RT Book, Section
A1 Oh, Dawn M.
A1 Oh, Kean T.
A2 Wallace, Robert B.
SR Print(0)
ID 1141961527
T1 Disabling Visual Disorders
T2 Maxcy-Rosenau-Last Public Health and Preventive Medicine, 15e
YR 2017
FD 2017
PB McGraw-Hill Medical
PP New York, NY
SN 9780071441988
LK accessbiomedicalscience.mhmedical.com/content.aspx?aid=1141961527
RD 2024/04/19
AB Although  the  prevalence  of  blindness  worldwide  is  not  precisely  known,  new  global  estimates  from  2002  World  Health  Organization  (WHO)  show  at  least  37  million  people  are  blind  and  another  124  million  people  have  low  vision.  This  figure  is  based  on  the  standard  international  definition  of  blindness:  a  visual  acuity  (VA)  of  less  than  3/60  or  corresponding  visual  field  loss  in  the  better  eye  with  best  possible  correction,  and  a  VA  of  <6/18  (but  greater  than  3/60  or  a  field  loss  of  less  than  20%)  constituting  “low  vision.”  Because  of  the  essential  nature  of  vision  for  most  endeavors,  the  frequency  of  blindness  also  reflects  a  global  loss  in  disability-adjusted  life  years,  and  is  considered  by  WHO  to  be  a  key  barrier  to  development  worldwide.  The  causes  of  blindness  and  visual  loss,  most  preventable  through  primary  intervention  or  secondary  therapy,  include  a  small  core  of  major  diseases  including:  cataract  (47.8%),  glaucoma  (12.3%),  diabetic  retinopathy  (4.8%),  macular  degeneration  (8.7%),  trachoma  (3.6%),  onchocerciasis  (0.8%),  and  corneal  opacities  (5.1%)  (Fig.  68-1).  However  the  fraction  of  the  blindness  burden  for  each  disease  differs  substantially  from  region  to  region  (Fig.  68-2).