Cataracts are cloudy constituents that develop in the natural lens of the eye over time. They often impair normal vision and require surgical removal. During cataract surgery, the opaque lens is removed by an ophthalmologist, and replaced with a transparent synthetic lens, greatly improving the patient's vision. The two main types of cataract surgery are phacoemulsification or phaco, and conventional extracapsular cataract extraction or ECCE.
ECCE
A manual incision of approximately 5 to 12 mm is made in the outer covering of the eye or cornea, via which the cloudy lens is manually extracted in ECCE. Local anesthetic is administered and the eyelid held up with a mechanical device. A circular tear is made in the front of the capsule that surrounds the lens and the hard centre removed through the incision. Remaining liquid from the lens is then removed by suction and a salty fluid injected to retain pressure inside the eye before the synthetic lens is inserted. A synthetic lens is then inserted into the eye through the incision and the replacement fluid removed by suction, according to All About Vision.
Clinical Uses of ECCE
Due to the relatively large incision in the cornea in this type of surgery, stitches are often required and recovery rates can be longer than with phaco. Furthermore, complications such as swelling of the cornea, increased ocular pressure and retinal detachment occur in a minority of cases. ECCE is sometimes chosen by ophthalmologists above other techniques if a patient has increased pressure inside the eye due to glaucoma, or if cataracts are particularly severe and likely to be hard to extract using other surgical techniques, according to the Encyclopedia of Surgery.
Phaco
A machine which emits high frequency sound waves through a titanium or steel tip is used to break down or emulsifies the cloudy natural lens in the phaco technique. A second instrument called a cracker or chopper is sometimes used to help break up large resistant chunks of the lens which can be further degraded by sound waves. These instruments are inserted into the eye through small incisions in the cornea which heal naturally without requirement for stitches. The emulsified lens is drained from the eye and replaced with a salty fluid to retain pressure inside the eye. A synthetic lens is then inserted into the eye through a small incision and replacement fluid drained away, according to the Eye Surgery Education Council.
Clinical Uses of Phaco
Because of the rapid recovery time and reduced risk of post operative complications, phaco is the preferred technique in highly resourced countries. The relatively expensive machines and use of disposable instruments, however, prohibits widespread use throughout the developing world, according to the British National Health Service.
ICCE
Due to the simplicity of the procedure and reduced need for specialist instrumentation, intracapsular cataract extraction or ICCE was formally very popular. ICCE is a surgical technique which involves removal of the lens and surrounding capsule intact, followed by replacement with a synthetic plastic lens. This technique is now rarely performed in developed countries due to the large cornea incision required and high rate of postoperative complications, according to a November 2001 article published in the "Community Eye Health Journal."
