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J. M. Neuville, K. Bronson-Castain, M. A. Bearse, Jr., J. S. Ng, W. W. Harrison, M. E. Schneck, A. J. Adams; OCT Reveals Regional Differences in Macular Thickness With Age. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3207. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the relationship between age and macular thickness in healthy subjects, as measured by optical coherence tomography (OCT). A new method of OCT acquisition and analysis that allows for greater spatial localization will be presented.
Thirty healthy subjects (14 males, 16 females) were recruited for participation in the study. Ages ranged from 13 to 68 years with 5 subjects per decade. Using Stratus OCT 3 (Zeiss), 12 radial scans (twice the standard) centered at the foveola were acquired sequentially. Each 6-mm scan was composed of 512 axial samples. Thickness measurements for each scan where then exported for further processing. Points between each radial scan were interpolated onto a uniform grid using triangle-based linear interpolation creating a contiguous topographic map of the central 20 degrees of the retina. This thickness map was segmented into 37 hexagonal regions that were scaled with eccentricity ranging in size from approximately 0.26-0.88 mm2. The number of points falling within a given hexagon ranged from 5,020 to 17,637. A mean retinal thickness for each hexagon was then computed from all points falling within the given hexagonal region. We examined six retinal regions: nasal, temporal, superior, and inferior regions, the fovea, and the entire scanned area. Linear regression was used to look at the relationship between retinal thickness and age. Critical P-values were adjusted for multiple comparisons.
We found a slight decrease in overall macular thickness with age (2.7 microns/decade; R2 = 0.16, P = 0.027). Comparing the 10 youngest subjects (age 13-27) to the 10 oldest subjects (age 51-68), differences in retinal thickness in the temporal, superior, inferior and foveal regions were not significant. However, the two age groups differed significantly in retinal thickness in the nasal region (P < 0.008). In addition, when looking across all subjects in this nasal region, retinal thickness was linearly correlated with age, decreasing by 4.1 microns/decade (R2 = 0.31; P < 0.002). This trend for thinning of the retina was seen in all areas outside of the fovea but was not statistically significant after correcting for multiple comparisons.
Macular thickness decreases with age and does so non-uniformly within the central 20 degrees, with the greatest thinning between the fovea and the optic disc. This might be due to thinning of the retinal nerve fiber layer. Our new method of OCT acquisition and analysis allows for greater spatial localization of change in retinal thickness due to age or pathological processes.
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