Definition
Prominent and anteriorly displaced Schwalbe's line. 

Signs
Thin grey-white curve adjacent to limbus.  (Looks like white arc inside the angle)

Characteristics
30% of population has posterior embryotoxon as an insolated, innocuous finding.  Systemic associations are rare.

Systemic Associations
Axenfeld anomaly - Posterior embroytoxin (Schwalbe's line) connects to strands of peripheral iris tissue
Rieger anomaly - iris hypoplasia, displaced pupils, glaucoma + iris strand connection
Rieger syndrome - dental, facial, renal, and cardiac abnormalities

Alagille syndrome - defects in bile ducts, cardiopulmonary malformations, vertebral defects.  Optic disc drusen common finding.
 
No Treatment Necessary if isolated finding