Bruch’s Membrane Contributes to the Structural Integrity of the Human Eye

This study investigates the biomechanical contribution of Bruch’s membrane (BM) to the overall structural integrity of the human eye. Using human cadaveric globes (n = 23), the authors quantified rupture thresholds and tensile moduli of the Bruch’s membrane–choriocapillaris (BMC) complex compared to adjacent sclera. Pressure inflation tests demonstrated that the BMC can withstand intraocular pressures up to 98.0 ± 21.4 mmHg before rupture, highlighting its mechanical robustness despite being only 10.3 ± 2.1 µm thick. Uniaxial tensile testing showed the BMC tangent modulus (3.0–9.7 MPa) was 2.8–3× higher than that of the sclera (1.1–5.7 MPa) across 0.01–0.03 strain, suggesting that the BMC contributes 6–8% of total ocular wall strength despite its thinness. These findings demonstrate that Bruch’s membrane provides substantial reinforcement to posterior globe integrity and may play a previously underappreciated role in glaucoma, pathological myopia, and staphyloma development.