Diseases and Surgical Procedures

Extra-capsular Cataract Extraction (ECCE)

Extra-capsular cataract extraction is a method for surgically removing a cataract, which is a clouding of the eyes naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye. Having a cataract can be compared to looking at the world through a foggy window. In extra-capsular extraction, an incision is made in the side of the cornea at the point where the cornea and sclera, the white part of the eye, meet. Carefully entering the eye through the incision, the surgeon gently opens the front of the lens capsule and removes the hard center, or nucleus, of the lens. The soft lens cortex is then suctioned out leaving the back of the capsule in place. An incision requiring sutures is necessary because the lens is removed in one piece. A plastic implant called an intraocular lens, or IOL, is substituted for the original lens. The implanted IOL allows light to be focused on the retina. It may be up to six weeks before the sutures are removed and best-corrected vision is achieved. During recovery, it may be necessary to avoid bending over or lifting heavy objects.

Causes of Cataract

The cause of most cataracts is unknown; they are usually related to the aging process. As age increases, the chance of developing cataracts increases. Other causes include a family history of cataracts, inflammation within the eye, prolonged exposure to the sun's ultraviolet ("UV") rays, eye injuries (trauma), medical problems such as diabetes, kidney diseases, and long-term use of some medicated eye drops such as steroids. Children and newborn infants can also develop them.

Symptoms of Cataract
The common symptoms of cataracts include:
  • Gradual blurring of vision, one eye appears to be clearer and brighter than the other
  • Colors appear dull, particularly greens and blues
  • Glare and light sensitivity
  • Double vision or "Ghosting"
  • Objects may appear yellow, hazy, blurred or distorted
  • The need for brighter light to read
  • Poor night vision and Halo effects around bright lights at night, e.g. car headlights and street lamps
  • Frequent need to change lens prescription

Cataract Surgery

In a cataract operation, the eye's natural lens is removed. Therefore, a new lens must replace the one removed for vision to be restored. This new lens can be in the form of special eyeglasses with thick lenses or contact lenses. Most commonly, it is in the form of an intraocular lens implant, which permanently replaces the old lens.

The artificial lens is made of plastic and is usually inserted at the same time the cataract is removed. Depending on the individual case, the lens is placed directly behind or, less frequently, in front of the iris, the "colored" part of the eye. Not every case is appropriate for this type of procedure, and the method of implantation used depends on the individual patient.

Once the surgeon determines that an intraocular lens replacement is appropriate, the patient undergoes a special preoperative evaluation. Like contact lenses and "prescription" eyeglasses, intraocular lenses differ in terms of refractive power, and the evaluation will determine the proper lens power of the implant. The length of the eye is measured and the curvature of the cornea is evaluated. Calculation of the implant power is based on this information and performed in a computer.

The natural lens has the ability to accommodate, or change shape, so that it is possible to focus at varying distances. The intraocular lens, which cannot change shape, is usually calculated for a middle distance so that the patient can see well enough to move about without glasses. Normal eyeglasses must still be worn to see up close up and far away. In most cases, though, patients notice significant improvements in vision resulting from intraocular lens implantation.

Surgery Type
Cataract surgery removes the cloudy lens, which usually takes 30 minutes and is performed on an outpatient basis. There are presently two (2) common types of Cataract Surgery:
  • Conventional Cataract Surgery: Extra-capsular Cataract Extraction or ECCE
  • Modern Cataract Surgery: Phacoemulsification or Phaco
The comparisons of these surgical types are as follows: