To determine the origin of fundus autofluorescence (AF) patterns in central serous chorioretinopathy (CSC).
Retrospective, observational case series.
We retrospectively studied 30 consecutive eyes of 30 patients with primary CSC using AF and spectral-domain optical coherence tomography (SD-OCT). We measured the AF using the Heidelberg Retina Angiograph with a 488-nm excitation light and a 500-nm cutoff barrier filter and compared the AF patterns with ophthalmoscopy and SD-OCT.
We observed a patchy increased AF in the macular area in 22 eyes (73%), in which the length of the photoreceptor outer segment at the central fovea tended to be longer than the other eyes ( P = .06). The punctate increased AF corresponded to the ophthalmoscopic precipitates in 17 eyes with precipitates. AF significantly ( P = .017) decreased in eyes with a prominent serous retinal detachment (SRD). Eight eyes (27%) had increased AF in the inferior SRD.
The patchy increased AF appears to originate from elongated photoreceptor outer segments in the detached retina. The autofluorescent fluorophores from the photoreceptor outer segments may be concentrated in precipitates or have settled into the inferior SRD.
Central serous chorioretinopathy (CSC), characterized by a serous detachment of the neurosensory retina in the macula, often causes metamorphopsia and micropsia. In the early stage of the disease, most patients have good visual acuity (VA) despite a macular detachment. Many optical coherence tomography (OCT) clinical studies have described the morphologic changes in CSC. Spectral-domain OCT (SD-OCT) showed elongated photoreceptor outer segments in the detached retina. Recently, noninvasive fundus autofluorescence (AF) imaging has been used to study fundus diseases. Spaide and Klancnik theorized that AF emanates not only from the retinal pigment epithelium (RPE) but also the photoreceptor outer segment, which contains a precursor of lipofuscin. In the current study, patients with CSC underwent AF and SD-OCT to determine a correlation between AF patterns and ophthalmoscopic and SD-OCT findings.
We retrospectively studied the fundus AF imaging of 30 consecutive eyes of 30 patients (23 eyes of 23 men, 7 eyes of 7 women) with primary CSC from November 2007 through June 2009 at Gunma University Hospital. The average patient age was 42.2 years (range, 27-64 years). The average duration of symptoms was 1.7 months (range, 1-6 months). All patients underwent a complete ophthalmic examination at second visit, including measurement of the best-corrected VA (BCVA) in decimal notation, slit-lamp biomicroscopy with a noncontact fundus lens (SuperField lens, Volk Optical Inc, Mentor, Ohio, USA), AF (Heidelberg Retina Angiograph [HRA]; Heidelberg Engineering, Dossenheim, Germany), fundus photography, fluorescein angiography (FA), indocyanine green angiography (ICGA) (TRC-50IX with IMAGEnet; Topcon, Tokyo, Japan), and SD-OCT (Cirrus HD-OCT; Carl Zeiss Meditec Inc, Dublin, California, USA). Patients were excluded if they had recurrent or chronic CSC or a history of another fundus disease.
The HRA is a confocal scanning laser ophthalmoscope. AF was excited by the argon blue wavelength (488 nm) used originally for FA. The barrier filter with a cutoff at 500 nm blocks excitation. A series of images was obtained, and an average image was compiled from the original series to reduce noise and provide more detailed images. The confocal detection unit uses a 400-μm pinhole aperture to suppress light from above or below the confocal plane. The scanning field was 30 degrees × 30 degrees. To avoid contaminating the fluorescence with residual dye from previous FA and ICGA examinations, the AF examination was performed before FA and ICGA.
During the SD-OCT examination, we used a 6-mm five-line raster scan, which comprised 4096 axial scans in each line. The spacing between individual line scan was 250 μm. The acquisition time was 0.76 second for a five-line raster scan. We measured the foveal thickness, which is the distance between the internal limiting membrane and the RPE at the central fovea, using the computer-based caliper measurement tool in the SD-OCT system. We also measured the length of the photoreceptor outer segment at the central fovea, which is the distance between the junction between the photoreceptor inner and outer segment (IS/OS) and the tip of the outer segment at the central fovea. To evaluate the retinal thickness and photoreceptor outer segment at the central fovea, we chose the OCT image with the steepest foveal excavation from the five-line raster scan across the foveal area.
We compared the AF patterns in CSC with the features of ophthalmoscopy and SD-OCT. We investigated the correlation between the AF patterns and the foveal thickness and the length of the photoreceptor outer segment at the central fovea using the Mann-Whitney U test.
The average BCVA was 0.93 (range, 0.3-1.5). We observed patchy increased AF in the macular area in 22 of 30 eyes (73%) ( Figure 1 ). The photoreceptor outer segment at the central fovea, the average length of which was 50 μm (range, 15-130 μm) in all eyes, tended to be longer in the eyes with patchy increased AF compared with the other eyes ( P = .06) ( Figure 2 ). In one case with a serous retinal detachment (SRD) that increased in size, the patchy increased AF was in the area of the original SRD, but we observed decreased AF in the new area of SRD progression ( Figures 3 and 4 ). We observed precipitates within the area of the SRD in 17 of 30 eyes. The punctate increased AF corresponded to the ophthalmoscopic precipitates in all 17 eyes ( Figure 1 ). The precipitates were seen as highly reflective subretinal and intraretinal dots in the SD-OCT images. The SRD involved the central fovea in all 30 eyes. The area of the SRD apart from the macular area had decreased AF in 15 of 30 eyes (50%) ( Figures 1, 4, and 5 ). The average foveal thickness was 380 μm (range, 220-690 μm). The AF in the extramacular area of SRD was more decreased in eyes with a thicker fovea ( P = .017) ( Figure 6 ). We observed increased AF in the inferior SRD in eight of 30 eyes (27%) ( Figure 5 ). The patient profiles and AF, SD-OCT, and angiographic findings are shown in the Table 1 .
|Patient No.||Age (Years)||Gender||BCVA||Duration of Symptoms (Months)||Foveal Thickness (μm)||Length of OS (μm)||Patchy Increased AF||Punctate Increased AF||Decreased AF in Extramacular Area of SRD||Increased AF at the Inferior SRD|