Sir,

We read with interest the correspondence by Lindfield et al1 questioning the necessity for the routine use of shields after small incision cataract surgery following a retrospective review of local practice, and feel that it raises an interesting point. We would, however, request clarification of a potential confounding factor that was not included in the reported data. The authors make no comment regarding the proportion of corneal sections that were sutured. If either group is disproportionately weighted to using corneal sutures, this could either further strengthen or weaken the author's argument.

Secondly, a 2003 ASCRS survey2 showed that 72% of small incision cataract surgery was performed through a clear corneal section with only 28% through a scleral tunnel (no UK data available). The cohort of Lindfield et al1 had a disproportionately high percentage of scleral tunnel patients compared with likely current standard practice.

Finally, the questionnaire response rate was extremely low, representing only 5% of the sample size, and arguably could represent a selection bias, in which patients most likely to fill in a survey regarding the wearing of the shield may have been those who took issue with it.

Nevertheless, we do feel that assuming there was no difference in suturing section rates, the findings of Lindfield et al1 may strengthen a case for conducting an adequately powered prospective randomised control trial to definitively answer their question. In the meantime, we would advise caution to surgeons considering changing their practice regarding shields, until we have sufficient evidence to dismiss the benefit of their use.