[Hypothesis on the pathogenesis of the papillary dysversion syndrome]

The tilted disc syndrome is an ocular anomaly characterized by dysversion of the optic nerve head, congenital crescent, vessel anomalies, ectasia and depigmentation of the infero-nasal fundus. Its pathogenesis is not known, but there are many theories as to its origin. The most convincing one links the tilted disc syndrome to an anomalous closing of the embryonic fissure. However this hypothesis does not adequately explains the origin of all the anomalies found in the syndrome. In this paper a new theory is suggested. The ganglion cell fibres of the infero-nasal retina could be misdirected toward the orbit through an anomalous embryonic fissure. In this way the fibres could not reach their central connections and degenerate. The hypoplasia of the infero-nasal quadrant of the eye could originate from the anomalous closing of the embryonic fissure and from the atrophy of the ganglion fibres; the crescent from the lack of fibres in the inferior optic disc; the anomalous appearance of the optic nerve head and the retinal vessels from a shifting of the disc upward due to the imbalance between the ganglion cell fibres coming from the superior and inferior retina.