Patterns of structural and functional changes in the retina and choroid in acute posterior multifocal placoid pigment epitheliopathy

Abstract

The study analyzes the patterns of pathological changes in the retina and choroid in acute posterior multifocal placoid pigmented epitheliopathy (APMPPE). The results of the examination of two patients with bilateral APMPPE were analyzed retrospectively. The examination had included visometry, tonometry, static perimetry, autofluorescence, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). The analysis revealed signs of the inflammatory nature of the choriocapillary vascular wall lesion with the development of their local obstruction and, consequently, local ischemia of the retinal pigment epithelium (RPE) and the outer layers of the retina in the acute period. At the same time, partial destruction of the ellipsoid zone, uneven hyperreflectivity of the RPE with local areas of its elevation and impaired connection with photoreceptors were revealed. The subsequent restoration of choriocapillaris perfusion was accompanied by significant restoration of the functional and structural state of the RPE over a larger area, as well as partial restoration of the ellipsoid zone of the retina. Two years after the onset of the disease, separate areas of defects of the RPE and the outer retina were observed, coinciding in localization with zones of severe circulatory deficiency at the level of choriocapillaris in the acute stage. According to the results of multimodal imaging, choriocapillaritis is the initial link in the pathogenesis of APMPPE. The change in RPE and the outer retina is secondary to the local ischemic zones due to choriocapillaris nonperfusion. The nature of RPE change over a larger area manifests as a functional structural disorder, with the potential for recovery in case of choriocapillaris reperfusion.