Introduction
Has a prevalance of 1-2 in 10,000
- 10-15% of the time, it is bilateral
- VA is rarely affected, but there can be an enlarged blind spot.
Pathophysiology:
- Very similar to the Jain and Johnson pathophysiology
- Small pocket next to the ON which the retina protrudes through
- Herniation of dysplastic retinal tissue seeps into the optic pit area
- Dysplastic neuroectodermal tissue herniates posteriorly into collagen-lined pocket through a defect in the lamina cribrosa
- Maculopathy develops under pressure variation, if the IOP pushes fluid past the dysplastic tissue which returns into the retina. The ICP pushes fluid past the pit sac which also enters the retina.
Dead Giveaways
The biggest giveaway is in the fundus image and OCT:
Fundus
A greyish-oval area at the temporal neural rim is very evident, as well as peripapillary atrophy at the optic disc, leading to a pigmented appearance
Pit and peripapillary atrophy seen
OCT:
The absence of the RNFL can be seen at points on the retina.
RNFL is absent on the left, as well as very evident maculopathy and schisis
diagnostic features
Whilst the VA is not usually affected, maculopathy develops in 25-75% of optic pits.
This causes VA loss and serous macular detachment and schisis
If it is unilateral the optic disc is enlarged compared to the fellow eye.