Compression of the optic chiasm causes an optic neuropathy that may be associated with reversible visual loss often immediately following surgical decompression. While the precise pathogenesis of retinal ganglion cell impairment and eventual death remains poorly understood, a number of putative mechanisms may play a role. In this article we review the evidence supporting various stages of visual loss and recovery in chiasmal compression. These include conduction block, demyelination, ischemic insult, and retrograde and anterograde degeneration. We also describe novel advances in magnetic resonance imaging with specialized modalities such as diffusion tensor imaging have provided further information to explain the underlying mechanism of visual loss. Functional measures including electrophysiology are time-consuming but have shown moderate prognostic ability. Optical coherence tomography has provided novel new biomarkers for predicting outcome following surgical decompression. Both retinal nerve fiber layer thickness and ganglion cell complex thicknesses have shown to have excellent predictive power. Such advances serve to inform patients and clinicians of pre-operative factors that predict the extent of visual recovery following medical or surgical treatment of para-chiasmal lesions.

视神经交叉的压迫会引起视神经病变，通常与手术减压直接相关，可能与可逆性视力丧失有关。尽管对视网膜神经节细胞损伤和最终死亡的确切发病机理仍知之甚少，但许多推测的机制可能起作用。在本文中，我们回顾了支持在大眼压迫中视力丧失和恢复的各个阶段的证据。这些包括传导阻滞，脱髓鞘，缺血性损伤以及逆行和顺行变性。我们还描述了磁共振成像的特殊技术，如弥散张量成像的特殊方式的新进展，提供了进一步的信息来解释视力丧失的潜在机制。包括电生理学在内的功能性措施非常耗时，但已显示出中等程度的预后能力。光学相干断层扫描技术为预测手术减压后的结局提供了新的新生物标记。视网膜神经纤维层厚度和神经节细胞复合物厚度均显示出极好的预测能力。这些进展有助于告知患者和临床医生术前因素，这些因素可预测在进行化学治疗或手术治疗后，双眼裂的病灶后视觉恢复的程度。