The phakic intraocular lens, ICL, is FDA approved to correct near-sightedness from -3.00 to -20.00 diopters, and for far-sightedness from +3.00 to +20.00. For a high amount of astigmatism, there is a customized lens called toric ICL.

 The optical effects of phakic IOLs are the same as those of a contact lens:  At younger ages (roughly before 40) it will help you focus at both near and distance objects .  However, when you have age-related farsightedness (presbyopia, which occurs at around 40), you will also need reading glasses to see well at near, regardless of whether you are using contact lenses or phakic IOL.

 As with any surgeries, there are side effects and complications that could occur.  The following is a summary report from the FDA study group* for patients with near-sightedness of 10 diopters or higher. 

• Implantable Collamer lens repositioning                  0%
• Implantable Collamer lens replacement                0.4%
• Trace of lens opacities                                               2.5%
• Increased Intraocular pressure                                0.4%

*From “United States Food and Drug Administration Clinical Trial of ICL for Moderate to High Myopia:  Three year follow-up” article published in 2004 by the American Academy of Ophthalmology. 

Some patients may experience dizziness due to the temporary increased eye pressure, but this will gradually disappear in a couple of hours after the treatment.