Congenital Absence of the Canaliculus and Punctum

ABSTRACT

Absence or atresia of the canaliculus and punctum is rare. The primordium of the lacrimal passage which is derived from surface ectoderm is developed along the line of the cleft between the lateral nasal and the maxillary processes at about 10 mm. (5th week) embryo. At 15 mm. (6th week) embryo, it becomes detached from the surface ectoderm to form an irregular solid rod of cells; the epithelial cord thus formed represents the rudiments of the lacrimal passages. By bud-like cutgrowths from the upper extremity of the uppermost rod of cells, these are rudiments of the lacrimal canaliculi and they reach the epithelium of the lid margins at the 35 mm. embryo. During the 3rd month the central cells of the solid rod begin to disintegrate; the originally solid naso-lacrimal passages thus become canalized. Although the lumina of the canaliculi become patent during the 4th month, the lacrimal puncta do not open onto the lid margins until just before the lids separate during the 7th month. The three main types of developmental anomaly affecting the passages are gross changes; due to failure in the regular fusing of the nasal and maxillary processes, samller changes due to an abnormal course being followed by the budding cells, and failures in canalization resulting in atresia. Authors presented 2 cases of absence of puncta combined with atresia of canaliculi which send to be resulted from failure in canalization.