Spectral Domain OCT And Autofluorescence In Active Posterior Uveitis

Abstract

Purpose: : To describe the spectral domain optical coherence tomography (SD OCT) and autofluorescence characteristics of posterior uveitis during the active phase of inflammation.

Methods: : A total of 16 posterior uveitis patients had fundus photography, fundus autofluorescence (FAF) imaging and Spectralis SD OCT. Additional studies including fluorescein angiography (FA), indocyanine green angiography (ICG), and microperimetry (MP-1) testing were obtained for some patients. Posterior uveitides included punctate inner choroidopathy (5), ampiginous (2), non-specific posterior uveitis (2) and serpiginous choroiditis (SC) (7). Three patients with SC had active lesions and follow up imaging for 5 to 8 months.

Results: : For acutely active SC lesions, SD OCT showed loss of definition in the outer retina including the outer nuclear layer (ONL), external limiting membrane (ELM), and inner segment/outer segment junction (IS/OS). The involved neurosensory retina was thickened, and enhanced depth imaging SD OCT also showed thickening of the underlying choroid. In some cases, recurrent lesions were associated with subretinal fluid. A "waterfall effect" due to increased reflectivity of the retina was also observed in the areas of active lesions. FAF hyperautofluorescence did not occur until a few weeks after an active lesion was detected by SD OCT as corroborated by clinical exam, FA and/or MP-1. Resolution of active lesions was associated with thinning or loss of the ONL, dipping of the outer plexiform layer towards the RPE, disruption of the ELM and IS/OS, and enhancement of the "waterfall" effect on SD OCT. The inactive scarred lesions showed loss of the outer retinal layers as well as the photoreceptors and persistence of the "waterfall" effect without choroidal thickening. On FAF, the areas of RPE damage eventually became hypoautofluorescent. MP-1 testing showed areas of decreased sensitivity corresponding to the active lesions on SD OCT which improved in some cases as the lesions became inactive.

Conclusions: : SD OCT can detect early changes in the deep retina and choroid in active SC while FAF hyperautofluorescence occurs later. Choroidal thickening and decreased sensitivity on microperimetry correspond to active lesions detected clinically and on SD-OCT. Both FAF and SD OCT are noninvasive, sensitive methods that can be useful to monitor recurrences and follow treatment response in posterior uveitis.

Keywords: uveitis-clinical/animal model • imaging/image analysis: clinical • chorioretinitis