Quantitative Analysis of Anterior Chamber Inflammation Using the Novel CASIA2 Optical Coherence Tomography

Abstract

We evaluated the clinical utility of a novel anterior segment optical coherence tomography (AS-OCT) device, CASIA2, to evaluate parameters indicative of anterior chamber (AC) inflammation severity in uveitis, including AC cell number, flare, and keratic precipitates (KPs). Prospective evaluation of a diagnostic device. Uveitis eyes were classified into active and inactive groups. The number of hyperreflective dots representing AC cells and optical density ratio (aqueous-to-air relative intensity [ARI] index) for flare qualification were calculated from AS-OCT images. In addition, a program was designed to quantify the posterior corneal surface smoothness (PCSS) of each image for KPs evaluation. The maximum, minimum, and average PCSS values were calculated from 128 images per eye and compared among active uveitis, inactive uveitis, and control eyes. Correlations between Standardization of Uveitis Nomenclature grade and both hyperreflective dot number and ARI index were evaluated. Receiver operating characteristic (ROC) curves were constructed to test the values of these indicators for uveitis diagnosis. AC hyperreflective dot count, ARI index, and maximum and average PCSS values were all significantly higher in the active uveitis group than in the inactive and control groups. Hyperreflective dot count and ARI index were associated with Standardization of Uveitis Nomenclature cell and flare grade. According to ROC curve analysis, maximum PCSS was the best indicator for the diagnosis of uveitis involving the anterior segment, meanwhile the hyperreflective dot number was the best to identify active AC inflammation from the inactive. Quantification of AC cell number, flare, and KPs using the CASIA2 device is a promising strategy for the objective assessment of AC inflammation.