Abstract
Purpose: :
To determine the normal thickness of anterior uveal structures in healthy subjects, specifically the ciliary body and iris, utilizing ultrasound biomicroscopy (UBM). Normative data may be useful for tumor screening involving these structures.
Methods: :
This prospective study included 28 eyes. Exclusion criteria included pre-existing systemic medical conditions, ocular surgery and eye disease. Measurements were made of the ciliary body and the iris. UBM radial views were imaged at 12, 3, 6 and 9 o’clock in both eyes. Maximum thickness measurements were obtained from the inner sclera to the apex of the ciliary body and to the apex of the ciliary processes, measuring perpendicular to the scleral wall. Iris thickness measurements were made at 0.8 mm from the iris root, midway along the length of iris, and at the bulbous juxtapupillary margin. Parameters recorded included average thickness, standard deviation and range for OD, OS and OU based on age, sex, race and height.
Results: :
The average age of all subjects was 35.7 +/- 11.6 years (range: 23-56). The mean thicknesses of the ciliary body, ciliary body + ciliary processes, iris at 0.8 mm from the iris root, midway along the length of the iris and at the iris juxtapupillary margin were 0.72 mm, 1.31 mm, 0.41 mm, 0.46 mm and 0.64 mm, respectively, for all subjects. Anterior uveal structure thicknesses were not correlated with age, race or gender. They were, however, correlated with height. Taller patients (height ≥ 5’7" or 67"; 170 cm) had a thicker CB (0.79 mm) than shorter patients (0.68 mm) (p<0.001).
Conclusions: :
This study provides standard, normative thickness data for anterior uveal structures in healthy subjects as measured by the UBM. This might be useful in the early detection of anterior uveal pathology, particularly neoplasia.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • uvea • ciliary body