Effect of primary iris and ciliary body cyst on anterior chamber angle in patients with shallow anterior chamber

Abstract

Objective: To evaluate the prevalence of primary iris and/or ciliary body cysts in eyes with shallow anterior chamber and their effect on the narrowing of the anterior chamber angle.

Methods: Among the general physical check-up population, subjects with shallow anterior chambers, as judged by van Herick technique, were recruited for further investigation. Ultrasound biomicroscope (UBM) was used to detect and measure the cysts located in the iris and/or ciliary body, the anterior chamber depth (ACD), the angle opening distance at 500 µm (AOD500), and the trabecular-iris angle (TIA). A-scan ultrasonography was used to measure the ocular biometry, including lens thickness, axial length, lens/axial length factor (LAF), and relative lens position (RLP). The effect of the cyst on narrowing the corresponding anterior chamber angle and the entire angle was evaluated by the UBM images, ocular biometry, and gonioscopic grading. The eye with unilateral cyst was compared with the eye without the cyst for further analysis.

Results: Among the 727 subjects with shallow anterior chamber, primary iris and ciliary body cysts were detected in 250 (34.4%) patients; among them 96 (38.4%) patients showed unilateral single cyst, 21 (8.4%) patients had unilateral double cysts, and 42 (16.8%) patients manifested unilateral multiple and multi-quadrants cysts. Plateau iris configuration was found in 140 of 361 (38.8%) eyes with cysts. The mean size of total cysts was (0.6547 ± 0.2319) mm. In evaluation of the effect of the cyst size and location on narrowing the corresponding angle to their position, the proportion of the cysts causing corresponding angle narrowing or closure among the cysts larger than 0.8 mm (113/121, 93.4%) was found to be significantly higher than that of the cysts smaller than 0.8 mm (373/801, 46.6%), and a significant higher proportion was also found in the cysts located at iridociliary sulcus (354/437, 81.0%) than in that at the pars plicata (131/484, 27.1%). In evaluating the effect of the cyst on the entire anterior chamber angle, the eyes with multiple and multi-quadrants cysts manifested significant narrowing of the entire anterior chamber angle as compared with the eyes without cysts, based on the data analysis in comparison of TIA, AOD500, and gonioscopic grading evaluation. The unilateral single or double cysts in the eyes had no significant effect on narrowing of anterior chamber angle as compared with eyes without cysts. The iris and/or ciliary body cysts did not seem to affect the axial length, ACD, lens thickness, RLP, LAF.

Conclusions: The prevalence of primary iris and ciliary body cyst was 34.4% in the subjects with shallow anterior chamber. The cysts larger than 0.8 mm, locating at iridociliary sulcus, or multiple and extensive cysts were inclined to cause the angle narrowing or closure.

Fig. 1

Division of circumference of the ciliary body in each eye into eight sectors In ultrasound biomicroscopy (UBM), each sector was scanned perpendicularly in transverse (a) and radial (b) positions

Fig. 2

Ultrasound biomicroscopy (UBM) images of the left eye 3 (a), 5 (b), and 6 (c) o’clock radial positions in a 47-year-old patient with one cyst (arrow) AOD500 and TIA: (a) 0.2786 mm and 27°; (b) 0.2104 mm and 14°; (c) 0.2587 mm and 22°. Compared with (a), in (c) the AOD500 and TIA were all smaller than the averages, so it was recorded that the corresponding anterior chamber angle narrowed

Fig. 3

Ultrasound biomicroscopy (UBM) images of the left eye 3 (a), 4 (b), and 6 (c) o’clock radial positions in a 41-year-old patient with one cyst (arrow) Compared to (c), the angle in (b) was closed, and thus it was recorded that the corresponding anterior chamber angle closed

Fig. 4

A cyst (arrow) characterized as round or ovoid, solitary or multiple, with a thin and hyperechogenic wall and a sonolucent interior The local angle of the cyst showed plateau iris configuration

Fig. 5

Locations of 922 cysts in 361 eyes with shallow anterior chamber The number of cysts exceeds the number of eyes because many eyes had multiple cysts in various sectors. nas.: nasal; sup.: superior; inf.: inferior; temp.: temporal

Fig. 6

Number distribution of the size of cysts The mean size of cysts is (0.6547±0.2319) mm

Fig. 7

Ultrasound biomicroscopy (UBM) images of the left eye 1 (a), 2 (b), 3 (c), 5 (d), 7 (e), and 9 (f) o’clock radial positions in a 31-year-old patient with multiple and multi-quadrant cysts (arrows)