Photoactivated chromophore for infectious keratitis corneal crosslinking (PACK-CXL) is not routinely used in clinical practice due to the uncertainty of its efficacy and safety. So researchers in the United Kingdom performed a systematic review to examine its efficacy and safety based on the current literature. Their findings demonstrated that adjuvant PACK-CXL could expedite the resolution of infectious keratitis with bacterial etiologies, and potentially fungal keratitis, by reducing the time to complete healing and the size of the infiltrate.

The review included 46 eligible studies (including four randomized clinical trials) with a total of 435 patients. The majority of the studies focused on either bacterial or fungal keratitis or a combination of both, with only one clinical trial including Acanthamoeba keratitis (three participants).

The researchers found that PACK-CXL shortened the time to complete corneal healing by seven days compared with standard antibiotic treatment alone. Also, infiltrates resolved quicker at seven days (-5.49mm2) and at 14 to 30 days (-5.27 mm2).

Nevertheless, the use of PACK-CXL in Acanthamoeba keratitis remains elusive, with contradicting evidence from in vitro and clinical studies, whereas PACK-CXL is contraindicated outright in cases of viral keratitis. Researchers concluded that assessing a greater number of adequately powered, high-quality randomized clinical trials is necessary to provide a true evaluation of PACK-CXL’s effectiveness and safety.  Standardized reporting of outcome measures will enable better applicability of the evidence and allow for easier comparison of the results across different studies.

Ting DSJ, Henein C, Said DG, Dua HS. Photoactivated chromophore for infectious keratitis-corneal cross-linking (PACK-CXL): a systematic review and meta-analysis. Ocul Surf. August 8, 2019. [Epub ahead of print].