Some (2.6%) patients seeking aesthetic blepharoplasty had undiagnosed hypothyroidism contributing to periorbital aging changes; 0.3% had undiagnosed hyperthyroidism. Characteristic features suggesting the possibility of hypothyroidism were edema, "festoons," and "secondary" bags. The characteristic features of hyperthyroidism were proptosis and edema. Treatment of the underlying medical condition reversed the changes to a variable extent. Aesthetic surgery was not necessary in some patients.