Abstract
Purpose: :
To compare retinal pigment epithelium/Bruch’s membrane (RPE/BM) complex thickness in patients with early age related maculopathy (ARM) and in age-matched healthy controls using spectral-domain optical coherence tomography (SD-OCT).
Methods: :
This is a retrospective,non-interventional,cross-sectional study. Analysis of SD-OCT datasets from 10 eyes of 10 consecutive patients with early ARM and 10 eyes from 10 normal age-matched controls was performed. The RPE/BM complex band was manually segmented using custom image analysis software. In areas of drusenoid pigment epithelium detachment in which BM was visible, RPE and BM were measured separately and then added. RPE/BM complex thickness was calculated in the 9 Early Treatment Diabetic Retinopathy Study (ETDRS) subfields.
Results: :
Mean patient age was 72.1 years (range: 58-83) in both groups. In the control group, mean RPE/BM thickness in the central (9), 1-4 and 5-8 subfields was 23.7±2.3 µm, 21.8±2.1 µm and 22.6±1.9 µm respectively. In the ARM group, mean RPE/BM thickness in the central (9), 1-4 and 5-8 subfields was 34.1±7.5 µm, 30.6±7.3 µm and 33.2±5.7 µm respectively. Central subfield RPE/BM thickness was positively correlated with age (r=0.729, p=0.017) in the control group, but not in the ARM group (r=0.218, p=0.545). Comparison of the thickness between ETDRS zones for each group, revealed statistically significant difference only between the 1-4 and 5-8 zones in the control group (p=0.006). RPE/BM was significantly thicker in the ARM group compared with the age-matched controls in all ETDRS subfields (p=0.01 - central subfield, p=0.02 - subfields 1-4, p=0.00 - subfields 5-8).
Conclusions: :
This study demonstrated that RPE/BM thickness can be measured by SD-OCT and that it is significantly higher in patients with early ARM compared to age-matched normal controls. Our ARM group consisted of patients with bilateral early ARM (n=5) and patients with early ARM in one eye and wet age related macular degeneration (AMD) in the fellow eye (n=5), but comparison of RPE/BM thickness between those two subgroups did not reveal any statistically significant difference. A larger cohort will be required in order to investigate the possible role of RPE/BM thickness as a risk factor in developing wet AMD.
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal pigment epithelium