Prevalence and causes of visual impairment and blindness among 9980 Scandinavian adults: the Copenhagen City Eye Study.
OBJECTIVE
To investigate the age-specific prevalence and causes of visual impairment and blindness in an epidemiologic study of an adult Scandinavian population.


METHODS
Population-based, cross-sectional study.


METHODS
The study population was composed of 9980 persons, ages 20 to 84, from the general population of Copenhagen, Denmark.


METHODS
This study is based on the third Copenhagen City Heart Study (CCHS III). Participants who reported visual impairment or blindness or had difficulty reading newspaper type and used prescribed eye medications were contacted from 1999 through 2000 and asked to complete a standardized interview concerning their ophthalmologic history. Verification of objective ophthalmologic data was done with a validated questionnaire response method.


METHODS
Best-corrected visual acuity in the better eye and primary causes of visual impairment and blindness. Visual impairment was defined as visual acuity worse than 20/40 but better than 20/200, and blindness was defined as visual acuity of 20/200 or worse.


RESULTS
The age-standardized prevalence rates of visual impairment and blindness were 0.66% and 0.20%, respectively, and rose significantly with age (P<0.001). For persons 20 to 64 years, myopia-related retinal disorders, diabetic retinopathy, optic neuropathy, and retinitis pigmentosa were the most common causes of impaired vision. For persons 65 to 84 years, cataract was the most common cause of visual impairment, whereas age-related macular degeneration was the major cause of blindness.


CONCLUSIONS
Visual impairment and blindness are strongly associated with increasing age, and the causes are determined by age. Among persons aged 20 to 64 years, an intervention for the predominating eye diseases might have some effect. Among those aged 65 to 84 years, cataract surgery could reduce visual impairment by one third.
Buch
Helena
H
Department of Ophthalmology, National University Hospital (Rigshospitalet), Copenhagen, Denmark. hbh@dadlnet.dk
Vinding
Troels
T
La Cour
Morten
M
Appleyard
Merete
M
Jensen
Gorm B
GB
Nielsen
Niels Vesti
NV
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001766:Blindness / Q000453:epidemiology* / Q000209:etiology*; D015984:Causality; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005128:Eye Diseases / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D015354:Vision, Low / Q000453:epidemiology* / Q000209:etiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*