Fifty eyes of 40 patients with serous (avascular) detachments of the retinal pigment epithelium were followed up for an average of 22 months. Of the 50 eyes, 14 (28%) developed bleeding beneath the retinal pigment epithelium and retina or subretinal neovascularization detected on fluorescein angiography. These changes did not occur in eyes of patients younger than age 56 years at diagnosis or in detachments less than 1 disk diameter in size, whereas 35.9% (14) of eyes in patients older than age 56 years developed vascular complications. Vascular complications were uncommon when the initial detachment did not involve the fovea. Visual acuity declined in only one (9.1%) of eyes in patients younger than age 56 years but in 20 (51.3%) of eyes in patients age 56 years or greater.