Heavy use of class A drugs, such as heroin, methamphetamine, or cocaine is linked to a heightened risk of partial or total blindness among US military personnel, finds research published online in the journal BMJ Military Health.
The condition, which affects the ability to read, drive, and recognise faces, is more common among military personnel than it is among civilians, possibly because of certain risk factors that are unique to active service in the US Armed Forces, say the researchers.
Several behavioural and health factors are associated with sight loss. These include HIV infection; high blood pressure; smoking; diabetes; poor diet; sedentary lifestyle; cancer; depression; gum disease; and social and economic deprivation.
It's not clear whether illicit drug use might compound these factors or represent an independent risk factor in its own right, or what role experience of military service might have.
To explore this further, the researchers drew on responses to the nationally representative National Health and Nutrition Examination Surveys for the years 2013 to 2018.
They compared dietary, lifestyle, and drug use factors in 106 serving or former soldiers and 1572 civilians.
The responses showed that those with experience of military service were significantly more likely to use illicit drugs than the civilians surveyed: 21% vs 13.5%. And proportionally more of them reported partial or total blindness than the civilians.
They were also more likely to have several other risk factors associated with sight loss, including HIV positivity, higher blood pressure, more years of smoking and lower levels of physical activity.
The researchers then ran the data through three separate analyses.
Their first showed that experience of military service was associated with a heightened risk of sight loss, while the second showed that older age, lower educational attainment, and lower household income were risk factors.
In the third analysis, health conditions, lifestyle factors, socioeconomic factors, military service and illicit drug use were all put into the mix, with experience of military service and Illicit drug use emerging as the strongest risk factors, followed by HIV positivity.
The researchers highlight several limitations to their study findings, including no information on the type, extent, or cause of sight loss or the timing of drug use. And there was little information on whether respondents were serving personnel or veterans.
"However, given the zero tolerance policy on drug use in the military, it is likely our military sample was composed entirely of veterans," they point out.
"This study indicates that (1) self-reported vision loss among service members or veterans is more prevalent than among civilians with no military experience, and (2) self-reported vision loss in military service members or veterans may be associated with severe or prolonged illicit drug use, such as heroin, methamphetamine, or cocaine," write the researchers.
And they conclude: "Given the relatively high prevalence of severe illicit drug use among service members or veterans compared with civilians, and the long term impacts on the eye, there is a need for medical and behavioural health programmes that provide vision screenings to drug-using veterans."
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Externally peer reviewed? Yes
Evidence type: Observational
Subjects: People
Journal
BMJ Military Health