Clinical and microstructural changes with different iontophoresis-assisted corneal cross-linking methods for keratoconus.

AIM

To compare the clinical and microstructural changes induced by different transepithelial iontophoresis-assisted corneal cross-linking (I-CXL) methods for keratoconus.

METHODS

A total of 42 eyes of 42 patients with progressive keratoconus were divided into two groups. Group A received I-CXL for 5min, while group B received I-CXL for 10min. Visual acuity, optical coherence tomography (OCT), specular microscopy and confocal microscopy were evaluated preoperatively and at 1, 3, 6, and 12mo postoperatively.

RESULTS

Twelve months after the operation, uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA) were improved in both groups, with a better outcome in the I-CXL 10min group (=0.025, 0.021, respectively). Kmax values decreased by 0.94±3.00 D in the I-CXL 10min group (=0.033) but increased by 1.87±3.29 D in the I-CXL 5min group (=0.012). OCT scans showed that the demarcation line was most visible and substantially deeper in the I-CXL 10min group. Confocal microscopy showed greater anterior stromal keratocyte decreases in the I-CXL 10min group than in the I-CXL 5min group at 3 and 6mo postoperatively (<0.001); however, anterior stromal keratocytes and subbasal nerve density were not significantly different between the two groups at 12mo postoperatively.

CONCLUSION

I-CXL for 10min more effectively halts the progression of keratoconus than I-CXL for 5min after 12mo of follow-up. However, long-term studies are needed to evaluate the efficacy and safety of I-CXL.