Abstract
Purpose :
To assess iris vascularization and flow density using optical coherence tomography angiography in a cohort of patients with anterior uveitis.
Methods :
One hundred patients with acute anterior uveitis, 100 patients with quiet recurrent anterior uveitis, and 100 normal age-matched subjects were consecutively scanned using a commercially available AngioVue OCTA system (Optovue, Inc., Fremont, CA) and the split-spectrum amplitude decorrelation angiography (SSADA) algorithm. Each subject underwent scans from 4 quadrants (superior, inferior, nasal, and temporal) in each eye by a trained operator. In order to enable blood flow density quantification, a built-in software correlated the SSADA signal at multiple time scales with various preset velocities. For eyes with quiet recurrent anterior uveitis, the time to the following flare up was compared to the iris flow density.
Results :
In our study of 100 normal subjects we found good repeatability (k coefficient, 0.71) for flow density assessment of iris vasculature measurements. Iris blood flow density measurements within the regions of interest were compared in the active uveitis group versus the normal patients (temporal iris flow density 76.17% vs 46.44% [P<0.01]; nasal iris blood flow density 72.09% vs 42.06% [P<0.01]). The established OCTA scanning protocol was then used in 100 patients with quiet recurrent anterior uveitis in which a mean iris blood flow density over 55.8% was positively correlated with a reactivation of the inflammation (defined as >1+ anterior chamber cells) within 13.2 days.
Conclusions :
This preliminary study describes the acquisition of OCTA images of the iris vasculature and analysis of the iris blood flow density in normal and active uveitis patients. Iris flow density seems to increase consistently with increase degree of inflammation in the anterior chamber. Furthermore, as ciliary flush detected by clinical examination precedes active anterior uveitis, an increased iris flow density seems to be predictive of a reactivation of a quiescent recurrent uveitis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.