Choroidal changes associated with Bruch membrane pathology in pseudoxanthoma elasticum

Area of Science:

• Ophthalmology
• Genetics
• Pathology

Background:

• Pseudoxanthoma elasticum (PXE) is a genetic disorder affecting elastic tissue, potentially impacting ocular structures.
• Bruch membrane alterations are a hallmark of PXE, but their specific effects on the choroid require further elucidation.

Purpose of the Study:

• To investigate the impact of Bruch membrane pathology on choroidal thickness and structure in patients with PXE.
• To correlate choroidal changes with disease severity and specific manifestations like choroidal neovascularization (CNV) and chorioretinal atrophy.

Main Methods:

• A monocenter, cross-sectional, prospective case series involving 51 patients with PXE (61 eyes) and 54 control subjects.
• PXE patients were categorized into three groups based on the presence of CNV or chorioretinal atrophy.
• Choroidal thickness was measured using enhanced-depth imaging optical coherence tomography (EDI-OCT).

Main Results:

• Significantly reduced subfoveal choroidal thickness was observed in all PXE groups compared to controls (p < 0.001).
• Choroidal thickness reduction was most pronounced in PXE patients with chorioretinal atrophy only.
• Structural changes included apparent loss of small choroidal vessels, with greater differences near the optic disc.

Conclusions:

• Bruch membrane pathology in PXE is associated with significant choroidal alterations, worsening with disease progression.
• These findings suggest a role for Bruch membrane in maintaining choroidal homeostasis.
• Alterations in Bruch membrane may contribute to the development of CNV and geographic atrophy, similar to age-related macular degeneration.