Blepharoptosis following anterior segment surgery: a new theory for an old problem.

Blepharoptosis is a well-known complication following anterior segment surgery. However, its precise aetiology remains elusive. There are currently two widely held views on the pathogenesis of persistent postoperative ptosis, namely the speculum and bridle suture theories. However, both suggested explanations fail to address important anatomical and epidemiological features of this condition. Until now, the majority of published literature describing persistent postoperative ptosis following anterior segment surgery has largely concentrated on dehiscence of the levator aponeurosis as the common mechanism underlying this postoperative complication. However, numerous studies have failed to show any correlation between pre or postoperative skin crease positions in such patients. This review article discusses previously proposed mechanisms responsible for both transient and persistent ptosis. Furthermore, we propose an alternative mechanism for the development of ptosis following anterior segment surgery, namely horizontal stretch of the upper eyelid induced by the use of the speculum. This mechanism also provides a plausible explanation for less commonly described oculoplastic complications, such as lower lid malpositions, following anterior segment surgery. Postoperative ptosis may also act as a paradigm for the development of involutional ptosis in general. In view of the frequency with which ophthalmologists perform anterior segment procedures such as cataract surgery, postoperative ptosis represents a significant concern for all ocular surgeons. Identifying the underlying mechanism is imperative, not only to identify those patients at greatest risk, but also to perhaps provide novel surgical approaches to the management of this complication.