Iridectomy is a procedure aimed at removing a part of the iris to treat eye diseases like closed-angle glaucoma or iris/ciliary body melanomas. Incisional surgery (surgical iridectomy) was the most common procedure in the past, but today, advancements have seen the same procedure performed via laser, in laser iridotomy. In iridectomy, the surgeon removes part of the iris instead of creating a hole, as happens in iridotomy.
Iridectomy can be performed routinely in patients undergoing trabeculectomy, Phakic IOL implantation, and IOL implantation in the eye’s anterior chamber. It is also used to prevent narrow-angle glaucoma in patients with a narrow-angle. A patient who has had narrow-angle glaucoma in one eye should also have iridectomy in the unaffected eye to prevent narrow-angle glaucoma because there is a 50% chance of being affected.
Patients who develop acute closed-angle glaucoma require immediate treatment because it can lead to permanent vision loss in two to five days. The condition presents with a sharp elevation of intraocular pressure (IO). The eye doctor will apply different types of eye drops or put the patient on intravenous drugs to quickly reduce IOP, shrink pupil size, and stop the production of aqueous humor. Once the pressure has been stabilized, the patient will need to have an iridectomy.
Also Known As
- Surgical Iridectomy
Several types of iridectomy exist, each dictated by where it is performed on the iris. The types include:
- Basal iridectomy - The surgeon removes the root.
- Preparatory iridectomy - It is done ahead of cataract surgery to make lens removal easier.
- Sector iridectomy - The surgeon removes a radial section of the iris, leaving the pupil to look like a keyhole. This procedure today is only used for iris melanoma or ciliary body melanoma.
- Peripheral iridectomy - The surgeon makes an opening in the iris’ periphery (on the sides, away from the centre) and removes a portion at the root, where the pupil is located. The surgeon has the option of doing it by laser or surgically, but leaving the pupil intact.
- Optical iridectomy - The surgeon enlarges the existing pupil or creates an artificial pupil in patients with a central corneal opacity. The goal is to improve vision. However, this procedure was abandoned when techniques in corneal transplantation were enhanced.
Before the Procedure
The patient needs several routine tests which may include:
- Urine tests
- ECG to check heart activity
- Blood tests including blood sugar and hemoglobin levels
Ophthalmic tests include:
- Tonometry to measure intraocular or fluid pressure in the eye, using a tonometer, after application of an anesthetic
- Gonioscopy to examine the angle between the cornea and iris using a unique mirrored contact lens and after anesthetic application. The doctor then uses a slit lamp to examine the image under magnification.
- In the case of iris melanoma, the eye doctor can use an ultrasound by applying a small probe on the eye to detect the tumor. The tumor can also be visible through angiography, a test that involves fluorescein dye injections on the arm. As the dye circulates, photographs are taken.
Patients undergoing traditional iridectomy are required to fast some hours before the procedure. The patient should avoid blood thinners and apply some eye drops a few days preceding the procedure.
Iridectomy involves incisions (surgical) where the surgeon excises a tiny part of the peripheral iris through a limbal incision. This procedure requires an operating room and is done under general anesthesia. A microscope and special instruments are used to make the incisions that do not require suturing because they are self-healing.
Risks & Complications
The risks and complications may include:
- Wound leak
- Eye inflammation
- Cataract formation
- Zonular or lens disruption
- Temporary elevation of IOP
- Failure of fluid pressure to go down
- Eye irritation two to three days after surgery
- Scarring at the incision or laser beam location
- Repeated iridectomies when the hole fails to remain open
- ● The risk of a second procedure mostly if the patient has brown eyes since the iris tends to be thicker
- ● Recurrence of the tumor (in case of melanoma) which may lead to enucleation (surgical removal of the eye)
- ● Glaucoma from an iridectomy aimed at treating melanoma. The glaucoma arises when new blood vessels are formed near the angle
Aftercare & Recovery
An hour after the procedure, the patient's IOP will be checked. If it has risen, more eye drops will be administered. The patient may experience blurred vision immediately after the procedure, but this should subside. Medications to treat inflammation are also prescribed and taken several times a day for a few days. Other medicines prescribed include drugs to minimize the risk of infection and relieve discomfort. The patient will wear a patch for several days.
In the long-term, the patient will take medications to control fluid pressure and periodic follow-ups with the ophthalmologist. The patient will also have regular check-ups to ensure that the tumor has been eliminated and has not recurred in melanoma patients. Those recovering from iris melanoma should avoid ultraviolet light exposure.