The purpose of this study was to identify the anatomical basis for perception of lower eyelid bags in patients seeking aesthetic surgery and to evaluate the cumulative contribution of different anatomic characteristics before surgery.The histories and photographs of patients whose motivation for aesthetic consultation was lower eyelid bags were analyzed. Six categories of anatomic basis for the lower eyelid bags were identified. For each patient, a score from 0 to 4 was given in each category. The cumulative contribution score for each category was calculated as total points for that category for all patients, divided by the 456 total available points. The authors also developed a "uniqueness score" to reflect the percentage contribution of the worst identified anatomic problem compared with the other problems. This was calculated for each patient as the maximum score in one category, divided by total points for that patient.A total of 114 consecutive cases were evaluated (67 men and 47 women; mean age, 52 +/- 11 years; age range, 23 to 76 years). The cumulative contribution score for each anatomic variable was as follows: cheek descent and hollow tear trough, 52 percent; prolapse of orbital fat, 48; skin laxity and sun damage, 35; eyelid fluid, 32; orbicularis hyperactivity, 20; and triangular cheek festoon, 13. Prolapsed orbital fat and tear trough deformity both received the higher score and were more common in men as compared with women. The average uniqueness score was 38 percent, with a range of 20 to 75 percent. No one category played a dominant role for most patients. Tear trough depression, skin laxity, and triangular malar mound were significantly more common in patients older than 50 years. Linear regression analysis showed that recommendation for surgery is based on the extent of fat prolapse, skin elasticity, and midface descent. Significant positive correlations were found in all six categories and in uniqueness scores calculated by different observers (r values ranged from 0.31 to 0.73; p < 0.001, Pearson correlation), with the highest score in agreement with the contribution of eyelids fat (r = 0.73) and skin laxity (r = 0.66); the uniqueness score correlation was r = 0.45 (p < 0.001).Eyelid bags do not have a single anatomic basis. For different anatomic problems, different treatments are recommended.