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In patients with juvenile idiopathic arthritis (JIA)-associated anterior uveitis, secondary open angle glaucoma and ocular hypertension frequently develop during the clinical course of disease.1 Appropriate topical antiglaucomatous treatment should be started immediately after diagnosis in order to prevent the occurrence of irreversible optic neuropathy. The main underlying causes of elevated intraocular pressure (IOP) include congestion of the trabecular meshwork due to cells and debris and morphological changes in the outflow pathway.2 As screening for glaucoma in these patients can be challenging due to their young age, it is helpful to know when elevated IOP first occurred with respect to disease activity.
Patients and methods
We retrospectively analysed the time of occurrence of elevated IOP in 30 JIA patients during the course of uveitis. Groups were defined as (1) during inactivity of inflammation (≤0.5 anterior chamber cells according to the Standardization of Uveitis Nomenclature classification),3 (2) during acute inflammation or (3) after intraocular surgery. IOP was measured by Goldmann applanation tonometry. The first instance of elevated IOP was documented if IOP was ≥24 mm Hg at two consecutive measurements. All patients with suspicion of steroid response were excluded in this study. Steroid response was defined as an increase of ≥6 mm Hg related to any kind of corticosteroid treatment at any time during the follow-up period.4 Patients with a first IOP elevation after 6 weeks with a continuing topical or systemic steroid maintenance dosage, or after 3 months after orbital floor triamcinolone were included. Laser flare measurements were performed using the KOWA FM-500 device (Kowa Company, Electronics and Optics Division, Tokyo, Japan). Secondary outcome measures included age at diagnosis of JIA, uveitis and glaucoma.
Results
Overall 24 girls and 6 boys (average age 9.7 years at first diagnosis of elevated IOP) involving 42 eyes affected with JIA-associated anterior uveitis were included. All eyes were categorised as open angle glaucoma. Another 10 patients were excluded due to assumed steroid response. Age of JIA and uveitis diagnosis did not differ significantly from the other groups. The uveitis duration at first IOP elevation was shorter with 2.5±1.17 years and was not statistically significant. All patients received at least one drop of topical corticosteroid therapy at the first instance of IOP elevation. All patients had undergone systemic immunosuppressive therapy (methotrexate, azathioprine or cyclosporine A) at some time during the course of disease. First IOP elevation was documented during episodes of inactive inflammation in 25 eyes, during active inflammation in 10 eyes and after recent intraocular surgery in another 7 eyes (table 1).
Patient characteristics regarding age at arthritis and uveitis diagnosis, first IOP elevation, laser flare photometry (Kowa FM-500, Kowa Company, Tokyo, Japan) and IOP level at the time elevated IOP (≥24 mm Hg) was first detected
Surgery included pars plana lensectomy (four eyes), cataract extraction (two eyes) and intravitreal triamcinolone injection (one eye). Due to restricted compliance, glaucomatous visual fields could not be detected in any of the 20 eyes tested. In 10 eyes, biomicroscopic assessment of the optic disc was impaired due to swelling (6 inactive, 3 active and 1 recent eye surgery group), while of the remaining, 25 had no optic neuropathy. In those seven (five inactive, one active and one recent eye surgery group) with optic neuropathy, no correlation to other ocular complications or length of uveitis could be detected. Mean time between achieving inactivity and first detection of elevated IOP was 4.5±5.3 months (median 2.0 months). Mean time between previous surgery and first detection of elevated IOP was 1.15±1.23 years (median 0.5 years). Age at JIA diagnosis was comparable among groups. Patients with first IOP elevation during an active episode were significantly younger at uveitis diagnosis. A positive correlation was found between early onset of uveitis and early occurrence of first IOP elevation (p=0.05, R=0.29). The IOP peaks did not differ between the groups.
Discussion
Our data show that in the majority of eyes with JIA-associated anterior uveitis and secondary elevated IOP, the IOP increased shortly after achieving inflammatory inactivity. This has also been documented in patients with Behcet's disease, while in other subgroups of non-infectious uveitis patients (sarcoidosis, Vogt–Koyanagi–Harada syndrome and idiopathic uveitis), IOP often first increased predominantly in the phase of active inflammation in the anterior chamber.5 In another recent study, 14 JIA patients developed IOP increase and still had active inflammation. No information on recent eye surgery or inflammatory activity at the first instance of IOP elevation was given, which might explain the difference with our findings.6 Therefore, congestion of the trabecular meshwork by cells or debris seems to be responsible only in a minority of JIA uveitis cases. We speculate that IOP increases in the inactive phase as a result of normal ciliary body production and decreased uveoscleral outflow compared with active inflammation, in addition to reduced trabecular outflow due to morphological changes.7 8 In patients in whom IOP increases after intraocular surgery, a combination of pathogenic factors, including trabecular meshwork congestion with inflammatory cells, might be responsible. An influence of steroids to further increase the IOP in all groups cannot entirely be ruled out.
JIA patients are at a particularly high risk for developing ocular hypertension and secondary open angle glaucoma. According to our data, IOP screening appears to be highly important after achieving uveitis inactivity to prevent functional damage in this challenging and difficult-to-treat uveitis complication.
Footnotes
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.