Common Beliefs About LASIK for Myopia and Hyperopia
LASIK, or laser-assisted in situ keratomileusis, is a popular solution for nearsightedness, farsightedness, and astigmatism. For many, the constant need to wear glasses can interfere with their professional and daily activities. LASIK offers a life-changing solution - almost like getting a new pair of eyes. As its popularity grows, so do the questions, concerns, and misconceptions shared widely across social media. To provide accurate and helpful information, Dr. Suphawadee Uea-jongmanee and Dr. Thitima Wangcharoen, ophthalmologists at MedPark Hospital, are here to provide accurate and valuable information.
Laser Vision Correction Isn’t Just About “LASIK”.
Many people assume that LASIK refers exclusively to all types of laser vision correction. In fact, LASIK is just one of several techniques available. There are currently three primary methods of laser vision correction:
- PRK (Photorefractive Keratectomy) involves gently removing the surface layer of the cornea, followed by laser ablation to reshape the curvature of the cornea and correct the refractive error.
- LASIK or Femto-LASIK utilizes a laser to create a corneal flap. The ophthalmologist flips open the flap to allow an excimer laser to correct the refractive error and subsequently reposition it to its original place.
- SMILE / SMILE Pro uses a femtosecond laser to create a thin lenticule, a disc-shaped piece of tissue, in the cornea and extract it through a small 4-mm side incision.
Can LASIK treat eye conditions like pterygium or cataracts?
The answer is No.
Pinguecula and pterygium develop on the conjunctiva. They are caused by prolonged exposure to sunlight and wind, leading to the formation of tissue growth. Pinguecula appears as a small, raised bump on the sclera. If it enlarges and extends onto the cornea, it is called a pterygium.
A cataract is a clouding of the natural crystalline lens located inside the eye. Typically age-related, it causes gradual loss of clear vision. Treatment involves surgical removal of the cloudy lens and implantation of an intraocular lens (IOL).
Glaucoma results from elevated intraocular pressure, which damages and degenerates the optic nerve at the back of the eye.
As each of these conditions involves structures other than the cornea, LASIK is not a solution for these eye diseases.
Is LASIK only effective for treating myopia?
The answer is No.
Laser vision correction encompasses several different techniques. Therefore, it is crucial to distinguish them individually as follows:
- PRK can treat nearsightedness, farsightedness, and astigmatism.
- LASIK or Femto-LASIK is suitable for nearsightedness, farsightedness, and astigmatism.
- SMILE / SMILE Pro currently corrects nearsightedness and astigmatism (future indications may expand.).
It is important to note that farsightedness in this context refers to congenital hyperopia, not age-related farsightedness or presbyopia.
Is LASIK a painful procedure that requires a prolonged recovery period?
The answer is No.
All laser vision correction procedures are painless. Anesthetic eye drops numb pain before and during surgery. The procedures are brief. However, some patients may experience mild eye irritation or dryness afterward. The length of recovery varies depending on the specific technique chosen.
SMILE / SMILE Pro involves laser application for only 8–10 seconds and a small incision, resulting in a shorter recovery time compared to LASIK or Femto-LASIK. PRK removes the corneal epithelium, resulting in a week-long recovery period.
Does LASIK guarantee a lifelong zero prescription?
The answer is No.
Achieving a perfect zero prescription in both eyes is not always necessary. The outcome depends on the patient’s age at the time of surgery as well as their visual habits. Ophthalmologists focus on correcting refractive errors, which allow patients to use their eyes naturally without the need for glasses or contact lenses.
Whether the vision prescription remains stable over time depends on multiple factors. Patients with very high degrees of hyperopia or myopia before LASIK are more likely to experience changes in their prescription in the future.
Similarly, unstable refractive errors before surgery can lead to fluctuations after the procedure. For this reason, candidates for LASIK should have a stable prescription for at least one year before surgery.
Other factors that may contribute to changes in vision include cataract development, aging, and excessive gazing or improper visual habits, all of which can influence refractive stability.
Is it possible to undergo LASIK multiple times?
The answer: It depends on the individual.
Many patients who have previously undergone LASIK may experience a return of myopia or hyperopia as they age and, therefore, consider retreatment, which begs the question of whether one can safely repeat LASIK.
Dr. Supawadee explains that LASIK involves thinning the cornea, and the extent of thinning depends on two factors, including the patient’s corneal thickness before surgery and the degree of refractive error requiring correction. If the cornea becomes too thin after the initial LASIK procedure, repeat surgery may not be possible, as this could compromise corneal strength and increase the risk of keratoconus. Careful evaluation by an ophthalmologist is essential to ensure retreatment is safe and appropriate.
Is it true that LASIK causes dry eyes?
The answer is Yes.
Dry eyes are a common and often unavoidable side effect, particularly in the early postoperative period. Because the laser can disrupt some of the corneal nerves responsible for stimulating tear production, leading to reduced tear secretion and symptoms of dryness. The symptoms typically improve within 6 to 12 months after surgery. Among the available procedures, SMILE Pro carries a lower risk of postoperative dry eye compared to other laser vision correction techniques.
Is it true that LASIK impairs your ability to drive at night?
The answer is No.
Most people can drive at night as usual after undergoing LASIK. However, some individuals may experience glare, especially those who had wide pupils before surgery or who already experienced such visual disturbances beforehand. The symptoms typically improve within 6 to 12 months. It is also important to note that the degree of night glare can vary depending on the type of laser vision correction performed. Among the available techniques, SMILE Pro results in fewer night vision disturbances compared to other methods.
Is it true that people with very high myopia cannot undergo LASIK?
The answer: It depends on the individual.
High myopia is a refractive error greater than -6.00 diopters. Whether LASIK is feasible depends on both the degree of myopia and the thickness of the cornea. Because LASIK reshapes the cornea with a laser, greater refractive errors require removing more corneal tissue. Excessive thinning of the cornea may compromise its structural integrity and pose risks to the patient. In cases of high myopia with thick cornea, LASIK may still be an option. However, the ophthalmologist will evaluate whether the procedure is safe to perform.
Is it true that LASIK cannot correct myopia in people over 40?
The answer is No.
Individuals over 40 can still undergo LASIK to correct nearsightedness. However, around this age, it is common to develop presbyopia, an age-related condition that affects near vision, making it difficult to see objects up close without eyeglasses for reading. To address this, an ophthalmologist may recommend a technique known as Monovision, with one eye corrected for distance and the other for near vision. The ophthalmologist will determine whether Monovision is appropriate.
Can high school students undergo LASIK?
The answer is No.
To be eligible for LASIK, individuals must be at least 18 years old and have a stable refractive error, defined as a change of no more than 0.5 diopters (commonly referred to as 50) per year in nearsightedness or astigmatism.
Ultimately, it is essential to consult an ophthalmologist for a comprehensive evaluation to determine whether laser vision correction is safe and appropriate, including the selection of the most suitable technique tailored to each individual.
