Purpose

To evaluate transient receptor potential vanilloid 1 (TRPV1)-mediated pain sensitivity in patients with short tear break-up time (TBUT) dry eye (DE) by using the capsaicin stimulus test.

Methods

This prospective cross-sectional comparative study included 22 eyes of 22 patients with short TBUT DE and 11 eyes of 11 non-DE control subjects. Patients were divided into two groups based on response to standard DE treatments: 10 non-responders (intractable DE) and 12 responders (responsive DE). Mechanical touch (M-touch) and mechanical pain (M-pain) were measured using a Cochet-Bonnet esthesiometer. Capsaicin-induced pain (C-pain) and C-pain duration (C-pain DT) were measured using a capsaicin stimulus test. Psychological distress was also assessed.

Results

M-touch sensitivity was similar among all three groups. M-pain sensitivity was higher in the responsive DE group than in the intractable DE and control groups (P < .001). C-pain sensitivity was lower (P < .001) in the intractable DE group than in the responsive DE and control groups, and C-pain DT was shorter (P = .006) in the intractable DE group than in the responsive DE group. Psychological distress was higher in the intractable DE group than in the control group (P < .001).

Conclusions

Patients with intractable short TBUT DE were less sensitive to the effects of capsaicin than patients with responsive short TBUT DE and controls. Altered neural activation may contribute to the development of DE symptoms in the short TBUT DE subjects. The capsaicin stimulus test may be used to better understand pain sensitivity in short TBUT DE patients.

中文翻译：

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辣椒素引起的疼痛敏感，在短时间内使干眼泪破裂。

目的

为了评估短暂的泪液破裂时间（TBUT）干眼症（DE）患者的短暂受体电位类香草酸1（TRPV1）介导的疼痛敏感性，使用辣椒素刺激试验。

方法

这项前瞻性横断面比较研究包括22例短TBUT DE患者的22眼和11例非DE对照受试者的11眼。根据对标准DE治疗的反应将患者分为两组：10位无反应者（难治性DE）和12位反应者（反应性DE）。机械触觉（M-touch）和机械疼痛（M疼痛）使用Cochet-Bonnet美容仪进行测量。使用辣椒素刺激试验测量辣椒素引起的疼痛（C疼痛）和C疼痛持续时间（C疼痛DT）。还评估了心理困扰。

结果

三组之间的M-touch敏感性相似。反应性DE组的M痛敏感性高于顽固性DE组和对照组（P  <.001）。 顽固性DE组的C痛敏感性低于反应性DE组和对照组（P <.001），顽固性DE组的C痛DT短 于反应性DE组（P = .006） 。顽固性DE组的心理困扰高于对照组（P  <.001）。

结论

顽固性短TBUT DE的患者对辣椒素的作用不如反应性短TBUT DE和对照的患者敏感。短暂的TBUT DE受试者中，神经激活的改变可能有助于DE症状的发展。辣椒素刺激试验可用于更好地了解短TBUT DE患者的疼痛敏感性。