Cataracts are the leading cause of blindness worldwide, as reported by the CDC and WHO. This common eye condition affects millions of people and occurs when the lens of the eye becomes cloudy, impairing vision. But what causes cataracts? With over two decades of experience as a board-certified ophthalmologist, I want to share what I’ve learned about the top 10 causes of cataracts, ranked from least to most common. From congenital factors to aging, I’ll delve into the intriguing world of cataracts and the factors that contribute to this condition.

Understanding Cataracts

Before discussing the causes, let me explain what cataracts are. The lens of the eye, located behind the iris, focuses light onto the retina, allowing us to see clearly. Cataracts develop when proteins in the lens clump together, creating cloudy areas that scatter light and reduce vision. Over time, these clouded areas can grow, severely impairing sight.

Cataracts can occur in one or both eyes, but they are not contagious. While cataracts are most commonly associated with aging, there are numerous other causes that I’ve encountered in my practice and research.

The 10 Causes of Cataracts

Here are the 10 primary causes of cataracts, ranked from least to most common, based on my professional experience and the latest research:

10. Congenital Cataracts

Congenital cataracts occur when a baby is born with or develops cataracts shortly after birth. These are often linked to genetic conditions, infections during pregnancy (such as rubella), or metabolic disorders. Although rare, I’ve seen how congenital cataracts can lead to severe vision problems if not treated promptly. Pediatric cataract surgery is life-changing for infants, and early intervention is crucial for their visual development.

9. Eye Trauma

Injuries to the eye can cause cataracts by damaging the lens or surrounding tissues. I’ve treated patients with traumatic cataracts that developed immediately after an injury or even years later. Common causes include blunt force trauma, penetrating injuries, or chemical exposure. I always stress the importance of wearing protective eyewear during sports or hazardous work to reduce the risk of eye trauma.

8. Radiation Exposure

Radiation exposure, whether from medical treatments like cancer therapy or prolonged exposure to UV rays, can increase the risk of cataracts. UV radiation from the sun is particularly harmful. I tell my patients to think of their sunglasses as sunscreen for their eyes. Sunglasses that block 100% of UVA and UVB rays are a simple and effective way to protect your vision.

7. Prolonged Use of Corticosteroids

Long-term use of corticosteroids, whether oral, systemic, or in the form of eye drops, can lead to steroid-induced cataracts. I’ve seen this in patients using steroids for conditions like asthma, autoimmune diseases, or chronic inflammation. While these medications are often necessary, I work closely with patients to minimize risks by adjusting doses or exploring alternative treatments when possible.

6. Smoking

Smoking is a significant risk factor for cataracts because it generates harmful free radicals that damage the proteins in the lens. Smokers are up to three times more likely to develop cataracts than non-smokers. I always encourage my patients to quit smoking—not just for their eyes, but for their overall health. The positive effects of quitting are well worth the effort.

5. Excessive Alcohol Consumption

Excessive alcohol use disrupts the antioxidant balance in the body, leading to oxidative stress that damages the lens. I’ve seen a higher prevalence of cataracts in patients with a history of heavy drinking. Moderation is key, and I remind patients that small lifestyle changes can have a significant impact on their eye health.

4. Systemic Diseases

Systemic diseases, particularly diabetes, are major contributors to cataracts. High blood sugar levels in diabetics can cause the accumulation of sorbitol in the lens, leading to swelling and cloudiness. Managing chronic conditions is critical, and I work with patients to ensure their systemic diseases are under control to minimize the risk of cataracts and other complications.

3. Poor Nutrition

Nutrition plays a vital role in maintaining eye health. A diet lacking in antioxidants, such as vitamins C and E, or carotenoids like lutein and zeaxanthin, increases the risk of cataracts. I always recommend a balanced diet rich in colorful fruits and vegetables to my patients. These simple dietary changes can make a big difference in preserving vision.

2. UV Exposure

Prolonged exposure to ultraviolet (UV) light is a well-known cause of cataracts. UV radiation accelerates protein breakdown in the lens, leading to clouding. This is why I always stress the importance of wearing sunglasses and wide-brimmed hats, especially for those who spend a lot of time outdoors. Prevention is simple but often overlooked.

1. Aging

The most common cause of cataracts is aging. As we get older, the lens naturally undergoes changes, including hardening, yellowing, and protein clumping. These changes often begin around age 40, though symptoms may not become noticeable until later. Age-related cataracts are nearly universal, but their progression and impact vary based on genetics and lifestyle.

Why Cataracts Are the Leading Cause of Blindness

Cataracts are the leading cause of blindness worldwide, particularly in low- and middle-income countries where access to affordable surgery is limited. According to the World Health Organization, cataracts account for over 50% of blindness globally. During my humanitarian missions, I’ve seen how transformative cataract surgery can be for patients who have lived with blindness for years. Restoring their sight not only changes their lives but also benefits their families and communities.

Prevention and Hope

The good news is that many causes of cataracts can be managed or prevented. Here are my top recommendations:

• Protect Your Eyes: Wear sunglasses that block UV rays and wide-brimmed hats to reduce UV exposure.

• Quit Smoking: Reducing oxidative stress benefits your eyes and overall health.

• Eat a Nutritious Diet: Include antioxidant-rich foods like leafy greens, carrots, and citrus fruits.

• Manage Chronic Conditions: Keep conditions like diabetes under control to reduce the risk of cataracts.

• Regular Eye Exams: Early detection of cataracts and other eye conditions is key to preventing severe vision loss.

If cataracts progress to the point where they interfere with daily life, cataract surgery is a safe and effective solution. In this outpatient procedure, I replace the cloudy lens with a clear artificial one, restoring clear vision.

Conclusion

Cataracts are a common condition, but they are also highly preventable and treatable. From congenital factors to lifestyle choices like smoking and UV exposure, understanding the causes of cataracts empowers us to take proactive steps to protect our vision. As an eye surgeon, I’ve witnessed the profound impact of cataract prevention and treatment. Whether you’re concerned about your own risk or simply curious about eye health, this knowledge can help you see the world more clearly.