Macular thickness in healthy eyes of adults (N = 4508) and relation to sex, age and refraction: the Tromsø Eye Study (2007-2008)

Abstract

Purpose: To provide sex-stratified normative data on retinal thickness and study the relationship with sex, age and refractive status.

Methods: Population-based study including 2617 women and 1891 men, aged 38-87 (mean 61 ± 8) years, without diabetes, glaucoma and retinal diseases, and spherical equivalent refraction (SER) within ±6 dioptres. Retinal thickness was measured with optical coherence tomography (spectral domain Cirrus HD-OCT).

Results: Women had thinner retina than men. Retinal thickness was significantly associated with refraction, where mean change in retinal thickness per 1 D increase in SER was -1.3 (0.2) μm in the fovea, 0.7 (0.1) μm in the pericentral ring and 1.4 (0.1) μm in the peripheral ring. In the fovea, there was a non-monotonic curved relationship between retinal thickness and age in both sexes with a maximum at about 60 years (p < 0.001). In the pericentral ring, the mean reduction in retinal thickness per 10-year increase was 2.7 (0.3) μm in women and 4.0 (0.4) μm in men and corresponding results in the peripheral ring were 2.3 (0.3) μm in women and 2.6 (0.4) μm in men. In both regions, there was evidence for a nonlinear pattern with an increased rate of change with higher age. There was a significant interaction between sex and age for retinal thickness of the pericentral ring (p = 0.041).

Conclusion: Women had thinner retina than men, and thickness varied with refractive status. Retinal thickness was associated with age in all macular regions, and the rate of change in retinal thickness varied at different ages.

Keywords: age; epidemiology; optical coherence tomography; population based; refraction; retina; sex.

Figure 1

Optical coherence tomography (OCT) scan and the nine sectors of the ETDRS grid. (A) The nine sectors of the ETDRS grid (right eye). Fovea (sector 1), pericentral ring (sectors 2–5) and peripheral ring (sectors 6–9). (B) Representative horizontal spectral domain Cirrus HD‐OCT (Carl Zeiss Meditec) scan through the fovea from the right eye of a healthy subject.

Figure 2

Predicted relationship between age and retinal thickness in the fovea, pericentral and peripheral ring of macula, by use of fractional polynomial multiple linear regression. Women are displayed in panels A–C and men in panels D–F, p = level of significance, φ = powers of model. φ = (a): First‐degree fractional polynomial (FP1) with the power a (describes a monotonic function). φ = (a b): Second‐degree fractional polynomial (FP2) with powers a and b (describes a non‐monotonic function). Models are adjusted for spherical equivalent refraction, and graphs centred at the sex‐specific median. Tromsø Eye Study 2007–2008.