# Association of Corneal Biomechanical Properties with Fingertip-Measured Advanced Glycation End Products and Carotenoids in Glaucoma Patients

## TL;DR

This study found no significant link between systemic markers of metabolism and eye tissue stiffness in glaucoma patients.

## Contribution

Demonstrates that AGEs and carotenoids do not strongly correlate with corneal biomechanics in glaucoma patients.

## Key findings

- AGEs and carotenoids showed no significant association with corneal hysteresis or resistance.
- AGEs and carotenoids were inversely correlated with each other.
- Demographic factors had stronger associations with corneal biomechanical parameters.

## Abstract

Background/Objectives: Advanced glycation end products (AGEs) and carotenoids are systemic indicators of metabolic and oxidative status, yet their influence on ocular tissue biomechanics remains unclear. This study investigated the relationships between systemic AGEs and skin carotenoid levels, as well as corneal biomechanical properties in glaucoma patients. Methods: A retrospective observational analysis was performed on 676 patients (1278 eyes) who attended the glaucoma clinic at Shimane University Hospital between May 2019 and August 2024. Fingertip skin autofluorescence (sAF)-based AGE scores using AGE Sensor® and skin carotenoid scores using the Veggie Meter® were collected as part of systemic evaluation. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal compensated intraocular pressure (IOPcc) were measured using the ocular response analyzer (ORA). Associations between systemic variables, AGEs, carotenoids, and ORA parameters were analyzed using univariate tests, mixed-effects regression models, and quartile-based comparisons. Results: The mean AGEs and carotenoid scores were 0.42 ± 0.10 arbitrary units and 338.5 ± 130.8 optical density units, respectively. Via a univariate analysis, an inverse association was found between carotenoid level and CRF; however, via multivariate analyses, neither AGEs nor carotenoid levels were associated with IOPg, IOPcc, CH, or CRF in any analysis. In contrast, demographic parameters showed significant associations with ORA parameters. Via quartile-based comparisons, a significant inverse correlation was found between AGEs and carotenoids (p < 0.0001). Conclusions: In conclusion, sAF-measured AGEs and skin carotenoids showed no remarkable associations with corneal biomechanical properties. AGEs and carotenoids demonstrated an inverse relationship with each other, and each marker was associated with several demographic parameters.