To characterize dark adaptation in patients with pseudoxanthoma elasticum, a systemic disease leading to calcification of elastic tissue including the Bruch membrane. In this prospective case-control study, dark adaptation thresholds were measured using a Goldmann-Weekers dark adaptometer. Additional assessments included best-corrected visual acuity testing, contrast sensitivity, low luminance deficit, and vision-related quality of life. 0.001). Two patients were treated with high-dose vitamin A which partially reversed impaired dark adaptation. Patients with pseudoxanthoma elasticum often have impaired dark adaptation. Positive effects of vitamin A supplementation may indicate restricted retinal access of vitamin A through the Bruch membrane as one possible underlying pathogenic factor.