Multimodal Imaging Including SD-OCT and Confocal Scanning Laser Ophthalmoscopy for Characterisation of Outer Retinal Pathology in Deferoxamine Maculopathy

Abstract

Purpose: : To investigate the value of multimodal confocal scanning laser ophthalmoscopy (cSLO) for phenotyping macular lesions in patients with deferoxamine maculopathy and to correlate these findings with morphological alterations detected by spectral domain optical coherence tomography (SD-OCT).

Methods: : 14 consecutive thalassemic patients with deferoxamine maculopathy (27 eyes) were included and examined with fundus photography, fundus autofluorescence (FAF), near-infrared autofluorescence (NIA), near-infrared reflectance (NIR) and OCT using a combined and simultaneous SD-OCT-cSLO. Patterns of abnormal FAF (minimal change, focal, speckled and patchy) were correlated with NIR, NIA and SD-OCT scans. Comparison of the size of the affected areas was enabled by digitally superimposing FAF, NIR and NIA images.

Results: : All patients showed FAF, NIR and NIA alterations in the macula. In FAF, areas with increased signal showed different intensity between fovea and parafovea, in NIA there was no significant difference in the intensity of the areas with increased signal. Abnormalities detected with FAF and NIA were more extensive and more severe compared to NIR in 8 of 14 patients. Areas of increased FAF appeared clearly larger compared with increased NIA only in patchy pattern. The different FAF patterns correspond to different changes on SD-OCT scans, including focal thickening of retinal pigment epithelium (RPE) and IS/OS junction layers (minimal change pattern), thick hyper-reflective material between IS/OS junction and RPE in the subfoveal area (focal pattern), disruptions of the IS/OS junction, ONL irregularity and disruptions of external limiting membrane (speckled pattern), and thick, hyper-reflective, dome-shape like lesions that completely upset the outer layers architecture, associated to focal hypereflective granularities in the ONL (patchy pattern).

Conclusions: : SD-OCT in combination with cSLO imaging using FAF, NIA and NIR locates the primary pathology of deferoxamine retinopathy to the RPE-Bruch complex. The findings indicate that multimodal cSLO and SD-OCT imaging of the outer retina allows for screening of patients at risk for deferoxamine toxicity.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • drug toxicity/drug effects • ipofuscin