Background and objective: To determine whether the choroidal thickness varies significantly according to the time of measurement in Japanese subjects without chorioretinal diseases.
Patients and methods: Twelve eyes of 12 subjects were examined with enhanced depth imaging spectral-domain optical coherence tomography. The choroidal thickness was measured in the mornings (9:00 to 9:30 AM) and evenings (7:30 to 8:00 PM) at three locations: the fovea, 1.5 mm temporal to the fovea, and 1.5 mm nasal to the fovea.
Results: The mean age of the subjects was 62.6 ± 14.5 years. For the morning measurements, the mean choroidal thickness was 308.5 ± 74.4 μm at the fovea, 276.2 ± 84.6 μm temporally, and 239.3 ± 98.4 μm nasally. For the evening measurements, the mean choroidal thickness was 328.8 ± 85.6 μm at the fovea, 284.8 ± 91.6 μm temporally, and 248.9 ± 101.5 μm nasally. The mean subfoveal (P < .0001) and nasal (P = .03) choroidal thicknesses were significantly thicker in the evenings than in the mornings. There was no significant difference in the mean temporal choroidal thickness (P = .08).
Conclusion: The choroidal thickness varies according to the time of measurement.
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