Cataracts form on the lens of the eye—the transparent structure located just behind the iris and the pupil.
The lens helps focus light on the retina, allowing for clear vision. When a cataract forms, it clouds this lens, making it harder for light to pass through in a straight path. As a result, you may see blurred images, glare from lights, or faded colors. Cataracts are a common age-related eye condition and are the leading cause of vision loss in the United States.
In this article, we’ll explore how and why cataracts develop on the lens, the different types of cataracts, how they affect vision, and when treatment—including cataract surgery—may be necessary.
What Is the Lens of the Eye?
The lens is a clear, flexible structure that sits behind the colored part of the eye (the iris). It changes shape to help you focus on nearby or distant objects. Over time, proteins inside the lens start to break down and clump together. This buildup creates cloudy areas that are known as cataracts.
Since the lens is responsible for focusing light, any clouding affects how clearly you can see. You might notice blurry vision, especially in bright light or while reading, driving, or trying to see details in a dimly lit place.
Cataract Formation: How It Begins
Cataract formation usually happens slowly and without pain. It starts with minor clouding that may not affect vision at first. As the cataract grows, more of the lens becomes cloudy. Vision becomes fuzzy, and glare may increase.
Several factors can contribute to cataract formation:
- Aging: Most cataracts are related to the natural aging process.
- Trauma: An injury to the eye can damage the lens and cause a cataract to form.
- Medical conditions: Diabetes and other systemic diseases can contribute.
- Medications: Long-term use of steroids is known to increase the risk.
- Sun exposure: UV rays from the sun may speed up the breakdown of lens proteins.
- Genetics: Some babies are born with congenital cataracts.
Regardless of the cause, all cataracts form on the lens itself.
Common Types of Cataracts
There are several types of cataracts, and each affects the lens in a slightly different way. Understanding the location and progression can help in recognizing symptoms and deciding on treatment.
Nuclear Cataract
A nuclear cataract forms in the center (nucleus) of the lens. This is the most common age-related type. It often causes increased nearsightedness at first. As it progresses, it can turn the lens yellow or even brown, affecting color vision and contrast.
Cortical Cataract
A cortical cataract affects the outer edge (cortex) of the lens. It begins as white, wedge-shaped streaks that extend toward the center. These streaks scatter light, which leads to problems with glare, halos around lights, and poor night vision.
Subcapsular Cataract
A subcapsular cataract forms near the back of the lens, just in front of the capsule that holds the lens in place. It tends to develop faster than other types of cataracts and is especially common in people with diabetes or those taking steroid medications. People with this type of cataract often notice glare from lights and trouble reading.
Congenital Cataracts
Congenital cataracts are present at birth or develop in early childhood. They may be caused by genetic conditions, infections during pregnancy, or metabolic disorders. Not all congenital cataracts need treatment, but when they affect vision, early surgery can prevent long-term problems.
Each type of cataract has a unique location and pattern on the lens, but all lead to some degree of lens clouding and visual disturbance.
Symptoms of Cataracts
Because cataracts affect the lens, the earliest signs often involve changes to how you see light and detail. Common symptoms include:
- Blurry vision
- Faded color perception
- Sensitivity to bright light and glare
- Halos around lights
- Increased nearsightedness in the case of nuclear cataracts
- Double vision in one eye
Many people also find that they need more light to read or complete close-up tasks. These symptoms may start slowly and worsen over time.
When Cataract Surgery Becomes Necessary
When cataracts interfere with daily activities or safety—such as reading, driving, or recognizing faces—your eye doctor may recommend cataract surgery.
Cataract surgery in Marysville, Ohio, is the most common eye operation performed in the United States, and it has a high success rate. During the procedure, the cloudy lens is removed and replaced with an intraocular lens (IOL), which restores proper focus.
The intraocular lens is a clear, artificial lens placed inside the eye. It can be customized to correct nearsightedness, farsightedness, and even astigmatism. Once placed, it stays in the eye permanently and does not require maintenance or replacement.
Advances in Intraocular Lens Technology
Modern intraocular lenses come in several forms to best suit your vision needs. Options may include:
- Monofocal lenses: Restore clear vision at one distance, typically far
- Multifocal lenses: Provide clear vision at multiple distances
- Toric lenses: Correct astigmatism as well as cataracts
Your eye doctor will help choose the right type of IOL based on your vision goals and eye health.
Cataracts Are Common and Treatable
Cataracts are a normal part of aging for many people, and they form on the same part of the eye—the lens—regardless of type. In fact, by age 80, more than half of the people in the United States either have cataracts or have had cataract surgery.
Thanks to modern treatments, including advanced IOLs and outpatient surgery techniques, most people regain clear vision shortly after treatment.
Summary: Key Takeaways
- Cataracts form on the lens, the transparent structure behind the iris.
- Clouding of the lens leads to blurry vision, glare, and trouble with color contrast.
- Common causes include aging, trauma, disease, and genetic factors.
- There are several types of cataracts: nuclear, cortical, subcapsular, and congenital.
- When vision becomes impaired, cataract surgery with an intraocular lens often restores sight.
- This is the most common eye surgery in the United States, with a strong success rate.
If you or someone you know shows signs of cataracts, schedule an evaluation with an eye doctor. Early diagnosis leads to better outcomes and helps maintain long-term eye health.
Disclaimer: This information is for educational use and should not replace a medical exam. Consult a licensed eye care provider for diagnosis and treatment.