[Corneal cross-linking in microbial keratitis to prevent à chaud keratoplasty: a retrospective case series]

Corneal cross-linking (CXL) with riboflavin is being used more frequently for the treatment of therapy-resistant microbial keratitis, since increasing drug resistance and specific pathogens, e.g. contact lens-associated Acanthamoeba, make this therapy appear as an attractive option to avoid a keratoplasty à chaud.

This retrospective case series of 11 consecutive patients (4 women, 7 men, aged 24-82 years) who received standardised antimicrobial CXL for therapy-resistant keratitis to avoid a keratoplasty à chaud, included 4 cases with detection of bacterial pathogens, one case with proven fungal infection and 6 cases without pathogen detection. Analysed data comprised ophthalmic medical history, general risk factors for microbial keratitis, treatment before and after CXL. The characterisation of the corneal ulcer included photometric measurements of the infiltrates with a median of 16.2 mm² and four unmeasurable cases due to extended, not circumscribed lesions.

Within the follow-up period (mean 134 ± standard deviation 82 days), a penetrating keratoplasty was successfully avoided in 6 patients (55 %). After CXL 9 patients (82 %) received additionally amniotic membrane transplantation. After CXL treatment, topical antibiotic therapy was continued for a mean 27 ± 13 days postoperatively. Steroids were applied in 91 % of the patients. The cornea cleared at least to some extent in 9 patients (82 %). Patients with neurotrophic keratopathy or potentially compromised immune system showed no increased failure rate.

These results suggest that antimicrobial CXL might be a useful option in patients with therapy-resistant corneal ulcer in order to avoid a perforating keratoplasty à chaud. For a comprehensive scientific assessment of this therapy, however, further, ideally prospective randomised interventional studies with large sample sizes are needed.