What is the fluid clearance rate inside the retina?
As I mentioned in a comment, the RPE (retinal pigment epithelium) is in charge of absorbing the "water" from the retina and beneath it. 


  Water is eliminated from subretinal space by active transport by the
  RPE. The transportation rate was estimated to range from 1.4 to 11 µl
  x cm-2 x h-1.