Intraocular lens power calculation changes before and after isotonic collagen cross-linking in keratoconus patients

PURPOSE: To find the intraocular lens (IOL) power calculation changes before and after isotonic collagen cross-linking (CXL) in keratoconus patients. METHODS: Thirty-five eyes of 25 patients who underwent isotonic CXL were included. The cases included conventional CXL (n = 16), accelerated CXL (n = 7), contact lens-assisted CXL (CACXL) (n = 9), accelerated CACXL (n = 3). All underwent ocular biometry (IOL master), corneal topography (Orbscan II), and simulated keratometry (Orbscan II) preoperatively and 1-year post CXL. Change in best-corrected visual acuity (BCVA), axial length (AL), simulated keratometry (Sim K), anterior chamber depth (ACD), and IOL power were analyzed in the overall data and then grouped based on flattening (Group A) and no flattening (Group B) of Sim K value post CXL procedure. RESULTS: For the overall data, there was no significant change in IOL power (P = 0.05) at the end of 1 year, BCVA showed a significant increase (P < 0.01), and Sim K reading showed a statistically significant flattening (P = 0.001); ACD and AL showed insignificant change. In intergroup comparison, there was no statistically significant change in IOL power. However, in Group A, a significant change in BCVA and Sim K values was observed. In both groups (Group A and Group B), IOL power was found to be negatively correlated with AL and Sim K values. CONCLUSION: Isotonic CXL did not affect IOL power calculation at the end of 1 year. However, significant change in BCVA and sim K reading was noted.