Effects of eyelid pressure on corneal tomography and biomechanics: Quantitative analysis using a novel blepharo-tensiometer

Purpose

This study aimed to validate a blepharo-tensiometer, and investigate the relationship between eyelid pressure (ELP) and corneal tomography/biomechanics.

Methods

Repeatability of the blepharo-tensiometer was evaluated at different inclination angles: 10°, 15°, and 20° for the upper eyelid (U10, U15, and U20) and 45°, 50°, and 55° for the lower eyelid (L45, L50, and L55). Reproducibility was evaluated in terms of different operators and inclination angles. Both the maximum and average ELP were evaluated. Best-corrected visual acuity, manifest refraction spherical equivalent, eyelid types, palpebral fissure height, exophthalmometry, axial length, and corneal tomographic/biomechanical parameters were measured. Spearman analysis and generalized estimating equations were used to explore potential correlations.

Results

This study included 36 eyes from 36 subjects. The ICCs for repeatability were comparable between different inclination angles, so U15 and L50 were selected for further analysis. The ICCs for reproducibility in terms of different operator or inclination angle also achieved good to excellent outcomes. Certain associations have been revealed between the ELP and corneal tomographic/biomechanical parameters. Tomographically, ELP influences corneal front J0, front asphericity, and the index of surface variance; whereas biomechanically, ELP affects the time at first applanation, deformation amplitude at highest concavity, and biomechanically corrected intraocular pressure.

Conclusions

The tensiometer showed good precision. The study also showed that ELP causes a flattening effect on the peripheral cornea, with greater ELP linked to better corneal biomechanical properties in healthy subjects. These findings may potentially illuminate new avenues in the field of corneal disorders and beyond.