Choroidal Thickness Measured by Ocular Coherence Tomography (SD-OCT) and Body Mass Index in Healthy Saudi Women: A Cross-sectional Controlled Study

Obesity is one of the major public health problems globally, especially among women. Obesity is associated with glaucoma, cataract, age-related macular degeneration and diabetic retinopathy. Although it is clear that the anatomy and physiologic functions of the choroid may be affected by obesity, data investigating the effect of obesity on the choroid is limited and/or unavailable for the Saudi population.

To assess Choroidal Thickness (CT) changes in a sample of healthy Saudi Arabian women with different Body Mass Index (BMI) using Spectral-domain Ocular Coherence Tomography (SD-OCT).

A total of 140 healthy women aged 18-29 years (mean age ± standard deviation SD, 24.5 ± 1.7 years) with different BMI, axial length (AL) ≤ 24 ± 1.0 mm, and spherical equivalent refraction (SER) of ≤ ±2.0 dioptres were enrolled for the study. The participants were age and refractionmatched, and grouped into underweight (BMI ≤ 18.0 kg/m2) (n = 30), normal (control group) (18.5-24.9 kg/m2) (n = 43), overweight (25.0-29.9 kg/m2) (n=37), and obese study groups (≥ 30.0 kg/m2) (n = 30). SD-OCT imaging was performed on one eye of each participant. Comparisons among groups for all locations and the associations between CT and other variables were examined.

The mean CT at the subfoveal region (285 ± 31 μm, range: 203 μm to 399 μm) was significantly greater, and it was the lowest in the nasal region (248 ± 26 μm, range 154 to 304) compared with other locations, across all the groups (p < 0.05). Compared with the control, the subfoveal choroid was thinner in the obese group (mean difference: 22.6 μm, 95% Confidence Interval; CI: 8.6 μm to 36.6 μm; p = 0.02) and across all locations (p < 0.05) but thicker at the temporal location in the underweight group (12.4 μm, 95% CI: -23.7 μm to -1.04 μm; p = 0.01). No significant association of subfoveal CT with any of the measured parameters, including age (p-values ranged from 0.10 to 0.90), was found.

BMI may have an influence on the CT of healthy individuals and could be a cofounder in research studies on CT. It is, therefore, recommended that BMI should be evaluated in the clinical diagnosis and management of conditions associated with choroid in healthy individuals.