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Crystalens® Phakic Implants RK CK ICRS Glasses & Contacts



Available since its U.S. FDA approval in 2003, the crystalens® is a type of implant that mimics the natural human lens. This "accommodating"  implant, when used with refractive lensectomy (also known as clear lens extraction), can greatly reduce or even eliminate the need for glasses, for both distance and reading! The topic of intraocular lenses (IOL) is a complex one, so let's spend a little time going over the concepts.

Routine refractive lensectomy (without the crystalens® implant) will not completely eliminate the need for glasses.  While distance vision can be made clear, reading vision is compromised (again, when a traditional intraocular lens implant is used).

In patients under approximately 40 years of age, the natural crystalline lens retains the ability to flex in a process called accommodation. This allows an individual to generate the extra focusing power needed to read up close. After 40, the ability to accommodate diminishes more quickly, which results in a person needing bifocals or reading glasses.  This need for reading glasses is accelerated by removal of the natural crystalline lens; for all purposes, the traditional intraocular lens implant cannot accommodate. 
The traditional monofocal intraocular lens implant only focuses at one point, either distance or near, or somewhere in between (intermediate), but almost never at two or all three points simultaneously.  Hence, the term monofocal or one focus. With monofocal implants, one of three strategies can chosen, if both eyes are having surgery:

 a) Implant selection so that both eyes focused at distance. While glasses may still be necessary for distance, they will almost certainly be necessary for reading and intermediate vision.
 b) Implant selection so that both eyes focused at near. While glasses may still be required for reading or intermediate vision, glasses almost certainly required for distance.
 c) Implant selection so that one eye focused at distance, and the other eye for reading.
Glasses may still be required for both distance and near, but choosing this option can reduce overall dependence on glasses. This is called monovision. Monovision can work well but it is a compromise. Decreased depth perception and difficulty with vision under dim lighting conditions (such as night driving) may occur. Golfers and pilots may not like this. People who drive at night extensively may not like monovision.

Crystalens in eye

The crystalens® implant is quite different from the traditional monfocal implant. It is a highly sophisticated implant that provides a continuous range of vision, from distance to intermediate, to near. This implant bends or flexes like a normal human lens, to create extra focusing power. The benefit of using this implant is that each eye can see distance, intermediate, and near. This is quite different than the monovision option using the more traditional monofocal lens implant, where only one eye is focused at distance, and the other eye is focused at near. In a study of the crystalens® implant, 93.8% of patients reported performing most visual tasks without glasses. About 74% never or almost never wore glasses after surgery. In the original FDA trials, of the patients who received crystalens® in both eyes, 92% could see 20/25 or better at distance, 96% could see 20/20 at arm's length, and 73% could see 20/25 at near, without glasses or contacts. Reading vision with the crystalens® in both eyes is good, but fine print, prolonged reading, or reading in dim lighting may require the use of weak reading glasses.    
The best visual results are obtained when both eyes receive the crystalens® implant. It is not recommended that only one eye receive the crystalens® implant. This is an implant designed to be used in both eyes.   

The optimal result with the crystalens® implant requires getting as close to a zero distance prescription as possible. A few patients who have refractive lensectomy using the crystalens®  implant, will require a "touch-up" procedure to realize the full potential of this lens implant. In other words, to fine-tune the visual results, sometimes an additional procedure may need to be done afterward. The additional procedure may involve correction of astigmatism with either a limbal relaxing incisions (LRI) or astigmatic keratotomy (AK), both of which can be done in the office. Another procedure which is sometimes used to refine the crystalens® results is laser vision correction, like LASIK, which is done at another facility. 
Are you a candidate for the crystalens® implant?
Only your ophthalmologist can tell you.  After a complete eye exam and additional testing, your doctor will be able to determine if you are a suitable candidate for crystalens®. Your doctor will talk to you about the risks of surgery, and those specific to multifocal implants. For patients who meet the criteria, the crystalens® implant can be a life-changing experience.

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