Sir,

We read with interest the article by Lindfield et al1 that reported that the use of eye shields following cataract surgery does not confer additional safety advantage. Although such studies are timely and relevant in the continuous effort to improve patient care, it is important to point out some limitations.

The frequency of complications such as endophthalmitis following cataract surgery are very rare, ranging from 0.05 to 0.30%.2, 3 Therefore, studies such as the current one, which included only 425 patients in the shieldless group,1 are not adequately powered to detect a significant difference in the rates of endophthalmitis. If even a single case of endophthalmitis had occurred in the shieldless group, the rate would have been 0.24%, which would certainly be a cause of concern, regardless of whether it was significantly higher compared with 0.10% in the shielded group. Therefore, the clinical implications of differences in complication rates between the two groups should be interpreted with caution.

In addition, only 10% of the study population were surveyed, and approximately half of the 46 patients (10% of the study population) felt that eye shields were ‘uncomfortable’ and preferred not to wear one.1 However, these patients did not have a prior experience of not wearing an eye shield to compare with. In a prospective randomized controlled trial of 60 consecutive patients undergoing bilateral cataract surgery with one eye patched and the other without postoperative patching, Stifter et al4 reported that within the first 4 hours of cataract surgery, pain scores were significantly higher in eyes who had no eye patches (mean score 1.7 vs 0.55, P <0.001), and postulated that this was related to the faster tear break up time in patients with no ocular protection (4.6 vs 7.1 s, P<0.001). At the end of this study, 65% of patients would have preferred to receive postoperative ocular protection.4 Another study5 also reported that patching could modulate inflammation and aid in wound healing.

In summary, this study contributes useful information regarding the benefits of postoperative ocular protection. However, much larger prospective studies will be required to determine if there are significant differences in the rates of postoperative complications with and without patching.