To describe the ocular pathologic changes in multiple sclerosis (MS), with attention to its effects on the uveal tract and retinal veins. Cases of 26 patients with MS and 3 patients with neuromyelitis optica were reviewed; retinal trypsin digestion was performed on remaining wet tissue for 20 of these patients. Eyes were specifically examined for inflammation of the retinal vessels, uveal tract, retina, optic nerve, and pars plana. Specimens were also examined for atrophy of the optic nerve, ganglion cell, and nerve fiber layers. Atrophy of the nerve fiber and ganglion cell layers was present in 73% of the cases with MS and correlated with optic nerve atrophy; choroiditis was present in 11.5%; bilateral cyclitis without other foci of inflammation was present in 1 case; and retinal phlebitis was present in 20% (most of which were only identified after trypsin digestion). Optic nerve inflammation was present in two of the patients with neuromyelitis optica. Uveitis and retinal phlebitis are manifestations of MS. Trypsin digestion with microscopic examination is a sensitive method of testing for phlebitis, which may explain why the frequency found in this series is higher than in others. These lesions are similar to the perivenular cuffing that occurs in the central nervous system in MS.