Publications by authors named "L M Ellwein"
Purpose: To estimate the nationwide prevalence of visual impairment and associated refractive error in school children in Bhutan.
Methods: The sample of this prospective cross-sectional national survey comprised of randomly selected classes in levels IV-IX (age 10 to 15 years) from schools throughout Bhutan. The examination included measurement of visual acuity (VA), evaluation of ocular motility, refraction under cycloplegia, examination of the external eye, media and fundus.
Purpose: To assess the influence of distance and near visual impairment on self-reported near visual functioning (VF) in a multinational study.
Design: Population-based cross-sectional study.
Participants: Participants aged 35 years or older were selected randomly with cluster sampling at 7 sites: rural sites in Nepal (Kaski) and India (Madurai), a semirural site in China (Shunyi), semiurban sites in South Africa (Durban) and Niger (Dosso), and urban sites in the United States (Los Angeles) and China (Guangzhou).
Background: To assess prevalence and causes of vision loss in Central and South Asia.
Methods: A systematic review of medical literature assessed the prevalence of blindness (presenting visual acuity<3/60 in the better eye), moderate and severe vision impairment (MSVI; presenting visual acuity <6/18 but ≥3/60) and mild vision impairment (MVI; presenting visual acuity <6/12 and ≥6/18) in Central and South Asia for 1990, 2010, 2015 and 2020.
Results: In Central and South Asia combined, age-standardised prevalences of blindness, MSVI and MVI in 2015 were for men and women aged 50+years, 3.
Purpose: To assess the potential of ready-made (spherical) spectacles (RMS) in meeting the need for refractive correction in visually impaired children in China.
Methods: Eligible children aged 5-17 years were identified from the three study sites in China. Distance visual acuity was measured with a retroilluminated logarithm of the minimum angle of resolution chart with tumbling E optotypes.
Purpose: To investigate the primary causes of visual impairment and blindness in rural China.
Design: Population-based, cross-sectional study.
Methods: Geographic cluster sampling was used in randomly selecting residents from a rural county/district within 9 provinces in the East Coast, Inland Middle, and West regions of mainland China.