Purpose
Slit lamp examination is the standard of care for recording the degree of anterior chamber inflammation in cases of uveitis. The number of visible cells in the anterior chamber are counted and graded on a scale of 0-4 based on the Standardization of Uveitis Nomenclature (SUN) Working Group. However, this method relies on the subjective evaluation of the number of cells and is subject to significant inter and intra-observer variation. This study was designed to determine the feasibility of utilizing Spectral Domain Anterior Segment Optical Coherence Tomography (AS-OCT) to objectively image and grade the degree of anterior chamber inflammation in eyes with uveitis.
Methods
Observational, case series of patients presenting to uveitis clinic with active uveitis. AS-OCT images were all taken on the RTVue-100 (Optuvue Inc, Fremont, CA). 3D Volume scans consisted of a 6mm x 6mm cube consisting of 512 B-scans each with 128 A-scans. Images were manually graded to evaluate for the presence or absence of cells in the anterior chamber. The number of cells as graded on clinical exam by a uveitis specialist was correlated to the number of cells seen in each individual line scan.
Results
83 eyes from 50 patients were imaged with a variety of types of uveitis. Based on slit lamp exam 5 eyes were quiet with no cells visible, 24 eyes had rare cell, 5 eyes had 1/2+ cell, 16 eyes had 1+ cell, 14 eyes had 2+ cell, 9 eyes had 3+ cell, and 10 eyes had 4+ cell. The range of cells seen on each individual AS-OCT line scan was 0-20 (mean 4.125, SD 4.8). 3 of the eyes with no cells seen on clinical exam had at least one cell on AS-OCT line scans. Pearson correlation coefficient comparing the manual measurements to the number of cells seen on individual AS-OCT line scans was 0.9296 (P<0.0001). Figure 1 shows a representative line scan in a patient with 4+ cells, figure 2 is a 3D cube scan from the same patient.
Conclusions
AS-OCT is a useful tool to objectively image and grade the degree of anterior chamber inflammation in eyes with active uveitis. The number of cells seen on clinical exam strongly correlates with the number of cells seen on AS-OCT line scans. This modality could be used in clinical trials to precisely and objectively grade response to treatment. A few patients were quiet on clinical exam but demonstrated cell on AS-OCT imaging, indicating they were still active despite being quiet on slit lamp exam.
Keywords: 746 uveitis-clinical/animal model •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
420 anterior chamber