Why is the macula susceptible to ischemia with retinal detachments?

The macula (the central retina that is most important for vision) is very thin, and derives its nutrition almost entirely from the choroidal bed underneath. Thus, when detached, it immediately loses its blood supply and dies. The photoreceptors and supporting cells quickly starve within 90 minutes, with resulting poor visual potential.

This becomes a factor when presented with a new retinal detachment – you must determine if the macula is on. If so, the patient needs surgery right away. If the macula is already off, the visual potential is poor, and the timing of surgery is not as urgent.