Crystalens Accommodating IOL

Crystalens is the brand name of an intraocular lens (IOL) that is designed to provide distance, midrange, and near vision for pseudophakic patients. Crystalens is commonly used in cataract patients, but may also be appropriate for patients considering RLE. Crystalens may be an appropriate alternative to monovision for some patients.

As we mature, the natural crystalline lens in the eye expands, firms, and loses its ability to accommodate from distance to midrange to near vision. This normal condition is known as presbyopia and develops in most people in between 40 and 60 years of age. It is first noticeable when it becomes difficult to read items close to you, often requiring reading glasses, bifocals, or trifocals.

During surgery for cataracts or RLE, the crystalline lens of the eye is removed and replaced with an artificial IOL. A conventional IOL is commonly focused for distance vision only. It does not change from distance to near vision, and reading glasses or monovision are required for the patient to be able to see items at all distances. The purpose of the Crystalens is to provide cataract and RLE patients with the ability to accommodate.

The Crystalens accommodating IOL is specially designed so it may move forward and backward within the eye in response to flexing of the same muscles that manipulated the crystalline lens for accommodation. This is sometimes called pseudoaccommodation, but is actually real accommodation with an artificial lens. The vaulting movement changes the focal point and may allow a patient to accommodate. This accommodation may reduce the need for reading glasses, bifocals, or trifocals, and does not require any special exercise or thought process on the part of the patient. Accommodation with a Crystalens is the same as accommodation with a natural lens. Two and three year follow data indicates that the pseudoaccommodation of the Crystalens does not significantly diminish with time.

In the FDA clinical trials it was found that a vast majority, but not all, patients implanted with a Crystalens accommodating IOL achieved a measurable improvement in accommodation. It was also indicated that the Crystalens provided vision quality equal to or better than a conventional IOL. It would appear that there is no significant downside to the Crystalens accommodating IOL, and the high probability of functional accommodation is most assuredly an upside.

Despite all the apparent good news, do not expect too much from an accommodating IOL. Accommodation will not be restored to the level of function you had when you were 30. For a few, accommodation will actually be less after a Crystalens, but will be more than with a conventional IOL. Keep expectations reasonable.

The Crystalens is not for everybody. If the natural ciliary muscle contractions are weak or the zonules are damaged, the Crystalens IOL may not accommodate even if implanted correctly. If the ciliary muscle or zonules do not function, a pseudoaccommodating IOL essentially becomes a conventional IOL. If the patient's pupils do not chemically dilate adequately, the doctor will be positioning the haptics around a blind corner, but if the patient's pupils naturally dilate too large, the Crystalens may induced glare in low light environments. It is possible that a posterior capsule opacification may occur, but a quick laser procedure usually takes care of this problem. The recovery time for a Crystalens may be slightly longer than with a conventional IOL. Also, the cost of the Crystalens is significantly more than a conventional IOL, and some insurance plans may not pay for all or part of the surgery if the patient elects to use a high technology Crystalens.