Definition and Overview
An iridectomy is an iris resection procedure where a portion of its tissue is removed treat an eye condition that affects directly or indirectly the iris, the part of the eye that helps control the size of the pupil to improve the focus of light. It is found immediately after the cornea.
Iridectomy can be either invasive or less invasive when performed using laser technologies.
Who Should Undergo and Expected Results
There are two major reasons why an iris resection is performed: glaucoma and melanoma.
Glaucoma is an eye condition characterised by vision loss or blindness caused by an increasing pressure that permanently damages the optic nerves.
The condition has many risk factors including age and other underlying conditions like diabetes. It can also develop as a result of an inflammation of the middle layer of the eye called the uveal tract or injury that destroys the optic nerves.
Iridectomy can be performed on patients diagnosed with closed-angle glaucoma, an eye condition that is sometimes referred to as narrow or closure angle. This involves the bulging of the iris because the drainage angle that keeps the intraocular pressure stable is blocked. This can be chronic, but it can also be acute, in which case the condition is considered as a medical emergency.
Meanwhile, melanoma of the iris is a type of primary cancer that develops in the cells that create the colour for the iris. As long as it remains untreated, the cancer can spread to the eyes, eventually leading to blindness. In more severe cases, the cancer can metastasize to other parts of the body such as the liver. Melanoma is curable, but once metastasis begins, it can become terminal.
Other possible reasons for iridectomy include the removal of the tissue as a preparation for a cataract surgery, placement of an intraocular lens in the anterior chamber, and treatment of trauma to the iris.
As for the expected results, patients with glaucoma may experience a more stable intraocular pressure. The procedure can also cure melanoma. However, it doesn’t stop these problems from recurring. If melanoma comes back, the possible step is to remove the affected eye completely.
How Does the Procedure Work?
Iris resection can be performed using laser or traditional surgical method. It is usually performed in an outpatient setting in an eye clinic or a hospital. Prior preparations include eye test, physical exam, evaluation of the eye's condition, and intake of certain medications.
The kind of iridectomy that would be recommended to the patient will depend on a number of factors such as the specific eye condition and its present state, desired outcome, parts of the iris that will be removed, and the purpose of the procedure. For example, if the goal is to expand the pupil so it can process more light, optical iridectomy is performed.
When the procedure is done before a cataract surgery, it is called preliminary iridectomy. If it’s glaucoma-related, it’s peripheral iridectomy, in which case the roots are removed. The procedure can also be preventive or therapeutic in nature.
During surgery, the patient lies on the operating table on his back while his eyes are left open by a clamp. General anaesthesia is then administered. Using surgical tools, an incision is made on the cornea to access the iris, and a portion of the tissue is removed. In cases where the condition is more severe, most of the iris will be removed.
In a minimally invasive procedure, a Nd:YAG laser is used. The patient’s eye is given a local anaesthesia to numb the pain. A special lens may also be placed to improve the surgeon’s vision of the iris. The patient sits comfortably on a chair with the chin resting steadily on a platform. The laser is then delivered straight to the iris to create holes that will relieve the eye pressure. Since this procedure may lead to the opening’s closure, this can be followed by conventional iridectomy.
Possible Risks and Complications
There’s the possibility the procedure won’t work. It can also leave scarring and cause bleeding, infection, discomfort, and pain. Pain, discomfort, and swelling are normal for most eye procedures. However, they’re expected to subside within the next few days after surgery.
Robin AL, Eliassi-Rad B. Laser Iridotomy. Morrison JC, Pollack IP. Glaucoma: Science and Practice. New York, NY: Thieme; 2003. (41)439-445.
Lam DSC, Tham CCY, Congdon N. Peripheral iridotomy for angle-closure glaucoma. Shaarawy TM, Sherwood MB, Hitchings RA, Crowston JG. Glaucoma. China: Saunders; 2009. Vol 2: (65)61-69.