Non-contact, high-resolution imaging for uveitis surveillance in juvenile idiopathic arthritis (JIA) is feasible and acceptable to patients with the disease, according to study results published in Arthritis & Rheumatology.
Disease activity in anterior uveitis is traditionally assessed using slit lamp biomicroscopy; however, this modality is “semiquantitative” and image interpretation is subjective. Optical coherence tomography (OCT) may represent a better metric of measuring inflammatory disease, with recent modifications to OCT allowing the imaging of the anterior chamber.
In the current study, researchers sought to assess the feasibility and accuracy of cross-sectional anterior segment OCT (AS-OCT) for the diagnosis of active uveitis in JIA.
In the cross-sectional observational study, the researchers enrolled children with and without uveitis from a specialist pediatric uveitis center in England between 2017 and 2018. The 2 groups of participants included children with JIA and a diagnosis of chronic anterior uveitis; and children without both JIA and uveitis. All children received routine clinical assessment of the anterior chamber with a slit lamp. The ordinal Standardized Uveitis Nomenclature (SUN) anterior chamber activity cell count grade was used to diagnose inflammation.
The AS-OCT scans of the anterior chamber were then acquired. Patients were asked to focus their eye that was being tested on the machine fixation beam. Image acquisition time was measured, and participants were asked to rate the acceptability of the acquisition process. The AS-OCT images were analyzed manually for the presence of anterior chamber inflammation. Examiners were blinded to the results of the initial clinical examination. Correlation between imaging-acquired cell count and clinical assessment was calculated using a multilevel linear regression model. Sensitivity, specificity, and repeatability were also reported.
A total of 26 children received AS-OCT imaging, among whom 18 (69.2%) were girls. Median age was 8 years (age range, 3-15 years). Twelve children had active anterior inflammation during their initial clinical examination. Time taken to acquire AS-OCT images from both eyes ranged from 1.5 to 22 minutes, with a median value of 8 minutes. Patients rated image acquisition acceptability as “high,” with a median visual analog scale score of 9.5 of a possible 10.
Intraobserver image agreement was high with regard to manual cell count (intraclass observer coefficient, 0.81; 95% CI, 0.63-0.98). There was moderate agreement on cell count between observers (kappa statistic [κ], 0.46; 95% CI, 0.28-0.63), and between-observer disagreement on the presence of intraocular cells in 25 of the 377 reviewed images (6.6%). Anterior segment OCT had high correlation with active inflammation as diagnosed by slit lamp examination. Sensitivity for active inflammation was 91.7% (95% CI, 61.5%-99.8%); specificity was 85.7% (95% CI, 57.2%-89.2%); and accuracy was 88.5% (95% CI, 69.9%-97.6%). In multilevel regression modeling, there was high positive correlation between clinical assessment and image-based cell count (coefficient, 3.3; 95% CI, 1.3-5.2; P =.002). No children without uveitis had a positive result on AS-OCT imaging.
These results support the feasibility and acceptability of AS-OCT imaging for the assessment of uveitis in children with JIA.
The primary study limitation was the small sample size and the fact that the study results may not be generalizable to all children with anterior chamber inflammation. While AS-OCT correlated well with slit lamp examination, further study is necessary to standardize the imaging protocol.
“Imaging-based metrics for uveitis holds the promise of providing sensitive, robust, validated measurement of disease status which, alongside [standardized] datasets and patient[-centered] metrics, can also improve service provision, prognostication and precision in disease management for affected or at-risk children,” the researchers concluded.
Akbarali S, Rahi JS, Dick AD, et al. Imaging based uveitis surveillance in juvenile idiopathic arthritis: feasibility, acceptability and diagnostic performance. Arthritis Rheumatol. Published online September 25, 2020. doi:10.1002/art.41530