Seyhan Yazar1, Paul G Sanﬁlippo2, David A Mackey3,1
Purpose: The mechanisms by which myopia predis- poses to glaucoma are incompletely understood. We investigated associations of optic nerve head (ONH) structural biometric measures with spherical equiva- lent (SE) and axial length (AL) while controlling for the effects of other biometry.
Method: We examined 1344 20-year-old partici- pants of the Western Australian Pregnancy Cohort (Raine) Study. Biometric measures of the eye were collected to establish an encyclopedic eye model. Intraclass correlation coefﬁcients were calculated for
16 biometric measures including SE, AL, Bruch membrane opening (BMO) area, and global retinal nerve ﬁbre layer (RNFL) thickness. Multiple linear regression models were compared.
Results: Complete set of measures were available for 915 participants. A model including AL, anterior chamber depth (ACD), height and sex explained 51.1% of the variation in SE measures (P < 0.001), and had a prediction accuracy of 73.5%. The best model explaining the variation in BMO area measures comprised AL, ACD, corneal power and RNFL thickness. For every one mm increase in AL, there was a 0.08 0.02 mm2 increase in BMO area (P < 0.001). BMO area remained in the best model explaining the variation in SE in the absence of AL. Conclusion: We found no direct association between SE and ONH structural biometric mea- sures. However, longer eyes seem to have larger BMO. This supports the hypothesis that damage to the lamina cribrosa is exacerbated by shearing forces due to a longer AL.