Comparison of pachymetry values during crosslinking with different riboflavin solutions

Objectives: To compare the effect of two different riboflavin solutions we use in the accelerated crosslinking (CXL) process on the pachymetry value. Materials and Methods: Patients who had accelerated CXL treatment with dextran-free riboflavin solution due to progressive keratoconus were retrospectively screened. Thirty-seven eyes of 27 patients (group 1) treated with Hydroxyl Propyl MethylCellulose (HPMC) and 0.1% riboflavin containing solution and 29 eyes of 23 patients (group 2) treated with D-alpha-tocopheryl polyethylene-glycol 1000 succinate (VE-TPGS) and 0.1% riboflavin containing solution were compared in terms of pachymetry changes during treatment. Results: In groups 1 and 2, the mean age was 23.92 ± 5.66 and 23.30 ± 4.89, respectively. Mean age, gender, initial keratometry values, mean central corneal thickness (CCT) before and after epithelial debridement did not differ significantly between the two groups. The CCT measured after riboflavin instillation was 453.22 ± 37.48 μ in the group 1 and 479.34 ± 38.54 μ in the group 2. After instillation of riboflavin, according to the initial CCT, there was an average thinning of 21.57 ± 16 μ in the group 1 and 18.72 ± 22.13 μ thickening in the group 2. According to the CCT measured after epithelial debridement, a thickening of 20.70 ± 21.77 μ in the group 1 and 62.76 ± 21.65 μ in the group 2 was observed. The rate of change of CCT after riboflavin instillation of significant differences existed between both groups. (p<0.001). Conclusion: VE-TPGS, which is utilized to increase the cornea's permeability to riboflavin tissue during crosslinking treatment, significantly increases the corneal thickness compared to HPMC and provides a safer tissue thickness for ultraviolet A.