Phenotypic Variations in Lower Eyelid Anatomy Across Ancestral Groups and Their Implications in Oculoplastic Surgery: A Narrative Review.

Background: Phenotypic variations in lower eyelid anatomy across ancestral groups significantly influence aesthetic and functional outcomes in oculoplastic surgery. Differences in skin thickness, fat distribution, muscle morphology, and bony architecture necessitate population-specific surgical strategies to optimize results and minimize complications.

Methods: A narrative review was conducted synthesizing anatomic and clinical data pertaining to lower eyelid structures across Asian, European, African, and Latin American ancestral groups. Key elements-including orbital malar ligament (OML) morphology, periorbital pigmentation, and fat pad dynamics-were systematically analyzed to identify clinically relevant variations and their implications for surgical planning.

Results: Distinct anatomic patterns were observed. East Asians demonstrated a high-fusion point of the orbital septum with the capsulopalpebral fascia, robust OML, and early infraorbital fat protrusion. Europeans exhibited thin dermis, attenuated fat pads, and predisposition to tear trough deformities. African populations displayed a hypertrophied orbicularis oculi muscle and a robust OML. Latin American individuals demonstrated intermediate features. Pigmentation patterns and culturally specific aesthetic ideals, such as the "aegyosal" in East Asian populations, further modified clinical approaches.

Conclusion: A nuanced understanding of ancestry-specific anatomic variations is essential for achieving culturally congruent and anatomically precise outcomes in lower eyelid surgery. Existing literature remains limited, particularly regarding deep retaining structures such as the OML. Future research integrating objective imaging and broader demographic representation is needed to advance personalized, inclusive oculoplastic care.