While laser refractive surgery is often the right choice for many patients, there are a number of circumstances where a lens-based approach might be the best way of correcting their vision, such as patients with very high myopia (-10.0 D or more), as correcting this amount of myopia would require too much of the cornea to be lasered away. There are a number of lens-based approaches – the right one depends on each patient’s individual ocular anatomy and the visual dysfunction needing corrected.
Phakic lenses are additional lenses that are placed in the anterior chamber of the eye – either in front of the iris (Artisan lens) or behind it (the implantable collamer lens (ICL) to correct for refractive error. We use phakic lenses in patients less than 45 years of age and have a high degree of refractive error (starting with nearsightedness of more than -10 D).
In patients older than 45 years of age and with a high degree of ametropia (e.g. myopia greater than -10 D) we replace the patient’s own lens with a trifocal or multifocal artificial lens. This option allows good vision for near and far, meaning that we’re able to then correct myopia up to -23.0 D and far-sightedness up to +12.0 D.
Under certain circumstances, we can combine refractive laser surgery with lens replacement, such as in a patient with very high myopia and very high astigmatism. We can use astigmatism-correcting (“toric”) intraocular lenses and the laser to treat the myopia – or vice versa: use the laser to treat the astigmatism, and the intraocular lens to correct the myopia. It all depends on each patient’s individual ocular anatomy – but the combination means that patients with extreme refractive errors can have them corrected.