Purpose

The diagnosis of neuropathic corneal pain (NCP) is challenging, as it is often difficult to differentiate it from conventional dry eye disease (DED). In addition to eye pain, NCP can present with similar signs and symptoms of DED. The purpose of this study is to find an objective diagnostic sign to identify patients with NCP, using in vivo confocal microscopy (IVCM).

Methods

This was a comparative, retrospective, case-control study. Patients with clinical diagnosis of NCP (n = 25), DED (n = 30), and age- and sex-matched healthy controls (n = 16), who underwent corneal imaging with IVCM (HRT3/RCM) were included. Central corneal IVCM scans were analyzed by 2 masked observers for nerve density and number, presence of microneuromas (terminal enlargements of subbasal corneal nerve) and/or nerve beading (bead-like formation along the nerves), and dendritiform cell (DC) density.

Results

There was a decrease in total nerve density in both NCP (14.14 ± 1.03 mm/mm²) and DED patients (12.86 ± 1.04 mm/mm²), as compared to normal controls (23.90 ± 0.92 mm/mm²; p < 0.001). However, total nerve density was not statistically different between NCP and DED patients (p = 0.63). Presence of nerve beading was not significantly different between patients and normal controls (p = 0.15). Interestingly, microneuromas were observed in all patients with NCP, while they were not present in any of the patients with conventional DED (sensitivity and specificity of 100%). DC density was significantly increased in both NCP (71.89 ± 16.91 cells/mm²) and DED patients (111.5 ± 23.86 cells/mm²), as compared to normal controls (24.81 ± 4.48 cells/mm² (p < 0.05). However, there was no significant difference in DC density between DED and NCP patients (p = 0.31).

Conclusion

IVCM may be used as an adjunct diagnostic tool for the diagnosis of NCP in the presence of neuropathic symptoms. Microneuromas may serve as a sensitive and specific biomarker for the diagnosis of NCP.

中文翻译：

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使用体内共聚焦显微镜观察微神经瘤：诊断神经性角膜疼痛的客观生物标志物？

目的

神经性角膜疼痛 (NCP) 的诊断具有挑战性，因为通常很难将其与传统的干眼病 (DED) 区分开来。除了眼痛之外，NCP 还可能出现类似的 DED 体征和症状。本研究的目的是使用体内共聚焦显微镜 (IVCM)寻找客观的诊断标志来识别 NCP 患者。

方法

这是一项比较性、回顾性、病例对照研究。包括临床诊断为 NCP (n = 25)、DED (n = 30) 和年龄和性别匹配的健康对照 (n = 16) 的患者，他们接受了 IVCM (HRT3/RCM) 角膜成像。中央角膜 IVCM 扫描由 2 名蒙面观察者分析神经密度和数量、微神经瘤的存在（基底下角膜神经的终末增大）和/或神经串珠（沿神经的珠状形成）和树突状细胞 (DC) 密度。

结果

与正常对照 (23.90 ± 0.92 mm/mm ²；p < 0.001 ) 相比，NCP (14.14 ± 1.03 mm/mm ² ) 和 DED 患者 (12.86 ± 1.04 mm/mm ² ) 的总神经密度降低）。然而，NCP 和 DED 患者之间的总神经密度没有统计学差异（p = 0.63）。神经串珠的存在在患者和正常对照之间没有显着差异（p = 0.15）。有趣的是，在所有 NCP 患者中都观察到了微神经瘤，而在任何传统 DED 患者中均不存在微神经瘤（敏感性和特异性为 100%）。NCP（71.89 ± 16.91 个细胞/mm ²）和 DED 患者（111.5 ± 23.86 个细胞/mm ²）的DC 密度显着增加)，与正常对照相比 (24.81 ± 4.48 个细胞/mm ² (p < 0.05)。然而，DED 和 NCP 患者之间的 DC 密度没有显着差异 (p = 0.31)。

结论

IVCM 可用作辅助诊断工具，用于在存在神经病理性症状的情况下诊断 NCP。微神经瘤可作为诊断 NCP 的敏感和特异的生物标志物。