Prevalence of Plateau Iris Syndrome among Patients Presenting with Primary Angle Closure and Primary Angle-Closure Glaucoma in a Tertiary Eye Care Hospital

PURPOSE: Glaucoma is a leading cause of visual impairment worldwide, and plateau iris syndrome (PIS) is the most common nonpupillary block mechanism of angle closure. This study aims to assess the prevalence of PIS among Saudi population. METHODS: It is a prospective observational study that examined patients previously diagnosed with chronic angle closure. Those patients already underwent peripheral laser iridotomy (PLI) and were assessed clinically and by ultrasound biomicroscopy (UBM). RESULTS: A total of 147 eyes in 77 patients were included in this study. The mean age among subjects was 61.2 years, and almost 69% were females. Chronic angle closure was noted to be bilateral in 91% of patients, whereas 5% had their left eye involved and 4% had right eye involved. The mean intraocular pressure (IOP) before PLI and after laser treatment was 19.3 and 16.2, respectively. The mean visual acuity before and after PLI was 0.3 logMAR. After UBM examination, plateau iris was found in 41.5% of subjects. The anterior chamber (AC) depth was noted to be deeper in PIS patients (P = 0.046). Other risk factors were observed in our study including place of residency (P = 0.048) and preintervention IOP (P = 0.032). CONCLUSION: PIS is the most common mechanism of nonpupillary block angle closure. In addition to clinical findings, UBM is important to reach the appropriate diagnosis. This study reviewed the prevalence of PIS with the aid of UBM; it was found consistent with previous reports. In addition, PIS risk factors included AC depth, place of residency, and preintervention IOP.