Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM:To compare the visual results of non-topographyguided and topography-guided photorefractive keratectomy(PRK)applying sequential and simultaneous corneal crosslinking(CXL)treatment for keratoconus.METHODS:Interventional and comparative prospective study.Sixty-nine eyes(36 patients)suffering from keratoconus(stages 1 Amsler-Krumeich classification)were divided into four groups:sequential topography-guided photorefractive keratectomy with CXL,simultaneous topography-guided photorefractive keratectomy with CXL,simultaneous nontopography guided photorefractive keratectomy with CXL,and sequential non-topography guided photorefractive keratectomy with CXL.The main outcome measures were pre-and postoperative uncorrected distance visual acuity(UDVA),best corrected distance visual acuity(CDVA),manifest refraction,contrast sensitivity,and keratometry.RESULTS:All analyzed visual,contrast sensitivity,and refractive parameters showed a significant improvement in the four groups(all P<0.05).A noticeable improvement was seen in keratometry in all the groups,and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups(P<0.05).Interestingly,the improvement in all parameters showed a degree of stability to the end of the follow-up.CONCLUSION:The treatment priorities in all four groups are safety,efficacy,and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus.No significant differences among groups in the recorded objective outcomes were found.