In this blog post, we’ll explore the differences between LASIK and LASEK, comparing their recovery times and levels of discomfort.
If you visit a high school today, you’ll find that more than 80% of students in a single class wear glasses. It’s even common for elementary school and kindergarten students to wear glasses. I, too, visited an ophthalmologist when I was seven years old, and after the doctor asked, “Why did you wait so long to come?” I started wearing glasses. However, as many students become concerned about their appearance alongside the inconvenience of glasses, they switch to contact lenses. But contact lenses also come with the hassle of daily cleaning, and prolonged wear can easily cause eye fatigue. That is why surgeries like LASIK and LASEK were introduced, and the number of people undergoing these procedures is steadily increasing. So, what are the principles behind these surgeries, and what are the differences between them?
Before explaining the principles of the surgeries, let’s first understand what myopia and hyperopia are. In order for us to see something, light must pass through the cornea and lens and focus precisely on the retina. However, in people with myopia, the image focuses slightly in front of the retina. Since the image does not appear clear in this case, glasses or contact lenses are used to help the image focus precisely on the retina. The reason the image focuses in front is that the cornea and lens are too thick, so concave lenses are used to reduce the convergence of light, allowing the focus to shift backward. Conversely, for people with hyperopia, the image is focused slightly behind the retina. In this case, convex lenses are used to better converge light, causing the focal point to be in front of the retina.
Meanwhile, unlike glasses or contact lenses, LASIK and LASEK use lasers to reshape the cornea, producing the same effect as wearing lenses. First, let’s examine how vision correction works for nearsightedness. The cornea consists of the corneal epithelium, which is the outer layer, and the corneal stroma beneath it. In LASIK, the procedure begins by creating a corneal flap—essentially a “lid”—that includes the corneal epithelium and a small portion of the corneal stroma. Depending on the method used to create this flap, there are two types: Micro-LASIK, which uses a metal blade, and IntraLASIK, which uses a femtosecond laser. Once the flap is cut and the corneal stroma is exposed, a laser is applied to the central part of the stroma to thin it. The corneal flap is then repositioned to ensure the cornea flattens out after surgery. This shifts the focal point of light further away from the retina, allowing for normal vision. For hyperopia, the basic surgical method is the same as for myopia, but the difference lies in the fact that the peripheral rather than the central part of the corneal stroma is ablated. However, vision recovery may be slightly slower compared to myopia.
In contrast, LASEK uses highly specialized techniques to peel back only the corneal epithelium. A laser is then used to thin the corneal stroma. Unlike LASIK, the flap is not repositioned; instead, the procedure involves waiting for the corneal epithelium to heal naturally. Similar to LASIK, LASEK thins the central part of the corneal stroma for myopia and the peripheral part for hyperopia.
As discussed earlier, the main difference between LASIK and LASEK lies in whether a corneal flap is created before reshaping the corneal stroma or whether only the corneal epithelium is peeled back. Therefore, people with relatively thin corneas who cannot have a corneal flap created are generally recommended to undergo LASEK rather than LASIK.
Additionally, after LASEK, a larger portion of the corneal stroma remains compared to LASIK. However, since LASEK requires waiting for the corneal epithelium to heal, the recovery period is longer and the pain is more severe than with LASIK. Furthermore, in terms of vision stability, LASEK is said to maintain stable vision post-surgery, whereas LASIK tends to result in a decline in vision over time.
Of the five senses, vision is arguably the most important. Since poor vision causes significant inconvenience in daily life, people have continuously sought ways to correct it. We have examined the principles and differences between LASIK and LASEK, the most recent technologies in this field. LASIK and LASEK differ in their surgical methods and the resulting effects. Furthermore, since the structure of each person’s eye is unique, it is advisable to visit an ophthalmologist for an examination and carefully determine which procedure—LASIK or LASEK—is best suited for your eyes.
