Purpose
Vogt-Koyanagi-Harada disease (VKHD), an autoimmune aggression against melanocytes, is characterized by an acute bilateral diffuse choroiditis with extraocular manifestations. Disease inflammation and therapy are monitored based on clinical and fundus imaging, i.e. fluorescein angiography and indocyanine green angiography. Fundus autofluorescence imaging (FAF) may indicate retinal pigment epithelium (RPE) functional and metabolic changes: blue autofluorescence (BL-FAF) may indicate lipofuscin abnormality; near-infrared light (NIR-FAF) may indicate melanin and melanin compounds abnormalities. The present study aimed to evaluate fundus autofluorescence imaging in patients with VKHD during a 12-month follow-up from disease onset.
Methods
Retrospective longitudinal study including 9 patients (18 eyes) with VKHD, diagnosed according to Revised Diagnostic Criteria, followed from disease onset for a minimum 12 months. All patients were treated with methylprednisolone 3-day pulsetherapy followed by oral prednisone (1mg/kg/day) with a slow 12-15 month tapper. Fundus autofluorescence (BL-FAF and NIR-FAF) was carried out as part of a multimodal fundus imaging analysis (Spectralis HRA+OCT, Heidelberg Engineering, Germany) alongside functional exams (RETI-port system; Roland Consult, Germany). Images obtained at M0, M1, M3, M6 and M12 were analysed by two readers. Autofluorescence changes were classified into hyper (Hy) and hypo (Ho) changes and into the patterns: diffuse (D), plaque (PL), granular (G) and reticular (R). The study was approved by the Institutional Ethics Committee.
Results
Nine patients (7F/2M), with median age of 33 y/o and median time to treatment of 12 days (3-46), were included. FAF at M1 disclosed two distinct patterns, a mild granular Hy-FAF with progressive return to normal (mild FAF) and a exuberant plaque and/or diffuse Hy-FAF with or not plaque Ho-FAF (severe FAF) (Figure). According to this classification, 8 eyes had mild FAF and 10 eyes had severe FAF. Severe FAF group had thicker subfoveal choroidal thickness at M1 (p=0.017); had more subretinal neovascular membrane (p=0.034) and more deranged full-field electroretinogram parameters (kappa=0.667; CI95%0.324-1.000) at M12.
Conclusions
FAF pattern at M1 can be a method for detection of severe RPE abnormalities and may be useful for managing treatment.