Dual Scheimpflug imaging as a screening method for occludable angles-a comparison with gonioscopy

Abstract

AIM: To evaluate dual Scheimpflug analyzer (Galilei) as a screening method for the diagnostic of gonioscopically narrow anterior chamber angles (ACA). METHODS: In 40 eyes of 40 patients with different ACA range, the ACA, anterior chamber volume (ACV) and anterior chamber depth (ACD) were analyzed using the dual Scheimpflug analyzer (Galilei G6 system). Correspondence between these parameters and Shaffer’s classification based on gonioscopy were studied. Receiving operator characteristic (ROC) curves and partition analysis were used to determine the efficacy of the Galilei system in screening for narrow angles. Agreement (Kappa statistics), sensitivity, and specificity for each eye, according to Galilei measures, were also assessed. RESULTS: Shaffer’s grade (from 0 to 4) were significantly associated with each of the measurements (P<0.001). In screening eyes with narrow angles with the Galilei, the area under the ROC curve was largest (0.90) when ACD was used as the reference, and partition analysis demonstrated that those eyes were most adequately partitioned with an ACD of 2.86 mm with 100% sensitivity and 80% specificity. CONCLUSION: The Galilei is a secure, repeatable and noncontact screening method for narrow angles. However it does not provide sufficient information about the ACA anatomy to be considered a substitute for gonioscopy.

Keywords

• gonioscopy
• narrow anterior chamber angle
• screening
• diagnostic accuracy
• angle closure glaucoma
• glaucoma imaging