Clear Lens Exchange (CLE)
Clear Lens Exchange, or CLE, is a surgical procedure designed to reduce or eliminate the need for glasses or contact lenses. It can be used to treat farsightedness and nearsightedness, presbyopia and cataracts. Unlike refractive procedures that change the shape of the cornea, CLE corrects vision by removing the eye’s crystalline lens and replacing it with an artificial lens known as an intraocular lens (IOL).
The Lens and Accommodation
In past years IOLs were single-focus only. This failed to replace the lost ability to accommodate which the lens has. If you look at these words, then at your fingernails, let’s say, and then out the window and back to this screen, your eyes are accommodating to those distances.
The lens changes its curvature, controlled by muscles known as ciliary muscles. We don’t feel that happening, as it’s automatic and just part of how the eye works. The eye’s lens is removed in a CLE procedure, so accommodation is lost with it.
Multifocal and Accommodating IOLs
Since the days of single-focus IOLs, several new IOLs have been developed which mimic that lost accommodative ability.
A Crystalens is inserted in place of the natural lens, and attached to those same little ciliary muscles. Now the muscles will control the Crystalens as you change focus from far to near. The natural lens changes its curvature for changing distances, but the Crystalens moves back and forward in simulation of that.
It moves forward slightly when you focus on a close object and back a little when you look into the distance. This mimics the lens becoming more steeply curved for close viewing and flatter for distance. You would not feel the Crystalens moving – it wouldn’t feel any different than changing your focus with the natural lens.
As of July, 2008, Crystalens HD is the only accommodating IOL with FDA approval (2008).
ReZoom is a multifocal IOL. It is not connected to the ciliary muscles, but is suspended in the same pocket vacated by the natural lens. The multiple focus ability it gives you comes from within its design and structure. It is made with five concentric zones, using a technology called Balanced View Optics™. Each zone refracts light entering the eye from an object, and each does it differently. The end result is that regardless of how far away an object is, the light coming from it is focused on the retina, and you can see it clearly. ReZoom IOLs received FDA approval in March, 2005.
ReSTOR is another multifocal IOL. It is made of a proprietary acrylic substance called AcrySof® and like the ReZoom IOL, has concentric areas called steps. Each refracts the light differently so that you can see clearly at all distances. Like the ReZoom IOL, ReSTOR IOLs received FDA approval in March, 2005.
Who is a Good Candidate for CLE?
If you would like to have improved vision, are in good general health, and are willing to accept the slight risk that comes with all surgeries, whether on the eyes or any other part of the body, you could be a good candidate. It can be a good procedure for anyone who:
- Is over 40
- Wants to depend less on glasses or contact lenses
- Has severe myopia or hyperopia
- Has severe myopia or hyperopia as well as early cataracts
- Would like to treat presbyopia with an IOL
- Is looking for an alternative to LASIK
What to Expect on Surgery Day
- A CLE is performed on an outpatient basis and takes about 15 minutes for each eye.
- Upon arrival, you will be given a local anesthetic to numb your eyes
- The skin around each eye will be thoroughly cleansed, and sterile coverings placed to keep the surgical area sterile
- Your eye will be held open with an eyelid holder to save you from having to do it
- Under an operating microscope, your eye doctor will create a small incision at the side of the eye, outside the field of vision
- Using an ultrasound probe, he or she will carefully fragment the natural lens and gently remove it with suction
- The IOL is implanted in the same natural pocket that housed the original lens
- The incision is then closed and a protective shield placed on the eye
- Your eye surgeon will prescribe special eye drops and ask that you be careful not to rub or press on your eye during the recovery period
What Are the Risks Associated With Clear Lens Exchange?
Any surgical procedure comes with inherent risk including bleeding, swelling, and infection. In eye surgery, the more specific risks are retinal detachment and capsular opacification (referring the capsule, or pocket, in which the IOL is placed).
During your pre-operative consultation, your eye doctor will answer any questions and thoroughly explain these and any other risks associated with CLE.
You can reduce these risks enormously by (a) choosing a well-qualified and experienced ophthalmologist; and (b) by following your eye surgeon’s post-surgery care instructions to the letter.