[Comparison of optical coherence tomography and ultrasound biomicroscopy for detection of plateau iris].

PURPOSE: To compare optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) for detection of plateau iris configuration and confirmation of plateau iris syndrome.

PARTICIPANTS: Three subjects with plateau iris configuration were recruited. All patients underwent gonioscopy, UBM, and OCT.

METHODS: The anterior chamber angle in each patient was imaged with a commercially available OCT unit. The angle configurations were assessed and compared with the UBM images.

RESULTS: Both OCT and UBM showed excellent performance in identifying eyes with plateau iris. The UBM confirmed the plateau iris diagnosis by showing the iris root indentation caused by the ciliary body. The OCT, which is a rapid, non-contact exam, and non-operator-dependent, can only show indirect signs, because it cannot detect structures behind the iris. Nevertheless, the indirect signs with OCT were accurate enough to make the diagnosis. The OCT also shows the angle closure risk in a sitting patient, and is therefore more physiologic than the UBM exam, for which the patient is supine. OCT can directly show a patent laser iridotomy and confirm its efficacy. The OCT can detect indirect signs of plateau iris syndrome after iridotomy.

CONCLUSION: The OCT unit can be practically employed to confirm a clinical suspicion of plateau iris configuration and syndrome.