Dissociation Between Progressive Retinal Nerve Fibre Layer Thinning and Perimetric Change in Multiple Sclerosis-Associated Uveitis

Background and Objective: Uveitis occurs more frequently in multiple sclerosis (MS) than in the general population and is often clinically silent. We determined the anatomical types and visual field defect patterns of MS-associated uveitis, and compared the 24-month course of peripapillary retinal nerve fibre layer (pRNFL) thickness and perimetric mean defect (MD) between symptomatic and asymptomatic patients.

Methods

Retrospective longitudinal study of 32 MS patients with uveitis diagnosed by SUN criteria, none with prior optic neuritis. Cirrus HD-OCT and Octopus 900 N1 perimetry were performed at three annual visits. Linear mixed models accounted for inter-eye correlation; annualized rates of change were calculated.

Results

Uveitis was identified in 32 of 852 referred patients (3.8%). Intermediate uveitis predominated (59.4%). Fourteen patients (43.8%) were asymptomatic, yet visual field defects were present at baseline in 84.4% of the full cohort, despite generally preserved visual acuity. pRNFL declined in every subgroup (p < 0.0001), including non-inflamed fellow eyes. Within the bilateral uveitis subgroup (n = 24), thinning was faster in asymptomatic than symptomatic patients (−2.75 vs. −1.40 µm/year; Mann–Whitney p = 0.033), persisting in direction and magnitude after exclusion of three patients with cystoid macular oedema, although significance in that restricted sample was test-dependent (Mann–Whitney p = 0.054); the corresponding MD difference did not persist (p = 0.292). These symptom-based comparisons were exploratory.