Enhanced depth imaging spectral-domain optical coherence tomography (EDI-SD-OCT)
1 has enabled noninvasive visualization and quantitative assessment of the choroid. Measurement of the choroidal thickness has been shown to be clinically relevant in diseases such as central serous chorioretinopathy
2 and Vogt-Koyanagi-Harada disease
3 (associated with thicker choroids), as well as myopia,
4–6 diabetic retinopathy,
7 and AMD
8 (associated with thinner choroids). In adults, subfoveal choroidal thickness also associates with age,
1,9,10 refraction,
9,10 axial length,
9,10 sex,
10–13 time of day,
14 and systolic blood pressure.
14 Age, myopic refractive error, and axial length
1,9,10 are the most frequently and consistently observed associations with decreasing choroidal thickness in healthy adults. A tipping point for the age-related attenuation of the subfoveal choroid has been reported at 30 years in one study
15 and at 60 years in another study.
16 Studies of choroidal thickness in children have found conflicting results. Thus, a study of 54 healthy Korean children found a decrease in subfoveal choroidal thickness with age, but no significant correlation between choroidal thickness and axial length or refraction.
17 A study of 194 emmetropic Australian children found an increase in choroidal thickness from 4 to 6 years to 7 to 9 years of age, but little difference between 7 to 9 years and 10 to 12 years.
18 Another recent study reported thinner choroid in myopic children, especially at the central fovea region.
19 In combination, age, refractive error, and axial length account for only a minor proportion of the variation in choroidal thickness in children, suggesting that other factors may be involved.
17–20