Patients with rhegmatogenous retinal detachments involving the fovea have visual loss that may not be recoverable despite anatomically successful surgery. Few guidelines exist to predict ultimate visual outcome with any certainty. We found that despite macular detachment, a device commonly used to predict visual acuity in cataractous eyes, the Potential Acuity Meter (Mentor O & O, Inc., Norwell, Massachusetts), provided acuity measurements even when Snellen visual acuity levels were poor or unmeasurable. In a study of 50 consecutive patients with clear media, we investigated a possible correlation between postoperative Snellen visual acuity with the preoperative Potential Acuity Meter results. We found that actual visual improvement correlated well with potential visual improvement as determined by Potential Acuity Meter measurements (R = .92). Preoperative assessment of patients with this device was a better predictor of final visual outcome than preoperative Snellen visual acuity, the extent of retinal detachment, or the duration of the retinal detachment by history.