Comment on: Fungal keratitis: The Aravind Experience.

Sir,

We read with interest the article entitled, “Fungal keratitis: The Aravind experience” by Prajna et al.[1] First, in the compilation of the clinical articles published on this topic by the researcher from that institution, shown in the Fig. 1 included in the article by Prajna et al., an older study than those referred (a masked, randomized clinical trial of three concentrations of chlorhexidine compared with natamycin 5%, published in 1997) is missing from the list. In fact, that study showed that chlorhexidine might be superior to natamycin. Compared with the response to natamycin as the referent, the relative efficacy was 1.17 with chlorhexidine 0.05%, 1.43 with 0.1%, and reached 2.00 with 0.2%. The superiority of 0.2% chlorhexidine over natamycin was statistically significant (relative efficacy 2.20, P = 0.043) in patients not having had prior antimycotic medication.[2] Since the investigators did not mention chlorhexidine 0.2% in their recent review, we wonder if they had any posterior negative experience using this substance in fungal keratitis.

The recent studies Mycotic Ulcer Treatment Trial I (MUTT I) and MUTT II, performed also by researchers from Aravind Eye Hospital, showed that topical natamycin was superior to topical voriconazole.[34] Since in the clinical trial from 1997, it was found that chlorhexidine 0.2% could be twice as effective as natamycin, would not it be worth conducting a new study with chlorhexidine and natamycin? Not only to probably corroborate the earlier findings from 1997 but also to evaluate a possible synergy between them?

Furthermore, in the recently published results from the study MUTT II (both for all cases of keratomycosis and for Fusarium keratitis), the researchers from Aravind indicated that all patients received topical voriconazole, 1%, and that after the results of the MUTT II study became available, topical natamycin, 5%, was added for all patients.[45] It would be interesting to know if they have found any kind of synergy between these two medications. In the current protocol of their hospital, do they use both topical medications concurrently?

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