Single-step Transepithelial PRK for Hyperopia

Although the initial refractive results of conventional manual or alcohol assisted PRK for hyperopia were encouraging, the frequently encountered post-PRK complications including undercorrection, overcorrection and regression of the hyperopic error had downgraded the conventional PRK as a preferred procedure for hyperopic correction.

Transepithelial PRK provides an alternative technique to uniformly remove the epithelium using the excimer laser to minimize the potential complications caused by mechanical or alcohol assisted epithelial removal in conventional PRK. Advances in transepithelial PRK technology have allowed refractive surgeons to remove the epithelium followed by stromal laser ablation in a single step instead of performing the procedure in 2 separate steps known as phototherapeutic keratectomy-photorefractive keratectomy (PTK-PRK).

Most of the previous studies paid particular attention to investigate the accuracy and safety of single-step transepithelial PRK in correcting myopia and myopic astigmatism. The aim of the current study is to evaluate the visual and refractive outcomes of the single-step transepithelial PRK procedure in correcting moderate hyperopia and hyperopic astigmatism.

Inclusion criteria

• Patients with moderate hyperopia with a hyperopic cycloplegic spherical equivalent between +2 and + 4.5 diopters D.
• A steep keratometry (Ks) ≤ 46 D.
• Minimum pachymetry of 500 μm with a calculated residual stromal bed exceeding 350 μm after epithelial and stromal ablation.

Exclusion criteria

• Patients not candidate for corneal refractive surgery,
• Steep cornea (Ks > 46 D) with an expected postoperative keratometry > 48 D,
• Large angle kappa as estimated by Chord mu > 0.25 mm,
• Hyperopic amblyopia whether unilateral or bilateral with CDVA less than 0.2 . logMAR acuity,
• Recent contact lens wear, dry eye disease and autoimmune disorders.