Can the combination of citicoline and vitamin B12 be beneficial in the healing of corneal nerves after corneal cross-linking?

Purpose: To evaluate the effect of topical citicoline, vitamin B12 and hyaluronic acid (OMK2 eye drops; Omikron Italia Srl, Italy) on the healing of corneal nerve after corneal cross-linking (CXL) treatment in patients with keratoconus (KC).

Methods: A total of 44 eyes of 22 patients with KC who underwent CXL were included in this prospective study. After CXL, one eye of these patients received OMK2 eye drop and standard post-CXL treatment (OMK2 group), while the fellow eye received only standard post-CXL treatment (control group). The following parameters were analyzed in the pre- and post-CXL procedure periods (1st, 3rd and 6th months): corneal sensitivity, tear film stability, central corneal thickness (CCT), and the corneal sub-basal nerve plexus (sbNP) parameters (including corneal nerve fiber density [CNFD], corneal nerve branch density [CNBD], corneal nerve fiber length [CNFL], corneal total branch density [CTBD], corneal nerve fiber area [CNFA], corneal nerve fiber width [CNFW]).

Results: Following CXL, a comparison of the baseline and month 6 data revealed that CNFA decreased in the control group (p < 0.001) and did not differ in the OMK2 group (p = 0.283). Other corneal sbNP parameters exhibited a decrease when comparing baseline and 6 months in each group (all p < 0.05). In addition, CCT in the OMK2 group was not significantly different between baseline and month 6 (p = 0.052). However, a decline in CCT of the control groups was observed during this specified time interval (p = 0.009). Corneal sensitivity or tear film stability parameters did not differ significantly between groups at any time point or over time within each group (all p > 0.05).

Conclusion: The use of OMK2 eye drop after CXL may provide more stable CNFA. In addition, it may also provide faster recovery in CCT.