Our Services Photo Refractive Keratectomy (PRK)

What is PRK?
PRK (Photo Refractive Keratectomy) is a refractive surgery to correct low to moderate myopia and astigmatism. For corrections of less than -8.0 dioptres, PRK is highly accurate and the effect is permanent. PRK involves a procedure in which the surface of the cornea is reshaped using an excimer laser. As the corneal curvature is changed, the light rays will focus on the retina to form a sharp image. With the modern technology advancement, PRK is rarely performed except in special cases.

The advantages of LASIK over PRK are minimal postoperative pain, a faster recovery and the larger range of refractive errors that can be treated effectively.



Am I a suitable candidate?
In general, suitable candidates:

• Are at least 18 years old
• Are in good general health
• Have no health issues affecting your eyes
• Have no active eye conditions which may affect healing
• Have a stable glasses or contact lens prescription for the last year

To find out if PRK is suitable for you, you should have a comprehensive eye examination by our ophthalmologist. During the examination, we will give you more specific information and answer any questions you may have. The examination will take about 3 hours because it is a very thorough examination.

How to prepare for PRK?

• Attend one of the public seminars organized by Guy Hugh Chan Refractive Surgery Centre to obtain basic information about refractive surgeries. Admissions are free. Reservation can be made by contacting 2855 6699 or online at www.hksh-healthcare.com.
• Make an appointment with our Centre for a complete eye examination and evaluation. Book the date of operation if you are suitable for PRK.
• Based on doctor's recommendation, you may receive a scanning examination with Wavefront technology.
• Wear eyeglasses and stop wearing contact lenses before PRK:
  
  • Soft lenses for 3 to 7 days
  • Hard or gas permeable lenses for 1 to 2 weeks

How is PRK performed?

• Anaesthesize the eyes with eye drops.
• Place a speculum to hold the lids apart.
• Use an excimer laser to apply laser with cool ultraviolet light pulses to sculpt the surface of the cornea.
• Place a bandage contact lens on the eye for protection and healing.
• Apply antibiotic and anti-inflammatory eye drops.

The Procedure

• Topical anaesthetic eye drops are instilled.
• The epithelium (superficial layer of the cornea) is removed and the refractive laser treatment begins.
• Bandage contact lens will be placed over the eye to relieve pain, and an eye shield will be used for protection.

Risk and Complication

• The surgery cannot guarantee absolute accuracy of the target refraction.
• Foggy vision in the morning and decreased cornea clarity (corneal haze) which will usually improve after a few weeks.
• Dry eyes and photophobia. They will usually subside in a few weeks or up to a few months time.
• Indoor and night vision blur. Halo or glare around light source may last for a few months or even permanently.
• Near vision blur. Reading glasses may be required for patients in presbyopic age.
• Increased light sensitivity, variation of vision or double vision.
• Over-correction, under-correction or induced astigmatism is possible, and which may require further surgery or corrective lenses.
• Irregular healing of the cornea may lead to irregular astigmatism and thus, decrease in best corrected vision.
• Corneal infection or inflammation may occur and lead to change in refractive power or even corneal scarring. The refractive error may need further surgery or corrective lenses.
• If incidences occur and cause termination of the procedure, you may need to return on a later day to complete the planned procedure.
• Cornea degeneration is very rare but may lead to corneal transplant. If rejection occurs, it may lead to blindness.

After the Procedure

• You may experience pain and tearing in the first few days.
• Refrain from driving or operating machinery. Take caution when using stairs to avoid accidents.
• Close your eyes and rest for all day after going home. Lie on your back while sleeping.
• If a bandage contact lens was placed over your operative eye, do not take it off by yourself.
• Do not rub or press on the eye.
• If there is discomfort in your eye, you can take the painkillers provided according to the instructions.
• Do not remove the eye shield until the next day and wipe off excessive tears outside the eye shield.
• Keep the eye shield on for protection for 1 week when you are sleeping to avoid accidental trauma.

Post-Operative Instructions

• Please take medication or instill eye drops as instructed by your doctor.
• Avoid soap, shampoo or tap water getting into your eyes for 1 week.
• No eye make-up, especially mascara for 2 weeks.
• No facial or swimming for 1 month.
• Use sunglasses when you are outdoors for 1 month to prevent foreign bodies and irritation of ultraviolet light.

Follow up Examination
You should return to your doctor for follow up on the day after the surgery, then at 1 week, 1 month, 3 months, and 6 months or whenever your doctor deems necessary.