Purpose

To examine the diurnal variation of corneal threshold and suprathreshold sensory processing, symptoms, and tear secretion in symptomatic and asymptomatic contact lens (CL) wearers and controls.

Methods

26 symptomatic and 25 asymptomatic CL wearers and 15 asymptomatic non-CL wearing controls participated. Cooling thresholds, symptoms and tear meniscus height (TMH) were measured on each of 3 measurement days (random order) on the following schedules; Day-1 within 1 h of awakening (Baseline) and 3, 6 and 9 h later, Day-2 baseline and 9 h later (CLs worn in CL group) and Day-3 baseline and 9 h later. Magnitudes estimates for threshold-scaled suprathreshold stimuli were also estimated on Day-3. Data were analyzed using mixed models and repeated measures ANOVA.

Results

Cooling thresholds for the symptomatic group were lower and decreased over Day-1 (p < 0.008) and after 8 h of CL wear on Day-2 (p < 0.001) and were paralleled by increased symptoms (all p < 0.001), whereas minimal variations were found in the asymptomatic and control groups. Magnitude estimates for suprathreshold stimuli were higher (p ≤ 0.002) in the symptomatic group but did not differ significantly over the day. TMH varied little over time and was lower in the symptomatic group, but the difference was not statistically significant.

Conclusion

Corneal sensitivity and symptoms, but not TMH, increased diurnally irrespective of CL wear in symptomatic CL wearers. These results reveal the essential role of neurosensory abnormalities in CL discomfort and suggest involvement of a central mechanism in the diurnally increased symptoms of these patients.

中文翻译：

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角膜感觉处理的昼夜变化在隐形眼镜不适中的作用。

目的

若要检查有症状和无症状的隐形眼镜（CL）佩戴者和对照者的角膜阈值和超阈值感觉处理，症状和泪液分泌的昼夜变化。

方法

26名有症状的CL佩戴者和25名无症状的CL佩戴者以及15名无症状的非CL佩戴者参加了试验。按照以下时间表在3个测量日（随机顺序）中的每个测量冷却阈值，症状和半月板撕裂高度（TMH）；第1天在唤醒后1小时（基线），3、6和9小时后，第2天基线和9小时之后（CL组佩戴的CL）和第3天基线和9小时之后。在第3天也估计了阈值缩放的阈上刺激的幅度估计。使用混合模型和重复测量方差分析对数据进行分析。

结果

有症状组的降温阈值在第1天降低和降低（p <0.008），在第2天CL磨损8小时后降低（p <0.001），并伴有症状增加（所有p <0.001），而最低在无症状组和对照组中发现变异。在症状组中，阈上刺激的幅度估计值较高（p≤0.002），但在一天中没有显着差异。TMH随时间变化很小，在有症状的组中较低，但差异无统计学意义。

结论

有症状的CL佩戴者，无论CL佩戴如何，角膜敏感性和症状均会随日增加，但TMH不会增加。这些结果揭示了神经感觉异常在CL不适中的重要作用，并暗示了这些患者的昼夜增加症状中涉及一种中心机制。