Ultrasound biomicroscopy in narrow peripheral anterior chamber eyes with or without peripheral anterior synechiae

AIM: To compare the configurations of the anterior ocular segment including the anterior chamber (AC) angle and ciliary body between eyes with a narrow AC angle (ACA) with and without peripheral anterior synechiae (PAS). PATIENTS AND METHODS: One hundred and one eyes of 101 consecutive patients with a temporal peripheral AC depth one-quarter of the corneal thickness or less were included. Gonioscopy and ultrasound biomicroscopy were performed under light and dark conditions. The existence of PAS was further confirmed with compression gonioscopy with indentation. Eyes with findings suggestive of plateau iris configuration or those with glaucomatous optic neuropathy were carefully excluded. The biometric parameters including the ACA, the angle opening distance at 500 μm, the trabecular-ciliary process distance, the iris-zonule distance, and the scleral-ciliary process angle were determined. RESULTS: PAS were found in 43 (43%) of the 101 eyes. There were no differences in age, refractive error, or intraocular pressure between PAS-positive and PAS-negative eyes (P>0.1). ACA, iris-zonule distance, scleral-ciliary process angle under light and/or dark conditions were significantly smaller in the PAS-positive eyes than in the PAS-negative eyes (P<0.05). CONCLUSIONS: Shallow peripheral AC depth and relatively anteriorly located ciliary body was significantly associated with the presence of PAS in eyes with a narrow ACA.