Cataract surgery rates have dramatically increased in the last two decades. However, clinical practice variation in cataract surgery has not been thoroughly studied. The aim of this review is to analyze clinical practice variation, including the causes and consequences of this phenomenon. Then, its role in health care planning and health care quality is focused, emphasizing the importance of reducing it and providing several practical strategies to accomplish it. The latest researches are presented in this article. They identify the development and implementation of clinical practice guidelines as the best tool to standardize care processes. Managing unwarranted or unwanted variation would improve quality of care and may lead to a significant saving in health care spending. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.