Laser Flare Photometry Successfully Identifies JIA-Associated Uveitis

Kaleo C Ede, MD

Credit: Yellow Pages

Laser flare photometry (LFP), a non-invasive tool to determine juvenile idiopathic arthritis-associated uveitis (JIA-U), demonstrated a low false positive rate when compared with a standard slit lamp exam, according to a study published in Pediatric Rheumatology.¹

Currently, the standard tools to screen for JIA-U include slit lamp examination, measurement of intraocular pressure, and age-appropriate visual acuity (VA) testing. Diagnosis of uveitis focuses on identifying the features of inflammation, including the presence of cells in the anterior chamber (AC) and AC flare, which lead to protein leakage due to the breakdown of the blood-aqueous humor barrier. As intraocular inflammation is graded using the Standardization of Uveitis Nomenclature (SUN) criteria, patients with JIA are often seen by ophthalmologists or optometrists.²

“JIA-U remains one of the most serious complications of JIA in children,” wrote Kaleo C Ede, MD, associated with the Division of Pediatric Rheumatology at Phoenix Children’s Hospital, and colleagues. “Historically, pediatric JIA is diagnosed by an optometrist or ophthalmologist; however, barriers to scheduling increase wait times that may delay diagnosis and treatment.”

The prospective, observational study determined the usefulness of LFP to diagnose JIA-U using a cohort of patients with clinically diagnosed JIA without uveitis recruited from a Pediatric Rheumatology clinic between January 2020 and September 2022. Eligible patients underwent ≥1 evaluation of both eyes using a Kowa FM-600 laser flare photometer during a routine rheumatology appointment, in addition to a standard slit lamp examination by ophthalmology during routine clinical care.

Data obtained included disease characteristics, treatment, demographics, LFP readings, and anterior chamber (AC) cell grade score using the SUN grading system. Additionally, descriptive analyses and the uveitis false positive rate data were summarized.

A cohort of 58 pediatric patients with JIA were included in the study, with a mean age of 8.4 years at diagnosis and 11.9 years at enrollment. The mean disease duration was 42 months. Patients were predominantly female (74.1%, n = 43) and White (63.8%, n = 37). Among the JIA subtypes, 32.8% (n = 19) had persistent oligoarticular JIA and 20.7% (n = 12) had rheumatoid factor negative polyarticular JIA. Approximately 1 out of 4 (27.6%, n = 16) patients were not receiving medication, although 34.5% (n = 20) were being treated with methotrexate, 34.5% (n = 20) were receiving adalimumab, 8.6% (n. 5) were treated with etanercept, and 10.3% (n = 6) were receiving tocilizumab treatment.

No eye exams detected uveitis based on systemic lupus erythematosus (SLE) with a SUN grade over 0 during the study period. Of the 135 LFP readings, 97.0% (n = 131) were normal, leading to a false positive rate of only 3% (95% confidence interval [CI]: .8%, 7.4%).

Investigators noted the low enrollment rate, culminating in a small sample size of participants, as a limitation of the study. They believe recruitment was significantly affected by the COVID-19 pandemic. Further, the incidence of new onset JIA-U was lower than originally hypothesized. Future research should include patients with existing JIA-U, as well as those with other forms of chronic anterior uveitis in order to examine if LFP is a useful tool to monitor treatment outcomes and ocular complications.

“LFP represents a potentially easy-to-use tool to compliment formal ophthalmologic SLE and may eventually aid in decreasing ocular complications from JIA-U,” investigators concluded. “The ability to systematically screen patients for JIA-U within the rheumatology clinic holds the potential to unveil signs at their earliest stages, a crucial stride toward not only timely detection but also the prospect of preventing vision loss in JIA patients.”

References

1. ^{Ede K, Shishov M, Wershba E, et al. Screening for juvenile idiopathic arthritis associated uveitis with laser flare photometry in the pediatric rheumatology office: a prospective observational study. Pediatr Rheumatol Online J. 2024;22(1):22. Published 2024 Jan 26. doi:10.1186/s12969-024-00961-9}
2. ^{Sen ES, Ramanan AV. Juvenile idiopathic arthritis-associated uveitis. Best Pract Res Clin Rheumatol. 2017;31(4):517–34. https://doi.org/10.1016/j.berh.2018.01.002.}