Choose the content to read

• What causes refractive errors?
• How many eye surgery techniques are available to correct refractive errors?
• What is the procedure for LASIK?
• Who is suitable for LASIK?
• What is the advantage of LASIK (Femto LASIK)?
• Is LASIK safe?
• What is the success rate of LASIK?
• LASIK Eye surgery at MedPark Hospital
• Sign up now for a discount on SMILE Pro

LASIK

There are several surgical techniques available to correct refractive surgery, including PRK, LASIK (Blade LASIK), Femto LASIK, ReLEx SMILE, and SMILE Pro. Typically, the ophthalmologist will recommend the most suitable surgical techniques based on each individual needs and considerations. Refractive surgical techniques to correct refractive errors are as follows:

What causes refractive errors?

Refractive errors are caused by an excessive or insufficient corneal curvature, causing incorrect light bending that does not correspond to the size and length of the eyeball. Consequently, the focal point of light does not fall on the retina, resulting in blurred vision.

How many types of refractive errors?

There are 4 types of refractive errors, outlined as follows:

1. Myopia (nearsightedness) is a condition in which light is focused in front of the macula, or before reaching the retina due to an improperly curved cornea or an elongated eye socket, causing individuals with myopia to see near objects clearly but experience blurry vision when looking at objects in a long distance.
2. Farsightedness (hyperopia) is a condition where light focuses behind the retina or beyond the macula. This condition may result from a flatter cornea, or a shorter eyeball length, resulting in blurred vision for nearby and distant objects in severe cases.
3. Astigmatism is a condition where an individual has double vision instead of single vision due to an imperfectly round cornea creating two focal points of light hitting the retina unevenly in the same plane. This uneven focus results in blurred vision at all distances.
4. Presbyopia is an age-related condition causing near vision to become blurred or double when looking at close objects. The condition is due to the loss of flexibility in the eye lens, preventing it from changing shape to focus on close-range objects. Presbyopia is common in individuals over the age of 40.

How many eye surgery techniques are available to correct refractive errors?

There are several surgical techniques available to correct refractive surgery, including PRK, LASIK (Blade LASIK), Femto LASIK, ReLEx SMILE, or the latest advancement in refractive eye surgery, SMILE Pro. Typically, the ophthalmologist will recommend the most suitable surgical techniques based on each needs and considerations. Refractive surgical techniques to correct refractive errors are as follows:

PRK

PRK (Photorefractive keratectomy) is the pioneering laser technique for correcting refractive errors. The procedure involves removing the cornea's outermost layer (Epithelium), either using an excimer laser or a diluted alcohol solution. Then, adjust the corneal curvature with an excimer laser to achieve standard, normal vision.

Following surgery, the ophthalmologist will protect the cornea with prescription-free contact lenses for approximately 5-7 days to reduce irritation while allowing the body to regrow the epithelial membrane, completely covering the cornea before removing the contact lens. PRK is a vision correction treatment that is appropriate for those whose ophthalmologist has determined that they are not suitable for Lasik eye surgery due to a thin cornea or dry eyes. The benefit of using PRK to correct refractive errors is that no laser is used to open the corneal flap. Thus, the cornea retains its natural strength.

Femto LASIK

Femto LASIK, or bladeless LASIK, is a surgical technique for correcting refractive errors that involve using a femtosecond laser to separate layers and open the corneal flap, then using an excimer laser to reshape the corneal flap precisely, point by point, to adjust the curvature of the cornea to achieve normal vision standards. The corneal flap is then delicately repositioned.

Unlike traditional LASIK, which uses a mechanical microkeratome blade, Femto LASIK utilizes a Femtosecond laser, which can emit ultra-short laser pulses at a high speed of 1 femtosecond (1 quadrillionth of a second). This laser technology is adept at separating corneal layers, lifting the corneal flap, and accurately determining the depth of the corneal layer without causing damage to surrounding tissues. This gentler approach is more considerate of the eyes' condition, resulting in a shorter recovery period and a quicker return to high-quality vision.

ReLEx SMILE

ReLEx SMILE (Refractive Lenticule Extraction) (SMILE: Small Incision Lenticule Extraction) is a vision correction surgical technology that uses small incisions to extract the lenticules without opening the corneal flap. ReLEx SMILE is derived from LASIK and Femto LASIK, using a femtosecond laser to separate the corneal layers into a lens-shaped disc known as a "Lenticule.". The ophthalmologist then pulls out the lenticule through a tiny side incision to adjust the curvature of the cornea to normal vision standards without requiring raising a corneal flap. Therefore, the small incision can heal without stitches after surgery.

ReLEx SMILE addresses the concerns associated with corneal flap elevation in traditional LASIK procedures, aiming to reduce the risk of infection. This technique offers a minimally invasive approach to corneal surgery while striving to preserve as much of the natural curvature of the cornea as possible.

SMILE Pro

SMILE Pro is the most advanced refractive surgery technology available. Utilizing the Visumax 800 machine, this advanced procedure involves carving out a lens-shaped disc, or "Lenticule," from the central corneal layer. Notably, the laser procedure is remarkably swift, taking only 8–10 seconds per eye, three times faster than the original ReLEx SMILE. The ophthalmologist then extracts the lenticule through a 2–4-millimeter side incision, effectively adjusting the shape and curvature of the cornea without raising a corneal flap to meet corrective refraction requirements.

SMILE Pro is a minimally invasive surgery, reducing complications and procedural times while leaving only a small incision that heals quickly, with restored vision as soon as the next day. Notably, SMILE Pro contributes to maintaining the strength of the cornea more effectively than conventional LASIK and is widely earning widespread recognition for its high safety profile within the ophthalmology community.

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What is the diagnosis before LASIK surgery?

At your first appointment, the ophthalmologist will conduct a detailed history inquiring about your age, medical conditions, and medications followed by taking a thorough eye examination to evaluate the level of refractive errors; nearsightedness, farsightedness, and astigmatism to determine whether the individual is a qualified candidate for LASIK surgery. To proceed with the procedure, candidates must have stable vision or minimal vision changes within a year not exceeding 50 to be eligible for the procedure.

Eyes Examination

• The ophthalmologist will schedule a comprehensive eye check to diagnose the eye condition, which will include a Vision acuity Test to measure vision, an Automated Refractometer for visual inspection and measurement, a Slit-lamp Examination to assess overall eye health, an Eye Tonometry Test to measure intraocular pressure, a Retinal examination to examine the retina, a Corneal Pachymetry Test to measure the thickness of the cornea, a Keratometry Test to measure the curvature of the cornea, and Manifest Refraction and Cycloplegic Refraction for measurement before and after instilling pupil dilation medicine. If the candidate's eyes are in good condition, the ophthalmologist will schedule LASIK surgery on a preferred date and time convenient.
• If the eye examination reveals that the eyes are in poor condition, such as with eye inflammation, dry eyes, or eye infection, a team of specialized ophthalmologists will treat the conditions before proceeding with LASIK eye refractive surgeries.
• If the test results reveal LASIK is not the right solution for the candidate, the ophthalmologist will recommend an alternative vision correction option suitable for the individual, such as PRK or ICL lens implant surgery.

Stop Using Certain Medications

• Those taking isotretinoin-based acne medications, such as Roaccutane or Acnotin, are advised to discontinue use at least one month before the eye examination and surgery date, as this class of medicines can cause side effects on the conjunctiva of the eyes and contribute to drier-than-usual corneal surfaces.
• Those with an underlying disease or taking certain medications to treat chronic diseases, including diabetes, hyperlipidemia, high blood pressure, thyroid, or sleeping pills, should notify the ophthalmologist during the first visit or before an eye assessment day. However, they are not required to discontinue taking medication prior to the day of surgery.
• Those taking Prednisone, Imitrex, Cardarone, or Accutane* must notify the ophthalmologist at their first appointment.

Avoid Wearing Contact Lenses

• Before the eye examination and surgery date, those who wear hard or semi-hard contact lenses must refrain from wearing them for at least 21 days. Those who wear soft contact lenses must refrain from wearing them for at least 7 days. During this period, candidates are advised to wear eyeglasses instead.

What is the LASIK surgery procedure?

Lasik surgery at MedPark Hospital adopts an international standard, using a high-performance femtosecond laser of VISUMAX 800, prioritizing safety, and treatment success outcomes. After the surgery, our ophthalmologist and multidisciplinary team will periodically evaluate the post-operative eye to ensure a successful treatment outcome, free of complications, and improved clear vision.

Preoperative LASIK surgery procedures

Avoid Wearing Makeup

• Refrain from wearing makeup, using cosmetics, eyelashes, and skin care products containing perfume ingredients or alcohol 1 day before surgery and on the day of surgery since unclean cosmetic debris can cause eye infections after surgery.

Intraoperative LASIK surgery procedures

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1. Cornea Flap Creation: The ophthalmologist instills anesthetic eye drops into the operative eye to numb the sensation before the surgery, then pulses a Femtosecond Laser (Visumax 800) to create the cornea flap into a spherical shape over the iris and pupil.

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2. Cornea Flap Opening: The ophthalmologist lifts the cornea flap, exposing the inner cornea for treatment.

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3. Laser Sculpting: The ophthalmologist uses an Excimer Laser to reshape the inner cornea's shape and the cornea's curvature to correct refractive errors, enabling light to focus on the retina in the proper position.

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4. Refractive Error Correction: Once the LASIK surgery procedure is completed, the ophthalmologist will reposition the corneal flap back to its original position without the need for stitching. The curvature of the cornea, the refraction point, and the convergence of light on the retina will gradually correct refractive errors such as myopia, hyperopia, and astigmatism to achieve normal vision acuity.

Post operative LASIK surgery procedures

• The ophthalmologist will cover the eyes with eye shields after surgery to prevent infection.
• The ophthalmologist and nurses will closely monitor the symptoms for 30 minutes after surgery.
• The nurses apply eye drops to prevent dryness and inflammation.
•  The ophthalmologist evaluates the patient's symptoms; if no complications are found, patients can return home.
• Patients can use the restroom, stand, walk, drink water, and eat normally.

What is the post operative care for LASIK?

• The ophthalmologist will schedule a follow-up appointment the day after surgery.
• Patients undergoing LASIK may experience eye discomfort, dryness, watery eyes, swollen eyelids, and light sensitivity during the first week before symptoms gradually improve.
• Apply antibiotic eye drops as prescribed by the ophthalmologist, clean the eyes, and replace the eye pads 1-2 times daily. 
• For the first week, beware of water getting into your eyes, and avoid washing your face.
• For the first week, avoid rubbing or squeezing your eyes, and wear eye shields at night while sleeping.
• For the first week, avoid exertional activities or exercise that may cause sweat to enter the eyes.
• For one month, avoid swimming or scuba diving. 
• Avoid excessive screen time or spending long periods on screen by scheduling screen-free breaks.
• Attending every ophthalmologist appointment for symptom monitoring and treatment evaluation.

What is the advantage of LASIK (Femto LASIK)?

• Precision and Accuracy: LASIK uses high-performance laser technology—the Femtosecond Laser and the Excimer Laser—to reshape the cornea shape and the cornea curvature, effectively correcting nearsightedness, farsightedness, and astigmatism precisely and accurately to restore normal vision acuity, resulting in a vivid clear vision.
• Fast and Pain-free: Lasik utilizes high-speed performance lasers, enabling a short operative time, painless, and stitchless surgery. After recovery, the wound will gradually heal and fully recover within a few months, depending on personal condition.
• Minimal Downtime and Quick Recovery: LASIK is a minimally invasive surgery, that speeds up the wound healing process and requires a short recovery period, individuals can use their eyesight the day after surgery. Typically, those who undergo LASIK surgery can noticeably improve vision within 2-3 days.
• Long Lasting-Result: Those who undergo LASIK can experience clear eyesight without the need to wear glasses or other vision aids, even as they age.
• Improved Quality of Life: LASIK improves a better quality of life, reduces limitations in daily life, minimizes the risk of possible accidents, and allows individuals to engage in various activities as desired, such as playing sports, reading books, using social media via multi-electronic devices, or driving. When life’s limitations are limited, individuals can pursue their lifelong interests.

Who is suitable for LASIK?

• Anyone aged 18 years and above.
• Have had a stable vision over the past 1 year.
• Have healthy eyes.
• Have adequate corneal thickness
• No corneal disease or underlying diseases, such as poorly controlled diabetes, or immunodeficiency.

Who is not suitable for LASIK?

• Those with corneal diseases, severe dry eyes, eye inflammation, photophobia, keratoconus, corneal abrasions, or corneal scars.
• Those with other eye diseases such as severe glaucoma, cataracts, macular degeneration, shingles, severe dry eyes, or cornea infections.
• Those with inadequate corneal thickness.
• Those who have unstable vision or a significant change in vision value of more than 50 in a year.
• Pregnant woman or a breastfeeding mother.
• Those with age-related presbyopia (the ophthalmologist will consider alternative treatment options).

What is the success rate of LASIK?

According to a study of those who had their vision corrected with LASIK (Femto LASIK), the post-surgery success rate ranged from 96-98%, with the following ratios.

• 99% of individuals achieved 20/40 vision or better.
• 90% of individuals achieved 20/40 vision, which is the same level as normal vision.

These findings indicate a very high success rate for visual acuity improvement following LASIK surgery. However, individual results may vary, depending on each condition.

Is LASIK safe?

LASIK is one of the safest surgical procedures available today. The surgery has a very low complication rate of less than 1%, significantly lower than the FDA-certified safety standard of 5%.

LASIK eye surgery at MedPark Hospital 

Eye Center at MedPark Hospital, Bangkok, Thailand is led by a team of expert ophthalmologist professors with extensive experience in performing LASIK both nationally and internationally, who are ready to provide diagnostic and therapeutic interventions in treating common and complex eye diseases including refractive errors, closely at every step from pre to post-operative, with LASIK, PRK, Femto LASIK, and the cutting-edge technology, SMILE Pro, combined with state-of-the-art AI technology and equipment under JCI standards integrated with advanced surgical techniques, assisting in fast, accuracy, safety, and maximizing treatment efficiency, while also providing post-treatment follow-up, ensuring normal vision acuity achievement, free of complications, fast vision recovery, contributing long-term healthy eye health, and enabling individuals to live life freely.