Introduction
Is specifically a horseshoe-shaped retinal tear, with the apex pointing to the posterior pole.
- Traction which occurs causes the retinal tear to remain attached to the vitreous at the apex flap, leading to ongoing VR traction.
- Usually seen in the peripheral retina, where the retina is thinner
- 73% in the superior fundus
Dead Giveaways
Fundus Appearance:
Appears quite literally like a flap. This flap will bend upwards, leading to an appearance resembling a horseshoe
Flap seen in centre, attached in the very superior (hind) aspect, with a horseshoe shape forming. 
Shows the horseshoe flap in the inferior. The size is notably small, since it is unlikely to progress. Whilst pigmentation is expected due to chronicity of the lesion, this pigmentation is due to laser treatment, which still indicates chronicity, but of the laser lesions.
OCT Appearance:
Will appear as a partial detachment, with one portion detached and attached to the vitreous cortex, but the posterior (or hind) aspects still intact and attached with no breaks
Shows the horseshoe flap attached to the cortical vitreous, with an exposed tear. Fluid vitreous can enter and cause RRD. Additionally, we see the hind portion still intact with the RPE, but this can detach with RRD.
diagnostic features
Prognosis:
Ongoing traction indicates a high risk of RRD
This is always considered an EMERGENCY, as it can eventually approach the macula. Can lead to very poor vision with high abundance of floaters.
However, if it is present in the inferior fundus, it is significantly less likely to progress, due to gravity
Schaeffer's Sign (Tobacco Dust):
Clumping of the pigmentary cells in the vitreous
Movement of vitreous into the retina breaks down MPS bonds in the RPE to release pigment. Tobacco dust always requires referral, indicating an increased risk of progression of breaks/tears to detachment, or indicate the presence of them.