New systematic review methodology for visual impairment and blindness for the 2010 Global Burden of Disease study.
OBJECTIVE
To describe a systematic review of population-based prevalence studies of visual impairment (VI) and blindness worldwide over the past 32 years that informs the Global Burden of Diseases, Injuries and Risk Factors Study.


METHODS
A systematic review (Stage 1) of medical literature from 1 January 1980 to 31 January 2012 identified indexed articles containing data on incidence, prevalence and causes of blindness and VI. Only cross-sectional population-based representative studies were selected from which to extract data for a database of age- and sex-specific data of prevalence of four distance and one near vision loss categories (presenting and best-corrected). Unpublished data and data from studies using rapid assessment methodology were later added (Stage 2).


RESULTS
Stage 1 identified 14,908 references, of which 204 articles met the inclusion criteria. Stage 2 added unpublished data from 44 rapid assessment studies and four other surveys. This resulted in a final dataset of 252 articles of 243 studies, of which 238 (98%) reported distance vision loss categories. A total of 37 studies of the final dataset reported prevalence of mild VI and four reported near VI.


CONCLUSIONS
We report a comprehensive systematic review of over 30 years of VI/blindness studies. While there has been an increase in population-based studies conducted in the 2000s compared to previous decades, there is limited information from certain regions (eg, Central Africa and Central and Eastern Europe, and the Caribbean and Latin America), and younger age groups, and minimal data regarding prevalence of near vision and mild distance VI.
Vision & Eye Research Unit, Postgraduate Medical Institute, Anglia Ruskin University, Cambridge, UK. rb@rupertbourne.co.uk
Rupert
R
Bourne
Holly
H
Price
Hugh
H
Taylor
Janet
J
Leasher
Jill
J
Keeffe
Julie
J
Glanville
Pamela C
PC
Sieving
Moncef
M
Khairallah
Tien Yin
TY
Wong
Yingfeng
Y
Zheng
Anu
A
Mathew
Suchitra
S
Katiyar
Maya
M
Mascarenhas
Gretchen A
GA
Stevens
Serge
S
Resnikoff
Stephen
S
Gichuhi
Kovin
K
Naidoo
Diane
D
Wallace
Steven
S
Kymes
Colleen
C
Peters
Konrad
K
Pesudovs
Tasanee
T
Braithwaite
Hans
H
Limburg
D001766:Blindness / Q000453:epidemiology*; D014943:Global Health; D006801:Humans; D015995:Prevalence; D015354:Vision, Low / Q000453:epidemiology*; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*