Ultrasound biomicroscopic findings in aniridia

To describe the ultrasound biomicroscopic features of eyes with aniridia.

Observational case series.

Nineteen eyes of 10 patients with aniridia (six males and four females) ranging in age from 3 months to 53 years (21.0 +/- 16.4, mean +/- SD), and 50 normal subjects (30 men and 20 women) ranging from 16 to 56 years (31.1 +/- 13.2) were evaluated. Ultrasound biomicroscopic findings were recorded in the 3-, 6-, 9-, and 12-o'clock directions. Adult patients (aged 16 years or older) with aniridia were compared with the age-matched controls.

Ultrasound biomicroscopy (UBM) detected extremely tiny irises in all eyes with aniridia. The eyes with aniridia showed significantly smaller values than the controls in ciliary body length (4.49 +/- 0.63 versus 5.79 +/- 0.44 mm, P <.001, unpaired Student t test), ciliary body thickness (0.75 +/- 0.17 versus 1.24 +/- 0.22 mm, P <.001), iris root thickness (0.47 +/- 0.14 versus 0.61 +/- 0.07 mm, P <.001), scleral-ciliary process angle (31.7 +/- 3.26 versus 43.1 +/- 4.48 degree, P <.001), and anterior chamber depth (1.99 +/- 0.43 versus 2.94 +/- 0.34 mm, P <.001). In the aniridia eyes, there was a significantly positive correlation between iris thickness and ciliary body thickness (Pearson r = 0.829, P =.001).

Ultrasound biomicroscopic imaging demonstrated that not only iris hypoplasia but also ciliary body hypoplasia exist in aniridia. Anterior inclination of the ciliary process was also found, which was thought to be at least partly responsible for the shallow anterior chamber.