OCT reveals regional differences in macular thickness with age

To assist identification of macular thickness abnormalities by optical coherence tomography (OCT), we use techniques that improve spatial localization across the retina to establish any age-related retinal thickness changes in healthy eyes.

Retinal thickness was measured in 30 eyes of 30 healthy subjects aged 13 to 69 years. Using Stratus OCT 3, 12 radial scans centered at the foveola were acquired and points between scans were interpolated to create a topographic map of the central 20 degrees . The thickness map was divided into 37 hexagonal regions. A mean retinal thickness for each hexagon was computed. Retinal thickness vs. age was evaluated for the entire scanned area, five anatomical regions, and within individual hexagons. The retinal nerve fiber layer (RNFL) contribution to total retinal thinning was analyzed in the papillomacular region.

There was a small but significant thinning of the overall macular area with increasing age (2.7 mum/decade; p = 0.027). Comparing the 10 youngest subjects (age 13 to 27 years) with the 10 oldest (age 51 to 68 years), retinal thicknesses in the temporal, superior, inferior, and foveal regions were not significantly different. However, the two age groups differed significantly in retinal thickness in the nasal region (p < 0.008). Across all subjects, retinal thickness in this region was linearly correlated with age, decreasing by 4.1 mum/decade (p < 0.002). Approximately 43% of the retinal thinning in the nasal region was attributed to RNFL loss.

The method of OCT acquisition and analysis used in this study allows for greater spatial localization of change in retinal thickness associated with aging or pathological processes. Based on the results of this study, the macula thins with increasing age but does so nonuniformly. The greatest amount of thinning occurs nasal to the fovea. RNFL loss accounts for much, but not all the thinning in this area.