Visual acuity in the sheet-web building spider Badumna insignis (L. Koch 1872) (Araneae, Desidae) was examined in relation to its microhabitat. We examined, using histological techniques, the major structural and functional features of the visual systems, including external and internal ocular organizations, resolution, sensitivity, focal lengths and the field of view for each eye. Badumna insignis showed little differentiation in its ocular arrangement from the presumed ancestral condition in spiders, with poor visual acuity and a small field of view. Resolution and sensitivity were low, particularly in the secondary eyes. The AM eyes were enhanced showing larger fields of view and higher sensitivity, resembling that of nocturnal uloborids. These eyes appear adapted for close-range recognition, due to short-range focus and good visual overlap.