Embryology of Lacrimal System and Congenital Lacrimal Anomalies

Lacrimal outflow embryology is complex and anomalous embryological development modification at any stage can lead to a wide variety of structural defects of the lacrimal outflow drainage system. The formation and invagination of a lacrimal lamina into a cord of surface ectoderm in the fronto-nasal fold leads to the formation of a lumen thereby forming the primitive lacrimal drainage structures which at the end of its process will lead to a patent lacrimal outflow system. When an alteration occurs during the cord stage this may create agenesis, accessory canaliculi and diverticula, whilst those modifications happening during the maturative stage may cause imperforate punctum and congenital nasolacrimal duct obstruction due to an altered canalisation of the cord. In this chapter we aim to highlight a comprehensive description of the lacrimal drainage developmental disorders encountered during clinical practice and to underline practical standardised management to common and complex presentations.