• Basic anatomical differences: In all groups of people, the anatomy of the lower eyelid tends to mirror the anatomy of the upper eyelid. For instance, there is typically more fat present in the Asian lower eyelid and the tissue layers enclosing this fat compartment (the orbital septum and lower eyelid retractors) relate and connect differently than in the Occidental lid. If the surgeon is aware of such differences, the "standard" Occidental operation can be modified very slightly and yield equally effective outcomes in those as Asian descent.
• Fat: As noted, the amount of orbital fat extending into the lower eyelid is increased, and the fibroadipose layer is more developed (see diagrams). One common error is that some doctors confuse fat and muscle when evaluating the lid and thus draw erroneous conclusions with respect to the selection of the appropriate surgical procedure.
• Skin quality: Asian lower eyelid skin tends to be more resistant to wrinkling at a young age. The skin is, however, more "reactive," which means that the scars from skin incisions may seem thicker at first and take a longer period of time to soften and mature to a final state. The most common Asian olive skin tone is graded as Fitzpatrick IV, a designation important in skin resurfacing procedures (see below).
• Eyelid crease: Because the normal lower eyelid does not possess a defined crease in either Asian or Occidental adults, the concept of a "double eyelid" has no relevance in lower eyelid surgery.
• Shape of the eyelid opening: The Asian eyelid opening (that is, the space between the upper and lower eyelids) tends to be more almond shaped (that is, less rounded). In most Asian and Occidental patients, the lateral canthus (the junction of upper and lower eyelids closest the ear) sits slightly higher relative to the medial canthus (the similar junction closest the nose). This normal upward canthal tilt is intensified in some Asian eyelids. Surgery must be designed to respect such anatomical starting points.