Throughout the body, damage to peripheral nerves normally involved in nociception may produce a constellation of symptoms—including irritation, itchiness and pain. The neurobiological processes involved in corneal symptoms of dry eye (DE) and neuropathic corneal pain (NCP) have not been clearly considered in terms of nociceptive processing. The conventional underlying presumption is that a labelled line principle is responsible; that these distinct perceptions are hard coded by primary afferent inputs to the central nervous system. This presumption oversimplifies the neurobiological mechanisms underlying somatosensory perception. The labelled line perspective that DE represents a chronic pain condition does not make intuitive sense: how can an eye condition that is not painful in most cases be considered a pain condition? Does not chronic pain by definition require pain to be present? On the other hand, NCP, a term that clearly denotes a painful condition, has historically seemed to resonate with clinical significance. Both DE and NCP can share similar features, yet their differentiation is not always clear. As is often the case, clinical terms arise from different disciplines, with DE evolving from ophthalmological findings and NCP inspired by pain neurophysiology. This review evaluates the current definition of these terms, the rationale for their overlap and how the neurophysiology of itch impacts our understanding of these conditions as a continuum of the same disease. Despite the complexity of nociceptive physiology, an understanding of these mechanisms will allow us a more precise therapeutic approach.

中文翻译：

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神经性角膜疼痛和干眼症：伤害感受的连续体

在全身，通常参与伤害感受的周围神经受损可能会产生一系列症状——包括刺激、瘙痒和疼痛。在伤害性处理方面尚未明确考虑涉及干眼症 (DE) 和神经性角膜疼痛 (NCP) 的角膜症状的神经生物学过程。传统的基本假设是标签线原则负责。这些不同的感知是由中枢神经系统的初级传入输入硬编码的。这种假设过度简化了体感感知的神经生物学机制。DE代表慢性疼痛状况的标记线透视图没有直观意义：在大多数情况下不疼痛的眼部疾病如何被视为疼痛疾病？根据定义，慢性疼痛不要求存在疼痛吗？另一方面，NCP 是一个明确表示疼痛状况的术语，在历史上似乎与临床意义产生共鸣。DE 和 NCP 可以共享相似的特征，但它们的区别并不总是很清楚。通常情况下，临床术语来自不同的学科，DE 从眼科发现演变而来，而 NCP 则受到疼痛神经生理学的启发。本综述评估了这些术语的当前定义、它们重叠的基本原理以及瘙痒的神经生理学如何影响我们对这些疾病作为同一疾病的连续体的理解。尽管伤害性生理学很复杂，