Outcomes of a New Trans-epithelial Photorefractive Keratectomy (Streamlight PRK) Compared to Conventional PRK Procedures

Outcomes of a New Trans-epithelial Photorefractive Keratectomy (Streamlight PRK) Compared to Conventional PRK Procedures

Photorefractive keratectomy (PRK) involves mechanical or alcohol assisted debridement of the epithelium that leads to potential basement membrane (BM) injury ,with resultant more significant haze and pain compared to laser assisted epithelial removal known as 2 step trans-epithelial PRK (PTK-PRK). Our study is focusing on comparing the outcomes of the conventional 2 step trans-epithelial PTK-PRK to the new single step trans-epithelial PRK (StreamLight PRK, Alcon lab, TX, USA).

Photorefractive keratectomy (PRK) is nowadays one of the commonest refractive procedures in laser vision correction (LVC). PRK differs from laser in situ keratomileusis (LASIK) in that it's a flapless procedure involving the removal of corneal epithelium with different techniques including manual removal , alcohol assisted removal or excimer laser assisted removal with phototherapeutic keratectomy (PTK). Mechanical or alcohol assisted debridement of the epithelium may lead to potential basement membrane (BM) injury ,with resultant more significant haze and pain compared to laser assisted epithelial removal known as 2 step trans-epithelial PRK (PTK-PRK).

Single step trans-epithelial PRK allows removing the epithelium and stroma in a single step with a single ablation profile.

Previous studies paid particular attention for comparing the 2 step PTK-PRK procedure or the new single step PRK procedure to the conventional PRK procedures involving epithelial removal whether manual or alcohol assisted.

The aim of this study is to focus on comparing the different outcomes of the new single step Trans-epithelial PRK (StreamLight Technology) versus the routine 2 step PTK-PRK in terms of postoperative vision, epithelial healing, pain scoring and haze evaluation.

• Inclusion Criteria: Candidates for Laser vision correction (LVC) with

  1. Myopia up to -6 diopters
  2. Myopic astigmatism up to -4 diopters
  3. Corneal thinnest location ≥ 500 um and a residual stromal bed ≥ 300um.

• Exclusion criteria

  1. Patients not candidates for LVC.
  2. Hyperopic patients.
  3. Systemic disease that contraindicates LVC.
  4. Intra- or post-operative complications.