Blue-light fundus autofluorescence imaging of pigment epithelial detachments

Abstract

Background: Pigment epithelial detachments (PEDs) occur in association with various chorioretinal diseases. With respect to the broad clinical spectrum of PEDs we describe fundus autofluorescence (FAF) characteristics of PEDs.

Methods: Ninety-three eyes of 66 patients (mean age 71.9 ± 11.1) with uni- or bilateral PED ( ≥ 350 µm) were included in a retrospective cross-sectional study. PEDs were secondary to age-related macular degeneration (n = 79), central serous chorioretinopathy (n = 7), polypoidal choroidal vasculopathy (n = 2), pattern dystrophy (n = 3) or idiopathic PED (n = 2). FAF images were recorded using confocal scanning laser ophthalmoscopy (488 nm excitation wavelength, detection of emission >500 nm). Diagnosis of PED was confirmed using spectral-domain optical coherence tomography. A qualitative FAF grading system was established, and grading was performed by two independent readers.

Results: PEDs showed highly variable characteristics on FAF imaging. FAF within the area of PED was found to be irregular/granular (n = 59, 63.4%), increased (n = 28, 30.1%), decreased (n = 3, 3.2 %), or normal (n = 3, 3.2%). Accompanying FAF changes included condensation of macular pigment (n = 67, 72.0%), focally increased FAF at the PED apex (n = 14, 15.1%) or elsewhere (n = 52, 55.9%), focally decreased FAF (n = 23, 24.7%), a cartwheel-like pattern (n = 10, 10.8%), a doughnut sign (n = 6, 6.5%), and a halo of decreased FAF encircling the PED (completely n = 20, 21.5% or incompletely n = 20, 21.5%).

Conclusions: PEDs show a variety of abnormal patterns on FAF imaging. These changes in FAF signals may be secondary to morphological and metabolic alterations within corresponding retinal layers and do not necessarily correspond with the underlying PED subtype or a specific pathology.

Fig. 1. Fundus autofluorescence (FAF) images showing the four main types of FAF changes within the area of pigment epithelial detachment (PED): A Irregular/granular FAF changes. B Increased FAF. C Decreased FAF. D Normal FAF.

A FAF image of a 78-years-old female with mixed-type PED due to neovascular age-related macular degeneration (AMD) showing irregular/granular FAF changes with both, increased FAF and spots of decreased FAF. SD-OCT shows an optically empty cleft under the vascularized part of the PED, sloughed RPE, and intraretinal hyperreflective foci. B Drusenoid PED with increased FAF within the area of PED in a 56-years-old patient with AMD. Apart from a large, subfoveal PED, there are soft confluent drusen and smaller PEDs, which are also characterized by increased FAF. There is no evidence of macular neovascularisation in fluorescein angiography. C This FAF image shows decreased FAF in the area of a PED (76-years-old male patient with mixed macular neovascularisation due to AMD). SD-OCT reveals SRF at the margin of the PED as well as overlying the PED. D FAF image of a 41-years-old male patient with central serous chorioretinopathy. The small juxtafoveal serous PED does not show essential FAF changes, whereas in the lower part of the FAF image increased FAF demarcates an area with SRF resulting from an expansile dot in FA. In SD-OCT overlying retinal layers are intact. White wedges mark the PED dimension in FAF images. White arrows in FAF images mark the position of the SD-OCT scan. Corresponding FA and SD-OCT scans are shown below the FAF images.

Fig. 2. Facultatively accompanying fundus autofluorescence (FAF) changes within the area of pigment epithelial detachment (PED): A Condensation/displacement of macular pigment. B Focally increased FAF. C Focally decreased FAF due to RPE atrophy. D Cartwheel-like FAF pattern. E Doughnut sign. F Halo of decreased FAF.

A FAF image of a mixed PED (serous-vascularized) of a 57.9-years-old female with macular neovascularization type 1 due to age-related macular degeneration (AMD). The inferior part of the PED presents with increased FAF, whereas FAF is decreased within the superior portion of the PED (in presence of subretinal fluid, not shown). The normal macular pigment distribution seems to be disturbed especially in presence of increased FAF. B Focally increased FAF may occur within the area of PED, at the apex, and elsewhere. In this left eye of a 68.9-years-old male with a large serous PED due to non-neovascular AMD focally increased FAF is associated with anterior RPE migration and an acquired vitelliform lesion in OCT. C Amongst the irregular/granular FAF pattern in this eye of a 63.9-years-old male patient there is an area with decreased FAF due to RPE atrophy in presence of a drusenoid PED. Fluorescein angiography (not shown) did not reveal any neovascularization. Besides intraretinal degenerative cysts, SD-OCT shows sloughed RPE, intraretinal hyperreflective foci, and basolateral RPE shedding. D FAF image of a 78.2-years-old female with drusenoid PED showing a cartwheel-like increased FAF pattern with centrifugal lines of increased FAF. E In case of this drusenoid PED (75.5-years-old female with intermediate AMD) FAF is focally decreased at the PED apex (“doughnut sign”) despite OCT shows anterior RPE migration. F The margin of this large serous PED is delineated by decreased FAF (74.9-years-old female patient with polypoidal choroidal vasculopathy). There is some FAF blurring according to anterior opacities.