Color FAF imaging - A novel diagnostic Biomarker for Posterior Uveitis Lesions

Spectrally resolved fundus autofluorescence can be used as a novel diagnostic biomarker for Posterior Uveitis lesions states a study that was published in the journal Scientific Reports. 

It is quite a challenge to clinically discriminate posterior uveitis lesions as most of the posterior uveitis lesions are not clearly understood. Spectrally resolved Fundus autofluorescence (Color-FAF) is a novel, non-invasive method that has been used in detecting various retinal lesions. Hence, researchers from the University Hospital Bonn, Department of Ophthalmology, Germany, conducted a study to evaluate Color-FAF imaging as a diagnostic imaging biomarker in different posterior uveitis entities. An exploratory, retrospective, cross-sectional study was conducted on patients with posterior uveitis. Green (GEFC) and red emission fluorescent components (REFC) of retinal and choroidal lesions in posterior uveitis were investigated to facilitate discrimination of the different entities. 

Optical coherence tomography, Color fundus photography, and spectrally resolved fundus autofluorescence (Color-FAF) was used to image the eyes. Retinal/choroidal lesions' intensities of GEFC (500–560 nm) and REFC (560–700 nm) were determined, and intensity-normalized Color-FAF images were compared for birdshot chorioretinopathy, ocular sarcoidosis, acute posterior multifocal placoid pigment epitheliopathy (APMPPE), and punctate inner choroidopathy (PIC). Possible confounders were revealed using Multivariable regression analyses. 

Key Findings: 

• 76 eyes of 45 patients were included with a total of 845 lesions.
• Mean GEFC/REFC ratios were 0.82 ± 0.10, 0.92 ± 0.11, 0.86 ± 0.10, and 1.09 ± 0.19 for birdshot chorioretinopathy, sarcoidosis, APMPPE, and PIC lesions, respectively, and were significantly different in repeated measures ANOVA (p < 0.0001).
• Non-pigmented retinal/choroidal lesions, macular neovascularizations, and fundus areas of choroidal thinning featured predominantly GEFC, and pigmented retinal lesions predominantly REFC.
• Color-FAF imaging revealed the involvement of both, short- and long-wavelength emission fluorophores in posterior uveitis.
• The GEFC/REFC ratio of retinal and choroidal lesions was significantly different between distinct subgroups. 

Thus, the researchers concluded that for differentiation of posterior uveitis lesions spectrally resolved fundus autofluorescence (Color-FAF) can be remarkably used as a new non-invasive diagnostic tool. 

For further reading: https://doi.org/10.1038/s41598-022-18048-4

Wintergerst, M.W.M., Merten, N.R., Berger, M. et al. Spectrally resolved autofluorescence imaging in posterior uveitis. Sci Rep 12, 14337 (2022).