Shallow and bullous retinal pigment epithelium elevations in age-related macular degeneration

OBJECTIVE: To assess prevalence and associations of shallow retinal pigment epithelium (RPE) elevations (RPEEs) and bullous RPE detachments (RPEDs). METHODS: Macular optical coherence tomographic images taken in the population-based Beijing Eye Study were examined for the presence of RPEEs/RPEDs. RESULTS: In the study cohort of 953 eyes (mean age:63.3 ± 9.3years), RPEE/RPED prevalence increased from 0/376 (0%) in the normal group and 0/373 (0%) in the group with early AMD stage, to 33/199 (16.6%;95%CI:11.4,21.8) and 1/5 (20.0%;95%CI:0.0,75.5) in intermediate and late AMD, respectively. In intermediate AMD, prevalences of RPEEs and RPEDs were 30/199 (15.1%;95%CI:10.0,20.2) and 9/199 (4.5%;95%CI:1.5,7.5), respectively. Higher total RPEE/RPED prevalence was associated with higher AMD stage (OR:55.3;95%CI:14.4,327;P < 0.001), higher drusen number (OR:1,05;95%%CI:1.02,1.07;P < 0.001), lower prevalence of external limiting membrane defects (OR:0.19;95%CI:0.05,0.57;P = 0.003), in addition to male sex (OR:11.0;95%CI:3.37,45.5;P < 0.001) and higher serum concentration of triglycerides (OR:1.48;95%CI:1.20,1.89;P < 0.001). RPEE/RPED prevalence was not significantly associated with choroidal thickness as a whole (P = 0.55) or separated in a large-vessel choroidal layer (P = 0.86), medium-sized vessel layer (P = 0.66) or small-vessel layer (P = 0.24), prevalence (P = 0.97) and location of any intraretinal hyperreflective foci, and prevalence of reticular pseudodrusen (P = 0.57). CONCLUSIONS: Any RPEE/RPED, RPEEs and RPEDs were found in 16.6%, 15.1% and 4.5% of eyes with intermediate AMD, respectively, with a higher RPEE/RPED prevalence correlating with higher drusen number, lower prevalence of external limiting membrane defects and higher serum concentration of triglycerides. The statistical independence of RPEEs/RPEDs from the prevalences of reticular pseudodrusen and intraretinal hyperreflective foci point to differences in their etiologies.