Abdominal obesity linked to a longer cone-mediated dark-adaptation recovery time in healthy eyes

ASSOCIATION BETWEEN OBESITY AND ALTERATIONS IN PHOTORECEPTOR-RETINAL PIGMENT EPITHELIUM-CHORIOCAPILLARIS COMPLEX IN HEALTHY EYES

PURPOSE

To investigate the effect of obesity on alterations in the photoreceptor-retinal pigment epithelium (RPE)-choriocapillaris complex.

METHODS

Two hundred and twenty participants with varying body mass index were enrolled and categorized into three groups: normal weight, overweight, and obese. Retinal and choroidal images were obtained using swept-source optical coherence tomography. Automatic segmentation was used for image analysis, evaluating retina thickness parameters such as retinal nerve fiber layer, ganglion cell layer and inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, myoid and ellipsoid zone, outer segment of photoreceptors, RPE, and choroidal parameters including choroidal thickness, luminal area, stromal area, total choroidal area, choroidal vascular index, and choriocapillaris flow void percentage. Differences in photoreceptor-RPE-choriocapillaris complex among the groups and their correlation with body mass index were explored.

RESULTS

Compared with the control subjects, participants with obesity exhibited thinner myoid and ellipsoid zone and outer segment of photoreceptors, increased choriocapillaris flow void percentage, and thicker RPE. Correlation analysis revealed a negative correlation between body mass index and myoid and ellipsoid zone (r = -0.17, P = 0.01) and outer segment of photoreceptors (r = -0.16, P = 0.02), whereas a positive correlation was observed with RPE (r = 0.15, P = 0.00).

CONCLUSION

Individuals with obesity may present with a thinner myoid and ellipsoid zone and outer segment of photoreceptors, thicker RPE, and reduced choriocapillaris perfusion, suggesting potential damage to the photoreceptor-RPE-choriocapillaris complex. These alterations in the photoreceptor-RPE-choriocapillaris complex alterations could serve as potential biomarkers for monitoring early pathologic and physiologic changes associated with obesity.

Evaluation of the subfoveal choroidal and outer retinal layer thickness in obese women

CLINICAL RELEVANCE

Obesity has become one of the most important health problems of today with its increasing prevalence. With the development of retinal imaging systems, obesity has been observed to be associated with changes in outer retinal layers and choroid in women.

BACKGROUND

The aim of this study was to examine retinal layer parameters and their relationship with body mass index in obese women.

METHODS

The study included 197 eyes of 197 women, of whom 44 were normal-weight, 40 were overweight, 40 were class 1 obese, 38 were class 2 obese, and 35 were morbidly obese. The thickness of the choroid was measured manually using an enhanced-depth imaging optical coherence tomography scanning program.

RESULTS

The mean choroidal thickness values in five locations were lower than those of normal-weight, overweight, class 1, and class 2 obese women, in morbidly obese women (p < 0.05 for all). Subfoveal outer retinal layer thickness and specific sublayer thickness of the photoreceptor layer values were significantly lower in morbidly obese women than in normal-weight women, but there were no statistically significant differences between the groups in retinal pigment epithelium thickness and Bruch's membrane thickness (p = 0.001, p < 0.001, p = 1.00, and p = 0.101, respectively). Furthermore, there were significant negative relationships between body mass index and subfoveal choroidal thickness, subfoveal outer retinal layer thickness, and specific sublayer thickness of the photoreceptor layer values (r = -0.327, p < 0.001; r = -0.259, p < 0.001; and r = -0.281, p < 0.001, respectively).

CONCLUSIONS

Morbid obesity was associated with a thinner choroid, subfoveal outer retinal layer, and specific sublayer thickness of the photoreceptor layer in women. Furthermore, retinal hypoxia associated with morbid obesity may be related to a decrease in photoreceptor layer thickness. Thinning of the outer retinal layer may also lead to atrophy of the cone sheath.