Type 2 diabetes complicated by dry eye syndrome: Analysis of dry eye symptoms, corneal neuropathy, and influencing factors

Abstract

BACKGROUND

Dry eye, also known as keratoconjunctival dryness, refers to a group of conditions that lead to eye discomfort and visual dysfunction. Being one of the most common complications of diabetes, it can lead to vision loss and, in severe cases, blindness in patients with diabetes.

AIM

To investigate ocular dryness manifestations, assess corneal neuropathy, and identify associated influencing factors in patients with type 2 diabetes (T2D) complicated with comorbid dry eye syndrome (DES).

METHODS

Data from 81 patients with T2D admitted to Xianyang First People’s Hospital between January 2022 and June 2023 (18 months) were retrospectively reviewed. Patients were divided into the DES and non-DES groups. Additionally, 50 individuals who concurrently underwent medical examinations served as the control group. Standardized assessments were conducted, including evaluations using the standard patient evaluation of eye dryness (SPEED) tool, noninvasive tear film breakup time (NIBUT) analysis, and Schirmer I test (SIt) determination of wetting length. Under a corneal confocal microscope, subbasal corneal neuropathy evaluations were conducted to determine the density, length, number, and tortuosity of the main nerves. Associations among SPEED scores, NIBUT, SIt results, and subbasal corneal neuropathy parameters in the DES group were examined. The DES and non-DES groups were further analyzed for differences in baseline characteristics, and potential risk factors for DES in patients with T2D were identified by multivariate logistic regression modeling.

RESULTS

The T2D + DES group showed an increase in the SPEED score, along with a decrease in the NIBUT and SIt wetting length, compared with the non-DES and control groups (P < 0.05); however, no marked inter-group differences were noted for fluorescein staining test scores between T2D + DES group and DES group. Compared with the non-DES groups, the DES group exhibited reductions in density, length, and number of the main nerves, as well as an increase in nerve tortuosity (all P < 0.05), and all these changes were more pronounced in the non-DES group than in the DES group (all P < 0.05). In the DES group, the SPEED score demonstrated a significant negative correlation with nerve density and the length and number of the main nerves but a positive correlation with nerve tortuosity. Conversely, both the NIBUT and SIt wetting length showed a positive association with the density and number of the main nerves; however, the SIt wetting length demonstrated an inverse correlation with nerve tortuosity. Multivariate modeling identified several independent risk factors for DES in T2D, such as age, diabetes duration, lacrimal gland dysfunction, and insufficient insulin secretion, as well as fasting blood glucose and glycated hemoglobin.

CONCLUSION

Patients with T2D are more susceptible to DES. The T2D + DES group exhibited significant reductions in the density, length, and count, along with increased tortuosity, of the main nerve. These corneal nerve changes are also intimately linked to the severity of DES.

Keywords: Type 2 diabetes; Dry eye syndrome; Dry eyes; Corneal neuropathy

Core Tip: Patients with diabetes are more likely to have dry eyes, experience a burning sensation and foreign body sensation, exhibit corneal epithelial changes, and have a significantly higher incidence of dry eye than those without diabetes. In this study, dry eye and corneal neuropathy symptoms were observed in patients with both dry eye and type 2 diabetes, and the correlation between the two was analyzed. This study also actively explored and summarized relevant factors influencing the occurrence of dry eye in patients with diabetes to provide effective preventive treatment and improve patients’ quality of life.