To investigate the roles of neural adaptation and sensitization in contact lens discomfort (CLD). Cooling stimuli (20 °C) were applied to the cornea in a group comprising 24 symptomatic and 25 asymptomatic contact lens (CL) wearers as well as 15 non-CL wearing controls, using a computerized Belmonte esthesiometer. The adaptation paradigm consisted of 20 repetitive stimuli at threshold, sub- and supra-threshold levels. The sensitization paradigm involved five levels of suprathreshold stimuli ranging between 1x to 2x threshold. Following each stimulus, participants rated the sensation magnitude regarding intensity, coolness and irritation. Measurements were taken with habitual CL (BL_CL), after 2 weeks of no-CL (No_CL) and after restarting habitual CL wear (ReSt_CL). The symptomatic subjects exhibited a lower threshold but reported enhanced sensations during the adaptation and sensitization paradigm, compared to the asymptomatic and control groups (all p ≤ 0.021). At the BL_CL and ReSt_CL visits, they showed increased ratings to repeated subthreshold stimuli (p = 0.025) and greater irritation during the sensitization paradigm (p ≤ 0.032). Ratings in asymptomatic and control groups were relatively unchanged over time (p ≥ 0.181). Logistic regression revealed a link between the augmented sensory responses and increased likelihood with CLD. The maladaptive sensory responses seen in CLD subjects, with reduced adaptation and heightened sensitization to ocular surface stimulation, suggest an imbalance between sensitization and adaptation in CLD. As CLD may represent a reversible subcategory of dry eye, it can serve as a human dry eye model for studying the neurosensory effect of ocular surface stimulation.

中文翻译：

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神经适应和敏化在隐形眼镜不适中的作用


研究神经适应和敏化在隐形眼镜不适 (CLD) 中的作用。使用计算机化的 Belmonte 感觉计，对 24 名有症状的隐形眼镜 (CL) 佩戴者和 25 名无症状的隐形眼镜 (CL) 佩戴者以及 15 名非 CL 佩戴者对照组的角膜施加冷却刺激 (20 °C)。适应范式由阈值、阈下和阈上水平的 20 个重复刺激组成。敏化范式涉及 1x 至 2x 阈值之间的五个阈值上刺激水平。每次刺激后，参与者都会对强度、凉爽和刺激等感觉强度进行评分。使用习惯性 CL (BL_CL)、无 CL (No_CL) 两周后以及重新开始习惯性 CL 佩戴 (ReSt_CL) 后进行测量。与无症状组和对照组相比，有症状的受试者表现出较低的阈值，但在适应和敏化范式期间报告感觉增强（所有 p ≤ 0.021）。在 BL_CL 和 ReSt_CL 访视中，他们对重复阈下刺激的评分增加 (p = 0.025)，并且在敏化范式期间表现出更大的刺激性 (p ≤ 0.032)。随着时间的推移，无症状组和对照组的评分相对没有变化 (p ≥ 0.181)。逻辑回归揭示了增强的感觉反应与 CLD 可能性增加之间的联系。 CLD 受试者中出现的适应不良感觉反应，即对眼表刺激的适应性降低和敏感性增强，表明 CLD 的敏感性和适应之间存在不平衡。由于CLD可能代表干眼的可逆亚类，因此它可以作为人类干眼模型来研究眼表刺激的神经感觉效应。