PURPOSE: Reflectance of retinal nerve fibre layer (RNFL) can contribute to detecting the presence of glaucomatous damage and defining its extent. As a step towards developing a normative database for RNFL reflectance, we assessed within-eye and between-subject variability for RNFL reflectance in healthy eyes. METHODS: Vertical 30° × 15° volume scans at the optic disc were gathered using SD-OCT (Spectralis OCT) from people free of eye disease. Scans were gathered for both eyes of 30 younger adults (mean ± SD = 27 ± 3 years) and for one eye of 30 older adults (68 ± 8 years). Reflectance was quantified for each voxel as the depth-resolved attenuation coefficient (AC). Values for AC were extracted for four slabs (0-52, 24-52, 24-36 and 36-60 μm) and at depths from 24 to 60 μm below the inner limiting membrane (ILM) in 4 μm steps. RESULTS: Between-subject and within-eye standard deviations (SDs) for the logarithm of AC were similar; median differences were 0.02-0.03 log unit across all four slabs and depths from 24 to 48 μm. Means for the logarithm of AC were higher for younger than older eyes by ~0.1 log unit; this age effect was not due to differences in the raw reflectance of the RNFL, but rather to age-related changes in reflectance of deeper retina affecting the calculation of AC. CONCLUSIONS: In both groups, within-eye variability in RNFL reflectance near the optic disc was similar to between-subject variability. A better understanding of within-eye variability would be useful for developing normative databases.
PURPOSE: Reflectance of retinal nerve fibre layer (RNFL) can contribute to detecting the presence of glaucomatous damage and defining its extent. As a step towards developing a normative database for RNFL reflectance, we assessed within-eye and between-subject variability for RNFL reflectance in healthy eyes. METHODS: Vertical 30° × 15° volume scans at the optic disc were gathered using SD-OCT (Spectralis OCT) from people free of eye disease. Scans were gathered for both eyes of 30 younger adults (mean ± SD = 27 ± 3 years) and for one eye of 30 older adults (68 ± 8 years). Reflectance was quantified for each voxel as the depth-resolved attenuation coefficient (AC). Values for AC were extracted for four slabs (0-52, 24-52, 24-36 and 36-60 μm) and at depths from 24 to 60 μm below the inner limiting membrane (ILM) in 4 μm steps. RESULTS: Between-subject and within-eye standard deviations (SDs) for the logarithm of AC were similar; median differences were 0.02-0.03 log unit across all four slabs and depths from 24 to 48 μm. Means for the logarithm of AC were higher for younger than older eyes by ~0.1 log unit; this age effect was not due to differences in the raw reflectance of the RNFL, but rather to age-related changes in reflectance of deeper retina affecting the calculation of AC. CONCLUSIONS: In both groups, within-eye variability in RNFL reflectance near the optic disc was similar to between-subject variability. A better understanding of within-eye variability would be useful for developing normative databases.
Authors: Michaël J A Girard; Nicholas G Strouthidis; C Ross Ethier; Jean Martial Mari Journal: Invest Ophthalmol Vis Sci Date: 2011-09-29 Impact factor: 4.799
Authors: Shuang Liu; Bingqing Wang; Biwei Yin; Thomas E Milner; Mia K Markey; Stuart J McKinnon; Henry G Rylander Journal: J Glaucoma Date: 2014-01 Impact factor: 2.503
Authors: L A Kerrigan-Baumrind; H A Quigley; M E Pease; D F Kerrigan; R S Mitchell Journal: Invest Ophthalmol Vis Sci Date: 2000-03 Impact factor: 4.799