This thesis is dedicated to my grandparents

emnants of streaks persisted at the periphery of such lesions, suggesting that angioid streaks
are persistent throughout the natural history of the disorder.
Although peau d'orange has previously been described as granular stippling on AFI 26 , the
pigment alterations seen on colour imaging did not yield any significant difference in fundus
autofluorescence in the present study. On infrared imaging, we observed the peau d'orange to be
more widespread than originally described, and present throughout the posterior pole and the
whole midperiphery. This might be due to pure technical reasons, since IR imaging is less
compromised by macular lutein and zeaxanthin pigment. This observation further strengthened
our belief that this technique has a significant higher sensitivity in detecting changes of the outer
retinal layers compared to colour fundus imaging.
We found IR imaging to be also superior in visualising comets and comet tails in
combination with RF imaging. Even comets barely visible or absent on colour pictures could be
seen with IRI and RFI. In contrast, on AFI not all comets were recognised. If comets and comet
tails indeed are the only pathognomonic ocular characteristic of PXE 7 , they are of significant
diagnostic value, especially in young patients in whom angioid streaks are often not yet present
(fig. 14). Since they can also occur in carriers, a thorough skin evaluation and molecular analysis
of the ABCC6 gene is indicated when such lesions are detected.
Drusen of the optic disc seem to be more common in PXE than in the general
population 27 . AFI proved to be efficient in detecting these optic disc drusen which were confirmed
on ultrasound. It may be assumed that a common process of abnormal mineralisation might be
the predisposing factor both for drusen of the optic nerve head and for comets and comet tails.
In end-stage fundi, increased autofluorescence in the junctional zone around atrophic
areas may represent areas of future RPE atrophy 11 . However, these findings are of limited
predictive value. The standard examinations to detect subretinal neovascularisation in such
patients remain fluorescein and indocyanine green angiography.
Conclusion
Because of extensive variability in clinical severity, the diagnosis of PXE is often delayed
until ophthalmological complications occur. Since novel ophthalmic therapeutic agents, such as
different agents with anti-VEGF action, have become available, the need for an early diagnosis
has become even more important. The present study showed that infrared, red-free and
autofluorescent imaging are of significant clinical relevance in PXE, as they contribute to
improved imaging quality and hence early diagnosis and more adequate follow-up. Serial,
prospective investigations of patients with these techniques can give us important clues as to the
natural history of this complex disorder. As such, we consider them part of the standard
evaluation of novel and known PXE patients and their family members.
References
1. Neldner KH. Pseudoxanthoma Elasticum. Clin Dermatol 1988; 6: 83-92.
2. Hu X, Plomp AS, van Soest A et al. Pseudoxanthoma Elasticum: a clinical,
histopathological and molecular update. Surv Ophthalmol 2003; 48: 424-438.
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