Prevalence and associations of intraretinal hyperreflective foci in age-related macular degeneration: the Beijing Eye Study.

BACKGROUND

To assess prevalence and associations of intraretinal hyperreflective foci (HRFs) in a general population.

METHODS

Participants of the population-based Beijing Eye Study underwent optical coherence tomography and macula photography.

RESULTS

The study cohort included 1641 eyes (mean age: 62.8±9.1 years; range: 50-93 years). Prevalence of any HRF or HRFs located only above the ellipsoid zone (EZ) increased from 33/590 (5.6%; 95% CI 4.0 to 7.0) and 22/590 (3.7%; 95% CI 2.2 to 5.2), respectively, in normal eyes to 371/725 (51.2%; 95% CI 47.7 to 54.7) and 246/725 (33.9%; 95% CI 30.4 to 37.4), respectively, in eyes with early age-related macular degeneration (AMD), to 283/314 (90.1%; 95% CI 87.1 to 93.1) and 260/314 (82.8%; 95% CI 78.8 to 86.8), respectively, in eyes with intermediate AMD, and to 12/12 (100%) and 12/12 (100%), respectively, in late AMD. HRFs above the EZ were spatially associated with EZ defects in 298/540 (55.2%) eyes and external limiting membrane (ELM) defects in 203/540 (37.6%) eyes. 52 (96%) of 54 eyes with macular hyperpigmentations showed HRFs above the EZ, and 52 (9.6%) of 540 eyes with HRFs above the EZ had corresponding macular hyperpigmentations. Higher HRF prevalence was associated (multivariable analysis) with higher AMD stage (OR: 1.75; 95% CI 1.36 to 2.26; p<0.001), and higher prevalences of EZ defects (OR: 36.6; 95% CI 8.56 to 157; p<0.001), reticular pseudodrusen (OR: 1.91; 95% CI 1.29 to 2.82; p<0.001), retinal pigment epithelium (RPE) elevations (OR: 34.5; 95% CI 10.4 to 111; p<0.001) and interdigitation zone thinnings (OR: 4.22; 95% CI 1.90 to 9.35; p<0.001).

CONCLUSIONS

The HRF prevalence was relatively high in early AMD and increased to late AMD. HRF location and shape suggested intraretinally migrated RPE cells as their equivalent. The majority of HRFs were not associated with an ophthalmoscopically detected macular hyperpigmentation. HRFs can also be found in locations with a localised interdigitation zone thinning with spatially corresponding EZ defects and ELM defects.