Ellipsoid zone defects in age-related macular degeneration: the Beijing Eye Study

Purpose To assess prevalence and associations of ellipsoid zone (EZ) defects on optical coherence tomographic (OCT) images in a general population affected by age-related macular degeneration (AMD) or free of any retinal disease. Methods For the participants of the population-based Beijing Eye Study, we assessed macular volume OCT scans for EZ defects. Results In the studied population of 1610 eyes (1103 participants; mean age: 65.4±9.8 years), EZ defect prevalence increased (p<0.001) from 1.0% (6/591) in the normal group to 13.3% (95/712), 56.3% (166/295) and 91.7% (11/12) in early AMD, intermediate AMD and late AMD, respectively. Higher EZ defect prevalence was associated with higher AMD stage (OR: 2.67; p<0.001), higher prevalences of external limiting membrane defects (OR: 175; p<0.001), intraretinal hyperreflective foci (iHRFs) internal to the EZ (OR: 42.9; p<0.001) and localised retinal pigment epithelium thinning (OR: 2.59; p=0.01), higher drusen number (OR: 1.03; p=0.001) and lower prevalence of iHRFs external to the EZ (OR: 0.05; p<0.001). In a reduced multivariable model, higher EZ defect prevalence was associated with higher prevalence of localised interdigitation zone thinning (OR: 10.2; p<0.001) and a lower prevalence of reticular pseudodrusen (OR: 0.12; p=0.04). Conclusions EZ defects were spatially associated with external limiting membrane defects and iHRFs located internal to EZ defects mostly in the outer nuclear layer. In addition, there was a spatial association between localised interdigitation zone thinnings with the presence of EZ defects and an association between a higher prevalence of reticular pseudodrusen and an absence of EZ defects. Future studies may explore the causes of these relationships.