Effects of axial elongation on ganglion cell complex thickness and retinal capillary density in the peripheral retina among highly myopic eyes

Abstract Background/Objectives: To investigate the effects of axial elongation on ganglion cell complex (GCC) thickness and retinal capillary density (CD) in the circular region (12 mm diameter) using wide-field swept-source optical coherence tomography angiography. Subjects/Methods: This retrospective and cross-sectional study included 506 eyes. Fovea-centred 15 × 12 mm² scans were acquired to measure the subregional GCC thickness and CD in the whole retina, superficial capillary plexus (SCP) and deep capillary plexus (DCP) among three groups: normal controls, high myopia (HM) eyes with an axial length (AL) 28 mm. The magnitude of GCC thickness and retinal CD changes with axial elongation was estimated using multivariable linear regression models. Results: The GCC thickness and retinal CD in HM eyes with an AL >28 mm were lesser than those in the other two groups in most regions (P<0.05). In HM eyes with an AL <28 mm, GCC beyond the 3 × 3 mm² area was generally thinner than that in normal controls (P<0.05), while a significant reduction in CD occurred only in the 9–12 mm whole retina, 9–12mm superior SCP and 6–12 mm DCP (P<0.05). The GCC thickness and retinal CD with axial elongation demonstrated the greatest reduction in the subregions beyond 6 × 6 mm². Conclusions: GCC thickness beyond the 3 × 3 mm² area and peripheral retinal CD beyond the 6 × 6 mm² area were more susceptible to axial elongation, thereby deserving particular attention.