The purpose of this paper was to evaluate the quality and scope of the published literature on functional impairment due to cataract in adults as reviewed for the Agency for Health Care Policy and Research Clinical Practice Guideline. We examined the method of literature retrieved and analysis performed in the course of development of literature-based recommendations for the guideline panel. To collect data, we reviewed the process of literature acquisition and identification and the quality assessments made by reviewers of 14 individual topics composed of 77 issues related to the guideline. We collated this information to provide an assessment of the quality and scope of the relevant literature. Less than 4% (310) of the approximately 8,000 articles initially identified as potentially relevant to the guideline were ultimately used. The majority covered three topics (surgery and complication, 100; Nd:YAG capsulotomy, 77; and potential vision testing, 40). Three other topics--indications for surgery, preoperative medical evaluation, and rehabilitation--were devoid of articles meeting inclusion criteria. For 43 issues, there was no identifiable relevant literature. With few exceptions, the quality of the literature was rated fair to poor owing to major flaws in experimental design. Case series (256 reports) of one type or another accounted for the majority of the included literature. There were 17 random controlled trials. This review revealed a sparse and generally low-quality literature relevant to the management of functional impairment due to cataract, despite a relatively large data base in reputable peer-reviewed journals.