We read with interest the article by Anwar and associates on diagnostic utility of polymerase chain reaction (PCR) in anterior uveitis. The study addresses an important diagnostic challenge in the management of infectious anterior uveitis. However, it has significant limitations, some of which have been aptly highlighted by the authors themselves.

Two-thirds of the patients in the study had chronic uveitis and one-third had received acyclovir therapy. We therefore differ with the authors’ conclusion that PCR should not be the first-line investigation for anterior uveitis. The majority of anterior uveitis cases in clinical practice are noninfectious (eg, HLA-B27-associated) cases that can generally be identified on the basis of specific clinical signs. In our opinion, once noninfectious causes are excluded, an early decision for anterior chamber paracentesis should be taken, especially if suggestive clinical signs like iris atrophy, pigmented keratic precipitates, endotheliitis, or ocular hypertension are present. Definitive diagnosis of infection by PCR at an early stage can help in prompt initiation of specific antimicrobial therapy. Conversely, a negative PCR outcome late in the course of disease, or after a therapeutic trial of acyclovir, can lead to prolonged treatment with corticosteroids for inherently recurrent infections like herpetic uveitis. We are also concerned about the relatively high incidence of adverse effects following anterior chamber paracentesis in this study. We speculate that this might be related to the practice of doing paracentesis in a sitting position on the slit lamp. The development of permanent central scotoma after paracentesis in 1 patient has also not been explained.

Finally, we wish that the authors had mentioned the DNA copy numbers in the samples with positive PCR outcomes for various organisms. A decrease in copy numbers post treatment, compared to pretreatment levels, would have better helped in establishing causality, especially in case of novel organisms like the Epstein-Barr virus. To conclude, early paracentesis for PCR in suspected cases of infectious anterior uveitis can help in prompt initiation of antimicrobial therapy, and thus influence our decision making in such cases.