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Abstract #81308 Published in IGR 20-3
Size and Shape of Bruch's Membrane Opening in Relationship to Axial Length, Gamma Zone, and Macular Bruch's Membrane Defects
Zhang Q; Xu L; Wei WB; Wang YX; Jonas JBInvestigative Ophthalmology and Visual Science 2019; 60: 2591-2598
PURPOSE: To assess axial elongation-associated characteristics in Bruch's membrane opening (BMO) as the inner optic nerve head lamella. METHODS: Participants of the population-based Beijing Eye Study without glaucoma underwent optical coherence tomography for measurement of the BMO size and shape. RESULTS: The study included 365 individuals (mean age, 61.0 ± 8.7 years; range, 50-88 years; axial length, 24.45 ± 1.99 mm; range, 21.32-30.88 mm). Larger horizontal (mean:1.62 ± 0.28 mm) and vertical (mean: 1.74 ± 0.27 mm) BMO diameters were linearly associated with longer axial length beyond an axial length of 26.0 mm (horizontal diameter: P < 0.001; standardized regression coefficient β: 0.66; nonstandardized regression coefficient B: 0.22; 95% confidence interval (CI): 0.16, 0.27; vertical diameter: P < 0.001; β: 40; B: 0.12; 95% CI: 0.06, 0.18). In multivariable analysis, wider largest gamma zone was associated with larger intrapapillary Bruch's membrane (BM) overhanging on the side opposite to the largest gamma zone (P = 0.006; β: 0.14; B: 0.35; 95% CI: 0.10, 0.60) and with longer horizontal BMO diameter (P < 0.001; β: 0.46; B: 0.59; 95% CI: 0.46, 0.73). The widest BM overhanging location (superior to nasal) was inversely correlated with the widest gamma zone location (inferior to temporal). Within the axial length group of ≥28.0 mm, eyes with macular BM defects had a less markedly increased BMO than those without macular BM defects (2.27 ± 0.18 vs. 2.71 ± 0.41 mm; P = 0.019). The difference between horizontal BMO diameter minus horizontal gamma zone width decreased (P < 0.001) with longer axial length. CONCLUSIONS: Beyond 26.0 mm of axial length, horizontal and vertical BMO diameter increased by 0.21 mm (95% CI: 0.16, 0.27) and 0.12 mm (95% CI: 0.06, 0.18), respectively, for each millimeter of axial elongation. Gamma zone may develop due to an axial elongation-associated BMO enlargement (β: 0.46) and, to a minor degree, a BMO shift in direction to the macula (β: 0.14). A large gamma zone may be protective against myopic macular BM defects.
Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
Full articleClassification:
2.12 Choroid, peripapillary choroid, peripapillary atrophy (Part of: 2 Anatomical structures in glaucoma)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
