Optical Coherence Tomography (OCT) Features of Inactive Multifocal Choroiditis with Panuveitis and Punctate Inner Choroidopathy (MFCPU/PIC) Lesions.

PURPOSE: To identify optical coherence tomography (OCT) biomarkers of inactive multifocal choroiditis with panuveitis and punctate inner choroidopathy (MFCPU/PIC) and to compare them with atrophic chorioretinal scars secondary to inflammatory and infectious mimickers.

DESIGN: Cross-sectional observational study.

SUBJECTS: Fifty-nine patients with inactive chorioretinal atrophic lesions, including 27 patients (57 lesions) with MFCPU/PIC and 32 patients (49 lesions) with non-MFCPU/PIC etiologies (sarcoidosis, tuberculosis, syphilis, serpiginous choroiditis, APMPPE, birdshot chorioretinopathy, and ocular toxoplasmosis), evaluated at Luigi Sacco Hospital (Milan, Italy).

METHODS: All patients underwent multimodal imaging including color fundus photography, near-infrared reflectance, fundus autofluorescence, and spectral-domain OCT (SD-OCT), with additional high-resolution OCT (HR-OCT). Lesions were randomly sampled (maximum three per eye). Quantitative OCT measurements included retinal pigment epithelium atrophy size (RPE-AS), Bruch's membrane defect size (BrM-HS), and choroidal thickness coefficient (CTC). Structural alterations across retinal layers were graded. Regression models with cluster-robust standard errors were used to account for intra-patient clustering.

MAIN OUTCOME MEASURES: Frequency of Bruch's membrane (BrM) disruption and inner retinal layer herniation; relationship between RPE-AS and BrM-HS; choroidal involvement; agreement between SD-OCT and HR-OCT.

RESULTS: BrM disruption was observed in 94.7% of MFCPU/PIC lesions compared with 6.1% of controls (p < 0.001), remaining strongly associated with MFCPU/PIC independently from age and RPE-AS. Inner nuclear layer (INL) herniation was significantly more frequent in MFCPU/PIC lesions (57.9% vs 4.3%, p < 0.001). RPE atrophy was present in all lesions, while BrM defects were consistently smaller and concentrically localized within areas of RPE atrophy. RPE-AS and BrM-HS were positively correlated (&#x3b2;&#x202f;=&#x202f;0.36, p&#x202f;=&#x202f;0.002). MFCPU/PIC lesions demonstrated lower CTC values (p < 0.001) and more frequent focal choroidal excavation. Agreement between SD-OCT and HR-OCT was good (&#x3ba;&#x202f;=&#x202f;0.60), with no added diagnostic yield of HR-OCT.

CONCLUSIONS: Bruch's membrane disruption and inner retinal layer herniation into focal choroidal excavation are highly characteristic OCT features of inactive MFCPU/PIC. These findings may facilitate diagnosis in the absence of active inflammation and support a distinctive lytic inflammatory mechanism involving the outer retina, BrM, and choroid.