Collagen fibers organized circumferentially around the canal in the peripapillary sclera are thought to provide biomechanical support to the sensitive tissues within the optic nerve head (ONH). Recent studies have demonstrated the existence of a family of fibers in the innermost sclera organized radially from the scleral canal. Our goal was to determine the role of these radial fibers in the sensitivity of scleral canal biomechanics to acute increases in intraocular pressure (IOP). Following the same general approach of previous parametric sensitivity studies, we created nonlinear generic finite element models of a posterior pole with various combinations of radial and circumferential fibers at an IOP of 0 mmHg. We then simulated the effects of normal and elevated IOP levels (15 and 30 mmHg). We monitored four IOP-induced geometric changes: peripapillary sclera stretch, scleral canal displacement, lamina cribrosa displacement, and scleral canal expansion. In addition, we examined the radial (maximum tension) and through-thickness (maximum compression) strains within the ONH tissues. Our models predicted that: 1) radial fibers reduced the posterior displacement of the lamina, especially at elevated IOP; 2) radial fibers reduced IOP-induced radial strain within the peripapillary sclera and retinal tissue; and 3) a combination of radial and circumferential fibers maintained strains within the ONH at a level similar to those conferred by circumferential fibers alone. In conclusion, radial fibers provide support for the posterior globe, additional to that provided by circumferential fibers. Most importantly, a combination of both fiber families can better protect ONH tissues from excessive IOP-induced deformation than either alone.

在视乳头周围巩膜中沿管周向组织的胶原纤维被认为为视神经乳头 (ONH) 内的敏感组织提供生物力学支持。最近的研究表明，巩膜最内侧的巩膜中存在一个纤维家族，这些纤维从巩膜管呈放射状排列。我们的目标是确定这些径向纤维在巩膜管生物力学对眼内压 (IOP) 急性升高的敏感性中的作用。遵循先前参数灵敏度研究的相同一般方法，我们创建了后极的非线性通用有限元模型，在 0 mmHg 的 IOP 下具有径向和圆周纤维的各种组合。然后我们模拟了正常和升高的 IOP 水平（15 和 30 mmHg）的影响。我们监测了四种 IOP 引起的几何变化：视盘周围巩膜拉伸、巩膜管移位、筛板移位和巩膜管扩张。此外，我们检查了 ONH 组织内的径向（最大张力）和全厚度（最大压缩）应变。我们的模型预测：1）径向纤维减少了椎板的后移，尤其是在眼压升高时；2) 径向纤维减少了眼压引起的巩膜周围和视网膜组织内的径向应变；和 3) 径向和圆周纤维的组合使 ONH 内的应变保持在与单独由圆周纤维赋予的应变水平相似的水平。总之，径向纤维为眼球后部提供支撑，除了圆周纤维提供的支撑。最重要的是，