Abstract
Purpose :
To describe the factors associated with retinal pigment epithelium-Bruch's membrane (RPE-BM) complex thickness, in a multi-site community-based study in the United Kingdom.
Methods :
67,318 people aged 40-69 years underwent questionnaire, physical and eye examination including macular SD-OCT. RPE-BM thickness was measured using Topcon Advanced Boundary Segmentation in 9 ETDRS subfields. Systematic selection process identified 34,652 eyes with high-quality SD-OCT images for analysis. We included people with no self-reported ocular disease, diabetes, or neurologic disorders, visual acuity ≥20/25, refraction within 6 diopters of emmetropia, and IOP 6-21 mmHg. Multivariable regression modelling was used to adjust for covariates, identify relationships between RPE-BM thickness, ocular and systemic features.
Results :
Mean RPE-BM thickness was 26.3 μm (SD 4.8) at central subfield, with nasal (inner 27.1 μm, outer 26.9 μm) and temporal subfields (inner 26.1 μm, outer 25.6 μm) significantly thicker than superior (inner 24.5 μm, outer 24.3 μm) and inferior (inner 24.7 μm, outer 24.0 μm) subfields (all p<0.001). Multivariable regression with age stratification suggests RPE thinning becomes apparent after age 45. Among those age ≤45, RPE-BM was significantly thicker among those of black or mixed race (+3.61 and +1.77 μm vs. white, respectively; p<0.001) and in higher hyperopia (+0.4 μm/diopter, p<0.001), but not for other variables considered. Among those aged >45, RPE-BM was significantly thinner in older age (-0.10 μm/year, p<0.001), Asians (-0.45 μm vs. white, p=0.02), taller height (-0.02 μm/cm, p<0.001), higher IOP (-0.03 μm per mmHg, p<0.001), and regular smokers (-0.27 μm vs. non-smokers, p=0.02). Again, RPE-BM was thicker in black or mixed races (+3.29 μm and +0.81 μm vs. white, respectively; p<0.001), and higher hyperopes (+0.28 μm/diopter, p<0.001). There was no significant association with sex, Chinese ethnicity, nor former or occasional smoking.
Conclusions :
RPE-BM thickness varies with age, ethnicity, refraction, IOP, and smoking. The novel significant association with IOP may have relevance for etiology of glaucoma. The quantification of relationships between age, ethnicity, smoking and RPE-BM are relevant to the study of age-related macular degeneration.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.