Cataract

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What is a cataract?
How can I tell if I have a cataract?
How fast do cataracts grow?
When to do cataract surgery
How do you remove a cataract?
Methods of cataract removal
Lens implants
Anesthesia for cataract surgery

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What is a cataract?
     A cataract is a lens inside of the eye that we are born with. It serves the function to allow light to enter the eye and to focus the light so that we see a sharp image.
     As we age, this lens becomes more cloudy. The result is that light cannot pass into the eye as well, and what does enter is not focused as well. This results in our vision becoming more blurry. This process usually occurs at a very slow rate (so slow that we sometimes cannot tell that our vision is worse). So, a cataract is a natural aging process. Everyone will develop a cataract if they live long enough.
     Some diseases (e.g. Diabetes, autoimmune diseases) and some medications (e.g. steroids) can accelerate the progression of cataracts. Sometimes, cataracts are congenital as well.

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How can I tell if I have a cataract?
     The most common symptom of cataracts is blurry vision. But there are many other common symptoms as well. The first symptom of a cataract may be progression to becoming more nearsighted. Other early symptoms may be poor night vision or glare. Cataracts can also affect a person's ability to detect contrast and can affect your color perception.
FOR EXAMPLE: The first image below is a normal view.
The second image is what you may see through a cataract when it blurs the vision and alters the contrast sensitivity.
The third image is what you may see when you add a yellowish color change (cataracts tend to make things more yellow).

   NORMAL        CATARACT        DENSER CATARACT
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How fast do cataracts grow?
     Cataracts tend to progress very slowly. The rate of progression varies on the individual and on the individual eye. It also depends on the presence of other illnesses and on the use of certain medications.

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When to do cataract surgery?
     There are very few (and rare) MEDICAL reasons to do cataract surgery:
   1. Cataract-induced glaucoma (extremely rare)
   2. To allow doctors to better view the back of the eye (in cases of Diabetes, macular degeneration, and other eye diseases)
     Otherwise, the time to have cataract surgery is the time when the cataract blurs vision enough to interfere with a patient's ability to perform daily functions (e.g. drive, read, work, etc.). Of course, this will vary widely based on the individual person.

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How do you remove a cataract?
     A cataract has to be removed via surgery, NOT laser. In other words, an incision has to be made; and instruments have to be inserted into the eye to physically remove the cataract. In Europe, scientists are experimenting with a laser that is strong enough to break up a cataract. However, even this laser has to be inserted into the eye through an incision to work. Currently, there are no lasers that can remove a cataract from the outside without making an incision into the eye. In addition, the implant has to be inserted into the eye through an incision.
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Methods of cataract removal
     The Egyptians performed the first recorded cataract surgeries. In a method called "Couching," a needle was stuck into the eye and the cataract was pushed into the back of the eye, out of the line of sight.
     In modern times, the first popular procedure was called Intracapsular Cataract Extraction (ICCE, for short). In this procedure, a large incision (about half the circumference of the cornea) was made in the sclera (the wall of the eye). The cataract was then removed as a whole (capsular bag and all). The incision was then sutured.
     A newer method then became widespread called Extracapsular Cataract Extraction (ECCE, for short). In this procedure, a smaller incision (about 11mm) was made in the sclera. A special needle was then used to create an opening in the front surface of the lens bag. The central lens nucleus was then removed through the opening. The softer cortex is then aspirated through a small vacuum instrument. The bag is left in place and intact (except for the opening in the front through which the cataract was removed). This allowed for safer placement of an artificial lens implant into the bag.
     More recently, a method know as Phacoemulsification (Phaco, for short) allows for much smaller incisions. The incision is only 3-4mm in length. The front surface of the lens bag is opened to gain access to the lens. An instrument using Ultrasound Energy is inserted through the small incision. Ultrasound is then used to break the central lens nucleus into smaller pieces, which are then aspirated through the small incision. The softer cortex is also aspirated the same way. This technique, in addition to the advent of foldable implants (implants which can be folded to fit through a small incision, and then open up once inside the lens bag in the eye) allows for small incisions to be made. This small incisions allow for faster healing, and sometimes, do not even require any stitches! This is by far the most widely used technique today.
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Lens implants
     With the old ICCE method, since the lens bag is removed, the eye is left empty. After surgery, patients would require thick "Coke-bottle" glasses or contact lenses. The newer methods allow for the lens bag to be left in place. This allows surgeons to be able to insert lens implants into the bag, thus alleviating the need for thick postop glasses or contact lenses. The implants allow for patients to be able to wear regular glasses, or in some cases, none at all. However, most people still require reading glasses.

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Anesthesia for cataract surgery
     The traditional anesthetic used for cataract surgery is a retrobulbar or peribulbar block, where local anesthetic is injected behind and around the eye. This effectively anesthetize the eye and also paralyze the muscles that move the eye. The surgery then is performed with the patient fully awake. However, the blocks make it so the patient cannot feel anything sharp or painful and cannot see.
     A new trend is to use just anesthetic eyedrops, without any injections. The drops anesthetize the eye, but does not paralyze the movement; so the patient has to cooperate by not looking around. The patient can also see some of the surgery going on. However, this new method avoids the risks inherent with the injections (e.g. bleeding, bruising, postop double vision, etc.).
     General anesthetic is rarely needed today. Exceptions may include patient's inability to cooperate, neurologic disease that may result in uncontrolled movements, young age, etc.
     The anesthesia used also depends on the surgeon and patient preference.

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