Cross-Sectional Soft-Tissue Composition and the Distribution of Blue Cutaneous Discoloration in the Lower Eyelid after Hyaluronic Acid Injection.

The soft-tissue composition of the eyelid varies from lateral to medial, in that the orbicularis area (in square millimeters) is greatest medially and least laterally, whereas the reverse is true for the preauricularis and postorbicularis fat. The purpose of this study was to describe the relative contribution of tissue types to the volume of the lower eyelid-midface junction. This is an observational cohort study of 11 subjects (20 eyes) without a history of orbital or periorbital surgery or abnormality. Quasi-sagittal surface coil magnetic resonance imaging scans in planes parallel to the long axis of each orbit were obtained during central gaze fixation. Measurements of the tissue area (in square millimeters) of the skin, preorbicularis fat, orbicularis, and postorbicularis fat were obtained in the center, medial, and lateral eyelid regions. Differences in tissue area across the eyelid were assessed. The segmental cross-sectional area and percentage of total segment represented by the orbicularis muscle increased from the lateral (9.4 mm; 21.8 percent) to the central (14.1 mm; 35.0 percent) and to the medial (18.5 mm; 47.0 percent) eyelid (p < 0.01). The inverse pattern was noted for both preorbicularis and postorbicularis fat, each occupying less area (in square millimeters) from lateral to medial (p < 0.01). Skin thickness did not vary significantly across the eyelid. The soft-tissue composition of the eyelid varies from lateral to medial in that the orbicularis increases in area, whereas the reverse is true for the preorbicularis and postorbicularis fat. This anatomical progression may help to explain the stereotypical location of blue discoloration in some patients after hyaluronic acid filler injection.