Enhanced depth imaging spectral-domain optical coherence tomography of subfoveal choroidal thickness in normal Japanese eyes

Purpose: To investigate the subfoveal choroidal thickness of healthy Japanese subjects using enhanced depth imaging optical coherence tomography and to evaluate the association between subfoveal choroidal thickness and age in a group of subjects with a wide age range. Subjects and methods: A total of 145 eyes of 145 healthy volunteers (85 women, 60 men, age range 5-88 years, mean age 45.7 years) with no ophthalmic or systemic symptoms were evaluated; 23 subjects were under the age of 20 years. Exclusion criteria included high myopia (greater than -6 D) of spherical equivalent refractive error. Results: The mean subfoveal choroidal thickness was 265.5 ± 82.4 lm. Although the subfoveal choroidal thickness showed a negative correlation with age (p < 0.05), subfoveal choroidal thickness in those subjects younger than 10 years old was significantly thicker than that in each of the other age groups. The subfoveal choroidal thickness remained unchanged from the age groups in the 10s to 20s, and it gradually decreased after the 30s. The subfoveal choroidal thickness tended to have a negative correlation with refractive error. Age and refractive error were statistically significant factors associated with subfoveal choroidal thickness (p < 0.01). The multiple regression formula was subfoveal choroidal thickness = 365.1 - 2.0 x age + 7.9 x refractive error. Conclusion: The subfoveal choroidal thickness in healthy Japanese subjects decreased in thickness by 20 μm every 10 years. The subfoveal choroidal thickness in subjects younger than 10 years was significantly thicker than in other age groups. The subfoveal choroidal thickness also depended on the refractive error.