Surgery to improve vision (refractive surgery)
Pokanga e whakapai ai i te tirohanga (pokanga hakoko)
Surgery that aims to remove or reduce your need for glasses or contact lenses is called refractive surgery.
This type of surgery changes the shape of the front layer of your eye (the cornea), replaces your natural lens or adds an extra focusing lens into your eye. Refractive surgery can be used for long-sightedness (hyperopia), short sightedness (myopia) and astigmatism.
Laser surgery
Laser surgery changes the way your eye focuses by reshaping your cornea (the top layer of your eye), using a specially designed laser. There are three types of laser refractive surgery.
- LASIK (laser in-situ keratomileusis). In this surgery a flap of cornea is cut on the front of your eye and moved aside. The laser then reshapes your cornea, and the flap is put back in place.
- PRK (Photo refractive keratectomy). In this surgery the very surface layer of your cornea (the epithelium) is removed, and the laser then reshapes your cornea. You grow a new epithelium over the surface within five days.
- LASEK (Laser epithelial keratomileusis). In this surgery the epithelium is removed as a flap (like LASIK but much thinner). After the laser reshapes your cornea, the epithelium is replaced.
Intraocular lenses (IOLs)
There are two forms of refractive surgery that involve putting a new lens in your eye (intraocular lenses).
- Clear lens exchange. This is much the same as cataract surgery. Your eye's natural focusing lens is removed and replaced with an artificial lens, which creates clear focus. The lenses used can correct astigmatism (toric IOLs) or can even change their focus to help with reading (multifocal IOLs).
- Phakic IOLs. In this surgery your natural focusing lens isn't removed, but another focusing lens is added just in front of it to create clear focus.
Written by Canterbury optometrists. Adapted by HealthInfo clinical advisers. Last reviewed March 2023.
Sources
The information in this section comes from the following sources, some of which may be clinically complex or not available to the general public
New Zealand Association of Optometrists – Vision problems.
Image and embedded video sources
Astigmatism illustration from Shutterstock (image ID 77804407). December 2014.
Eye chart with glasses image from Shutterstock (image ID 103354703). March 2025.
Eye surgery image from Shutterstock (image ID 1064124212). January 2023.
Hyperopia illustration from Shutterstock (image ID 641320765). January 2023.
Myopia illustration from Shutterstock (image ID 641320765). January 2023.
Myopia video from Free Medical Education on YouTube.
Presbyopia illustration from Shutterstock (image ID 83736829). November 2014.
Presbyopia video from the American Academy of Ophthalmology on YouTube.
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