More than 60% of all blind people in the world are female, but research often focuses on a male population or a mixed population. A 2018 journal article looks at why females may be more at risk and why research needs to incorporate both sex and socioeconomic differences*

What differences must be addressed?

Cataracts are the biggest cause of blindness and visual impairment around the world, and women are more likely than men to develop them. Despite this, the research on the mechanisms behind this risk factor is limited. 

A trachoma, or the development of scar tissue on the inside of the eyelid and could lead to blindness, is also more common in girls and women than boys and men. In fact, it affects girls two times and women four times more frequently.

To address these disparities, medical guidance should look at biological differences to inform clinicians and patients of the risk factors for blindness. The researchers also urge that the medical community incorporate socioeconomic differences into their research for more comprehensive care.

In addition to biological differences, researchers recommend that socioeconomic differences, often referred to as gender differences and defined in this study as the social, economic and cultural resources allocated to a specific gender, be included in medical guidance. According to the BMJ Open Ophthalmology study, “…patterns of health and illness reflect not just biological variables but also a wide range of external influences.”

What are the physiological, or biological, differences?

Physiological, or biological, differences between men and women tend to focus on the hormonal aspects of reproductive systems and differential functioning of male and female immune systems. 

In regards to hormones, one study found that estrogen had a protective role in cataract formation, which explains why postmenopausal women, whose estrogen levels lower, are more at risk. Pregnancy may also lead to blurred vision, but the mechanism behind this change is not well known. 

As it relates to the immune system, eyes are impacted by autoimmune disorders, like rheumatoid arthritis, Graves’ disease, Sjögren’s syndrome. Autoimmune eye disease prevalence rates are more than 500 per 100,000 in those with Graves’ disease. This is significant because at least 85% of people suffering from autoimmune disorders, like Graves’ disease, are women.

“It is clear therefore that some of the greater burden of blindness experienced by women can be explained by biological sex differences but that more research is needed to make sense of how they operate,” shared the researchers.

What are the socioeconomic differences?

Women whose roles lie in childcare or hygiene-related tasks or who are exposed to unsanitary water may be more at risk of trachoma, which can lead to loss of vision. “The blindness will inevitably affect women’s capacity to carry out the tasks expected of them, but it is important to look beyond the effects of vision impairment itself,” the researchers stated. These other effects could be emotional turbulence, such as embarrassment or shame, and a hit to finances, due to the inability to perform labor. 

These same side effects can also occur in women who develop cataracts. Moreover, it’s important to recognize that, while women are much more likely than men to develop cataracts, they are significantly less likely to receive a surgical intervention to restore their vision. 

Taking into account social differences, such as a person’s role in their household or ability to access care, allows researchers to more holistically approach care for patients of different socioeconomic status.

What is the solution?

The Vision 2020 Initiative by the International Agency for the Prevention of Blindness (IAPB) aims to eliminate all avoidable blindness by 2020 but does not adequately address the issues of gender equity. The same goes for the World Health Organization (WHO) in its Universal Eye Health: A Global Action Plan for the Prevention of Blindness 2014-2019.

It is important that researchers analyze the biological and socioeconomic gaps between need and use of eye care services in future studies. An estimate suggests that if women’s access to cataract surgery were equal to that of men, the overall incidence of global blindness would decrease by 12.5%. 

By addressing physiological and social disparities, blindness can be curbed throughout the world in the world’s most vulnerable population.

*Doyal, L., & Das-Bhaumik, R. G. (2018). Sex, gender and blindness: a new framework for equity. BMJ Open Ophthalmology, 3(1), e000135. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6146307/

Any sources from outside of Prevent Blindness do not imply an endorsement from Prevent Blindness. The contents of the material used are the responsibility of the authoring organization, Responsum Health.