Blindness and low vision: what are the horizons of prevention?

Pubblicato il

Wednesday, 30 May 2018

Argomento

Cecità e Ipovisione

Data and projections to identify the best strategies

Visual impairments are of the utmost importance in determining people's quality of life and the costs to health services. The Global Burden of Disease Study (GBD) 2015 ranked, on a worldwide scale, visual and auditory deficits as second only to spinal pain as a cause of years lived with disability (YLDs). Even in the over-65 population, sense organ deficits rank as the most common cause of YLDs.
Trends in blindness and low vision in high-income countries and Central and Eastern Europe were the subject of a meta-analysis, published in the British Journal of Ophthalmologyby Prof. Rupert Bourne of Anglia Ruskin University and a large number of colleagues from around the world. These data are an update of a 2010 meta-analysis and are based on a total of 46 cross-sectional population-based clinical studies, in which visual acuity was assessed through clinical testing and in which 'blind' is defined as people with visual acuity of less than 3/60 in the better eye, and 'visually impaired' as people with visual acuity of no more than 6/18, but at least 3/60.
The estimated total number of blind people in the world in 2015 resulted from 36.2 million peopleof which 70,000 in Australasia, 980,000 in North America and 1.16 million in Western Europe.
The cataract is still the most frequent cause of blindness, with a prevalence of 35.73%, followed by uncorrected refractive defects, glaucoma, AMD, corneal diseases, trachoma and diabetic retinopathy. The ranking of the leading causes of blindness has basically remained stable since 1990, but researchers report that in rich countries, AMD has risen to second position (15.39%) and glaucoma to third (13.5%), even though these diseases can now be much better managed thanks to the therapeutic offerings currently available.
Uncorrected refractive defects are the predominant cause of moderate to severe visual impairment, followed by cataracts.
It is interesting to note the growing importance as a cause of blindness of the diabetic retinopathygrowth in Europe from 2.42% in 1990 to 3.3% in 2015. This figure is to be seen as closely related to the increasing prevalence of diabetes mellitus and the progressive ageing population.
Taking into account the constancy of the trends identified up to 2015, we can extrapolate broad indications for the most appropriate health policy interventions, and given the weight of uncorrected refractive defects in terms of low vision, a primary objective should be to eliminate the barriers that prevent adults from accessing appropriate correction. Moreover, it is precisely the diagnosis of refractive defects that can be an opportunity to identify other visual problems, first and foremost cataracts, that can be appropriately remedied. Targeted screening for glaucoma and AMD can be of great importance in order to adopt the therapies available today to counteract irreversible visual deterioration at an early stage.
Diabetic retinopathy, given the growing trend, should be the focus of special attention especially in rich countries, where diet and lifestyles seem to favour the increasing prevalence of type 2 diabetes.
Finally, a few words on the importance of the presbyopiaWith an increasingly long-living and active population, it becomes very important to enhance the use of the most advanced forms of correction of this physiologically age-related eye condition.