Introduction
Appears as a splitting of the neurosensory retina, with vertical pillars within the area of schisis.
- Typically originates from the peripheral microcystoid degeneration, forming cysts in the OPL and ONL.
- These cysts can coalesce, leading to widespread detachment of the neurosensory retina (does not maintain the neurosensory retina unlike RRD).
- In bullous retinoschisis, there is a splitting of the retina anterior to the OPL, such as a schisis in the RNFL, and this is typically thinner than regular schisis.
- Bullous retinoschisis typically develops due to a thinning or breakage in the inner retina, but outer retina is also fairly common (11-24%)
- In order for RRD to occur, breaks in the retina must occur in both inner and outer retina
Dead Giveaways
Fundus Appearance
On fundus photography, retinoschisis appears as a translucent smooth dome-shaped lesion.
There is a negative Schaeffer's sign
Lesions are relatively immobile, causing absolute scotomas
Note the inferior temporal bubble like appearance. Vessels in this region may appear darker in colour, or diverted from their normal path
OCT Appearance
Is the major giveaway to the presence of schisis due to the pillars that form
Note the pillars in the peripheral retina. The retina appears to be very thin, and this is due to the natural thinning of the retina in the periphery 
From OCT-scans, shows the bullous retinoschisis (left) and standard retinoschisis (centre). 
Another example of bullous retinoschisis. Despite the lack of pillars, definitely not RRD due to the intact RPE. White flecks can be seen on the surface (Gunn's dots)
diagnostic features
Differentiation from Rhegmatogenous Retinal Detachment:
Unlike the schisis, RRD is a separation of the neurosensory retina from the RPE, due to subretinal fluid.
RPE is typically intact but shows atrophy overtime
Instead of smooth, appears wrinkled, corrugated and irregular, with an opaque appearance
Is associated with Schaeffer's sign, with clear point of retinal breakage
Lesions is very mobile, and can move, leading to relative scotoma
RRD on OCT shows that separation of RPE from the neurosensory retina 
RRD has this corrugated and wrinkling appearnce. The retinal break is visible as a horseshoe retinal tear.