Research now suggests a relationship between decreased choroidal thickness and retinal oxygenation in individuals with morbid obesity—a relationship also associated with a decrease of the photoreceptor layer thickness and outer retinal layer thickness in morbidly obese females.

The study identified 44 females in the normal-weight group (BMI=18.50 to 24.99), 40 in the overweight group (BMI=25.00 to 29.99), 40 in class 1 obese group (BMI=30.00 to 34.99), 38 females in class 2 obese group (BMI=35.00 to 39.99) and 35 females placed in the morbidly obese group (BMI=40 and above). The researchers then used enhanced‐depth imaging OCT to measure the thickness of the subfoveal choroid, outer retinal layer, specific sublayer thickness of the photoreceptor layer, the retinal pigment epithelium and Bruch’s membrane.

In morbidly obese females, the researchers noted that the mean choroidal thickness values were lower than those of normal‐weight as well as overweight and class 1 and class 2 obese females. However, there were no statistically significant differences between the morbidly obese and other groups in retinal pigment epithelium thickness and Bruch's membrane thickness. The study concluded that retinal hypoxia associated with morbid obesity may be related to a decrease in photoreceptor layer thickness, and that this thinning of the outer retinal layer may also lead to atrophy of the cone sheath.

The researchers believed that new-generation OCT could improve their study as the devices could be more suitable than enhanced-depth imaging OCT for evaluating choroidal thickness.

“With OCT devices, such as swept-source, the choroid-scleral junction can be selected more clearly, which allows deeper ocular tissues to be viewed quickly and easily using a longer wavelength laser,” they noted.

Öncül H, Çalayan M, Alakus MF, et al. Evaluation of the subfoveal choroidal and outer retinal layer thickness in obese women. Clin Exp Optom. June 29, 2020. [Epub ahead of print].