Posner-Schlossman Syndrome European Study Group: study protocol and baseline patients characteristics of a multicentre study

Background: The aim of the Posner-Schlossman Syndrome European Study Group (PSS-ESG) is to acquire a comprehensive dataset of European patients with PSS. Here, we present the first report on the study protocol and the clinical findings of the patients at baseline. Methods: The PSS-ESG is a retrospective, multicentre study designed to evaluate patients with PSS. The study, designed and driven by a European Expert Committee includes three datasets: (1) the baseline, (2) the follow-up and (3) the intraocular pressure (IOP)/glaucoma dataset. Results: A total of 11 centres adhered to the PSS-ESG and 107 patients were included (68 males, 39 females) mostly Caucasian (93.4%). At uveitis onset, the patient's age ranged between 11 and 76 years, (mean age: 42±15 years). Best-corrected visual acuity was >0.5 in 80.3% of the eyes, IOP was >40 mm Hg in 44% of the eyes. Keratic precipitates were found in 78.5% of the eyes. No flare or cells in anterior chamber were detected in 56% and 53% of the cases, respectively. PCR analysis on aqueous sample was positive for cytomegalovirus-DNA in 50.6% out of the 81 tested patients. Conclusions: The PSS-ESG is the first multicentre study aimed to collect a comprehensive dataset of patients with PSS in non-Asian countries. A middlde-aged Caucasian male with a low-grade anterior chamber inflammation, keratic precipitates, preserved visual acuity and marked increased in IOP seemed to be the standard PSS patient across the 11 uveitis and glaucoma centres participating in the PSS-ESG.