We read with interest the article titled ‘Macular hole surgery without prone positioning’ by Tranos et al.1

The authors claimed, ‘we have shown that macular hole surgery without prone posturing results in similar closure rates to conventional surgery with strict early postoperative posturing.’ We would like to challenge the construct of their study and the validity of its conclusion.

First, the authors did not state how the subjects were assigned to the posturing and non-posturing groups. Although both groups appeared to be comparable, the process of patient assignment to one of the two groups was not randomised and thus could be a source of bias.

Second, the exact posture and the duration of posturing by the subjects were not quantified, which is a fundamental flaw in this study. Although the subjects in the non-posturing group were told ‘to avoid lying supine’, no other specific posturing instructions were given. Could the patients in the non-posturing group have adopted prone or semi-prone positioning without the authors’ knowledge? It is possible that the ophthalmologists who initially examined the patients could have explained the need for strict facedown positioning when treatment was discussed before the patients were referred for macular hole surgery. The patients could also have read about this routine on patient information sheets or the internet, or even witnessed other postoperative patients position themselves facedown in the ward. Moreover, there exists an entire spectrum of postures that can satisfy their definition of ‘non-posturing’, ranging from facedown prone position all the time to lying on one's side all the time, that patients can adopt and the failure to account for this gravely undermines the conclusion of the study. Ideally, an objective measure of the patients’ actual posture (eg, the angle of head tilt) at all times and the duration of such posturing would be helpful for this study. A measuring device, such as the ‘Maculog’ proposed by Verma et al,2 may be useful in this respect.

Similarly, the compliance of the subjects with the head positioning in both groups was not described. This may be significant, especially in the posturing group, as the actual posturing time may be only half of the perceived posturing time.2

In our opinion, this study has yet again failed to shed light on this unresolved controversy. A large randomised controlled trial with an objective measure of patients’ posture and compliance will better elucidate the role of prone positioning after macular hole surgery.