Fundus autofluorescence in pseudoxanthoma elasticum

Purpose: Pseudoxanthoma elasticum (PXE) is an inherited multisystem disorder of the elastic tissue. Typical ocular manifestations include angioid streaks, peau d'orange, salmon spots, and choroidal neovascularization (CNV). Changes in Bruch membrane lead to progressive atrophy of the retinal pigment epithelium (RPE), secondary CNVs, and visual loss. The RPE-photoreceptor complex was studied in vivo using fundus autofluorescence (FAF) imaging. Methods: Forty-six patients (92 eyes) with PXE were investigated using digital fundus photography, fluorescein angiography (FA), and FAF imaging. The diagnosis was confirmed by multisystem clinical examination, mutation analysis of the ABCC6 gene, and skin biopsy. Results: The mean age of the patient cohort was 50 years (range, 13-74 years), and mean visual acuity was 20/125. Fundus changes typical for PXE were observed in all eyes. Angioid streaks were detected in all but six eyes. Peau d'orange was hardly detectable on FAF, whereas comet tail lesions were apparent. Retinal pigment epithelium atrophy typically was widespread and heterogeneous, located mostly adjacent to angioid streaks or CNVs. Pattern dystrophy-like changes were only found in patients with previous CNV formation in the same or the contralateral eye. Conclusion: Abnormalities of the RPE-photoreceptor complex detected by FAF imaging were more diverse and widespread than expected from conventional fundus imaging. The exhibition of pattern dystrophy-like changes may be a transitional state toward a neovascular event in a subgroup of patients. The extensive alteration of the RPE suggests an important role of pathologic RPE changes in the evolution of visual loss in PXE.