Aim: Acute idiopathic maculopathy (AIM) is a rare inflammatory macular disease that occurs in young patients and leads to severe transitional visual loss, central scotoma, and serous macular detachment, often following flu-like disease. Although clinical characteristics have been well described, little information is available on new multimodal imaging and functional evaluation. Our aim was to analyse the structural and functional characteristics of AIM, therefore providing new insights into the clinical course of this disease.
Hypotheses: We hypothesized that: (1) different fundus autofluorescence (FAF) patterns may be the result of different stages of the disease, which correspond to characteristic morphological and functional features in AIM; (2) outer retinal layers gradually restore, with recovery of visual acuity when the ellipsoid zone restores; (3) during the course of the disease choroidal thickness decreases and the choroidal vascularity index increases; (4) retinal thickness correlates with improvement of functional features.
Methods: Retrospective multicenter case series of 16 patients diagnosed with AIM. We reviewed the medical records and multimodal imaging including color fundus photography, optical coherent tomography (OCT) and FAF. Retinal function was evaluated with best corrected visual acuity (BCVA), microperimetry, and multifocal electroretinography (mfERG). As controls, subjects with the same age and sex without signs of pathologic ocular changes were included.
Results: Four sequential patterns of FAF were found corresponding to a specific appearance of OCT and color fundus photography during the course of the disease. The relationship of these patterns with the duration of the disease, BCVA and OCT features was significantly different, including an improvement in retinal function measured by microperimetry and mfERG. Mean baseline BCVA was 0.63±0.54 logMAR (Snellen equivalent 20/85) and was significantly correlated with the ellipsoid zone disruption seen in OCT. Recovery of visual acuity correlated with gradual restoration of outer retinal bands and took on average 4 months. Eyes with AIM were characterized by choroidal thickening and decreased choroidal vascularity index in the acute phase, which decreased and increased in the resolved phase, respectively. The retinal thickness analysis showed the involvement of different retinal layers during the course of the disease that were associated with functional improvement, including BCVA, microperimetry and mfERG.
Conclusions: This study, which constitutes the largest and longest longitudinal study of AIM to date, presents an original scientific contribution to knowledge of the characteristic structural and functional features of AIM. On the basis of which, we were first to propose the staging of AIM. The findings of this study further our understanding of the pathogenesis of this rare disease and help clinicians in the correct diagnosis and patient support.
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