As medical technology and the popularity of laser vision correction have advanced, laser eye surgery is increasingly replacing the need for glasses and contact lenses. Laser eye surgery is a procedure performed by an eye surgeon with training in refractive surgery.
Laser vision correction aims to do just that – correct your vision with a laser. This means that you no longer need to wear glasses or contact lenses in order to see clearly. In some cases, you may still need some sort of optical correction for near tasks, such as reading. However, with the progress made in laser eye surgery and technology, some types of laser eye surgery can even fix that.
How Does Laser Vision Correction Work?
All the different types of laser eye surgery are based on the premise of reshaping the cornea. The cornea is the front part of the eyeball and is the first surface responsible for bending or refracting light as it enters the eye.
Blurry vision as a result of refractive error arises because the light is not refracted to an accurate point onto the retina as it passes through the eye. In short-sightedness (myopia), light comes to a focal point before it reaches the retina. In long-sightedness (hyperopia), it comes to a point only after the retina. In astigmatism, light is focused at two different points, depending on which angle the rays entered the eye.
By modifying the curvature of the cornea through laser eye surgery, your eye surgeon is able to adjust where light comes to focus. Of course, the aim is to get this focal point right on your retina, which is where you’ll achieve the sharpest sight.
The Types of Laser Eye Surgery
You may be more familiar with some types of laser eye surgery compared to others. Your refractive eye surgeon may not offer all procedures but will still ensure that the most appropriate laser vision correction surgery is offered to you. Each laser eye surgery technique has its own eligibility criteria. If you’re not suitable for one method, your eye surgeon may be able to suggest something else.
LASIK (laser-assisted in situ keratomileusis)
If there was one type of laser eye surgery that you’ve heard of, it’s probably LASIK. LASIK uses a femtosecond laser or manual bladed tool to create a hinged flap out of the uppermost layers of the cornea. When this flap is moved to the side, an excimer laser can be used to vaporise parts of the deeper corneal tissues to reshape them. Afterwards, the flap is repositioned. LASIK can be used to treat high myopia and moderate degrees of hyperopia and astigmatism. It is not suitable for people with thin corneas.
PRK (photorefractive keratectomy)
PRK is one of the older types of laser eye surgery but is still used today. Unlike LASIK, only the very top layer of corneal tissue is removed, rather than creating a thicker flap. Once this epithelium has been taken away, the excimer laser can be applied to the underlying layers of tissue. This means PRK is a valuable laser eye surgery technique for people with thinner corneas, as the thickness of a corneal flap doesn’t need to be taken into account. It can also correct for high myopia, moderate hyperopia and astigmatism. While having PRK eliminates any of the flap-related complications found in LASIK, it does have a longer recovery time and tends to be associated with more discomfort.
SMILE (small incision lenticule extraction)
SMILE laser vision correction is the newest addition to the suite of refractive surgeries. During the SMILE procedure, a femtosecond laser is used to form a precisely-shaped disc of tissue out of the central layers of the cornea. This is performed without needing to remove the upper layers, such as in PRK and LASIK. The disc, also known as a lenticule, is then removed from the eye through a keyhole incision.
The result is a cornea that has been reshaped from the inside. SMILE surgery is thought to be useful for people with dry eye as it is minimally invasive and less likely to exacerbate this condition. At the moment, it is suitable only for myopia and astigmatism, not hyperopia.
Laser Blended Vision
Laser blended vision, also known as Presbyond, is a modified LASIK surgery. Its aim is to provide the patient with a degree of both far distance sight as well as functional near sight, such as for reading or computer tasks. A computer algorithm calculates an adjusted corneal curvature that allows each eye to see both far and near, and the excimer laser performs its reshaping accordingly. Typically, your dominant eye will be adjusted mainly for long-distance sight with some near, and vice versa for your non-dominant eye. It can take some time for your brain to adjust to this new visual experience, so your eye surgeon will make sure you have a good chance at adapting before offering you this procedure.
In addition to these more common types of laser eye surgery, there are other types of refractive operations. These include LASEK (laser-assisted sub-epithelial keratomileusis), which is a mix between PRK and LASIK, and refractive lens exchange or intraocular contact lenses, which don’t require laser equipment. If you’re interested in surgical vision correction, speak to your eye surgeon by calling on 03 9000 0389 about which technique is most appropriate for you.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
References
Types of laser eye surgery – how to choose.
https://boweneye.co.nz/bowen-eye-news/types-laser-eye-surgery-how-choose
Zeiss Presbyond.
https://www.zeiss.com/meditec/int/products/refractive-lasers/excimer-laser/presbyond.html
LASIK eye surgery.
https://www.mayoclinic.org/tests-procedures/lasik-eye-surgery/about/pac-20384774#:~:text=During%20LASIK%20eye%20surgery%2C%20an,in%20the%20eye%20(C).
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