What is the visual prognosis for retinal detachment?

Depends on the type.

1. For a rhegmatogenous retinal detachment where fluid from the vitreous cavity passes through a retinal break into the subretinal space to cause separation of the neural retina from the underlying retinal pigment epithelium, prognosis depends on the extent of damage to the macula. If the macula becomes detached, only about 50% end up with 20/40 vision or better despite surgical repair. In eyes with no macular detachment present, 90% can be expected to have 20/40 vision or better following surgery.

2. For an exudative retinal detachment where the neural retina is elevated secondary to the accumulation of subretinal fluid in the absence of a retinal break, prognosis is dependent upon the underlying cause (ie. neoplasm, inflammatory disease, congenital abnormalities) and whether or not it is reversible. In general, the retina tolerates exudative subretinal fluid better than fluid from rhegmatogenous retinal detachment. Therefore, provided the mechanism of fluid accumulation can be altered, good visual outcome can result even for relatively longstanding macular detachments.


Source

Yanoff & Duker: Ophthalmology, 3rd ed.

Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease