I read with interest the article by Joseph and associates evaluating the efficacy of quantitative real-time polymerase chain reaction (qPCR) in the diagnosis of postoperative bacterial endophthalmitis after cataract surgery. This technique offers a rapid pathogen identification and may be very useful in the treatment of postoperative endophthalmitis, in which the type of organism plays an important role in the final visual outcome. Their conclusions, however, should be interpreted with care.
First, the authors included patients with signs and symptoms suspicious for endophthalmitis within 1 year of cataract extraction. This is different from the criteria for acute postoperative endophthalmitis: endophthalmitis within 6 weeks after surgery. Inclusion up to 1 year after surgery creates bias by possible inclusion of noninfectious endophthalmitis and fungal endophthalmitis and makes it difficult to compare their results with those of previous studies of acute postoperative endophthalmitis.
Second, in the statement by the authors that their culture positive rate of 34% falls within the range reported in previous studies, they may have overlooked that the 2 largest studies of acute postoperative endophthalmitis after cataract surgery to date report a culture positive rate of 69% and 66%. In answering the question on the superiority of qPCR in acute postoperative endophthalmitis and in comparing the results with the previous study of qPCR by Bispo and associates, it would be interesting to know what the sensitivity was for qPCR in their study for the subgroup of patients seeking treatment within 6 weeks after surgery. In conclusion, I think that the article by Joseph and associates could add useful information to the discussion of effective diagnostic testing in acute postoperative endophthalmitis if these points of discussion are addressed.