Abstract：
Dry eye disease (DED) is a growing global health problem with a significant impact on the quality of life of patients. While neurosensory abnormalities have been recognised as a contributor to DED pathophysiology, the potential role of in vivo corneal confocal microscopy in detecting nerve loss or damage remains unclear. This systematic review with meta-analysis (PROSPERO registered CRD42022381861) investigated whether DED has an impact on sub-basal corneal nerve parameters.
PubMed, Embase and Web of Science Core Collection databases were searched from inception to 9 December 2022. Studies using laser scanning confocal microscopy to compare corneal nerve parameters of DED with healthy eyes were included. Study selection process and data extraction were performed by two independent members of the review team.
Twenty-two studies with 916 participants with DED and 491 healthy controls were included, with 21 of these studies included in subsequent meta-analyses. There was a decrease in total corneal nerve length (-3.85 mm/mm2 ; 95% CI -5.16, -2.55), corneal main nerve trunk density (-4.81 number/mm2 ; 95% CI -7.94, -1.68) and corneal nerve branch density (-15.52 number/mm2 ; 95% CI -27.20, -3.84) in DED eyes compared with healthy eyes, with subgroup analysis demonstrating that these differences were more evident in studies using NeuronJ software, a semi-automated procedure. While this review found evidence of loss of corneal nerve parameters in eyes with DED compared with healthy controls, particularly with the use of a semi-automated image analysis method, it is evident that there is substantial heterogeneity between studies in terms of corneal nerve imaging methodology.
Standardisation is required in terms of terminology and analysis, with more research needed to potentially improve the clinical applicability and practicality of corneal nerve imaging. Further investigation is also required to confirm the diagnostic accuracy of this imaging modality and its potential for monitoring DED treatment efficacy.
PubMed, Embase and Web of Science Core Collection databases were searched from inception to 9 December 2022. Studies using laser scanning confocal microscopy to compare corneal nerve parameters of DED with healthy eyes were included. Study selection process and data extraction were performed by two independent members of the review team.
Twenty-two studies with 916 participants with DED and 491 healthy controls were included, with 21 of these studies included in subsequent meta-analyses. There was a decrease in total corneal nerve length (-3.85 mm/mm2 ; 95% CI -5.16, -2.55), corneal main nerve trunk density (-4.81 number/mm2 ; 95% CI -7.94, -1.68) and corneal nerve branch density (-15.52 number/mm2 ; 95% CI -27.20, -3.84) in DED eyes compared with healthy eyes, with subgroup analysis demonstrating that these differences were more evident in studies using NeuronJ software, a semi-automated procedure. While this review found evidence of loss of corneal nerve parameters in eyes with DED compared with healthy controls, particularly with the use of a semi-automated image analysis method, it is evident that there is substantial heterogeneity between studies in terms of corneal nerve imaging methodology.
Standardisation is required in terms of terminology and analysis, with more research needed to potentially improve the clinical applicability and practicality of corneal nerve imaging. Further investigation is also required to confirm the diagnostic accuracy of this imaging modality and its potential for monitoring DED treatment efficacy.
摘要：
目的：干眼症（DED）是一个日益严重的全球健康问题，对患者的生活质量产生重大影响。虽然神经感觉异常已被认为是DED病理生理学的一个因素，体内角膜共聚焦显微镜在检测神经丢失或损伤方面的潜在作用尚不清楚.这项系统的荟萃分析（PROSPERO注册的CRD42022381861）研究了DED是否对基底角膜下神经参数有影响。
方法：PubMed，Embase和WebofScience核心收藏数据库从开始到2022年12月9日进行了搜索。包括使用激光扫描共聚焦显微镜比较DED与健康眼睛的角膜神经参数的研究。研究选择过程和数据提取由审查小组的两名独立成员进行。
结果：纳入了22项研究，其中916名DED患者和491名健康对照者，其中21项研究纳入随后的荟萃分析.角膜神经总长度减少（-3.85mm/mm2；95%CI-5.16，-2.55），与健康眼相比，DED眼的角膜主神经干密度（-4.81数量/mm2；95％CI-7.94，-1.68）和角膜神经分支密度（-15.52数量/mm2；95％CI-27.20，-3.84），亚组分析表明，这些差异在使用NeuronJ软件的研究中更为明显，半自动程序。虽然这篇综述发现了与健康对照组相比，DED患者眼睛角膜神经参数丢失的证据，特别是使用半自动图像分析方法，很明显，在角膜神经成像方法方面，研究之间存在很大的异质性。
结论：在术语和分析方面需要标准化，需要更多的研究来潜在地提高角膜神经成像的临床适用性和实用性。还需要进一步研究以确认这种成像方式的诊断准确性及其监测DED治疗功效的潜力。
方法：PubMed，Embase和WebofScience核心收藏数据库从开始到2022年12月9日进行了搜索。包括使用激光扫描共聚焦显微镜比较DED与健康眼睛的角膜神经参数的研究。研究选择过程和数据提取由审查小组的两名独立成员进行。
结果：纳入了22项研究，其中916名DED患者和491名健康对照者，其中21项研究纳入随后的荟萃分析.角膜神经总长度减少（-3.85mm/mm2；95%CI-5.16，-2.55），与健康眼相比，DED眼的角膜主神经干密度（-4.81数量/mm2；95％CI-7.94，-1.68）和角膜神经分支密度（-15.52数量/mm2；95％CI-27.20，-3.84），亚组分析表明，这些差异在使用NeuronJ软件的研究中更为明显，半自动程序。虽然这篇综述发现了与健康对照组相比，DED患者眼睛角膜神经参数丢失的证据，特别是使用半自动图像分析方法，很明显，在角膜神经成像方法方面，研究之间存在很大的异质性。
结论：在术语和分析方面需要标准化，需要更多的研究来潜在地提高角膜神经成像的临床适用性和实用性。还需要进一步研究以确认这种成像方式的诊断准确性及其监测DED治疗功效的潜力。
