Photorefractive Keratectomy (PRK)

Why is it needed?

It is an elective procedure. It is done for patients who are tired of relying on their glasses or contact lenses. It is an ideal procedure for thin cornea, scarred cornea, or irregularly-shaped cornea with lower refractive powers.

Benefits of the Photorefractive Keratectomy

• It takes approximately 5 to 15 mins per eye for the procedure

• Independent of glasses

• Flapless/bladeless procedure

• A suitable procedure for pilots, professional athletes, or other individuals in whom there is a higher risk of flap dislocation

• No flap based complications

Preparations before Photorefractive Keratectomy

• Patients should be above 18 years of age

• Should have had stable refraction of +/- 0.5 D for 6 months

• Should be off contact lenses for 2 weeks

• Old glass power and present degree of refractive error ( before and after applying dilating drops) will be assessed

• Pentacam scan – it will help evaluate the shape and thickness of the cornea

• Dry eyes will be ruled out

• Proper medical history regarding diabetes mellitus, pregnancy, thyroid disorder, abnormal wound healing, or chronic usage of any medicine should be informed to your doctor.

• A thorough eye examination (anterior and posterior) will be done to rule out any abnormalities

What is the Treatment Procedure for PRK

Photorefractive Keratectomy (PRK) is a type of laser eye surgery used to correct vision by reshaping the cornea. The procedure involves the following steps:

1. Preoperative Preparation: The patient undergoes a comprehensive eye examination to determine suitability. Numbing eye drops are applied to minimize discomfort.
2. Removal of the Epithelium: The outer layer of the cornea (epithelium) is gently removed using an alcohol solution or a surgical instrument.
3. Laser Reshaping: An excimer laser is used to reshape the cornea by removing microscopic layers to correct vision errors.
4. Application of a Bandage Contact Lens: A soft contact lens is placed over the cornea to protect it during the healing process.
5. Postoperative Care: Patients are prescribed eye drops to prevent infection and promote healing. Regular follow-up visits are scheduled to monitor progress.

Precautions and Care after Photorefractive Keratectomy

• After the surgery, a group of eye drops and oral medications will be started, which should be followed as advised by your doctor.
• The eye drops should be applied without touching the tip of the bottle to the eye.
• The bandage contact lens will be removed after 4-6 days after the surgery. The patient should not rub their eyes as that would cause the contact lens to fall out. If the contact lens falls out, the lens should not be replaced by the patient. Meet your doctor as soon as possible who will place a new contact lens.
• For the first few postoperative days, the vision tends to be a little blurry due to the epithelial formation, which should not be alarming.
• A normal diet should be followed
• UV protective dark goggles should be worn while going out for the first 6 months.
• Facewash and hair wash are to be avoided for one week
• Avoid driving till your vision is absolutely clear
• Makeup applications should be avoided for 1 month
• Swimming should be avoided for 3 months.

What is Trans PRK Surgery?

Trans PRK (Transepithelial PRK) is an advanced version of traditional PRK that uses a laser to remove the corneal epithelium instead of manual methods. This results in a more precise and seamless procedure.

Procedure Steps:

1. One-Step Laser Treatment: A single laser removes the corneal epithelium and reshapes the underlying cornea in one step.
2. No Manual Scraping: Unlike conventional PRK, Trans PRK does not involve the manual scraping of the epithelium, making it a touch-free procedure.
3. Faster Recovery: With less trauma to the cornea, healing time is reduced compared to traditional PRK.

Benefits of Trans PRK:

• Minimally invasive and contact-free.
• Reduced risk of human error.
• Faster healing and less post-operative discomfort.
• Suitable for patients with thinner corneas.

Result of Photorefractive Keratectomy

The patient will gain his preoperative vision but without being dependent on glasses.

Who Should Avoid Photorefractive Keratectomy?

PRK may not be suitable for everyone. Individuals who should avoid PRK include:

1. Patients with Thin or Abnormally Shaped Corneas: Those diagnosed with keratoconus or irregular corneal topography.
2. Individuals with Severe Dry Eye Syndrome: PRK can exacerbate dry eye symptoms, leading to discomfort and delayed healing.
3. People with Autoimmune Disorders: Conditions like lupus or rheumatoid arthritis can impair the healing process.
4. Pregnant or Nursing Women: Hormonal changes during pregnancy and breastfeeding can affect vision stability.
5. Those with Unstable Vision Prescription: Candidates should have a stable prescription for at least a year before considering surgery.
6. Patients with Ocular Infections or Eye Diseases: Active eye infections or diseases like glaucoma may complicate the procedure.

Key Considerations Before PRK:

• A thorough consultation with an eye specialist is necessary to determine candidacy.
• Alternative procedures such as SMILE or ICL may be recommended based on individual conditions.

Written by: Dr. Ramya Sampath – Regional Head – Clinical Services, Chennai