Corneal Epithelial Remodeling and Its Effect on Corneal Asphericity after Transepithelial Photorefractive Keratectomy for Myopia Article Swipe

Purpose. To evaluate the changes in epithelial thickness profile following transepithelial photorefractive keratectomy (T-PRK) for myopia and to investigate the effect of epithelial remodeling on corneal asphericity. Methods. Forty-four patients (44 right eyes) who underwent T-PRK were retrospectively evaluated. Epithelial thickness was measured using spectral-domain optical coherence tomography at different corneal zones (central, 2 mm; paracentral, 2–5 mm; and mid-peripheral, 5-6 mm) preoperatively and at 1 week and 1, 3, and 6 months postoperatively. The correlation between the changes in corneal epithelial thickness (ΔCET) and postoperative<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>Q</mml:mi></mml:mrow></mml:math>-value changes (ΔQ) was analyzed 6 months postoperatively. Results. Epithelial thickness at 6 months showed a negative meniscus-like lenticular pattern with less central thickening, which increased progressively toward the mid-periphery (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mn fontstyle="italic">3.69</mml:mn><mml:mo>±</mml:mo><mml:mn fontstyle="italic">4.2</mml:mn></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mn fontstyle="italic">5.19</mml:mn><mml:mo>±</mml:mo><mml:mn fontstyle="italic">3.8</mml:mn></mml:math>, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mn fontstyle="italic">6.23</mml:mn><mml:mo>±</mml:mo><mml:mn fontstyle="italic">3.9</mml:mn></mml:math> μ m at the center, paracenter, and mid-periphery, resp.,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mi>P</mml:mi><mml:mo>&lt;</mml:mo><mml:mn fontstyle="italic">0.01</mml:mn></mml:math>). A significant positive relationship was observed between epithelial thickening and ΔQ 6 months postoperatively (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mi>r</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.438</mml:mn></mml:math>, 0.580, and 0.504, resp.,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M7"><mml:mi>P</mml:mi><mml:mo>&lt;</mml:mo><mml:mn fontstyle="italic">0.01</mml:mn></mml:math>). Conclusions. Significant epithelial thickening was observed after T-PRK and showed a lenticular change with more thickening mid-peripherally, resulting in increased oblateness postoperatively. Epithelial remodeling may modify the epithelial thickness profile after surface ablation refractive surgery for myopia.