Abstract
Purpose :
To determine Bruch’s membrane opening minimum rim width (BMO-MRW) in a normal Brazilian population and evaluate the effects of age, axial length (AXL), central corneal thickness (CCT) and optic nerve head (ONH) anatomy on this parameter and on retinal nerve fiber layer (RNFL) thickness measurements with spectral-domain optical coherence tomography (SD-OCT).
Methods :
175 normal subjects (58% female) aged between 18 and 78 years (approximately 25 subjects in each decade group) were included in the study. Subjects had normal clinical examinations and visual fields. ONH (24 radial scans centered on BMO) and peripapillary circle scans (3.5-mm nominal scan diameter) were acquired relative to the fovea to BMO center axis (FoBMO) with the Spectralis SD-OCT (Figure 1). AXL and CCT data were also obtained. One eye of each subject was selected randomly for analysis. Associations between BMO-MRW and RNFL measurements with age, AXL, CCT and BMO area were evaluated.
Results :
The mean CCT was 530 ± 34 µm (range 442 – 635) and mean AXL was 23.43 ± 0.98 mm (range 21.02 - 27.59). The mean FoBMO angle was -6.45 ± 3.67, ranging from +3.72 ° to - 15.32° and was not associated with AXL, CCT, BMO area or refractive error (P>0.05). Mean BMO area was 1.89 ± 0.4 mm2 and was not associated with AXL, CCT or refractive error (P>0.05). Univariate regression analysis showed that global BMO-MRW declined significantly with BMO area (R2=0.15, P<0.001). It also declined significantly with age (R2=0.05, P=0.001), with the steepest decline occurring inferotemporally (R2= 0.05, P=0.001) (Figure 2). In multivariate analysis, BMO area and age explained ~24% of BMO-MRW variation.
Conclusions :
This study provides SD-OCT BMO-MRW data for a population of healthy Brazilian individuals. Adjustment of measured BMO-MRW by age and BMO area should be considered.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.