Extracapsular cataract extraction (ECCE) is a type of cataract surgery. In this procedure, the lens is removed while the capsule covering the lens is allowed to remain partially intact. The the surgeon implants the intraocular lens (IOL) on the remaining capsule.
The lens (crystalline lens) lies immediately behind the iris. It is about 9mm long and 4mm wide. It is made of protein fibers and water. The lens contains three cell layers, namely, the cortex, the subcapsular epithelium and a central nucleus. These give rise to the three types of cataracts: nucleus, cortex and posterior subcapsular cataract. An individual can develop more than one type of cataract.
Most cataracts develop due to age although some are present at birth or develop in childhood. As people age, the protein fibers get thicker. They form a clump which causes opacity in the lens. Cataracts may affect both eyes but the speed of progression in each eye may vary.
Types of surgery
ECCE comprises of:
- Manual expression - The surgeon removes the lens by making an incision in the cornea (transparent covering of the front of the eye) or sclera (white part of the eye). Manual expression makes use of small incisions. However, surgeons in developing countries still use large incision standard extracapsular extraction. It requires sutures and healing takes longer.
- Phacoemulsification - The surgeon uses an ultrasound device to break up the lens into tiny fragments inside the capsule. The fragments are then removed by aspiration.
Surgeons use ECCE to restore clear vision. They do so by removing the clouded lens and replacing it with an IOL.
Preparation & expectation before Surgery
The patient may undergo the following to prepare for surgery:
- Keratometry, a special test necessary before an IOL implant. It’s a painless procedure which establishes how strong the IOL implant is. The surgeon measures the eyeball’s length using a keratometer. He/she will also use the device to measure the curvature of the cornea.
- Be made aware that if one was using glasses before the procedure, one might continue with them after the implantation of an IOL.
In manual expression or conventional extracapsular cataract extraction, the following may occur:
- The ophthalmic assistant will clean the area around the eye with an antiseptic. He/she then uses sterile drapes to cover the patient’s face.
- The assistant will give the patient local anesthesia to numb the tissues around the eye and topical anesthesia to numb the whole eye. To relax the patient, a sedative may be administered intravenously.
- The surgeon uses a speculum on the eyelid to keep the eye open and prevent blinking.
- An incision is made at the intersection of the cornea and sclera. The incision is small since the surgeon implants foldable acrylic IOLs.
- The surgeon then does a circular incision at the front of the lens capsule before carefully opening it and applying pressure using special instruments. This action removes the hard nucleus of the lens.
- Using suction, the surgeon removes the lens’ cortex.
- The surgeon injects viscoelastic fluid into the now empty capsule to help the capsule maintain its shape and then inserts the IOL.
- The surgeon will remove the viscoelastic liquid and close the incision using two to three stitches.
In phacoemulsification, the same procedure is followed except the surgeon breaks up the lens’ nucleus into smaller pieces using an ultrasound probe inserted through the incision. The front part of the capsule is also removed.
After care, recovery, results
About 95% of patients register substantially improved vision after surgery. Patients can report to work the following day. However, complete healing takes place between three weeks to four months. Once healing is complete, the doctor should check the patient’s regular eyeglasses in case a change of lens prescription is necessary.
The patient should wear eyeglasses during the day and wear a protective shield at night following surgery. They should also avoid rubbing the eye or situations where something can bump the eye.
The patient will use eye drops for a week or two to reduce swelling, prevent infection and manage pain. The eye drops must be used exactly as directed.
Frequent check-ups are necessary beginning a day after the procedure. The surgeon will then check the patient weekly for several weeks.
Risks & complications
Risks or complications include:
- Swelling of the cornea
- Cystoid macular edema
- Retinal tear or detachment
- The IOL may shift or dislocate
- The incision may leak or rupture
- Intraocular pressure may increase
- The external eye may get infected
- Uveitis which is inflammation that affects eye tissue including the iris
- Hyphema which is the presence of blood inside the anterior chamber of the eye
- About 25% of patients who have their cataracts removed eventually develop clouding in the posterior lens capsule that holds the new IOL. This new condition is called posterior capsular opacification (PCO) which is treated by capsulotomy, a form of laser surgery.