Methods
Fifty-eight eyes with mild irregular preoperative topography underwent topography-guided PRK. Randomly, one of the patient’s eyes had the ablation profile customized from the epithelium, while the contralateral from the Bowman’s layer, ie after epithelium removal. Axial corneal keratometry (in the 3rd and 5th central millimeter rings), potential automated corneal visual acuity (logMAR), refractive errors (spherical, cylindrical and axis) and corneal high-order aberrations (total RMS, coma, trefoil and spherical aberration) were analyzed. Two-way multivariate analysis of variation was used to calculate differences between the groups pre- and 3 months post-operatively (CI 95%).
Results
The mean age of the patients was 30.10 ± 5.11 (ranging from 20 to 40 years old). From the twenty-nine patients, 20 patients were female (68.97%) and 9 were male (31.03%). Preoperatively, there was no significant difference between the two treatment groups (p=0.156). As expected, significant differences were found between the variables before and after surgeries (p=0.000). However, Wilks' Lambda test did not show significant effect between pre- and post-operative parameters based on the treatment groups (p=0.992), that is topography guided by the epithelium or the Bowman's layer.
Conclusion
To our best knowledge, this is the first clinical demonstration of Bowman's topography-guided excimer laser ablation. The topographic and refractive outcomes of Bowman's topography-guided PRK in mild irregular corneas appear to be comparable to those traditionally customized from the corneal epithelium.