Purchase this article with an account.
Natalia Alpizar-Alvarez, Erick Hernandez-Bogantes, Lihteh Wu; Diurnal Variation of Macular Choroidal Volume in Healthy Volunteers. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3048.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The chorioscleral interface may be irregular in different areas of the same eye. Single point choroidal thickness measurements may be misleading. The purpose of this study is to report the pattern and magnitude of diurnal variation of macular choroidal volume (MCV) measured by spectral domain optical coherence tomography (SD-OCT) in normal subjects.
SD-OCT with enhanced depth imaging (EDI) and image tracking (at least 49 average images) using a standarized protocol was performed in 14 healthy volunteers at 2 hr intervals starting at 8 am and finishing at 6 pm. Twenty five choroidal scans centered at the fovea were performed using a raster protocol. The choroidal thickness was segmented manually for each choroidal scan. The retinal boundary reference lines placed by the built in automated segmentation software were moved to the choroidal boundaries. A standarized grid centered on the fovea was positioned automatically by the SD-OCT software. This grid divided the macula into 3 circles of 1 mm (central), 3 mm (inner) and 6 mm (outer) diameter. The automated software calculated the volume in each of these circles. Intraocular pressures (IOP), systolic (SBP) and diastolic (DBP) blood pressures were also measured at the same time points.
The mean age of the study subjects was 34.4 years (range, 23 to 59 years, SD ± 10.8) with 4 males and 10 females. The mean spherical equivalences (SE) in the OD and OS were -0.64 and -0.56 D respectively. The mean axial length (AL) was 23.52 mm (range, 22.06 to 25.67 mm, SD ± 1.02) in the OD and 23.52 mm (range, 21.02 to 26.05 mm, SD ± 1.20) in the OS. The mean MCV in the OD and OS fluctuated during the day from 8.95 to 9.70 µm3 (p=0.3577) and from 8.23 to 9 µm3 (p=0.1651) respectively. The largest fluctuation in MCV in the OD was 1.68 µm3 and the minimal fluctuation was 0.27 µm3 compared to 1.75 µm3 and 0.33 µm3 in the OS. There was a highly significant difference between the maximal and minimal MCV in both eyes (p<0.0001 and p=0.0001). The mean diurnal variation of MCV were 0.74 (7.8%) and 0.78 (8.6%) µm3 OD and OS respectively. The amplitude of MCV variation did not correlate with age, AL, SE, SBP, DBP or IOP.
The MCV fluctuates significantly during the day in healthy subjects. Factors that influence MCV fluctuation remain to be identified.
This PDF is available to Subscribers Only