Work

Association of Adduction-Induced Optic Nerve Head Strain with Visual Field Loss Progression in Myopic Normal-Tension Glaucoma The Wenzhou Glaucoma Progression Study

Year: 2026

Type: preprint

Abstract: ABSTRACT Purpose To characterize the biomechanical response of the optic nerve head (ONH) in myopic versus non-myopic individuals with normal-tension glaucoma (NTG), and to evaluate the association between ONH strains and the rate of visual field (VF) progression. Design Retrospective clinical cohort study. Participants A total of 118 NTG eyes from 77 patients with ≥ 2 years of follow-up and 5 VF tests were enrolled, including 66 eyes with myopia and 52 eyes without. Methods Each participant underwent three-dimensional (3D) optical coherence tomography (OCT) imaging of the ONH under three mechanical loading conditions: 20° adduction, 30° abduction and acute intraocular pressure (IOP) elevation by applying a 0.80 N force to the lower eyelid. Effective strains across the global ONH complex and within specific segmented tissues (pre-lamina, lamina cribrosa, choroid, and sclera) were quantified using a validated 3D strain-mapping algorithm. Results Myopic NTG eyes exhibited significantly higher ONH strains compared to non-myopic eyes under acute IOP elevation (10.1±2.7% vs. 9.3±1.8%, P = 0.044) and abduction (9.2±2.3% vs. 8.4±2.1%, P = 0.048). In the non-myopic group, ONH strains varied significantly across conditions (P < 0.001), with adduction (9.9± 2.0%) and acute IOP elevation (9.3±1.8%) eliciting greater strains than abduction (8.4±2.1%). These condition-dependent variations were less pronounced in the myopic group (10.1±2.7% vs. 9.8±2.7% vs. 9.2±2.3%, P = 0.07). Multivariable linear mixed-effects analysis revealed that in myopic NTG, higher ONH strains induced by adduction were significantly associated with faster MD decline (estimate: -0.139 dB/year per 1% increase, P = 0.03, adjusted for age, spherical equivalent and baseline perimetric mean defect). Conversely, larger strains during acute IOP elevation were associated with slower progression (estimate: 0.184 dB/year per 1% increase, P = 0.004). Tissue-specific analysis confirmed that adduction-induced strains in the choroid and pre-lamina tissue as well as IOP-induced strains across all ONH tissues were significantly correlated with the rate of perimetric progression in myopic eyes (all P < 0.05). Conclusions In this cohort, greater adduction-induced ONH strain was associated with faster perimetric deterioration in myopic NTG. These findings support further investigation of gaze-related optic nerve traction as a potential non-IOP-related biomechanical factor in myopic NTG.

Source: medRxiv

DOI: 10.64898/2026.10.15.26365686