Uveitic Macular Edema Outcomes by Subtype: Results of a Randomized Controlled Trial

Abstract

Purpose: To compare outcomes of uveitic macular edema from a randomized controlled trial (RCT) and assess differences based on subtype. To determine the expected change in visual acuity based on percent change in macular thickness.

Methods: A secondary analysis of macular edema outcomes was conducted from a RCT comparing methotrexate and mycophenolate mofetil for non-infectious intermediate, posterior or pan- uveitis. Patients underwent optical coherence tomography (OCT) scans monthly for 6 months. Macular edema was defined as a central subfield thickness greater than 2 standard deviations above the normative retinal thickness. Subtype was determined by OCT fluid patterns and categorized as cystoid, diffuse or serous. 6-month outcomes included resolution, defined as normal macular thickness and absence of fluid on OCT; improvement, defined as a 20% reduction in retinal thickness; and percent change in retinal thickness. Mixed effects logistic and linear regression models were used to account for within-person correlation between eyes.

Results: 33 out of 80 enrolled patients had macular edema at baseline, and 25 completed follow-up. Edema resolution was achieved in 3/9 (33%) eyes with cystoid edema, 1/4 (25%) eyes with diffuse edema, and 20/22 (91%) eyes with serous retinal detachments (SRD) (p=0.0002). SRDs, due to Vogt-Koyanagi Harada (VKH) in 86% of cases, were more likely to resolve compared to cystoid (p=0.004) and diffuse (p=0.02) edema. All eyes with macular edema that improved also resolved, except 1 eye with a SRD. There was no detectable difference in resolution or improvement of macular edema or percent change in retinal thickness based on uveitic anatomic location or treatment arm. The median change in visual acuity was -0.58 logMAR [IQR -0.76, -0.38], equivalent to a 30-letter improvement, for eyes with resolved edema, and 0 [IQR -0.42, 0.34], equivalent to no improvement, for unresolved eyes (p<0.0001). A 20% decrease in retinal thickness approximated to an 8-letter [95% CI: 5, 10 letters] improvement in visual acuity.

Conclusions: SRDs, especially those secondary to VKH, respond well to antimetabolite therapy, whereas cystoid and diffuse macular edema do not reliably resolve and may require more aggressive therapy. The relationship our study found between change in retinal thickness and change in visual acuity corroborates results from the Multicenter Uveitis Steroid Treatment trial.

Keywords: 746 uveitis-clinical/animal model • 462 clinical (human) or epidemiologic studies: outcomes/complications • 585 macula/fovea