The global burden of trichiasis in 2016.

• Main Authors: Rebecca M Flueckiger, Paul Courtright, Mariamo Abdala, Amza Abdou, Zaid Abdulnafea, Tawfik K Al-Khatib, Khaled Amer, Olga Nelson Amiel, Sossinou Awoussi, Ana Bakhtiari, Wilfried Batcho, Assumpta Lucienne Bella, Kamal Hashim Bennawi, Simon J Brooker, Brian K Chu, Michael Dejene, Djore Dezoumbe, Balgesa Elkheir Elshafie, Aba Ange Elvis, Djouma Nembot Fabrice, Fatma Juma Omar, Missamou François, Drabo François, Jambi Garap, Michael Gichangi, André Goepogui, Jaouad Hammou, Boubacar Kadri, George Kabona, Martin Kabore, Khumbo Kalua, Mathias Kamugisha, Biruck Kebede, Kaba Keita, Asad Aslam Khan, Genet Kiflu, Makoy Yibi, Garae Mackline, Colin Macleod, Portia Manangazira, Michael P Masika, Marilia Massangaie, Takafira Mduluza, Nabicassa Meno, Nicholas Midzi, Abdallahi Ould Minnih, Sailesh Mishra, Caleb Mpyet, Nicholas Muraguri, Upendo Mwingira, Beido Nassirou, Jean Ndjemba, Cece Nieba, Jeremiah Ngondi, Nicholas Olobio, Alex Pavluck, Isaac Phiri, Rachel Pullan, Babar Qureshi, Boubacar Sarr, Do Seiha, Gloria Marina Serrano Chávez, Shekhar Sharma, Siphetthavong Sisaleumsak, Khamphoua Southisombath, Gretchen Stevens, Andeberhan Tesfazion Woldendrias, Lamine Traoré, Patrick Turyaguma, Rebecca Willis, Georges Yaya, Souleymane Yeo, Francisco Zambroni, Jialiang Zhao, Anthony W Solomon
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2019-11-01
• Series: PLoS Neglected Tropical Diseases
• Online Access: https://doi.org/10.1371/journal.pntd.0007835

<h4>Background</h4>Trichiasis is present when one or more eyelashes touches the eye. Uncorrected, it can cause blindness. Accurate estimates of numbers affected, and their geographical distribution, help guide resource allocation.<h4>Methods</h4>We obtained district-level trichiasis prevalence estimates in adults for 44 endemic and previously-endemic countries. We used (1) the most recent data for a district, if more than one estimate was available; (2) age- and sex-standardized corrections of historic estimates, where raw data were available; (3) historic estimates adjusted using a mean adjustment factor for districts where raw data were unavailable; and (4) expert assessment of available data for districts for which no prevalence estimates were available.<h4>Findings</h4>Internally age- and sex-standardized data represented 1,355 districts and contributed 662 thousand cases (95% confidence interval [CI] 324 thousand-1.1 million) to the global total. Age- and sex-standardized district-level prevalence estimates differed from raw estimates by a mean factor of 0.45 (range 0.03-2.28). Previously non- stratified estimates for 398 districts, adjusted by ×0.45, contributed a further 411 thousand cases (95% CI 283-557 thousand). Eight countries retained previous estimates, contributing 848 thousand cases (95% CI 225 thousand-1.7 million). New expert assessments in 14 countries contributed 862 thousand cases (95% CI 228 thousand-1.7 million). The global trichiasis burden in 2016 was 2.8 million cases (95% CI 1.1-5.2 million).<h4>Interpretation</h4>The 2016 estimate is lower than previous estimates, probably due to more and better data; scale-up of trichiasis management services; and reductions in incidence due to lower active trachoma prevalence.