Effects of myopia and glaucoma in the prelaminar neural canal and anterior lamina cribrosa using 1060-nm swept-source OCT

PurposeInvestigate the effects of myopia and glaucoma in the prelaminar neural canal and anterior lamina cribrosa using 1060-nm swept-source optical coherence tomography DesignRetrospective, cross-sectional study MethodsO_ST_ABSSettingC_ST_ABSClinical practice Patient or study population19 controls (38 eyes); 38 glaucomatous subjects (63 eyes). Inclusion criteria for glaucomatous subjects: i) optic disc neural rim loss; ii) peripapillary nerve fibre layer (NFL) loss on spectral domain optical coherence tomography (SD-OCT); iii) glaucomatous visual field defect with an abnormal pattern standard deviation (P<.05); iv) stable SD-OCT, visual field, and optic disc clinical examination for 6 or more months. Inclusion criteria for control subjects: no evidence of retinal or optic nerve pathology. Exclusion criteria: i) retinal diseases or optic neuropathy other than primary open-angle glaucoma; ii) intraocular pressure less than 10 mmHg or higher than 20 mmHg; iii) ocular media opacities; iv) any surgery-related complication deemed inappropriate for the study. Intervention or observation proceduresSwept-source optical coherence tomography Main Outcome Measure(s)Bruchs membrane opening (BMO) and anterior laminar insertion (ALI) dimension, prelaminar neural canal dimension, anterior lamina cribrosa surface (ALCS) depth ResultsGlaucomatous eyes had more bowed and nasally rotated BMO and ALI, more horizontally skewed prelaminar neural canal, and deeper ALCS than the control eyes. Increased axial length was associated with a wider, longer, and more horizontally skewed neural canal, and decrease in the ALCS depth and curvature. ConclusionOur findings suggest that glaucomatous posterior bowing or cupping of lamina cribrosa can be significantly confounded by the myopic expansion of the neural canal. This may be related to higher glaucoma risk associated with myopia from decreased compliance and increased susceptibility to IOP-related damage of LC being pulled taut.