Ultrasound Biomicroscopy Measurements of the Normal Thickness for the Ciliary Body and the Iris in a Middle East Population

Purpose: Ciliary body (CB) and iris thicknesses may change with certain eye diseases as well as between different populations. Here, we report Ultrasound Biomicroscopy Measurements (UBM) of the normal thickness for the CB and the iris from a homogenous population in the Middle East. Patients and Methods: Sonomed 35-MHz (SONOMED, INC. New York, USA) images were obtained at 4 radial meridians, and the thickness was measured at 3 locations along the radial length of the iris and at the thickest part of the CB. Parameters included mean thickness, median thickness, range, and standard deviation. Results: Of 46 adult patients, 83 normal eyes were included in this analysis. The overall mean, median iris thicknesses at the iris root, midway along the radial length of the iris, and at the juxtapupillary margin in mm were 0.42, 0.41 ± 0.08, 0.52, 0.51± 0.08, and 0.72, 0.71± 0.1, respectively. The overall mean, median thicknesses of the CB and CB + ciliary processes in mm were 0.72, 0.71 ± 0.1, and 1.42, 1.37 ± 0.2 respectively. Gender, age, side, and height had no impact on iris and/or CB thickness (p>0.05). However, the iris thickness was significantly thicker in the superior quadrant than inferiorly, and in the nasal quadrant than the temporal quadrant (p=0.04), and the CB thickness and the CB + ciliary processes thickness were significantly thicker in the superior quadrant than inferiorly (P = 0.04 and 0.02 consecutively). Conclusion: We measured in this study the normal thickness of the CB and the iris in normal eyes from homogenous population in the Middle East using ultrasound biomicroscopy. Our findings are essential for the ophthalmic community worldwide and in the Middle East region and can be used as a normative thickness data for the iris and CB in healthy eyes.