Related Experiment Video
Updated: Oct 13, 2025

Characterization of Sickling During Controlled Automated Deoxygenation with Oxygen Gradient Ektacytometry
Published on: November 5, 2019
Prevalence of Dark without Pressure and Angioid Streaks in Sickle Cell Disease
Background And Objectives:
To investigate the prevalence of areas of dark without pressure (DWOP) and angioid streaks (AS) in patients with sickle cell disease (SCD).
Patients And Methods:
This was a consecutive series of 77 adults with SCD.
Results:
DWOP appeared as multiple patches in 35 of the affected eyes and as a single lesion in 3 eyes. OCT finding demonstrated the ellipsoid layer was hyporeflective in DWOP. AS were identified in six cases (3.9%) and were bilateral in five cases. The prevalence of AS was higher with increasing age, being 67% in the patients older than age 45 years.
Conclusion:
The prevalence of DWOP in adults with SCD is 25% in this study, which is higher than previously reported, and the prevalence of AS is around 4%, which is midway between prior estimates. Recognition of the clinical examination and imaging features of DWOP reduce the need for additional investigation. [.
Related Concept Videos
Multiple Allele Traits
Photoreceptors and Visual Pathways
Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation
Changes in Skin Color: Clinical Perspectives
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...

