Clinical Impact of 8 Prospective, Randomized, Multicenter Glaucoma Trials Joseph F. Panarelli, MD,* Michael R. Banitt, MD, MHA, MPH,* Paul A. Sidoti, MD,wz Donald L. Budenz, MD, MPH,y and Kuldev Singh, MD8 Purpose: To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice. Methods: An electronic survey was distributed to the members of the American Glaucoma Society (AGS). Each participant was asked 2 study-specific questions and 1 standard question common to all 8 RCTs assessing the study’s impact on clinical practice. RCTs included in the survey were the Advanced Glaucoma Intervention Study (AGIS), Collaborative Initial Glaucoma Treatment Study (CIGTS), Collaborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating all responses. The practice setting and duration of glaucoma practice was determined for all AGS members who responded. Results: A total of 206 (23.0%) of 894 AGS members participated in the survey. Among those who responded, 46.4% were self clas- sified as academic practitioners and 53.6% worked in a private practice setting. Mean Likert scores for the standard question evaluating the overall impact of the RCT were OHTS 4.47, CNTG Study 4.13, AGIS 3.78, TVT Study 3.53, EMGT 3.48, CIGTS 3.44, GLT 3.39, and 2.69 EGPS. Conclusions: Substantial differences were observed in the clinical impact of several RCTs in glaucoma. The reported impact of each study likely reflects several factors including study timing, design, conduct, and interpretation of results. Key Words: trabeculectomy, randomized clinical trial, survey (J Glaucoma 2015;24:64–68) O ver the past 3 decades, several multicenter randomized clinical trials (RCTs) have provided valuable infor- mation to help guide the glaucoma practitioner. The relative impact of specific studies on clinical practice has been difficult to objectively quantify, as different practi- tioners undoubtedly attach varying degrees of significance to the findings of each of these studies and how they impact their specific practices. Although it is generally accepted that a well-designed RCT provides the highest level of evidence supporting or refuting a medical hypothesis, the degree to which a given trial impacts practice may relate to the quality of the study and the relevance of the findings to current practice. There are several barriers to the appropriate design, conduct, and interpretation of findings from RCTs that should be considered when determining whether to change practice patterns based upon a particular study. 1,2 Not all trials are equally rigorous at the outset or relevant at the time of completion. Although there are difficulties in assimilating the results of RCTs into the care of patients, there are also difficulties in evaluating their impact on practice patterns. Peer surveys have been used in the past as a metric to assess the impact of RCTs. Schwartz 3 surveyed the members of the American Glaucoma Society (AGS) to determine the clinical significance of studies regarding the use of argon laser trabeculoplasty. Mansberger and Cioffi 4 performed a survey of ophthalmologists to estimate their ability to predict the risk of glaucoma development in ocular hyper- tensive patients. The present survey attempts to determine the clinical impact of 8 multicenter RCTs by surveying members of the AGS. METHODS Institutional Review Board approval for this study was obtained from the University of Miami Human Sub- jects Research Committee. The survey, consisting of 26 questions created by authors representing different institu- tions, was generated and electronically mailed to all 894 members on the AGS listserv. Each participant was asked to answer 2 study-specific questions and 1 general question common to all 8 RCTs assessing the study’s impact on clinical practice. The RCTs included in this survey were the Advanced Glaucoma Intervention Study (AGIS), Collab- orative Initial Glaucoma Treatment Study (CIGTS), Col- laborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating individuals’ responses as follows: 5 for strongly agree, 4 for agree, 3 for neither agree nor disagree, 2 for disagree, and 1 for strongly disagree. A Likert scale is commonly used in studies involving ques- tionnaires as a way to assign quantitative value to qual- itative data so that additional statistical analysis can be Received for publication September 4, 2012; accepted January 11, 2013. From the *Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL; wDepartment of Ophthalmology, New York Eye and Ear Infirmary, New York; zNew York Medical College, Valhalla, NY; yDepartment of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC; and 8Depart- ment of Ophthalmology, Stanford University, Palo Alto, CA. M.R.B. is supported in part by NIH-NEI Grant EY014957. P.A.S. is supported by grants from the David E. Marrus Glaucoma Research Fund and the Herman Peters Pediatric Glaucoma Research Fund. K.S. is supported by the Arlene Coffman Glaucoma Research Fund. The Bascom Palmer Eye Institute is supported by NIH Center Core Grant P30EY014801, Research to Prevent Blindness Unrestricted Grant, Department of Defense (DOD-Grant# W81XWH-09-1-0675). Disclosure: The authors declare no conflict of interest. Reprints: Joseph F. Panarelli, MD, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 900 NW 17th Street, Miami, FL 33136 (e-mail: jpanarelli@med.miami.edu). Copyright r 2013 by Lippincott Williams & Wilkins DOI: 10.1097/IJG.0b013e318295200b ORIGINAL STUDY 64 | www.glaucomajournal.com J Glaucoma  Volume 24, Number 1, January 2015