Aims To compare the shape of the anterior surface of the peripapillary sclera (PPS) between glaucoma and healthy subjects.
Methods 88 primary open angle glaucoma (POAG), 98 primary angle closure glaucoma (PACG) and 372 age-matched and gender-matched healthy controls were recruited in this study. The optic nerve head of one randomly selected eye of each subject was imaged with spectral domain optical coherence tomography. The shape of the PPS was measured through an angle defined between a line parallel to the nasal anterior PPS boundary and one parallel to the temporal side. A negative value indicated that the PPS followed an inverted v-shaped configuration (peak pointing towards the vitreous), whereas a positive value indicated that it followed a v-shaped configuration.
Results The mean PPS angle in normal controls (4.56±5.99°) was significantly smaller than that in POAG (6.60±6.37°, p=0.011) and PACG (7.90±6.87°, p<0.001). The v-shaped PPS was significantly associated with older age (β=1.79, p<0.001), poorer best-corrected visual acuity (β=3.31, p=0.047), central corneal thickness (β=−0.28, p=0.001), peripapillary choroidal thickness (β=−0.21, p<0.001) and presence of POAG (β=1.94, p<0.009) and PACG (β=2.96, p<0.001). The v-shaped configuration of the PPS significantly increased by 1.46° (p=0.001) in healthy controls for every 10-year increase in age, but not in glaucoma groups.
Conclusions The v-shaped configuration of the PPS was more pronounced in glaucoma eyes than in healthy eyes. This posterior bowing of the PPS may have an impact on the biomechanical environment of the optic nerve head.
- sclera and episclera
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Contributors Design of study: XW, TAT, MJAG, C-YC and TA. Conduct of study: TAT, XW and MEN. Collection and management of data: TAT, XW, YCT and HMH. Analysis and interpretation of data: XW, TAT, HMH, YCT and MJAG. Preparation of manuscript: XW, TAT, TA and MJAG. Review or approval of manuscript: NGS, TA, C-YC and MJAG.
Funding The study was supported by Beijing Natural Science Foundation (7194288 (XW)) and National Natural Science Foundation of China (12002025 (XW)), by the Singapore Ministry of Education Academic Research Funds Tier 1 (R-397-000-294-114 (MG)) and Tier 2 (R-397-000-280-112 and R-397-000-308-112 (MG)), by the National Medical Research Council (TA; NMRC/STAR/0023/2014), and by the National Institute for Health Research, Biomedical Research Centre, Moorfields Eye Hospital National Health Service, Foundation Trust and University College London, Institute of Ophthalmology (NGS). The sponsor or funding organisation had no role in the design or conduct of this research. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the UK Department of Health.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. The deidentified participant data were generated at the Singapore Eye Research Institute, Singapore and derived data supporting the findings of this study are available from the corresponding author (MJAG) on request.
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