Photorefractive keratectomy (PRK)

Photorefractive keratectomy (PRK) is a laser procedure performed to correct nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. The procedure begins with exposing the cornea by removing the flap cover it. An excimer laser is then used to adjust the curvature of the cornea. This method is suitable for patients with thin corneas and those in certain occupations, such as soldiers, pilots, etc.

The main reason for photorefractive keratectomy is to correct vision and reduce the person's dependency on glasses or contact lenses. The decision depends on the patient’s lifestyle and level of eyesight.
  • Healthy eye
  • 18 years or older
  • Stable eyesight
  • No serious eye diseases (e.g. severe keratoconus, severe dry eye, uncontrolled glaucoma, macular degeneration, etc.)
  • No serious systemic diseases (e.g. autoimmune, collagen vascular disease, rheumatoid arthritis, uncontrolled diabetes, etc.)
  • No medical contraindications
  • No history of steroid side effects
  • Not pregnant or breastfeeding
  • Realistic expectation of the final results
  • Understand the risks and complications
  1. Avoid soft contact lenses for at least 3 days and hard contact lenses for at least 7 days before the procedure.
  2. Avoid overusing or straining the eyes before the surgery as this can cause the eyes to become too dry.
  3. Do not wear make-up, perfume, hair oil, and any other hair products on the day of the procedure.
  4. Wash your hair the day before or on the day of the procedure. Wash your face before the procedure.
  1. ผู้ป่วยที่มีโรคประจำตัว เช่น โรคลมชัก อาจมีอาการชักขึ้นมาในระหว่างเลเซอร์ได้ ดังนั้นผู้ป่วยควรแจ้งแพทย์/พยาบาลให้ทราบถึงโรคประจำตัว เพื่อเตรียมการป้องกันที่เหมาะสม
  2. ห้ามกลอกตาขณะทำการรักษาด้วยแสงเลเซอร์อย่างฉับพลัน เนื่องจากอาจทำให้แพทย์รักษาได้ไม่ตรงบริเวณที่ต้องการซึ่งส่งผลต่อการแก้ไขสายตา ดังนั้นผู้ป่วยควรปฏิบัติตามที่แพทย์สั่งอย่างเคร่งครัด
The patient will lie on their back on the operating table. The area around the eyes will be cleaned and numbing drops will be administered. The patient should focus on the red-orange light in the center of the operating microscope. The ophthalmologist will remove the corneal epithelium using a blade or mechanical brush or by the laser. Next, the excimer laser is used to remove the ultra-thin layer of the corneal surface to reshape the cornea to form the small lenses as programmed by computer.

The sound of the excimer laser is quite loud, similar to that of a machine gun. There may be a burning smell from the ablated cornea tissue, which is normal for this procedure. Antibiotic eye drops are used to prevent eye infection and soft contact lenses are used to cover the wounds.
  1. After the procedure you should return home and rest your eyes as much as possible.
  2. On the day of the procedure the treated eye(s) should be kept covered to prevent you from touching or rubbing them and to avoid any impact to them. They should then be covered only while sleeping for a week or two after the procedure.
  3. Avoid washing your face and hair. Use a washcloth for your face and get your hair washed at a salon, if necessary, for about a week after the procedure or as recommended by your doctor.
  4. Use the prescribed medication and eye drops.
  5. Keep all follow-up appointments.
  6. Take pain medication as needed.
  7. If you experience any abnormal symptoms, such as increased redness or discharge or if your vision worsens, see your doctor as soon as possible.
  8. Some burning, irritation, and tearing is normal after the procedure.
  9. Avoid staring at a computer screen for more than 2 hours a day for at least 2 weeks after the procedure.
  10. Do not swim, dive, or use a sauna for at least two weeks after the procedure.
  • Pain or discomfort in the first 72-96 hours
  • Feeling something in the eye
  • Floaters, double vision, sensitivity to light, and tearing
  • Haze: Loss of clarity of the cornea, usually not affecting vision and usually resolving over time.
  • Glare, starbursting, halo effect around light, or other low-light vision problems that may interfere with the ability to drive at night or see well in dim light. Although there are several possible causes for these difficulties, the risk may be increased in patients with large pupils or high degree of correction. For most patients, this is a temporary condition that improves with time or is correctable by wearing glasses at night or using eye drops. For some patients, however, these problems are permanent. It is not possible to predict who will experience these night vision or low light problems and who will permanently lose the ability to drive at night or function in the dim light.
  • Loss of correct vision. A decrease in the correct vision even with glasses or contact lenses.
  • Intraocular pressure (IOP) elevation. An increase in the inner eye pressure due to post photorefractive keratectomy medications, which is usually resolved by dose adjustment.
  • Mild or severe infection. Mild infection can usually be treated with antibiotics and usually does not lead to permanent vision loss. Severe infection, even if successfully treated with antibiotics, could lead to permanent scarring and loss of vision that may require corrective laser surgery or, if severe, corneal transplantation.
Before the Procedure
  • Please plan to stay in Thailand for at least 1 week through the duration of the treatment.
  • It is recommended that you stay in a hotel close to the hospital for convenience in traveling to the hospital before and after the procedure.
After the Procedure
  • After the procedure your eye(s) will be covered for at least 1 day. A family member or friend should come with you to the hospital and accompany you home. You will be able to see immediately the next day.
  • You will return for a follow-up appointment the next day. If you have no abnormal symptoms, you can travel back to your home country, depending on your doctor’s recommendations.
  • Please return for follow-up appointments regularly after the procedure. See your doctor the day after the procedure and then 1, 3, and 6 months after the procedure. If it is not convenient for you to travel to the hospital to see a doctor, you may see an ophthalmologist closer to your home or in your home country.
The patient should achieve a good result. Any complications that occur after PRK are usually correctable without affecting vision.
What if the procedure is not performed?
Vision problems will continue.
  • Glasses
  • Contact lenses
  • Other refractive surgical procedures, such as LASIK (laser-assisted in situ keratomileusis), LASEK (laser-assisted epithelial keratomileusis), EPI-LASIK (epithelial laser in situ keratomileusis), EPI-K, etc.

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