Introduction: The purpose of this study was to examine the cause-specific prevalence and 5-year incidence of visual impairment and blindness among middle-aged and older citizens of Reykjavík.

Material and methods: A random sample of 1045 persons aged 50 years or older underwent a detailed eye examination in 1996 and 846 of the survivors participated in a follow-up examination in 2001. Visual impairment was defined according to World Health Organization definitions as a best-corrected visual acuity of <6/18 but no worse than 3/60, or visual field of ≥5° and <10° around a fixation point in the better eye. Best-corrected visual acuity of <3/60 in the better eye was defined as blindness. The causes of visual impairment or blindness were determined for all eyes with visual loss.

Results: The prevalence of bilateral visual impairment and blindness was 1.0% (95% CI 0.4-1.6) and 0.6% (95% CI 0.1-1.0), respectively and the 5-year incidence was 1.1% (95% CI 0.4-1.8) and 0.4% (95% CI 0.0-0.8), respectively. The prevalence of visual impairment among 60-69 year old participants was 0.6%, but among those aged 80 years or older the prevalence was 7.9%. The major cause of bilateral visual impairment and blindness both at baseline and follow-up was age-related macular degeneration. Cataract accounted for less severe visual loss. The two most common causes of unilateral visual impairment at baseline were amblyopia and cataract. Cataract was the main cause of unilateral visual impairment at 5-year follow-up.

Conclusion: Prevalence and 5-year incidence of both uni- and bilateral visual impairment and blindness increases with age. Age-related macular degeneration was the leading cause of severe visual loss in this population of middle-aged and older Icelanders.

Gunnlaugsdóttir E, Arnarsson AM, Jónasson F

¹Department of Ophthalmology, Landspítali University Hospital, Reykjavík, Iceland, ²Faculty of Medicine, University of Iceland, Reykjavík, ³Neuroscience research, University of Akureyri, Akureyri.

Figure 1: Prevalence of bilateral visual impairment (10 persons, 20 eyes)

Figure 2: Prevalence of unilateral visual impairment (46 persons, 46 eyes)

Table 1: Prevalence (%) and 5-year incidence of visual impairment and blindness according to World Health Organization criteria.

Fjöldi= number of participants; n= persons with visual impairment or blindness 95% CI = 95% Confidence Interval.