Iridectomy - Important Information

During a basal iridectomy, the surgeon creates a small opening in the iris of the eye. This allows for the exchange of aqueous humor between the anterior and posterior chambers of the eye.

The anterior chamber can deepen again, allowing aqueous humor to drain freely. Intraocular pressure regulates itself automatically, and the pressure on the sensitive optic nerve in the back of the eye is relieved.

Intraocular pressure is necessary to maintain the shape of the eye and the distances between the cornea, lens, and retina. This pressure is generated by aqueous humor within the eye.

The fluid is produced in the posterior chamber (between the lens and the vitreous body). It flows into the anterior chamber through a space between the iris and the lens. As it does so, it bathes the lens and supplies it with nutrients. The Schlemm’s canal in the anterior chamber then drains the aqueous humor out of the eye.

The Structure of the Human Eye @bilderzwerg /AdobeStock

The production of aqueous humor increases intraocular pressure, while its drainage lowers it. Normally, intraocular pressure regulates itself. If more aqueous humor is produced than can be drained, intraocular pressure rises steadily. The natural regulation mechanism fails, for example due to:

• Overproduction of aqueous humor: Too much aqueous humor is produced to be drained
• Insufficient drainage: Aqueous humor circulation to the anterior chamber is impaired, causing the aqueous humor to accumulate in the posterior chamber. In this case, iridectomy / iridotomy is helpful
• The drainage channels do not drain enough fluid

Excessively high intraocular pressure can damage the optic nerve at the retina. Visual acuity deteriorates permanently (see Glaucoma).

An iridectomy is indicated when, from a medical standpoint, access to the posterior chamber is necessary.

This is the case when:

• Too much fluid accumulates in the posterior chamber
• Intraocular pressure is too high
• Intraocular pressure rises alarmingly

The word “iridectomy” is derived from Greek and refers to the “removal of a portion of the iris.” The first such procedures were performed in the 19th century. During the procedure, the doctor made a 4–6 mm incision or puncture at the edge of the cornea. Through this opening, he inserted a small pair of forceps into the anterior chamber of the eye.

They grasped the iris at the edge of the pupil and then pulled it out through the opening. They then cut it off with scissors. This often resulted in severe eye injuries or scarring on the iris, which subsequently impaired the patient’s vision.

Today, a laser is used for this procedure (laser iridotomy). This method does not require the doctor to open the eye. The laser method is now widely used because it is significantly less invasive. 

Basal iridectomy is used only in exceptional cases. For example, laser iridotomy requires a clear cornea. If the cornea is severely clouded, a surgical iridectomy is necessary. Some doctors prefer basal iridectomy because the surgical opening in the iris is larger than that created by the laser.

A basal iridectomy is always preceded by several examinations. Only after an accurate diagnosis is made will the ophthalmologist prescribe a specific treatment. 

Depending on the symptoms, the following examinations are necessary:

• Eye measurement
• Measurement of corneal thickness (pachymetry)
• Corneal topography 

If the findings indicate that access from the anterior to the posterior chamber of the eye is necessary, the doctor will order a basal iridectomy/iridotomy.

The ophthalmologist explains to the patient exactly what precautions must be taken before the surgery. The patient must strictly adhere to these instructions. 

Possible measures include:

• Do not wear contact lenses for a certain period of time before the procedure
• Consulting with the doctor about taking certain medications and discontinuing them if necessary

Basal iridectomy is a low-risk surgical procedure that takes only a few minutes. It is usually performed on an outpatient basis in the operating room under local anesthesia. If the patient requests general anesthesia, they must pay for it themselves.

The patient lies on their back and receives local anesthesia. Using a microscope, the surgeon makes a small incision in the cornea to gain access to the anterior chamber of the eye. 

Here, the surgeon excises a small portion of the iris. This creates a connection between the chambers of the eye, allowing aqueous humor to flow from the posterior to the anterior chamber once again.

Transparent cornea, with the iris behind it @ Adrian /AdobeStock

Normally, no further treatment is necessary after the procedure. The opening in the cornea usually heals within a few weeks without discomfort or pain.

Immediately after the procedure, please note the following

• Due to the anesthesia, you must not rub your eyes for at least half an hour after the surgery. The numbness could cause you to seriously injure yourself.
• If you have been given pupil-dilating medication, you must not actively participate in traffic for several hours. 

In the days following the procedure, you should:

• Avoid straining your eyes: Limit sun exposure, avoid sports, minimize screen time, and rest
• Do not rub your eyes
• Consult your doctor before taking any medications, especially eye drops, eye ointments, and pain relievers!

Since the procedure involves opening the eyeball, complications may arise in rare cases, such as:

• Endophthalmitis
• Retinal detachment 
• Massive bleeding
• Injury to the lens
• Mild inflammation 
• Mild sensation of a foreign body in the eye

However, these side effects usually subside within a few days after the procedure. Overall, side effects are relatively rare with basal iridectomy.

In conclusion, surgical iridectomy is an established surgical procedure in ophthalmology used to lower intraocular pressure and prevent complications such as acute angle-closure glaucoma. The term “iridectomy” describes the targeted removal of tissue, although iridectomy can also be complemented by iridotomy, which is a less invasive procedure. In this procedure, a small incision is made at the outer edge of the iris to create a hole in the iris. This small opening in the iris allows aqueous humor to circulate more freely within the eye, thereby balancing the pressure between the anterior and posterior chambers.

Iridectomy is typically performed when the outflow of aqueous humor is impaired or in cases of narrow-angle glaucoma. By creating a connection between the anterior and posterior chambers of the eye, the aqueous humor can drain, thereby reducing intraocular pressure. The incision creates a new pathway for the fluid to enter the anterior chamber without causing fluid to accumulate in the eye. Particular care is taken around the edge of the cornea to preserve the function of the iris, which also regulates pupil size.

Modern laser techniques are also used to make the procedure less invasive and improve the healing process. Nevertheless, there are risks associated with iridectomy, such as an incomplete iridectomy or certain complications like inflammation. Without treatment, irreversible damage to vision could occur, particularly in cases of recurrent glaucoma attacks.

After surgery, mild symptoms such as tearing or sensitivity to light may occur, particularly sensitivity to light in the first few hours. Therefore, a follow-up visit with an ophthalmologist is important to monitor the healing process and detect potential complications early. Overall, iridectomy is a well-established eye surgery that effectively helps regulate intraocular pressure and prevent long-term damage.

What is an iridectomy?
An iridectomy is a surgical procedure on the eye in which a small piece of the iris is removed. This allows aqueous humor to drain more effectively and lowers intraocular pressure. This method is frequently used to treat glaucoma.

When is an iridectomy performed?
An iridectomy is primarily performed for angle-closure glaucoma or an acute glaucoma attack. It serves to improve drainage in the anterior chamber and prevent damage to the optic nerve.

How is the surgery performed?
An iridectomy is usually performed under local anesthesia. The surgeon makes a small incision at the edge of the iris and creates an opening through which the aqueous humor can drain. The procedure is generally painless.

What are the risks associated with iridectomy?
As with any surgery, iridectomy can lead to complications such as bleeding or inflammation. In rare cases, the opening may close again, requiring repeat treatment.

What does follow-up care involve?
Regular checkups with an ophthalmologist are important after iridectomy. Eye drops support healing and help prevent inflammation. The healing process should be carefully monitored.