The eye is an amazing organ with multiple parts all working together to receive light, convert it to neural signals, and send this signal onwards to certain areas of the brain for visual processing. However, when even just one of these anatomical components doesn’t quite function as it’s supposed to, we end up with various eye diseases, vision problems, and, for millions around the globe, refractive error. Although the term ‘laser eye surgery’ can refer to not only laser surgery for vision correction but also for the treatment of eye diseases such as diabetic retinopathy, many people will equate laser surgery with the idea of surgical correction of refractive error. So, what is laser eye surgery and what can it do for you?
Starting with Refractive Error
Before going into the details of exactly what is laser eye surgery, it would help to first understand the problem that refractive laser eye surgery attempts to address – refractive error.
Refractive error refers to a state of the eye when the light entering its front anatomical components fails to be bent (refracted) in such a way so as to focus to a sharp point on the retina at the back of the eye. The mismatch between the refractive power of the eye and eyeball length can result in prescriptions for farsightedness, nearsightedness, or astigmatism.
The result of refractive error is blurry vision, either for only certain distances or for all distances. The vision correction provided by optical aids such as glasses and contact lenses works by adjusting the refraction of light as it passes through the lens so that by the time it passes through your own refractive anatomy – namely, the cornea and the crystalline lens – it will be able to focus perfectly onto the retina, resulting in clear vision.
However, there are some shortcomings of spectacles and contacts, such as inconvenience in certain situations and the ongoing costs of maintaining these aids as they wear down or run out. So, in the 1980s the first laser eye surgery procedure was approved for surgical vision correction.
What is Laser Eye Surgery?
Laser eye surgery is a form of vision correction using laser technology. While optical aids such as glasses and contacts are worn externally, laser surgery procedures surgically adjust the anatomy of the eye itself to change the way light passes through it.
The goal of refractive laser eye surgery is to provide vision correction that significantly reduces a patient’s dependence on glasses or contacts. This may look different from individual to individual. For some people, this may mean excellent unaided vision for all long-distance viewing such as when playing sport or driving, and for occasional near activities such as reading they are quite happy to put on reading glasses. For other people, such as those who spend the majority of their time reading or sewing, they may prefer to have perfect vision for near work and wear glasses for driving and movies instead.
Depending on the type of refractive error, age of the patient, and the laser surgery technique used, some lucky patients may find themselves with clear vision for both distance and near activities without needing any glasses.
How Does Laser Eye Surgery Work?
The cornea is located at the very front surface of the eye, that clear dome of tissue that covers the colored iris. The crystalline lens is hidden just behind the iris and is responsible for adjusting its shape with the help of muscles to accommodate for focusing on near objects.
Refractive laser surgery treatments are targeted at reshaping the cornea to change the passage and refraction of light through this surface. There are other refractive surgery methods that involve the crystalline lens but these aren’t typically considered laser procedures – operations such as cataract extraction or refractive lens exchange (RLE) are also able to effectively correct the eye’s refractive error and reduce a patient’s need for optical aids.
There are two types of medical laser tools that are used for refractive laser eye surgery, though not all laser surgery methods require the use of both – these are the femtosecond laser and the excimer laser.
Here’s a brief summary of a few of the most well-known laser eye surgery procedures.
Photorefractive keratectomy (PRK)
PRK involves manual removal of the superficial layers of the cornea known as the epithelium, which can be done mechanically or chemically. This then exposes the deeper tissues of the cornea known as the stroma. An excimer laser can then be applied to reshape the stromal tissue in a process known as photoablation.
Laser-assisted in situ keratomileusis (LASIK)
This may be the most well-known laser eye surgery procedure. Similar to PRK, an excimer laser is used in photoablation of the corneal stroma, but instead of entirely removing the epithelial layers, a hinged flap of superficial corneal tissue is created instead. This flap can then later be repositioned after photoablation and allowed to self-seal, which has some benefits in recovery time. Traditionally, this corneal flap was created using a bladed tool, but more recently some surgeons are preferring to use the femtosecond laser to form the flap.
Small incision lenticule extraction (SMILE®)
One of the most recent advancements in refractive surgery, SMILE® offers a minimally invasive way of surgically correcting refractive error. Using a femtosecond laser, a sliver of tissue called a lenticule is formed within the cornea and then removed via a keyhole incision in the outer layers. This causes minimal disruption to the corneal layers, maintaining better structural integrity.
If you’re interested in laser eye surgery and how it can improve your lifestyle, book your initial appointment with us now and call us now: (03) 9070 5753.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.