Clinical factors affecting corneal epithelial healing after epithelium-off collagen cross-linking in patients with keratoconus: a prospective cohort study.

PURPOSE

To analyze the clinical factors affecting corneal epithelial healing time after epithelium-off (epi-off) corneal collagen cross-linking (CXL) in patients with keratoconus (KC).

METHODS

This prospective cohort study without blinding or randomization comprised 86 patients with KC (86 eyes) who underwent epi-off CXL. The tear film breakup time (TFBUT), corneal curvature, Schirmer's test, axial length, and corneal endothelial cell count may possibly affect corneal epithelial healing were recorded and analyzed by linear regression.

RESULTS

The corneal epithelium healing time was 2-12 (median, 4.5) days after surgery. The group with a shorter healing time had longer TFBUT (P < 0.001), thicker thinnest corneal thickness (P < 0.01), lower grading of KC (P < 0.01), and lower corneal curvature (all P < 0.05). The healing time of the corneal epithelium demonstrated significant negative correlations with TFBUT and thinnest corneal thickness (t = - 3.686, P < 0.001 and t = - 5.044, P < 0.001, respectively). Conversely, positive correlations were observed with maximum keratometry (Kmax), simulated keratometry 2 (SimK2), and average keratometry (Kavg) (Kmax: t = 2.695, P < 0.01; simK2: t = 3. 134, P < 0.01; Kavg: t = 3.020, P < 0.01). Multiple linear regression analysis indicated that simK2 was positively correlated with corneal healing. Meanwhile, the TFBUT and thinnest corneal thickness were negative correlated with corneal epithelial reconstruction.

CONCLUSION

Corneal thickness, corneal curvature (simK2), and the TFBUT may influence epithelial healing following epi-off CXL in patients with KC. Patients exhibiting steep simK2 and thinner cornea, which may correlate with lacrimal instability, should been closely monitor corneal epithelial healing after epi-off CXL and provide treatment to promote epithelial repair.