Mani Baskaran1, Rajesh S Kumar2, David S Friedman3, Qing-Shu Lu4, Hon-Tym Wong5, Paul T K Chew6, Raghavan Lavanya7, Arun Narayanaswamy7, Shamira A Perera8, Paul J Foster9, Tin Aung10. 1. Department of Glaucoma, Singapore Eye Research Institute and Singapore National Eye Center, Singapore, Republic of Singapore; EYE-Academic Clinical Program, Duke-NUS Medical School, Singapore, Republic of Singapore; Department of Glaucoma, Medical and Vision Research foundation, Sankara Nethralaya, Chennai, India. 2. Department of Glaucoma, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates, Cleveland Clinic Lerner College of Medicine, Case Western, Reserve University, Cleveland, Ohio. 3. Glaucoma Center of Excellence, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts. 4. EYE-Academic Clinical Program, Duke-NUS Medical School, Singapore, Republic of Singapore; Department of Biostatistics and Epidemiology, Singapore Clinical Research Institute, Singapore, Republic of Singapore. 5. Department of Glaucoma, Tan Tock Seng Hospital, Singapore, Republic of Singapore. 6. Department of Glaucoma, National University Hospital and the Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore. 7. Department of Glaucoma, Singapore Eye Research Institute and Singapore National Eye Center, Singapore, Republic of Singapore. 8. Department of Glaucoma, Singapore Eye Research Institute and Singapore National Eye Center, Singapore, Republic of Singapore; EYE-Academic Clinical Program, Duke-NUS Medical School, Singapore, Republic of Singapore. 9. National Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom. 10. Department of Glaucoma, Singapore Eye Research Institute and Singapore National Eye Center, Singapore, Republic of Singapore; EYE-Academic Clinical Program, Duke-NUS Medical School, Singapore, Republic of Singapore; Department of Glaucoma, National University Hospital and the Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore. Electronic address: aung.tin@singhealth.com.sg.
Abstract
PURPOSE: To examine the efficacy of laser peripheral iridotomy (LPI) in patients who received a diagnosis of primary angle-closure suspect (PACS). DESIGN: Prospective, randomized controlled trial. PARTICIPANTS: This multicenter, randomized controlled trial (ClinicalTrials.gov identifier, NCT00347178) enrolled 480 patients older than 50 years from glaucoma clinics in Singapore with bilateral asymptomatic PACS (defined as having ≥2 quadrants of appositional angle closure on gonioscopy). METHODS: Each participant underwent prophylactic LPI in 1 randomly selected eye, whereas the fellow eye served as a control. Patients were followed up yearly for 5 years. MAIN OUTCOME MEASURES: The primary outcome measure was development of primary angle closure (PAC; defined as presence of peripheral anterior synechiae, intraocular pressure [IOP] of >21 mmHg, or both or acute angle closure [AAC]) or primary angle-closure glaucoma (PACG) over 5 years. RESULTS: Of the 480 randomized participants, most were Chinese (92.7%) and were women (75.8%) with mean age of 62.8 ± 6.9 years. Eyes treated with LPI reached the end point less frequently after 5 years (n = 24 [5.0%]; incidence rate [IR], 11.65 per 1000 eye-years) compared with control eyes (n = 45 [9.4%]; IR, 21.84 per 1000 eye-years; P = 0.001). The adjusted hazard ratio (HR) for progression to PAC was 0.55 (95% confidence interval [CI], 0.37-0.83; P = 0.004) in LPI-treated eyes compared with control eyes. Older participants (per year; HR, 1.06; 95% CI, 1.03-1.10; P < 0.001) and eyes with higher baseline IOP (per millimeter of mercury; HR, 1.35; 95% CI, 1.22-1.50; P < 0.0001) were more likely to reach an end point. The number needed to treat to prevent an end point was 22 (95% CI, 12.8-57.5). CONCLUSIONS: In patients with bilateral asymptomatic PACS, eyes that underwent prophylactic LPI reached significantly fewer end points compared with control eyes over 5 years. However, the overall incidence of PAC or PACG was low.
PURPOSE: To examine the efficacy of laser peripheral iridotomy (LPI) in patients who received a diagnosis of primary angle-closure suspect (PACS). DESIGN: Prospective, randomized controlled trial. PARTICIPANTS: This multicenter, randomized controlled trial (ClinicalTrials.gov identifier, NCT00347178) enrolled 480 patients older than 50 years from glaucoma clinics in Singapore with bilateral asymptomatic PACS (defined as having ≥2 quadrants of appositional angle closure on gonioscopy). METHODS: Each participant underwent prophylactic LPI in 1 randomly selected eye, whereas the fellow eye served as a control. Patients were followed up yearly for 5 years. MAIN OUTCOME MEASURES: The primary outcome measure was development of primary angle closure (PAC; defined as presence of peripheral anterior synechiae, intraocular pressure [IOP] of >21 mmHg, or both or acute angle closure [AAC]) or primary angle-closure glaucoma (PACG) over 5 years. RESULTS: Of the 480 randomized participants, most were Chinese (92.7%) and were women (75.8%) with mean age of 62.8 ± 6.9 years. Eyes treated with LPI reached the end point less frequently after 5 years (n = 24 [5.0%]; incidence rate [IR], 11.65 per 1000 eye-years) compared with control eyes (n = 45 [9.4%]; IR, 21.84 per 1000 eye-years; P = 0.001). The adjusted hazard ratio (HR) for progression to PAC was 0.55 (95% confidence interval [CI], 0.37-0.83; P = 0.004) in LPI-treated eyes compared with control eyes. Older participants (per year; HR, 1.06; 95% CI, 1.03-1.10; P < 0.001) and eyes with higher baseline IOP (per millimeter of mercury; HR, 1.35; 95% CI, 1.22-1.50; P < 0.0001) were more likely to reach an end point. The number needed to treat to prevent an end point was 22 (95% CI, 12.8-57.5). CONCLUSIONS: In patients with bilateral asymptomatic PACS, eyes that underwent prophylactic LPI reached significantly fewer end points compared with control eyes over 5 years. However, the overall incidence of PAC or PACG was low.