Background/Aims To investigate the relationship between the lamina cribrosa (LC) curvature and the microvasculature within the LC in treatment-naïve eyes with normal-tension glaucoma (NTG) and in healthy eyes.
Methods Forty-one eyes with treatment-naïve NTG and 41 age and sex-matched healthy control eyes were included. The optic nerve head (ONH) area was scanned using spectral-domain optical coherence tomography (OCT) to examine the LC curvature quantified as the LC curvature index (LCCI). OCT angiography of the ONH area was performed to determine the LC vessel density (LCVD) in the en face images obtained from the layer segmented at the level of the LC. The LCVD was calculated as the percentage area occupied by vessels within the measured region.
Results The LCCI was larger (9.53±1.33 vs 6.55±1.02, p<0.001) and LCVD was smaller (28.0%±6.1% vs 35.2±6.3%, p<0.001) in NTG eyes than in healthy eyes. There were overall significant associations of a smaller retinal nerve fibre layer (RNFL) thickness (p<0.001), a smaller visual field mean deviation (MD) (p=0.003) and a larger LCCI (p≤0.004) with a smaller LCVD. In NTG group, the LCVD was positively associated with the RNFL thickness (p=0.012) and visual field MD (p=0.023), and negatively associated with the axial length (p≤0.013) and LCCI (p≤0.007). In healthy group, a smaller RNFL thickness (p=0.023) was associated with a smaller LCVD.
Conclusion A larger LCCI was significantly associated with a smaller LCVD in treatment-naïve NTG eyes but not in healthy eyes, indicating that mechanical strain potentially influences the perfusion within the LC in eyes with NTG.
- optic nerve
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Contributors Study concept and design: JAK and EJL. Acquisition, analysis or interpretation of data: all authors. Provided materials: MJAG and JMM. Statistical analysis: JAK. Drafting of the manuscript: JAK and EJL. EJL had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Funding This work was supported by Seoul National University Bundang Hospital Research Fund (No 02-2017-037).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the Seoul National University Bundang Hospital Institutional Review Board, and it conformed to the tenets of the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data are available upon request.