Sir,

Dr de Smet and associates have conducted an interesting study on surgical interventions for cases of uveitis-induced chronic hypotony. After a joyous reading of the whole article, we think that an important issue should warrant further discussion.

Subtenon's capsule triamcinolone acetonide injection was shown to be effective in the management of intraocular inflammation.1, 2 It has an overt advantage over systemic steroid for effaced systemic adverse effect and slow-releasing depot.1 The biological action of subtenon triamcinolone acetonide is long and can be up to 6 weeks or even longer.1, 2

From the methodology, it can be learned that some of the patients with intraocular inflammation were given one to two subtenon's injection prior to the surgical intervention.3 Interestingly, if one inspected Table 1 of the article, it was noted that duration of hypotony in patient numbers 1–4 ranged from 8 to 12 weeks.3 Apparently, there was no washing-out period for the subtenon steroid administered. Hence, out of the six patients enrolled, four of them (66.7%) might undergo the antihypotony surgeries superimposing with the ongoing anti-inflammatory effect of the subtenon steroid depot. This is a significant confounding factor. These inadvertently overlapped medical and surgical managements may blur the attribution that the observed postoperative improvement was solely due to surgical manipulation. If uncontrolled, it may imperil the reproducibility of the proclaimed intraocular pressure-stabilizing effect of the surgery. We would like to learn more from the authors about their precautions against this important confounding influence.