Asymmetry in Macular Choroidal Thickness Profile between Both Eyes in a Healthy Population Measured by Swept-source Optical Coherence Tomography.

PURPOSE To determine the difference in macular choroidal thickness (CT) profile between eyes in healthy individuals using swept-source optical coherence tomography. DESIGN Cross-sectional noninterventional study. PARTICIPANTS One hundred and forty eyes from 70 healthy patients with spherical equivalent between ± 3 D and with difference ≤ 0.25 D between eyes were scanned using a swept-source optical coherence tomography (Topcon Corporation). METHODS Cross-sectional noninterventional study. One hundred and forty eyes from 70 healthy patients with spherical equivalent between ± 3 D and with difference #0.25 D between eyes were scanned using a swept-source optical coherence tomography (Topcon Corporation). A horizontal CT profile of the macula was created in both eyes by manually measuring the subfoveal CT from the posterior edge of retinal pigment epithelium (RPE) to the choroid/sclera junction. Three determinations were performed at successive points 1,000 mm nasal to the fovea and 5 more temporal to the fovea. The differences in CT between both eyes were analyzed. RESULTS Mean age was 25.4 ± 19.9 years (from 4 to 75). The mean spherical equivalent was 0.18 ± 1.37 D (from -3 to +3). Mean macular nasal CT was thicker in the right eye (RE) than in the left eye (LE) (228.11 ± 69.23 μm vs. 212.27 ± 62.71 μm; P = 0.0002; Student's t-test paired data). Mean subfoveal CT and mean temporal CT was not statistically significantly different between the eyes. No statistically significant differences were observed comparing spherical equivalent in the RE compared with the LE. Both men and women showed a thicker mean nasal choroid in the RE versus the left (men, 226.97 ± 61.56 μm vs. 209.87 ± 60.31 μm; women, 229.63 ± 79.39 μm vs. 215.47 ± 66.68 μm, P = 0.003 and P = 0.03, respectively; Student's t-test paired data). At each nasal determination, CT in the RE was statistically significantly thicker than the LE (N1: 283.72 ± 81.10 μm vs. 269.76 ± 75.81 μm [P = 0.001]; in N2: 230.45 ± 73.47 μm vs. 211.33 ± 66.92 μm [P = 0.0002]; and in N3: 170.16 ± 61.00 μm vs. 155.72 ± 53.87 μm [P = 0.008], respectively). CONCLUSION To the best of our knowledge, this is the first report suggesting thicker macular nasal choroid in the RE compared with the LE. In contrast, subfoveal CT and temporal CT were not found to be different between eyes.