Poor and elderly in Mozambique at higher risk for blindness

Researchers reported that poverty and old age increased chances of being blind. Policy makers could use this information to improve blindness prevention programs. 

Eye diseases like ‘cataracts’ and ‘glaucoma’ can lead to blindness. 

A ‘cataract’ is a cloudy layer on the lens of the eyeball. In glaucoma, a person’s sight is reduced because the nerve at the back of the eye is damaged. 

Researchers already know that blindness is linked to poverty. However, surveys on blindness commonly used by researchers worldwide do not ask respondents about their economic status. In Mozambique, researchers do not know the exact number of people with blindness and what might be causing it.

To find out, they conducted a survey to assess eyesight of adults above age 50 in the Sofala region of Mozambique. The researchers also checked what was the cause if poor eyesight was noticed. They also asked respondents about their poverty level and if they wore eyeglasses.

Their results showed that 3.2% of participants were blind, while 17.5% had reduced eyesight.

The researchers reported that cataracts caused 55.1% of blindness and glaucoma 24%. 

They said ‘refractive errors’, which includes being nearsighted (objects far away are blurry) or farsighted (objects nearby are blurry), caused 29% of poor eyesight. Cataracts caused 48% of poor eyesight. 

The researchers said that 73% of blindness reported could be prevented or treated.

They observed that poverty and old age increased a person’s chances of being blind. The researchers found only weak evidence that women, people with no formal education, and those living in rural areas, were more likely to be blind.

The researchers said over 8000 people in Sofala region would need eyeglasses and 400 would need eye operations to remove cataracts.

This was the first study to report the prevalence of blindness in the Sofala region, and highlighted the need for eye care services there. The researchers reported that age and poverty increases chances of being blind.

While these were very important results, the researchers cautioned that their sample size was small. They also said they were only able to check for causes of blindness that needed simple instruments. 

They said they only assessed poverty using daily expenditure, and this might not be enough.

The researchers recommended that surveys on blindness should also measure poverty, and that better ways of measuring poverty be developed.

They also said patients who had cataract surgery should be monitored, and healthcare workers should be trained in advanced surgical techniques and biometry tools, which measure eyeballs.

The researchers said their results can be applied to Mozambique and beyond.

Abstract

Objective: Although the correlation between visual impairment and poverty has been established, economic assessment is not a standard component of blindness surveys. The purpose of this study was to determine the prevalence of avoidable blindness and its association with poverty in Sofala province of Mozambique.

Methods: As part of a Rapid Assessment of Avoidable Blindness, 94% of a random sample of 3600 people >50 years responded to questions regarding daily per capita expenditure. The WHO definition of blindness (presenting visual acuity <3/60) was used to determine the visual status of participants, and the World Bank’s threshold of living on <$1.25 International Dollar a day demarcated the poverty line.

Results: The prevalence of blindness was 3.2% [95% Confidence Interval (CI): 2.6, 3.8]. People living below the poverty line had a significantly greater odds of being blind [Odds Ratio (OR): 2.6 (CI: 1.6 to 4.5)]. Age above 60 [OR: 7.0 [CI: 4.6 to 10.80] predicted blindness but the association with illiteracy, gender or rural residence was not significant.

Conclusions: Blindness disproportionately affects people living below the poverty line. Development initiatives could augment the impact of blindness prevention programs. Measuring poverty should become a standard component of visual impairment surveys.

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