Clinical and Imaging Characteristics of Uveitic Optic Disc Edema.

BACKGROUND

We define uveitic optic disc edema as disc edema that is partly or solely associated with uveitis. Our study describes the clinical and imaging characteristics of patients with UDE evaluated at the University of Minnesota.

METHODS

We retrospectively reviewed medical records of patients with UDE seen by a single uveitis provider for a 3-year period. Inclusion criteria were (1) the presence of uveitis and optic disc edema in one or both eyes and (2) optical coherence tomography (OCT) optic disc raster and retinal nerve fiber layer (RNFL) thickness measurements obtained within 2 weeks of one other. Disc raster OCT scans were analyzed to determine retinal height at the disc, focus of thickening, and retinal reflectance. Automated visual field (VF) testing and fluorescein angiography (FA) images were reviewed when available. FA pixel intensity was used to quantify disc fluorescence. Brain MRI scans were reviewed when available.

RESULTS

Fifty-five eyes from 31 patients were analyzed. Patients' ages ranged from 11 to 78 years. Uveitis was present in all anatomic compartments, including retinal vasculitis and choroiditis. A total of 24 patients (77.4%) presented with unilateral disc edema and 7 patients (22.6%) had bilateral disc edema. VF testing was organized into 7 descriptive categories based on severity: normal, scattered/nonspecific defects, blind spot enlargement, central/paracentral defects, nasal/arcuate defects, mixed defects, and generalized depression. Each eye was assigned a primary VF defect type with an associated severity score. Overall, 12.7% of eyes had no/minor VF defects, 40.0% had focal VF defects, and 47.3% had severe VF defects. The average RNFL thickness for all eyes was 149 μm. A statistically significant positive correlation was found between the severity of VF defects and RNFL thickness when the entire group was analyzed (P = 0.042). Structural optic disc raster OCT scans showed no focal thickening (7.3%), isolated nerve fiber layer thickening (5.5%), focal inner-middle thickening (32.7%), and diffuse retinal thickening (54.5%). Disc fluorescence on FA showed a statistically significant positive correlation with maximum disc height (P = 0.0177), but did not correlate with mean reflectance on OCT. We did not detect a relationship between OCT reflectance and maximum disc height. Twenty-nine of 31 patients underwent brain MRI and 5 of these patients with bilateral disc edema showed radiographic features, suggestive of elevated intracranial pressure (ICP). Only 4 of 31 patients had elevated opening pressure of greater than 25 cm H2O by lumbar puncture.

CONCLUSIONS

UDE as a distinct clinical entity has not been well categorized in the literature. A multimodal imaging approach including OCT RNFL, OCT disc raster scan, VF testing, and FA can aid in diagnosis of UDE. OCT disc raster height may be used as a surrogate for FA intensity and may be a useful adjunctive modality for monitoring UDE severity along with serial OCT scans. Increased intracranial pressure was rare in our patient cohort so neuroimaging should not be obtained solely based on optic disc appearance and imaging abnormalities.