Response to comment on: Comment on: Clinical presentations and comparative outcomes of primary versus deferred intraocular lens explantation in delayed-onset endophthalmitis

Dear Sir,

We would like to thank Kannan et al.[1] for the interest expressed in our article.[2] As the readers have expressed some concerns about the article, we would like to explain the points raised as below.

The readers point out that as Table 5 shows baseline favorable visual acuity (VA) of >20/400 to be present in 7.27% cases in primary explantation group, significantly lesser than 27% in the delayed group (P = 0.046), poor presenting VA seems to be an indicator toward the requirement of earlier intraocular lens (IOL) explantation. While we appreciate the readers having done statistical calculations themselves, a point of caution and a usual mistake made in interpreting statistics is to consider P value alone without considering the 95% confidence intervals (CI). If the 95% CIs are calculated for the difference in the two groups here, the readers would see that the values range from 0.139% to 34.1%. The interpretation here is, though the P value is significant, as the lower limit of the CI is less than 1 and also due to the wide nature of the CI, the significance of the P value is questionable. As a rule in statistics, P value should never be interpreted without taking into consideration the 95% CIs. The fact that the final favorable vision improved much better in the primary explantation group has already been addressed in the manuscript and has made us propose in the last line of the manuscript that “in cases where an IOL explantation is contemplated, it is better done sooner than later”.

Attempts to identify the organisms were made by sending the explanted lens for culture and also sending the capsular bag and vitreous sample. In the primary explantation group, this was done at the time of explantation.

We agree with the readers' point that clear differentiation is difficult between endogenous and a late postoperative etiology in the cases pointed out. This is a limitation of the retrospective nature of the study and this limitation has already been highlighted in the manuscript.

We would also like to congratulate the readers on their experience with SFIOL implantation following IOL explantation in fungal endophthalmitis. The readers report by their experience of four cases that scleral-fixated IOL (SFIOL) is a good modality for rehabilitation of these cases. In their experience, three cases (75%) had success and one case (25%) did not. We would like to apply statistics to their experience here. The P value for the proportional difference here is 0.19 and the 95% CIs for the difference vary from -13.5% to 78.9%. As the CI straddles zero, it means that in the real world, the results as seen by the author (success-failure ratio) could very well be reversed. Hence, it is too small a number to conclude that SFIOL is a good modality for rehabilitation on the basis of the data provided.

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