If you’ve been wearing glasses or contact lenses for a long time, the thought of laser eye surgery may be quite appealing. If you’ve only just started considering laser eye surgery, LASIK is probably the most familiar term to you. In fact, many people consider LASIK to be synonymous with laser eye surgery. However, once you’ve started doing a bit of research, you may be surprised to find that your eye surgeon actually has a few more techniques up his or her sleeve when it comes to laser vision correction. Keep reading to find out about the different laser eye surgery types.
How Does Laser Eye Surgery Work?
All laser eye surgery types are based on the concept of modifying the curvature of the cornea. The cornea is responsible for the majority of the refractive power of the eye. This refers to the degree that light bends when it passes through various anatomical structures in the eye. The other part of the eye that plays a part in refraction is the crystalline lens, which sits behind the coloured iris. None of the laser eye surgery types affects the lens or its function.
In cases of short-sightedness (myopia), light bends too much when it passes through the cornea and lens. This means it comes to a focus too soon; that is, at a point in front of the retina. In farsightedness (hyperopia), this focal point falls behind the retina. For those who experience astigmatism, this is when light is actually focused at two different points within the eye. One or neither of these focal points may be on the retina. In order to achieve clear sight, we need the focal point of light entering the eye to come to a sharp focus on the retina.
By adjusting the curvature of the cornea through the various laser eye surgery types, your eye surgeon aims to correct the passage of light through your eye so that it comes to a perfect focus on your retina. This is achieved by using a laser tool to remove specific areas of corneal tissue.
The Different Laser Eye Surgery Types
There are actually quite a number of laser eye surgery techniques. Some of them differ by only a minute detail. Your eye surgeon may not necessarily offer all the methods, so if you have your heart set on a certain technique, it’s best to do your research. However, your eye surgeon will always ensure that you are offered the laser eye surgery method that is the best option for you. This can be influenced by a number of factors, including:
- Your refractive error; commonly known as your prescription
- Your corneal thickness and the amount of tissue your surgeon has to work with for removal
- Your lifestyle, including hobbies and occupation
- Your age
In order to confirm that you are suitable for laser eye surgery, your eye surgeon will conduct a comprehensive eye test. If you’re found to not meet the eligibility criteria for laser eye surgery, don’t be dismayed – there are actually other refractive surgery options available. These are ones that don’t involve reshaping the cornea, such as implantable contact lenses or refractive lens exchange.
However, for the majority of people, laser eye surgery can be of benefit. Here are the main types of laser vision correction.
LASIK (laser-assisted in situ keratomileusis)
LASIK is unique in the way that a hinged flap of cornea is created. This flap is comprised of the outermost layers of the cornea. By moving this flap to the side during the surgery, the laser tool, known as an excimer laser, is able to vaporise the deeper tissue to reshape the cornea. After this, the flap is replaced and typically left to self-seal. A benefit of LASIK is a relatively short recovery time with little discomfort. A disadvantage is that the flap may be involved in various complications, such as becoming dislodged during rough activity or catching debris beneath it. LASIK can treat high degrees of myopia, and moderate levels of hyperopia and astigmatism.
PRK (photorefractive keratectomy)
PRK is an older laser vision correction technique compared to LASIK. However, it is still considered to be safe and effective and offers good visual outcomes. Instead of creating a flap of cornea, as in LASIK, PRK involves the complete removal of the epithelium. The excimer laser then reshapes the underlying layers. Because of this, PRK is more suitable for people with corneas that are too thin to undergo LASIK. A downside of PRK is that there is more irritation and discomfort associated with the recovery period. The treatable range with PRK is similar to that of LASIK; it all depends on your corneal thicknesses.
SMILE (small incision lenticule extraction)
SMILE surgery is the newest technique available to refractive surgeons. Unlike both LASIK and PRK, SMILE doesn’t require the removal of the upper layers of corneal tissue. Instead, another laser tool, called a femtosecond laser, is able to separate a disc of tissue from the deeper layers without disrupting the overlying cells. This disc is then removed from the eye through a keyhole incision, resulting in a modified corneal curvature. SMILE offers a recovery experience similar to LASIK and a lower risk of dry eye. At the moment, it’s only available for myopia.
Presbyond or laser blended vision
Laser blended vision is a variation of LASIK, designed for people experiencing presbyopia (the age-related deterioration of near sight). It involves correcting one eye predominantly for distance sight, with a little bit of reading vision, and vice versa for the other eye. With the two eyes together, you can achieve decent far and near vision.
Contact us on 03 9000 0389 today for a consultation.
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
Recent Comments