Cataract – A Public Health Challenge
Cataract is the leading cause of blindness worldwide, accounting for more than 51% of all cases of global blindness. Despite being treatable through a simple and cost-effective surgery, cataract continues to pose a major public health challenge, particularly in low- and middle-income countries. This challenge is not only medical but also social and economic, affecting millions of people’s independence, productivity, and quality of life.
What is Cataract?
A cataract is the clouding of the natural lens inside the eye. The lens plays a crucial role in focusing incoming light onto the retina, enabling clear and sharp vision. When the lens becomes opaque, it scatters or blocks light, leading to blurred or dimmed vision.
Cataracts typically develop gradually with age, but they can also result from:
- Eye injuries or trauma
- Diabetes and other systemic diseases
- Long-term exposure to ultraviolet (UV) radiation
- Smoking and alcohol use
- Use of certain medications (e.g., corticosteroids)
- Genetic or congenital conditions
Symptoms of Cataract
Cataracts typically develop gradually over time, and in their early stages, they often do not produce noticeable symptoms. However, as the condition progresses and the lens becomes increasingly cloudy, various visual disturbances and functional impairments begin to affect daily life. Below is a detailed overview of common symptoms:
- Blurred or cloudy vision
- Difficulty seeing at night or in low light
- Sensitivity to light and glare
- Seeing “halos” around lights
- Fading or yellowing of colors
- Frequent changes in eyeglass or contact lens prescription
- Double vision in one eye
These symptoms affect daily activities such as reading, driving, and recognizing faces—contributing to loss of autonomy, increased risk of falls, and psychosocial impacts like anxiety and depression.
Epidemiology and Global Burden of Cataract
The prevalence of cataracts increases significantly with age. It affects about 3.9% of people aged 55–64 years and rises sharply to 92.6% among those aged 80 years and older. In 2010, cataracts blinded 10.8 million people, a figure projected to reach 40 million by 2025 as the global population ages.
However, previous studies have largely focused on the overall visual impairment caused by cataracts, with limited attention given to the varying degrees of vision loss —such as moderate, severe, and blindness. Recent findings suggest that:
- Moderate vision loss constitutes the majority of cataract-related cases when assessed using age-standardized prevalence rates.
- However, age-standardized DALY rates (disability-adjusted life years) are dominated by blindness, indicating that even at lower prevalence, blindness causes a greater loss of healthy life years and greater reductions in quality of life.
DALY reflects the gap between actual health and ideal health, and in the case of cataracts, it shows how vision loss—especially blindness—severely affects independence, productivity, and well-being.
Cataracts account for a significant proportion of visual DALYs globally, disproportionately affecting populations in low-income countries where access to surgery is limited.
Health Impact and Complications
Cataracts have profound effects on individuals and society. Beyond vision loss, the condition is associated with numerous health risks:
- Increased risk of dementia: Visual impairment caused by cataracts may contribute to cognitive decline and a higher likelihood of developing dementia.
- Higher rates of falls and traffic accidents: Visual impairment increases the chance of fall-related injuries and road traffic crashes, especially among the elderly.
- Reduced quality of life: Poor vision leads to social isolation, reduced mobility, and psychological distress.
- Increased mortality: Cataract-induced vision loss is linked to a higher risk of mortality due to its impact on physical health and independence.
Treatment and Accessibility Challenges
Despite being highly treatable through surgery, cataracts continue to cause avoidable blindness. Currently, no drugs have been approved to prevent or treat cataracts pharmacologically. Surgery remains the only effective treatment, with advances in techniques making it relatively low-risk and highly successful in restoring vision.
However, access to surgery is not equitable:
- In high-income countries, cataract surgery is routine.
- In low-income settings, financial constraints, lack of trained personnel, poor infrastructure, and limited awareness contribute to delayed or absent treatment. Consequently, a large proportion of cataracts remain untreated, leading to preventable blindness.
Gender Inequality in Cataract Burden
One of the most overlooked yet significant barriers in addressing the global burden of cataract is gender disparity. Although cataracts affect both men and women, the impact is disproportionately borne by women, who represent the majority of cataract patients globally but are significantly less likely to receive treatment. This disparity reflects broader issues of inequality in health care access, education, socioeconomic status, and cultural norms—particularly in low- and middle-income countries.
Unequal Disease Burden
Women have a higher prevalence of cataracts, largely due to their longer life expectancy, which increases their exposure to age-related eye conditions.
- Since age is a key risk factor, women are more likely to develop cataracts over their lifetime.
- For example, in Japan, women live on average 86.8 years, compared to 80.5 years for men.
Inequitable Access to Surgery
Despite making up 60% of global cataract cases, women are 1.39 times less likely than men to receive cataract surgery. Barriers include:
- Less financial independence
- Lower literacy rates
- Limited mobility or familial support
- Cultural norms deprioritizing female health
Broader Patterns Across Eye Diseases
This gender gap is not unique to cataracts. Similar disparities are seen in:
- Uncorrected refractive error
- Age-related macular degeneration
- Diabetic retinopathy
These findings underline a structural inequality in global eye health, where gender biases in healthcare access amplify disease burden for women.
Call to Action and Policy Recommendations
To address cataracts as a global health priority, the following strategies should be implemented:
- Expand Access to Surgery
- Train and deploy more ophthalmologists, focusing on low-resource areas
- Develop affordable, high-volume surgical centers, particularly in underserved areas
- Implement mobile screening units and outreach programs
- Integrate Eye Care into Public Health Systems
- Make cataract screening a part of routine health checkups for older adults
- Subsidize or fully cover cataract surgery in national health programs
- Raise Public Awareness
- Educate the public about cataract symptoms and the safety of surgery
- Reduce stigma and cultural misconceptions about eye surgery
- Strengthen Monitoring and Data Use
- Utilize global burden of disease (GBD) data and disability-adjusted life years (DALYs) to prioritize interventions and guide the efficient allocation of resources for cataract care
- Track cataract surgical coverage (CSC) and outcomes to measure impact
Conclusion
Cataract is a preventable and treatable cause of blindness, yet millions continue to suffer from its disabling effects due to systemic barriers in access, awareness, and equity. The global burden is rising, with the heaviest toll falling on the elderly and on women—groups that are too often marginalized in healthcare systems.
Eliminating cataract blindness will require more than just surgical capability—it will demand equity-focused health policies, community engagement, gender-sensitive interventions, and sustained investment in public health infrastructure.
- Changing Trends in the Global Burden of Cataract Over the Past 30 Years: Retrospective Data Analysis of the Global Burden of Disease Study 2019 - PMC
- Global, regional, national burden and gender disparity of cataract: findings from the global burden of disease study 2019 | BMC Public Health | Full Text
- Understanding the cataract treatment disparities among older adults in India - PubMed
- Cataracts: Signs, Symptoms & Treatment Options
