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Refractive Intraocular Lenses (RIOL's)
Some patients have extremely strong refractive errors. While laser vision correction with the excimer laser (LASIK and PRK) provides an excellent method to correct low to moderately high refractive errors, these procedures often cannot be used for patients with more extreme levels of nearsightedness (myopia) and farsightedness (hyperopia). In these cases, there may not be enough tissue to safely sculpt from the cornea to achieve a complete correction of vision and/or the individual's pupil may be too large to achieve an acceptable level of visual quality.
"Phakos" is the Greek word for lens and "phakic" is the medical term for individuals who still have their natural crystalline lens. In cataract surgery, the cloudy, natural crystalline lens is removed (aphakia) and replaced with a man-made clear lens (pseudophakia). These "intra-ocular lenses" (IOL's) have been used with great success for more than four decades in cataract surgery. Implanting an IOL, therefore, is a very common procedure in ophthalmology with more that one million of these procedures performed each year.
Recently, new approaches to IOL's, called "phakic IOL's," have been developed to insert into the eye without removing the natural lens. This technique offers the promise of helping individuals who have to this point not been candidates for refractive surgery. Even though intra-ocular lenses were approved by the U.S. Food and Drug Administration (FDA) for use in cataract surgery decades ago, the process of inserting these lenses in phakic eyes has only recently received regulatory approval in the U.S. Two versions are now available: the VERISYSE lens from Advanced Medical Optics(AMO) and the VISIAN lens from Staar Surgical.
The STAAR VISIANCollamer ICL™ phakic IOL is one such style of refractive lens. The VISIAN lens, FDA approved in December 2005, is a posterior chamber implant that is situated behind the iris and in front of the natural crystalline lens. Results of the use of this lens from other parts of the world have been quite impressive. The procedure has been regularly performed in Canada and Europe, as well as in Latin America, for several years. For more technical details refer to the following FDA link: http://www.fda.gov/cdrh/mda/docs/p030016.html
The Company is currently enrolling candidates in clinical trials for the VISIAN Toric(tm), as well as candidates for hyperopia. The VISIAN Toric IOL is capable of correcting nearsightedness with astigmatism while the hyperopic VISIAN is capable of correcting farsightedness.
The AMO VERISYSE(tm) phakic IOL is another one such style of refractive lens. The VERISYSEVISIAN lens, FDA approved in September 2004, is an anterior chamber implant that is situated in front of the iris and in front of the natural crystalline lens. Results of the use of this lens from other parts of the world have also been impressive. As with the VISIAN lens, the VERISYSE lens procedure has been regularly performed in Canada and Europe, as well as in Latin America, for several years. For more technical details refer to the following FDA link: http://www.fda.gov/cdrh/mda/docs/p030028.html
To further refine the refractive IOL approach to more extreme vision correction, a "bioptic" procedure can be performed whereby the IOL procedure is followed by the LASIK procedure to correct any remaining refractive error, particularly where significant astigmatism exists than cannot be directly treated by the IOL procedure.
Furthermore, this revolutionary "bioptic" approach may be recommended for those with early or significant cataract where lens extraction is required followed by either monofocal, multifocal(ReZoom or ReStor) or accommodative(CrystaLens) IOL's. For more details on these novel approaches and other refractive technologies, please consult our professional staff.
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