A model of an experimental arhegmatogenous retinal detachment is presented, to allow the measurement of the transport of radioactive labeled substances out of the subretinal space. Experiments were performed on 19 male cats. 131I-iodo-o-hippurate and 22Na were used as test substances. There was no significant difference between the rate of disappearance of 131I-hippurate if injected retroretinally or intravitreally. The rate of disappearance of 131I-hippurate could be slowed down by intravenous infusion of penicillin-G. The rate of disappearance of 22Na following retroretinal injection is not only slower than the rate of disappearance of 22Na injected intravitreally, but significantly slower than the rate of disappearance of 131I-hippurate. For graphic analysis ("curve peeling") of the terms embodied in the curves, more densly situated points of measurements will be necessary. Then the experimental model will serve well to analyze the components influencing the transport of labeled sodium out of the subretinal space.