Corneal topographic analysis after excimer photorefractive keratectomy

Objective To evaluate the corneal surface changes and visual quality after excimer photorefractive keratectomy (PRK) for myopia. Methods Corneal topographic analysis was performed on 23 patients (38 eyes) with myopia after PRK at the 1-, 3-, 6- month postoperative follow-up visi ts. Results The corneal sphericity was changed after excimer PRK. As time went on, the mean surface regularity index (SRI) and the surface asymmetry index (SAI) decreased gradually, and the corneal surface became more smooth; mea n simulated keratoscope readings (SimK) showed a gradual restoration. At th e 6-month postoperative examination, corneal topography showed four main pa tterns of ablation: round or oblong (50%), collar-button (23.68%), semicirc ular (18.42%) and central island (7.9%). Patterns of ablation were correlat ed with visual acuity. Conclusion The quantitative analysis of corneal topography is essential for evaluating corneal surface changes after PRK and helpful in the surgical d esign of PRK and in predicting the refractive outcome with greater precisio n.