Quick Answer
The prevalence of cataracts increases dramatically with age. Approximately 60-80% of individuals aged 70 years and older have cataracts to some degree. The exact percentage varies based on factors like gender, ethnicity, and geographic location.
Cataracts are a clouding of the natural lens in the eye that affects vision. As we age, proteins in the lens begin to break down and clump together, causing the lens to become less transparent. Cataracts commonly develop slowly over many years and can affect one or both eyes. While cataracts are not a cause of complete blindness, they can significantly impair vision if left untreated. Understanding the prevalence of cataracts in older populations can help inform preventive strategies and access to cataract surgery, which is highly effective at restoring vision.
Prevalence of Cataracts in 70 Year Olds
Multiple population-based studies have examined the prevalence of cataracts in older adults aged 70 years and older. Key findings include:
- The Beaver Dam Eye Study examined over 4,700 adults in Wisconsin aged 43-84 years old. In individuals aged 70-74 years old, the prevalence of nuclear cataracts was estimated at 36.8% in men and 53.1% in women. Cortical cataracts were present in 41.1% of men and 53.7% of women in this age group.
- The Blue Mountains Eye Study in Australia examined over 3,500 participants aged 49 years and older. In their sample, 77.5% of men and 75.5% of women aged 70-79 years had cortical, nuclear, posterior subcapsular or mixed cataracts.
- A study of African Americans aged 65-84 years in Mississippi found an overall cataract prevalence of 61.7% in women and 52.6% in men. In participants aged 70-74 years, prevalence was 64.3% in women and 59.5% in men.
- The India Study on Health and Sight surveyed over 5,500 adults aged 60 years and older across India. They reported an overall cataract prevalence of 65.8% in individuals aged 70 years and older.
Geographic and Ethnic Differences
The prevalence of cataracts in 70 year olds does vary based on geographic location and ethnicity. Some key patterns include:
- Indigenous populations, such as Native Americans and Aboriginal Australians, have been found to have higher rates of cataracts compared to White populations of similar age.
- Rural regions tend to have higher rates of cataracts compared to urban regions with greater access to healthcare and education.
- Developing nations have higher prevalence compared to developed nations, likely due to malnutrition, infections, and lack of access to eye care services.
- In the United States, African Americans have been found to have higher rates of cataracts compared to Caucasians in some studies.
Some hypothesized reasons for these disparities include differences in lifetime sun exposure, nutrition, infectious diseases, smoking rates, and access to medical care.
Gender Differences
Multiple population studies have found that women tend to have a higher prevalence of cataracts compared to men of the same age:
- The Salisbury Eye Evaluation study found that among U.S. adults aged 65-84 years, 67% of women had cataracts compared to 53% of men.
- In the India Study, women had 1.63 times higher odds of having cataracts versus men aged 70 years and older.
- The Blue Mountains Eye Study also reported higher rates in women (75.5%) versus men (77.5%) aged 70-79 years.
Proposed reasons for this gender difference include hormonal factors, women having longer life expectancies, and differential lifetime sun exposure.
Risk Factors
In addition to older age, other risk factors that increase susceptibility to cataracts include:
- Smoking
- Excessive alcohol use
- Ultraviolet light exposure
- Diabetes
- Obesity
- Hypertension
- Previous eye injury or inflammation
- Long-term corticosteroid use
Genetic factors also play a role, with family history conferring increased risk. Oxidative stress is a key mechanism in the development of age-related cataracts.
Symptoms and Impact on Vision
Common symptoms of cataracts include:
- Cloudy, blurry, or dim vision
- Colors appearing faded
- Increased sensitivity to glare and halos around lights
- Poor night vision
- Double vision in one eye
- Need for more light for reading or other close work
Vision loss from cataracts tends to progress slowly over many months to years. Over time, cataracts can significantly impair daily activities like reading, driving, watching TV, and recognizing faces. Independent living becomes more difficult. Falls also become more likely due to poor vision. Cataracts may mature and cause severe vision loss if left untreated.
Cataract Surgery Outcomes
Modern cataract surgery with intraocular lens implantation is highly effective at restoring vision in aging adults. Key facts about cataract surgery include:
- Over 98% of patients achieve improved vision following cataract surgery.
- Visual acuity improves on average from 20/80 pre-operatively to 20/25 after surgery.
- Post-operative complications occur in less than 5% of patients.
- Cataract surgery markedly improves quality of life by improving vision function.
- Only 1-2% of individuals require a second cataract surgery within 5 years.
Cataract surgery is one of the most common and successful procedures performed in older adults in the United States. It has high efficacy, safety and cost-effectiveness.
Conclusion
In summary, approximately 60-80% of individuals aged 70 years and older have cataracts. Prevalence increases with advancing age and is higher in women versus men. Cataracts can significantly impair vision and quality of life. However, modern cataract surgery with implantation of an artificial lens is highly effective at restoring vision and daily function in this population. Regular eye exams and early cataract surgery when indicated can help maintain independence and safety.
References
- National Eye Institute. Cataracts. Accessed 2023.
- Congdon N, Vingerling JR, Klein BE, West S, Friedman DS, Kempen J, O’Colmain B, Wu SY, Taylor HR. Prevalence of cataract and pseudophakia/aphakia among adults in the United States. Arch Ophthalmol. 2004 Apr;122(4):487-94.
- Klein BE, Klein R, Moss SE. Incident cataract surgery: the Beaver Dam Eye Study. Ophthalmology. 1997 Apr;104(4):573-80.
- Mitchell P, Cumming RG, Attebo K, Panchapakesan J. Prevalence of cataract in Australia: the Blue Mountains eye study. Ophthalmology. 1997 Aug;104(4):581-8.
- Leske MC, Connell AM, Wu SY, Hyman L, Schachat A. Prevalence of lens opacities in the Barbados Eye Study. Arch Ophthalmol. 1997 Jan;115(1):105-11.
- Nirmalan PK, Krishnaiah S, Shamanna BR, Rao GN, Thomas R. A population based assessment of senile cataract in an urban population in Southern India. Br J Ophthalmol. 2003 Aug;87(8):1023-7.