Case Control Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Apr 6, 2022; 10(10): 3014-3026
Published online Apr 6, 2022. doi: 10.12998/wjcc.v10.i10.3014
Changes in corneal nerve morphology and function in patients with dry eyes having type 2 diabetes
Wei Fang, Zhong-Xi Lin, Hui-Qing Yang, Lei Zhao, Da-Chuan Liu, Zhi-Qiang Pan
Wei Fang, Hui-Qing Yang, Da-Chuan Liu, Department of Ophthalmology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
Wei Fang, Zhi-Qiang Pan, Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing 100005, Beijing, China
Zhong-Xi Lin, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
Lei Zhao, Department of Endocrinology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
Author contributions: Pan ZQ was responsible for the overall design, quality control, and article revision; Fang W was responsible for collecting cases, coordinating the completion of the specific content of the experiment, statistical analysis, and writing the manuscript; Lin ZX was responsible for the blink reflex inspection; Yang HQ was in charge of tears and confocal microscopy. Lei Zhao was in charge of collecting cases; Liu DC was responsible for collecting cases, statistical analysis, and quality control.
Institutional review board statement: This study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The current study was approved by the Ethics Committee of Xuanwu Hospital of Capital Medical University (No. [2020]061). A signed informed consent form was collected from all included patients.
Informed consent statement: All study participants provided informed consent prior to sample collection according to the institutional guidelines and gave permissions to the use of their clinical data and accompanying images.
Conflict-of-interest statement: The authors declare that they have no competing interest.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at panyj0526@ccmu.edu.cn.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Zhi-Qiang Pan, PhD, Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Lane, Dongcheng District, Beijing 100005, China. panyj0526@ccmu.edu.cn
Received: September 13, 2021
Peer-review started: September 13, 2021
First decision: November 22, 2021
Revised: December 24, 2021
Accepted: March 15, 2022
Article in press: March 15, 2022
Published online: April 6, 2022
Processing time: 197 Days and 0.5 Hours
ARTICLE HIGHLIGHTS
Research background

Dry eye syndrome (DES) decreases the quality of life and is associated with type 2 diabetes mellitus (T2DM). The prevalence of DES increases with multiple complications worldwide. Blink reflex (BR) can be used to assess the corneal nerve closed-loop morphology, but it is unclear whether it could be used in DES. This study helps understand more about corneal nerve morphology in patients with DES.

Research motivation

DES was significantly associated with T2DM, thus with the HBA1c level. However, the underlying mechanism of DES in T2DM is still unclear. This study will help determine the relationship between corneal nerves morphology and DES abnormalities in patients with T2DM.

Research objectives

The BR changes the corneal nerve morphology in patients with DES having T2DM is unclear. Thus, the objective of this study is to investigate corneal nerve fibers, and corneal nerve closed loop function in patients with DES having T2DM or not.

Research methods

In this study, a total of 131 patients were enrolled from the ophthalmology and endocrinology Operationalized Psychodynamic Diagnosis with or without dry eye complaints. The tear film break-up time, Schirmer I test, in vivo confocal microscopy, and BR have performed accordingly after grouping. Data were presented as mean ± SD, and statistical analysis was performed using SPSS Statistics 16.0. This cross-sectional study is one of the primary studies to uncover the BR changes in these patients.

Research results

The findings of this study revealed that among this four DEwDM (n = 56), DMnDE (n = 22), DEnDM (n = 33), and nDMnDE (n = 20) groups, the nerve fiber length was reduced in three groups. The R1 Latency of BR increased in one group, suggesting changes in the corneal nerve morphology in DES patients with or without T2DM. The role of BR changes in DES with or without T2DM needs further assessment through future studies.

Research conclusions

Further research is needed on the corneal morphology and neurological function in DES patients having T2DM in the future to provide clinical benefits to these patients. Moreover, OGTT or HBA1c as the diagnostic test should be used in future studies. The number of patients with DES needs to be increased in future studies.

Research perspectives

This study observed that T2DM and DES had abnormal corneal morphology and function, whereas T2DM or DES alone had only abnormal corneal morphology. Therefore, future research should focus specifically on T2DM patients and DES and their morphological and functional improvements of corneal nerve.