Temporal inferior vein submerging into intrachoroidal cavitation and gamma zone

To describe the appearance of the temporal inferior vein submerging into the parapapillary region with characteristics of parapapillary gamma zone and parapapillary beta zone.

Ophthalmoscopy in a 28-year-old man showed a sagittally rotated optic nerve head with marked temporal inferior parapapillary atrophy, in which the temporal inferior vein appeared to partially disappear.

Serial optical coherence tomography images showed from inferior to superior, an intrachoroidal cavitation covered by intact Bruch membrane with retinal pigment epithelium (fulfilling the criteria of parapapillary beta zone). The intrachoroidal cavitation continued into an area with opened Bruch membrane (fulfilling the definition of parapapillary gamma zone) and a lamellar defect of the deep scleral layer. The lamellar defect became perforated leading to an apparent herniation of the retinal tissue into the almost extraocular space. From this herniation site, the inferior temporal vessel trunk submerged into an intrascleral or extrascleral pathway in the direction to the optic disk while the defect in the deep scleral layer was closed. Finally, more superior, the intrachoroidal cavitation decreased in volume and extent while Bruch membrane was absent (gamma zone).

This report describes an unusual course of the inferior temporal vessel trunk and an associated unusual anatomy of the parapapillary region with beta zone and gamma zone, and an additional defect in the deep scleral layer allowing the exit of the temporal inferior vessel trunk into the extrascleral space. The illustration may also show the usefulness of the differentiation between beta zone and gamma zone in the parapapillary region.