One-Year Visual, Refractive, Tomographic, and Aberrometric Outcomes of Repeat Corneal Collagen Crosslinking in Eyes with Progressive Keratoconus

OBJECTIVES: To evaluate visual, refractive, tomographic and aberrometic outcomes of repeat corneal collagen crosslinking (CXL) using Dresden protocol in the management of keratoconus progression at 1-year follow-up.
METHODS: Charts of consecutive progressive keratoconus patients who underwent repeat corneal collagen CXL using Dresden protocol and had at least 1 year follow-up were retrospectively evaluated. Best spectacle-corrected distance visual acuity (CDVA), manifest refraction, slit lamp biomicroscopy, corneal tomography, corneal aberrometry and endothelial cell counts were evaluated before repeat CXL and at postoperative year-1. At postoperative 1-month, corneal demarcation line depth were evaluated using anterior segment optic coherence tomography.
RESULTS: Overall, seven eyes of seven patients with the mean age of 23 (ranged 19 to 27) years were included. The interval between the initial and repeat CXL procedures was 60 (ranged 28 to 89) months. At postoperative month-1, a clear demarcation line could be observed in all patient eyes. The mean demarcation line depth was 250 (ranged 220 to 360) µm. At postoperative month-12, mean CDVA, manifest refraction, topographic indices, and aberrometric outcomes remained stable (p>0.05). Maximum keratometry was reduced more than 1D in two (28.6%) eyes, and remained stable in the remaining five (71.4%) eyes. No significant endothelial cell loss or any other sight-threatening complication was encountered in any patient eye.
DISCUSSION AND CONCLUSION: Repeat corneal CXL seems to be safe and effective in halting keratoconus progression at 1-year follow-up.

Keywords: Corneal collagen crosslinking, keratoconus, repeat crosslinking, retreatment, progression