RESUMO
BACKGROUND: Progressive herniation of lower eyelid fat has generally been accepted as a part of the aging process in the lower eyelid. Numerous theories have been proposed for the mechanism of periorbital aging, but to the best of the authors' knowledge, the actual occurrence of lower eyelid fat herniation has not been documented. METHODS: Using data of orbital and facial computed tomography from 167 patients, the authors evaluated curvature and protrusion of lower eyelid fat and its changes in different age groups. The relation of its occurrence to the position of the ocular globe was also evaluated. RESULTS: A statistically significant effect of age groups was detected for curvature (percent) of lower eye lid fat. Specifically, when compared with the reference group (younger than 30 years), each increase of 1 year shows a curvature increase of 0.48 percent for the group that was 30 to 69 years old (95 percent confidence interval, 0.27 to 0.69; p < 0.01). For the age group of 70 years or older, each increase of 1 year could predict a 1.22 percent increase of curvature (95 percent confidence interval, 0.81 to 1.63; p < 0.01). CONCLUSIONS: The authors found that although the amount of lower eyelid fat varies greatly between individuals, the process of lower eyelid fat herniation does occur. It retains a steady incline after the third decade of life and slows at approximately age 70. In the authors' study, ocular globe position appears unrelated to this process of herniation.