IT HAS long been recognized that ophthalmoscopy of the extreme periphery of the fundus has great significance in evaluating detachments, but few accurate and complete funduscopic observations have been recorded. In the latter part of the nineteenth century, the anterior limits of the visible fundus were determined both in clinical and in laboratory studies. The conclusions, however, were somewhat contradictory. In 1948, further experiments were conducted along these lines at the Massachusetts Eye and Ear Infirmary, in Boston, using the direct and the indirect method of ophthalmoscopy and comparing the results. The ora serrata, which forms a transition zone between the pars optica and the pars ciliaris retinae, is located 7 to 8 mm. back of the limbus.1The retina is firmly attached to the choroid in this region. The ora makes a well defined serrated line, composed of approximately 48 toothlike projections of retinal tissue, directed anteriorly. These