The most common and advanced cataract surgery technique is phacoemulsification or "phaco." The surgeon first makes a small incision at the edge of the cornea and then creates an opening in the membrane that surrounds the cataractous lens. This thin membrane is called the capsule. Next, a small ultrasonic probe is inserted through the opening in the cornea and capsule. The probe's vibrating tip breaks up or "emulsifies" the cloudy lens into tiny fragments that are suctioned out of the capsule by an attachment on the probe tip. After the lens is completely removed, the probe is withdrawn leaving only the clear (now empty) bag-like capsule, which will act as support for the intraocular lens (IOL).

The phaco probe emulsifies the cataract and removes the resulting fragments.
( Photo courtesy Walter Stark, MD, Wilmer Eye Institute, Johns Hopkins University Hospital)

Phacoemulsification allows cataract surgery to be performed through a very small incision in the cornea. Stitches are seldom needed to close this tiny entry, which means that there is less discomfort and quicker recovery of vision than with other surgical techniques. Small incisions do not change the curvature of the cornea like larger ones that were required with older surgical techniques. This allows for more rapid rehabilitation of vision and possibly less dependence on glasses for good distance vision.

After removal of the cataract-damaged lens, an artificial intraocular lens (IOL) is implanted. Made from soft acrylic or solid medical-grade silicone, IOLs are folded so they can be implanted with a small injector, which uses the same incision through which the phaco probe was inserted at the beginning of the procedure. As the IOL is implanted, it unfolds and anchors itself behind the eye's pupil over the remaining clear capsule. The IOLs to be implanted are selected based on power calculations made before surgery.

The replacement for the cataract-damaged natural lens, the intraocular lens (IOL), is positioned in the capsular bag of the eye. Throughout the procedure, most patients are awake, relaxed, and feel no pain. (Photo courtesy Walter Stark, MD, Wilmer Eye Institute, Johns Hopkins University Hospital)

Laser Cataract Surgery

Many people believe that cataract surgery is typically performed with a laser. In fact, this is one of the most common misperceptions in medicine.

The phaco probe that is most commonly used in modern cataract surgery vibrates rapidly at ultrasonic frequency to break up the cataract and allow it to be removed through a small opening in the phaco probe. A recently developed instrument now uses a laser to break up the cataract, but the laser is not as powerful as ultrasound, and it cannot be used to remove advanced cataracts. Other methods of breaking up the lens are under investigation, like the use of tiny, powerful jets of water. Currently, there is no evidence that laser phaco machines produce better outcomes than ultrasound phaco machines.

The anatomy of the eye and the presence or absence of other conditions like glaucoma may determine the best method to use for cataract surgery. Patients considering cataract surgery may want to discuss procedural details with their ophthalmologist, but the decision as to which surgical technique is most appropriate is a decision that is best left to the surgeon.