Foveal and parafoveal retinal thickness measured with SD-OCT in French elderly subjects: the Alienor Study

Abstract

Purpose: : To describe foveal and parafoveal thickness measured with SD-OCT, in elderly subjects without retinal diseases.

Methods: : The ALIENOR (Antioxydants, Lipides Essentiels, Nutrition and maladies OculaiRes) Study is a population-based epidemiological study on nutrition and age-related eye diseases. In 2009-2010, 625 subjects, aged 75 years or more, had a measure of retinal thickness using Spectralis SD-OCT (Heidelberg, Germany), without pupil dilation. We excluded subjects with retinal diseases (57 late AMD, 110 epiretinal membranes, 28 vitreomacular tractions, 5 retinal occlusions, 3 macular holes, 59 other retinal diseases). Among the 412 subjects without retinal diseases, SD-OCT measurements of retinal thickness could be obtained in 402 (97.6 %). Foveal retinal thickness was the average retinal thickness in the central area, with 1 mm diameter. Parafoveal retinal thickness was the average retinal thickness in 4 quadrants, 500 microns to 3 mm from the central point.

Results: : Mean (± standard deviation) foveal and parafoveal retinal thickness in the right eye were: foveal 274 ± 21 microns, upper quadrant 325 ± 19 microns, temporal quadrant 317 ± 18 microns, inferior quadrant 324 ± 19 microns, nasal quadrant 330 ± 19 microns. Foveal retinal thickness was higher in men than in women (279 versus 270, p<0.0001), but was not significantly associated with age. By contrast, parafoveal thicknesses in the 4 quadrants were similar according to gender, but were 6-7 microns lower in subjects aged 85 years or more, than in subjects 75-84 years (p<0.008). Measurements in right and left eyes were highly correlated (r=0.81, r=0.76, r=0.71, r=0.74, r=0.67 for foveal and parafoveal superior, temporal, inferior and nasal quadrants, respectively, p<0.0001 for all).

Conclusions: : Reliable retinal thickness measurements can be obtained with SD-OCT in the vast majority of elderly subjects, even without pupil dilation. Although statistically significant, variations according to age and gender are of minor clinical relevance. Foveal and parafoveal retinal thickness in elderly subjects appear similar to those of middle-aged subjects.

Keywords: macula/fovea • aging • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)