PTK, TransPTK and WetPTK (PhotoTherapeutic Keratectomy)

What are PTK, TransPTK, and WetPTK?

The PTK, TransPTK and WetPTK are corneal resurfacing procedures performed using an excimer laser to regularize the cornea, fade corneal scars, treat corneal dystrophies and relieve recurrent erosion syndrome.

PTK = Photo TherapeuticKeratectomy, or PPhotoTherapeutic Keratectomy in English.

Each form of PTK has specific indications:

• They all help to fade superficial corneal scars.
• The PTK is primarily used to treat recurrent corneal erosion syndrome.
• The TransPTK and the WetPTK are advanced phototherapeutic keratectomy techniques that allow for optimized regularization of the corneal surface.

How does it work?

PTK removes thin superficial layers of the cornea, thereby promoting better adhesion of newly regenerated epithelium and reducing the risk of recurrent corneal erosions.

TransPTK is an advanced technique distinguished by its use of the masking effect of the corneal epithelium for optimized regularization of irregular corneas. Unlike conventional PTK, where the epithelium is mechanically removed before laser application, TransPTK allows for ablation through the epithelium (Transepithelial) in a single step.

The WetPTK is a variant of PTK which uses a thin layer of liquid (saline solution or lubricant) as a masking agent during excimer laser ablation. It allows for a smoother and more uniform regularization of the cornea, especially in cases of very localized irregularities, often as an immediate adjunct to a TransPTK.

TransPTK and WetPTK can be combined with corneal collagen cross-linking (CXL) to strengthen the cornea in patients suffering from corneal ectasia and keratoconus.

What are the risks?

The PTK, TransPTK and WetPTK, although effective and generally safe, carry certain risks and side effects, including:

• Corneal haze (opacification/scarring): Rarely, excessive stromal scarring can lead to a loss of transparency, affecting visual quality. This risk can be reduced by applying mitomycin C (MMC) during or after the procedure, as well as Losartan eye drops after the procedure.

• Effect regression: Some conditions, such as corneal dystrophies, may recur after some time. In such cases, it is generally possible to repeat these laser treatments (PTK, TransPTK, WetPTK).

• Post-operative discomfort: Especially during the first 24 to 48 hours, due to the erosion created by the laser, which usually heals within a few days. The use of a bandage contact lens reduces discomfort.

• Persistent epithelial defect: A persistent epithelial defect after PTK can occur in cases of impaired healing, prolonging discomfort and delaying recovery. To prevent stromal melting, specific treatments may be initiated, such as prolonged wear of a bandage contact lens, the use of healing-promoting eye drops (e.g., Insulin), the administration of metalloproteinase inhibitors (e.g., Tetracyclines), and sometimes the placement of an amniotic membrane.

• Infection and inflammation: Although rare, these complications can occur and require appropriate treatment. Standard post-operative treatments with antibiotic and anti-inflammatory eye drops prevent these complications.‍

• Temporary irritation: May occur after initial healing, characterized by a feeling of dryness and/or light sensitivity.

Each procedure offers specific benefits, but their indication must be carefully evaluated to minimize risks and optimize visual outcomes.

What is the recovery?

Recovery after the procedures of PTK, TransPTK and WetPTK varies depending on the extent of the treatment and the patient's individual characteristics. Generally, healing follows these stages:

1. Initial Phase (1 to 7 days):

• Discomfort: Especially within 24 to 72 hours after the procedure, which can be relieved by painkillers, eye drops, and wearing a bandage contact lens.

• Temporary blurred vision: Caused by epithelial regeneration and post-operative inflammation.

• Bandage contact lens wear: A therapeutic contact lens is often placed to protect the eye, promote epithelial healing, and reduce discomfort.

• Increased light sensitivity and a feeling of dryness.

2. Intermediate Phase (1 to 4 weeks):

• Removal of the bandage contact lens and discontinuation of antibiotic eye drops upon complete closure of the epithelial defect.
• Vision progressively improves as the epithelium stabilizes and evens out.
• Use of eye drops (anti-inflammatory and lubricating) to accelerate recovery.
  

3. Stabilization Phase (1 to 3 months):

• Vision continues to improve, and any opacities (corneal haze) gradually resolve.
• Regular follow-up is necessary to assess healing and treatment effectiveness.

4. Late Phase (beyond 3 months):

• ‍‍For the majority of patients, only one treatment is necessary; however, in cases of residual irregularity or recurrence of symptoms, PTK, transPTK, and WetPTK can generally be repeated until the desired result is achieved.
• In cases of persistent haze, treatment with Losartan eye drops may be initiated, or a new application of MMC can be performed in the operating room.