Prospective comparison of ultrasound biomicroscopy and anterior segment optical coherence tomography for evaluation of anterior chamber dimensions in European eyes with primary angle closure

Abstract

Purpose To compare the accuracy in measurement of the anterior chamber (AC) angle by anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in European patients with suspected primary angle closure (PACS), primary angle closure (PAC), or primary angleclosure glaucoma (PACG). Design Cross-sectional study. Methods In all, 55 eyes of 33 consecutive patients presenting with PACS, PAC, or PACG were examined with AS-OCT, followed by UBM. The trabecular-iris angle (TIA) was measured in all four quadrants. The angle-opening distance (AOD) was measured at 500 lm from the scleral spur. The BlandAltman method was used for assessing agreement between the two methods. Results The mean (±SD) superior TIA was 19.3 ± 15.81 in AS-OCT and 15.7 ± 15.01 in UBM (P ¼ 0.50) and inferior TIA was 17.9 ± 12.91 (AS-OCT) and 16.7 ± 14.11 (UBM) (P ¼ 0.71). The superior AOD 500 was 0.17 ± 0.16 mm in UBM and 0.21 ± 0.16 mm in AS-OCT (P ¼ 0.06). BlandAltman analysis showed a mean SD of±9.41 for superior and inferior TIA and a mean SD of ±0.10 mm for superior and inferior AOD 500 .Conclusions This comparative study shows that AS-OCT measurements are significantly correlated with UBM measurements but show poor agreement with each other. We do not believe that AS-OCT can replace UBM for the quantitative assessment of the AC angle.

Quantitative Analysis of Anterior Chamber Angle by Ultrasound Biomicroscopy in a Healthy, Young Male Population

“…Mansouri ve ark. 'n›n yapt›klar› çal›flmada ise; UBM ve ÖS-OKT ile yap›lan ön kamara ölçümleri aras›nda önemli korelasyon oldu¤u ancak zay›f kararl›l›k gösterdi¤i, ön kamara aç›s›n›n niceliksel ölçümünde ÖS-OKT'nin UBM'nin yerini alamayaca¤›na inand›klar›n› belirtmifllerdir (10).…”

Angle Closure Glaucoma: Pathogenesis and Evaluation. A Review

“…For some Authors there's poor agreement between AS OCT and UBM: the first giving higher measurements than the second, but the reasons still remain unclear. It has been hypothesized that it can be due to the different calibration, to illumination condition, or to pressure of the eyecup [68,96].…”

“…Determination of angle parameters using semiautomated software leads to variability in measurements and this is largely due to the need of manual identification of the sclera spur [96]. Using Visante OCT the scleral spur individuation is possible in approximately 70% of anterior segment images [97].…”

Measurements of anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter using two Scheimpflug imaging devices

“…The Pentacam HR (Oculus, Wetzlar, Germany) and the Galilei G4 (Ziemer, Switzerland) are two clinical tomographers that are both based on Scheimpflug cameras. Beside corneal parameters, these devices also have the ability to measure the ACD, ACA, PD, and ACA, and they (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) or WTW distance (20)(21)(22) . However, to our knowledge, a side by side comparative study has not previously been reported.…”

“…Furthermore, the WTW distance is useful in determining the optimum IOL size, and the PD is essential in determining the optical zone where the laser pattern has to be applied. Also, an anterior chamber angle (ACA) evaluation is essential to establish the risk of angle disclosure (1) . Recent technological advances have allowed the ACD, WTW, PD, and ACA measurements to be quantified with the following noninvasive techniques: Scheimflug photography (Pentacam-Galilei), scanning slit topography (Orbscan/OrbscanII), and partial (IOLMaster) and low coherence interferometry (Visante-optical coherence interferometry and Lenstar).…”