the angle at which the cornea and iris meet.
3. Optical coherence tomography (OCT): This test is done to check for the changes in the optic nerve that could indicate glaucoma.
4. Ocular pressure test (tonometry): This test is performed to measure intraocular pressure.
5. Pachymetry: This test is done to measure corneal thickness.
6. Slit-lamp exam: This test is done for the examination of the inside of the eye by a special microscope, called a slit lamp.
7. Visual acuity test (eye charts): This test is done to check for loss of vision.
8. Visual field test (perimetry): This test is performed to check for any changes in the peripheral vision.

The following preparation may be needed before a glaucoma surgery:

• The doctor should be aware of any medical disorders that you have.
• The doctor should be told about any supplements, medications, or herbs that you are taking.
• If you are allergic to any medications, anesthetic agents, latex, iodine, or tape, inform the doctor.
• The doctor will instruct you to stop blood-thinning medications like warfarin and aspirin a few days before the procedure.
• Quit smoking at least a few days before the surgery.
• If the scheduled surgery is going to be performed under general anesthesia, the doctor will instruct you to not eat or drink anything eight hours before the procedure.
• The doctor prescribes some eye drops before surgery to prevent pain during the surgery.

Glaucoma treatment aims at improving the fluid flow from the eye, reducing the fluid production, or both. This can be done in the following ways:

• Eye drops or medications:
• Eye drops are used as the initial means of treatment.
• The eye drops help in either reducing the amount of fluid made by the eye or improving the drainage.
• The different types of eye drops that could be used for the treatment of glaucoma include prostaglandins, cholinergic agents, beta-blockers, carbonic anhydrase inhibitors, nitric oxide releasers, and rho kinase inhibitors.

1. Laser therapy:
Laser treatment is recommended when eye drops fail to improve the symptoms of glaucoma.
A high-energy beam of light is aimed at a part of the eye to stop fluid buildup inside it.
The procedure is usually performed by first putting local anesthesia drops in the eyes to numb them, and then the procedure is performed.
The different types of laser treatments are:

• Laser trabeculoplasty: A laser is used for opening up the drainage tubes within the eyes, allowing more fluid to drain out and reducing the eye pressure inside.
• Cyclodiode laser treatment: A laser is used for destroying some of the eye tissue that produces the liquid, which reduces the eye pressure.
• Laser iridotomy: A laser is used to create holes in the iris, allowing fluid to drain from the eye.

2. Surgery:
A glaucoma surgery is performed in those cases where eye drops or lasers have been ineffective in treating glaucoma.
Glaucoma surgery can be carried out under local anesthesia, which is used to numb the area of the procedure, or general anesthesia, in which the patient is put to sleep during the procedure.
The different types of glaucoma surgeries are:

• Trabeculectomy: This procedure involves the removal of a part of the drainage tubes to allow the fluid to drain more easily. Most patients do not need to take eye drops after this procedure.
• Trabeculotomy: This procedure vis similar to trabeculectomy, but it involves the use of an electric current to remove a small part of the drainage tubes from the eyes.
• Viscocanalostomy: This procedure involves the removal of a part of the sclera, to allow easy drainage of fluid from the eye.
• Deep sclerectomy: The drainage tubes in the eyes are widened in this procedure. This may be done by implanting a tiny device in the eyes sometimes.
• Trabecular stent bypass: A tiny tube is placed into the eye to increase the fluid drainage.

The following are the post-procedure steps following glaucoma surgery:

• You can usually go home a few hours after the surgery.
• You need to visit the surgeon the day after the surgery for a checkup.
• Many follow-up appointments are needed in the following weeks after glaucoma surgery. The surgeon may do minor adjustments during these appointments.
• You will be given eye drops to relieve pain after surgery.
• You can resume work two weeks after the surgery.
• It is normal to have a slightly blurred vision for up to six weeks after the surgery. The vision will return back to normal after that.
• Routine daily activities can be resumed within the first few days after the procedure.
• Avoid swimming, bending the head below the waist, or heavy lifting for approximately four weeks after the surgery.

The following complications may be associated with glaucoma surgery:

• Pain 
• Infection
• Allergic reaction to materials, medications, or equipment used
• Heavy bleeding inside the eye
• Bleeding in front of the eye making vision worse
• Excessive fluid drainage
• Inflammation in the other eye
• Sharp increase in eye pressure
• Decrease eye pressure
• Development of cataract (the clouding of the normally clear lens of the eyes)
• Reduced vision
• Loss of vision
• Failure of surgery

• Glaucoma cannot be prevented. But the following tips help in detecting glaucoma in its early stages and preventing loss of vision, or slowing the progress of the condition:
• Get regular dilated eye examinations done
• Have frequent eye screening tests if you have a family history of glaucoma
• Exercise regularly to reduce intraocular pressure
• Take prescribed eye drops regularly to reduce the risk of high eye pressure leading to glaucoma
• Wear eye protection while playing contact sports or high-speed racket sports, and while using power tools to prevent injury to the eye