What are the normal retinal nerve‑fiber‑layer (RNFL) thickness values across the lifespan, from birth through old age?

RNFL Thickness Variations Across the Lifespan

RNFL thickness demonstrates dynamic, age-dependent changes throughout life: it increases during early childhood (birth through age 8), stabilizes during late childhood and young adulthood, then progressively declines with aging at approximately 0.3-0.5 μm per year in adults.

Infancy and Preterm Period

Birth weight is the strongest predictor of RNFL thickness at birth, with each 250g increase in birth weight associated with a 5.2 μm increase in RNFL thickness at 36 weeks postmenstrual age 1.

• Extremely low birth weight infants show significantly thinner RNFL (55.5 ± 8.3 μm) compared to very low birth weight infants (66.7 ± 10.2 μm), a difference that persists even after adjusting for gestational age 1
• At 36 weeks postmenstrual age, average RNFL thickness in preterm infants ranges from approximately 55-67 μm depending on birth weight 1
• Right eyes demonstrate 3.4 μm thicker RNFL compared to left eyes 1

Early to Mid-Childhood (Ages 5-8 Years)

RNFL thickness increases significantly with age during the early school years, contrary to the declining pattern seen in adults 2.

• Children aged 6-8 years show mean global RNFL thickness of 106.29 ± 9.36 μm, with age positively correlated with RNFL thickness (β = 0.509; p = 0.001) after adjusting for axial length 2
• At ages 5-15 years, average global peripapillary RNFL thickness is 107.6 ± 1.2 μm, which is notably thicker than adult values, particularly in the superior and inferior sectors 3
• The sectoral distribution shows thickest RNFL in the inferior temporal region (155.12 ± 19.42 μm), followed by superior temporal region (154.67 ± 19.99 μm) 2

Critical Developmental Pattern in Young Children

Temporal peripapillary RNFL demonstrates a unique biphasic pattern: it decreases by nearly 35% between birth and approximately 18 months of age, then slowly increases up to 12 years when measured at a fixed distance from the disc center 4. This initial decrease likely reflects ongoing myelination and neural pruning during early visual system maturation.

Optic Disc Development Through Childhood

• Disc and cup diameter increase by 30% and 40% respectively between birth and 13 years when measured as absolute distance 4
• However, when expressed as visual angle (accounting for eye growth), disc and cup diameter remain relatively constant at 5°-5.5° and 2° respectively throughout childhood 4
• Central subfield macular thickness (271.2 ± 2.0 μm) shows significant correlation with age in children 3

Adult Age-Related Decline

Progressive RNFL thinning occurs throughout adulthood, with both cross-sectional and longitudinal studies confirming this decline 5.

Cross-Sectional Age-Related Changes:

• Average RNFL: -0.33 μm/year (p = 0.011) 5
• Inferior quadrant: -0.45 μm/year (p = 0.037) 5
• Temporal quadrant: -0.31 μm/year (p = 0.046) 5

Longitudinal Age-Related Changes (More Accurate):

• Average RNFL: -0.52 μm/year (95% CI: -0.86 to -0.17) 5
• Superior quadrant: -1.35 μm/year (95% CI: -2.05 to -0.65) 5
• Inferior quadrant: -1.25 μm/year (95% CI: -1.78 to -0.71) 5
• Nasal and temporal quadrants show no detectable reduction in longitudinal analysis 5

Important Clinical Caveat:

Baseline RNFL thickness is the only significant factor influencing the rate of age-related decline—thicker baseline RNFL is associated with faster rates of thinning 5. This must be considered when interpreting serial OCT measurements for glaucoma detection, as individuals with naturally thicker RNFL may show more rapid apparent decline that is actually physiologic rather than pathologic.

Clinical Implications by Age Group

For pediatric patients (birth to adolescence): Stable RNFL measurements do not necessarily indicate stable disease status, as normal development should show increasing RNFL thickness during early childhood 2. Failure to show age-appropriate increases may indicate pathology.

For adult patients: Expected physiologic decline of 0.5-1.3 μm/year (depending on quadrant) should be factored into interpretation of progressive RNFL thinning, particularly when baseline measurements are above average 5.