Endoscopic Evidence of the Punctum-Canalicular Junction

Scanning electron microscopy studies have demonstrated a distinct puncto-canalicular junction between the luminal surfaces of the punctum and the vertical canaliculus. This junction was slightly elevated with a smooth inner punctal surface proximally and rugae-like surface distally. A 38-years-old male underwent balloon punctoplasty for punctal stenosis. A high-magnification end-on endoscopy view of the dilated punctum showed a distinct and slightly elevated puncto-canalicular junction (Fig. A,B black arrows) with a smooth and pale proximal portion correlating with the luminal surface of the punctum just within the punctum rim. The segment just distal to the junction represents the luminal surface of the vertical canaliculus, which was more pinkish with fine mucosal folds (Fig. A,B). This anatomy correlated well with the earlier ultrastructural findings of the junction (red arrow, Fig. C) along with the proximal smooth (red star, Fig. C) and distal rugae-like surface (red diamond, Fig. C). The presence of a distinct puncto-canalicular junction is now convincingly demonstrated clinically and matches up with electron microscopic description. Further fundamental work is required to ascertain this junction’s anatomical and functional significance.

The Puncto-Canalicular Junction.