Topographic Differences in the Age-related Changes in the Retinal Nerve Fiber Layer of Normal Eyes Measured by Stratus Optical Coherence Tomography

Purpose: To determine whether there are regional differences in the age-related changes in peripapillary retinal nerve fiber layer (RNFL) thickness as measured by time-domain optical coherence tomography (OCT). Methods: Fast peripapillary RNFL scans obtained with the Stratus time-domain OCT with nominal diameter of 3.46-mm centered on the optic disc were carried out on 425 normal participants over a wide age range. One eye was randomly selected for scanning or analysis. Average RNFL-, clock hour-, and quadrant-specific rates of RNFL thickness change were calculated and compared. Results: The 425 study participants ranged in age from 18 to 85 years with mean (+/- SD) of 46 (+/- 15) years. The mean (+/- SD) average measured RNFL thickness was 104.7 (+/- 10.8) micrometers (mm). The decline in the average RNFL thickness was 2.4 mu m per decade of age. Changes in RNFL thickness per decade of age ranged from -5.4 (P < 0.001) at clock hour 1 to -0.9 (P = 0.28) at clock hour 6. Similarly, the rate of thickness change per decade of age in the superior quadrant was -4.3 (P < 0.001) versus -1.5 (P = 0.006) in the inferior quadrant. The slopes of thinning superiorly and inferiorly were highly significantly different (P = 0.001). Conclusions: The age-related decline in normal RNFL measurements does not occur at equal rates around the disc and occurs mainly superiorly.