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.