Abstract Cyclo-oxygenase inhibitors, which are formulated as ophthalmic eyedrop preparations, have recently become commercially available for use by ophthalmologists in the United States to inhibit intraoperative miosis during cataract surgery and to prevent postoperative inflammation. In addition, they are available worldwide as ocular antiinflammatory drugs and are used in the prevention and treatment of pseudophakic and aphakic cystoid macular edema. Understanding the rationale behind the use of these agents requires an understanding of the pathophysiology of the cyclo-oxygenase inhibitors. In this review recent advances in laboratory and clinical science are emphasized. The role of COIs during and following surgery is examined.