Clear lens exchange is an elective procedure that can be performed to improve the focus of the eye and reduce dependence on corrective lenses. It can be an option for two categories of patients:

• Patients who are not candidates for LASIK eye surgery or PRK eye surgery.
• Patients over the age of 50 years who wish to reduce their dependence on corrective lenses and improve the clarity and brightness of their vision.

The eye has two elements that focus light:  the cornea and the lens.  The cornea provides approximately 70% of the focusing power of the eye, and it is this structure that is reshaped by a laser in LASIK and PRK.  The lens of the eye provides the other 30% of the focusing power of the eye.  In clear lens exchange, the natural lens of the eye is removed and replaced with an appropriately powered intraocular lens (IOL).

1)   Clear Lens Exchange For Patients Who Are Not Candidates for LASIK/PRK:

Certain patients may not be candidates for laser vision correction.  Their corneas may be too thin, or they may be too nearsighted or farsighted, for example.  In these individuals, rather than treating the cornea, the lens can be treated instead, by clear lens exchange.  Multifocal lens implants may be an option for certain individuals, to further reduce dependence on glasses for reading.

2)   Clear Lens Exchange for Patients Over the Age of 50 years:

As the lens of the eye ages, it yellows and hardens.  These normal changes affect the quality of vision as well as color perception, even when the visual acuity is unaffected.  In other words, the vision of a 25-year-old patient who sees 20/20 will be superior to the vision of a 50-year-old patient who sees 20/20, due to natural aging changes of the lens of the eye of the 50-year old.  Because the change is so gradual, patients tend to be unaware of the change in their vision.  Patients over the age of 50 undergoing clear lens exchange benefit not only in reducing their dependence on corrective lenses, but also in the improved clarity and vividness of their vision.  The improvement in vision is enhanced by the use of the lens implant, as the lens is designed to improve vision by minimizing distortion of light as it comes to a focus at the back of the eye.   Much like wavefront laser treatments, the new lenses have a wavefront design to reduce aberrations, and this has been shown to improve night vision.

The clear lens exchange procedure is identical to cataract surgery, except that there is no cloudiness of the lens prompting surgery.  It is exclusively for refractive purposes. The technique used (essentially the same as cataract surgery) has become one of the most successful procedures being performed today, worldwide.  Patients that undergo this procedure will never develop cataracts or require cataract surgery in the future. 

A complete eye examination is performed prior to surgery and the eyes are measured with specialized instruments in order to determine the proper lens implant power.  Surgery is performed as an outpatient procedure, with light sedation. 

Astigmatism is surgically corrected at the time of the clear lens exchange as necessary, to optimize the vision without glasses.  An intra-operative procedure called a limbal relaxing incision may be used or an astigmatism correcting IOL can be implanted. 

The results are seen almost immediately after surgery and the procedure typically does not cause dry eyes.  If the desired refractive change is not achieved, a cornea-based refractive surgical technique such as Lasik or PRK may be used in combination with clear lens exchange to “fine tune” the vision. 

At vivid laser centre, we are currently using the Crystalens accommodating IOL as well as the Restore multifocal IOL.

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