Association of Optic Disc Tilt and Torsion with Open-Angle Glaucoma Progression Risk: Meta-Analysis and Meta-Regression Analysis

Abstract

Purpose: To evaluate the association of optic disc deformation with open-angle glaucoma (OAG) progression risk.

Design: Meta-analysis and meta-regression analysis.

Methods: Reports on the association of optic disc tilt and/or torsion with OAG progression published to June 2020 were identified in the PubMed, EMBASE, and Cochrane databases. Tilt ratio was measured as the longest-to-shortest diameter ratio of the optic disc. The angle (in degrees) between the vertical meridian and the disc's long axis was defined as the torsional angle. We used random-effects models to combine the pooled effects. Random-effects meta-regression was used to quantify the study characteristics' potential moderating influences. The protocol was registered in the PROSPERO International Database (CRD42020201151).

Results: Eleven longitudinal studies (1100 participants) were included. For 10 of them evaluated for tilt ratio and glaucoma progression, the pooled hazard ratio (HR) was 0.988 (95% confidence interval [CI] 0.921-1.059; I² = 59%) per 0.1-unit increase. In the meta-regression-based subgroup analysis, risk tended to decrease as the patients' mean age increased (P = .08). For 7 of the studies (605 patients) reporting data on torsion and glaucoma progression, the pooled HR was 0.936 (95% CI 0.860-1.018; I² = 32%) per 10-degree increase. The meta-regression analyses showed that the glaucoma progression assessment methods had a modulating influence (P = .01). In studies assessing just functional glaucomatous progression, the pooled HR was 0.890 (95% CI 0.831-0.952; I² = 0%).

Conclusion: Evidence for the effects of optic nerve deformation on glaucoma progression is still lacking. Future research using stratified analysis according to age and tailored diagnostic criteria will allow for more rigorous analyses for this topic.