In cataract surgery, the lens inside your eye that has become cloudy is removed and replaced with an artificial lens (called an intraocular lens, or IOL) to restore clear vision. The procedure typically is performed on an outpatient basis and does not require an overnight stay in a hospital or other care facility.
About Human Eye
The human eye is an vital organ of human body, which reacts to light for several purposes. The eye as a conscious sense organ allows vision. The eyes are undoubtedly the delicate and most sensitive and amazing organs we possess.
The human eye can distinguish about 10 million colors. They present us with the window through which we view the world, and are responsible for four fifths of all the information our brain receives – which is probably why we rely on our eyesight more than any other sense.
The human eye is the organ which
- Gives us the sense of sight
- Allows us to observe and learn about the surrounding world
- Are used in almost every activity we perform, whether reading, working, watching television, writing a letter, driving a car, and in countless other ways.
- Processes light any object reflect or emit and allows us to see and interpret the shapes, colors, and dimensions of those objects.
In absence of light eyes are not able to sense objects around.
When the eye’s naturally clear lens becomes clouded, it’s called a cataract. Most cataracts are the result of the natural process of aging. Others may be present at birth or develop as a result of physical, drug, or chemical injury. Cataract surgery, one of the most common operations performed in the U.S., clears up the cloudiness.
What Happens During Cataract Surgery?
During cataract surgery, the cloudy lens is removed or cleaned out and replaced by a clear manmade lens.
Most cataract surgeries are done with a technique called phacoemulsification (FAY-co-ee-mul-sih-fih-CAY-shun), also called “small cut (incision) cataract surgery.” The cut (incision) can be smaller, because the harder center section of the lens is liquefied and then vacuumed out.
Under local anesthesia, a surgeon performing phacoemulsification makes a small opening on the side of your cornea. A device that sends out ultrasound vibrations is inserted into the eye and breaks the lens into small pieces. The fragments are then removed by suction through the small cut in the eye.
Your eye doctor may use a laser to make the cut. The hope is that a more precise cut will further improve recovery from cataract surgery.
After the cataract is removed, the surgeon usually replaces it with a new, man-made lens called an intraocular lens or IOL. This procedure is called “intraocular lens implantation.”
The IOL is clear plastic, acrylic, or silicone with an optical power chosen by the surgeon to help restore normal vision, oftentimes minimizing the dependence on eyeglasses after surgery. This lens is permanent and needs no special care.
The IOL focuses light onto the retina to help improve your vision. Still, even if your natural lens is replaced with an intraocular lens, you probably will need a new eyeglass prescription. However, most people can see fairly well at a distance without glasses after modern cataract surgery with a cataract lens replacement.
Cataract surgery is done as an outpatient procedure in an operating room, so you don’t have to stay in the hospital. The actual surgery usually lasts less than an hour. It is safe and in many ways desirable to be awake with some level of sedation during the surgery. A sedative is given and numbing drops are placed on the eyes. Another option is to use a novacaine injection placed around your eye. General anesthesia (breathing tube and fully asleep) is rarely used with cataract surgery. Talk to your surgeon about your options.
Doctors usually won’t remove cataracts in both eyes at the same time. If you need both eyes done, you will be scheduled for separate surgeries, usually a few weeks apart.
Types of surgery
There are a number of different surgical techniques used in cataract surgery:
- Phacoemulsification (Phaco) is the most common technique used by developed countries. It involves the use of a machine with an ultrasonic handpiece equipped with a titanium or steel tip. The tip vibrates at ultrasonic frequency (40,000 Hz) and the lens material is emulsified. A second fine instrument (sometimes called a “cracker” or “chopper”) may be used from a side port to facilitate cracking or chopping of the nucleus into smaller pieces. Fragmentation into smaller pieces makes emulsification easier, as well as the aspiration of cortical material (soft part of the lens around the nucleus). After phacoemulsification of the lens nucleus and cortical material is completed, a dual irrigation-aspiration (I-A) probe or a bimanual I-A system is used to aspirate out the remaining peripheral cortical material.
- Manual small incision cataract surgery (MSICS): This technique is an evolution of ECCE (see below) where the entire lens is expressed out of the eye through a self-sealing scleral tunnel wound. An appropriately constructed scleral tunnel is watertight and does not require suturing. The “small” in the title refers to the wound being relatively smaller than an ECCE, although it is still markedly larger than a phaco wound. Head to head trials of MSICS vs phaco in dense cataracts have found no difference in outcomes, but shorter operating time and significantly lower costs with MSICS.
- Extracapsular cataract extraction (ECCE): Extracapsular cataract extraction involves the removal of almost the entire natural lens while the elastic lens capsule (posterior capsule) is left intact to allow implantation of an intraocular lens. It involves manual expression of the lens through a large (usually 10–12 mm) incision made in the corneaor sclera. Although it requires a larger incision and the use of stitches, the conventional method may be indicated for patients with very hard cataracts or other situations in which phacoemulsification is problematic.
- Intracapsular cataract extraction (ICCE) involves the removal of the lens and the surrounding lens capsule in one piece. The procedure has a relatively high rate of complications due to the large incision required and pressure placed on the vitreous body. It has therefore been largely superseded and is rarely performed in countries where operating microscopes and high-technology equipment are readily available. After lens removal, an artificial plastic lens (an intraocular lens implant) can be placed in either the anterior chamber or sutured into the sulcus.
- Femtosecond laser appears safe but has few benefits over phacoemulsification.
Cryoextraction is a form of ICCE that freezes the lens with a cryogenic substance such as liquid nitrogen. In this technique, the cataract is extracted through use of acryoextractor — a cryoprobe whose refrigerated tip adheres to and freezes tissue of the lens, permitting its removal. Although it is now used primarily for the removal of subluxated lenses, it was the favored form of cataract extraction from the late 1960s to the early 1980s.