Clinical features distinguishing angle closure from pseudoplateau versus plateau iris

• Published in: British journal of ophthalmology Vol. 92; no. 3; pp. 340 - 344
• Main Authors: Shukla, S, Damji, K F, Harasymowycz, P, Chialant, D, Kent, J S, Chevrier, R, Buhrmann, R, Marshall, D, Pan, Y, Hodge, W
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01.03.2008; BMJ; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Ciliary Body - diagnostic imaging; Ciliary Body - pathology; Cysts - complications; Cysts - diagnostic imaging; Diagnosis, Differential; Female; Glaucoma and intraocular pressure; Glaucoma, Angle-Closure - etiology; Humans; Iris Diseases - complications; Iris Diseases - diagnostic imaging; Iris Diseases - therapy; Laser Therapy; Male; Medical sciences; Microscopy, Acoustic; Middle Aged; Miscellaneous; Ophthalmology; Retrospective Studies; Symptomatology; Eye disease; Iris (eye); Ophthalmology; Comparative study; Angle closure glaucoma
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjo.2007.114876

Purpose: To evaluate clinical aspects of patients with the diagnosis of plateau iris (PI) or pseudoplateau iris (PPI) made by ultrasound biomicroscopy (UBM) in order to determine if there are any clinical factors that can help differentiate between these two entities.Method: A retrospective cohort of consecutive UBM patients with the diagnosis of PI or PPI. The diagnosis of PI was based on an anteriorly positioned ciliary body that abutted the peripheral iris, a narrow (<10°) or closed angle for at least 180°, and the anterior portion of the iris positioned anterior to scleral spur. The diagnosis of PPI was similar to plateau except that large or a cluster of small cysts had to be present in the iridociliary sulcus.Results: There were a total of 76 patients (29% male), 21 with PPI and 55 with PI. Patients with PPI were more likely to be male (p = 0.005), slightly younger (51.5 (SD 10.7) vs 57.9 (10.2) p = 0.0190), have a “bumpy” peripheral iris appearance (p = 0.003), have greater trabecular meshwork pigmentation (2.0 (0.7) vs 1.3 (0.6) p = 0.004) and have fewer clock hours of gonioscopic angle closure versus plateau iris patients (5.1 (4.3) vs 9.2 (4.2) p = 0.0009). Spherical equivalent was not significantly different between groups (0.50D (1.69) PPI vs 1.33D (2.42) PI; p = 0.187).Conclusions: In patients being referred to a UBM clinic for evaluation of angle-closure mechanism, younger males with a bumpy peripheral iris have a higher likelihood of having a diagnosis of pseudoplateau iris. However, clinical factors do not appear to discriminate well between PPI and PI. UBM is extremely helpful in confirming underlying mechanism and guiding therapy.