I read with interest the article published by Das and associates and commend them for an excellent study.

I have a few clarifications to seek from the authors. First of all, I would like to know if there were any recurrences in the placebo or polyhexamethylene biguanide (PHMB) groups. If so, was it more in the placebo group? There has been no mention of the mean duration of the follow-up. Secondly, was there any immune-related endothelitis associated with uveitis in the 12 eyes? Thirdly, did any of the patients in either group require any additional systemic albendazoles? Did the patients in the placebo group who were switched to PHMB have a similar outcome compared to those who were initially on PHMB?

It is known that fluoroquinolones as monotherapy or in combination with albendazole may have a role in the resolution of microsporidial keratoconjunctivitis. This has also been explored in in vitro studies. In lieu of potential toxicity with PHMB, fluoroquinolones would be a better first-line option.

In our small series of 6 patients referred to us (unpublished data) at Alexandra Hospital, Singapore, with positive microsporidial cysts, those who were on topical chloramphenicol and lubricant therapy were still symptomatic. Healing response was better, with faster resolution of symptoms, when we changed to gatifloxacin eye drops, even though visually nonsignificant corneal scars remained. Even though our sample size is small, I believe that future randomized controlled trials can show us the way.

My preference would be to use topical fluoroquinolone along with lubricants for treating microsporidial keratoconjunctivitis rather than lubricants alone.