Optic disc drusen in Pseudoxanthoma elasticum are associated with the extent of Bruch's membrane calcification

Abstract

Purpose : In Pseudoxanthoma elasticum (PXE), optic disc drusen (ODD) were identified besides outer atrophy and macular neovascularization as a risk factor for vision loss (PMID: 12504737). We now investigated in longitudinal data the frequency, location, extent and progression of ODD in PXE patients, and their association with angioid streak (AS) length and retinal atrophy.

Methods : This retrospective study included patients data from a dedicated PXE clinic at the Department of Ophthalmology, University of Bonn, Germany (observation period from 02/2008 to 7/23). Inclusion criteria were a confirmed diagnosis of PXE based on criteria by Plomp et al. (PMID: 20358627) and a minimum of one follow-up examination. Two readers evaluated the presence, localization, and extent of ODD on fundusautofluorescence (FAF) during baseline and review assessments. Furthermore, AS length and the atrophy area at baseline were quantified on FAF.

Results : A total of 152 eyes from 76 PXE patients (49 female, mean age 51.7 ± 10.4 years) were included. At baseline, 31 of 152 eyes exhibited ODD (i.e., prevalence of 20.4%). Of these, 13 patients had unilateral and 9 patients bilateral ODD. ODD were predominantly localized nasally (48.4%). During the observation period (median 101 months, IQR 66.2 – 135), only one patient developed ODD de novo in one eye, none of the patients showed progression of ODD size. At baseline, the group of patients with ODD had significantly longer AS (median 7,020µm, IQR 4,604 - 9,183) than the group without ODD (median 5,111 µm, IQR 3,992 - 7,020, p<0.001). No association with age or the size of atrophy at baseline was found.

Conclusions : ODD are evident in every fifth PXE patient, which is markedly more frequent than in the general population (~3.4%). The association of more extensive AS length (an indicator of state and extent of ocular calcification in Bruch’s membrane) and ODD suggests that ODD are tightly related to ectopic calcification, possibly affecting the lamina cribrosa. Prospective studies are necessary to determine the impact of ODD on visual function in PXE and whether intraocular pressure – a potential treatment target – modifies this relationship.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1 illustrates that AS are significantly longer in eyes with ODD.

 

Figure 2 shows AS lengths of left and right eyes. Notably, ODD are only visible beyond a distinct AS length of approx. 5,000 µm.

<!--[endif]----> <!--![endif]---->