Abstract
A 75-year-old patient presented with vertical tarsal plate buckling of both upper eyelids following a conjunctival mullerectomy. Clinical examination demonstrated significant lid laxity and lateral canthal tendon instability as well as short surgical scars on the conjunctival surface. The purported mechanism was an imbalance between the strong vertical force exerted by the resected muscle applied to a short width of tissue and the relatively weak horizontal lid stabilizing forces. This case underscores the importance of carefully considering all anatomic forces supporting eyelid dynamics prior to ptosis surgery.