The World Health Organisation (WHO) considers exposure to ambient air pollution among the main contributors to global disease outbreaks. Air pollution has, in fact, been associated with pulmonary and cardiovascular diseases, as well as with pathological conditions of the central nervous system such as Alzheimer's disease, Parkinson's disease and stroke.
Glaucoma is a degenerative ocular neuropathy, which is one of the leading causes of blindness and low vision globally. Increased intraocular pressure (IOP) has been identified as the main risk factor editable for glaucoma and is a sufficient, but not necessary condition for the onset of the disease. Glaucoma is a disease complex, whose precise aetiological mechanisms are still not fully known. Some authors claim that people living in urban areas are 50% more likely to develop glaucoma than those living in rural areas, thus identifying air pollution as a risk factor that could contribute to the onset of the disease. Very recently, moreover, it has been proposed an association between glaucoma disability and national levels of Atmospheric Particulate Matter 2.5 micrometre (PM2.5).
If air pollution is indeed found to be associated with glaucoma, it would constitute a new risk factor potentially editable and would add weight to future campaigns to reduce air pollutants.
A recent paper, published in Investigative Ophthalmology and Visual Scienceused data from the UK Biobank to assess the relationship between air pollutants PM2.5, self-referring glaucoma, IOP and mean thickness of the inner plexiform layer of macular ganglion cells (GCIPL). The authors analysed a cohort of 111,370 participantswho underwent eye tests from 2006 to 2010 at sites across Great Britain. Participants were asked about the presence of glaucoma and underwent eye tests to measure intraocular pressure (IOP) and macula thickness. The data collected from the participants were combined with measures of air pollution in their areas of residence, with a focus on PM2.5.
The research team reported that people living in the 25% of the most polluted areas were at least 6% more likely to report glaucoma than those who lived in the least polluted areas. Residents in the most polluted areas also had, a significantly higher probability of having a thinner retinal macular area (typical change in glaucoma progression). The results showed, however, no association between intraocular pressure and air pollution, which, according to the researchers, suggests that air pollution influences the risk of glaucoma through a different mechanism, probably related to neurotoxic and/or vascular effects.
Source:
Sharon Y. L. Chua et al. The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort. Investigative Ophthalmology and Visual Science, 2019.
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Dr. Carmelo Chines
Direttore responsabile