How cataracts form and why they blur your vision
A cataract is a clouding of the lens inside your eye. The lens sits behind the colored part of your eye (the iris) and focuses light onto the back of the eye so you can see clearly. When proteins in the lens break down and clump together over time, they create a cloudy area that blocks light from passing through.
This cloudiness develops slowly in most cases. You might not notice it at first — many people describe early cataracts as looking through a dirty window or seeing a slight haze. As the cataract grows thicker, it scatters light and makes vision blurrier. Colors may look faded or yellowed. Bright lights can cause glare or halos around them, and you may need more light to read or do close work.
Cataracts almost always develop in both eyes, though usually one eye clouds faster than the other. The condition does not spread from one eye to the other — each eye develops its own cataract independently.
Key Takeaways
- Cataracts form when proteins in the eye's lens clump together and cloud your vision, usually over months or years.
- Age is the most common cause, but injury, certain medications, diabetes, and prolonged sun exposure can speed up cataract formation.
- Early cataracts can sometimes be managed with stronger glasses, better lighting, or anti-glare sunglasses, but surgery is the only way to remove a cataract.
- Cataract surgery is outpatient, takes about 15 minutes per eye, and involves replacing the clouded lens with an artificial one.
- Medicare covers cataract surgery when vision loss affects your daily activities, and most private insurance plans do as well.
Why cataracts develop: age, injury, and other causes
Age is the most common reason cataracts form. The proteins in your eye's lens naturally break down over decades. Most people over 60 have at least the beginning of a cataract, though not all notice vision problems. By age 80, more than half of Americans have had cataract surgery or have a cataract that affects their sight.
Other causes speed up cataract formation. Diabetes can cause cataracts to develop earlier and progress faster, especially if blood sugar is not well controlled. Certain medications — particularly corticosteroids taken by mouth for long periods — increase the risk. Eye injury can trigger a cataract in the injured eye months or even years later. Prolonged sun exposure without UV protection may contribute to cataract development over time. Smoking and heavy alcohol use are also linked to earlier cataracts.
Some people are born with cataracts or develop them in childhood, usually due to infection during pregnancy, genetic conditions, or eye injury. These are less common but require earlier attention because they can interfere with normal vision development.
Symptoms that signal a cataract is affecting your sight
Early cataracts often cause no symptoms at all. You might have one and not know it until your eye doctor spots it during a routine exam. As a cataract thickens, you will notice changes in how you see.
Common signs include blurred or cloudy vision at any distance, difficulty seeing at night or in dim light, sensitivity to light and glare (especially from oncoming headlights while driving), colors looking faded or taking on a brownish or yellowish tint, and needing more light to read or do detailed work. Some people notice they need new glasses more often, or that their vision prescription keeps changing.
These symptoms develop gradually. If your vision changes suddenly — especially if one eye goes blurry while the other stays clear — contact an eye doctor right away, as this can signal a different problem that needs prompt attention.
When to see an eye doctor and what to expect
Schedule an eye exam if you notice any of the symptoms above, or if you have not had your eyes checked in the past year. If you have diabetes, a history of eye problems, or take medications that increase cataract risk, annual exams are especially important.
During the exam, your eye doctor will test your vision with a standard eye chart, measure the pressure inside your eye, and look at the lens with a special microscope called a slit lamp. This lets them see whether a cataract is present and how dense it is. They may also dilate your pupils (widen them with drops) to examine the back of your eye.
The doctor will ask about your symptoms, how long you have noticed them, and how much they affect your daily life — reading, driving, watching television, or other activities that matter to you. This conversation helps determine whether a cataract is the cause of your vision problems and whether surgery would help. You do not need surgery just because a cataract is present; you need it when the cataract is causing vision loss that interferes with things you want to do.
Managing cataracts before surgery becomes necessary
If a cataract is small and not yet affecting your sight much, your eye doctor may recommend watching it rather than operating. This is called "watchful waiting," and it is safe — a cataract will not damage your eye if you wait. You will have regular eye exams to track whether it is growing and whether your vision is changing.
While you wait, several things can help you see better. Update your glasses or contact lens prescription — a new prescription can sometimes improve vision enough to delay surgery. Use brighter lighting for reading and close work. Wear anti-glare sunglasses outdoors and when driving, especially in bright sun or at night when oncoming headlights cause problems. Reduce glare indoors by using lampshades, adjusting screen brightness on computers and phones, and positioning light sources to the side rather than in front of you.
There is no medication, eye drop, or supplement that stops or reverses a cataract once it has formed. Claims about cataract-dissolving drops are not supported by scientific evidence. The only way to remove a cataract is surgery.
How cataract surgery works and what recovery looks like
Cataract surgery is one of the most common surgical procedures in the United States. It is performed as outpatient surgery, meaning you go home the same day. The surgeon removes the clouded lens and replaces it with an artificial lens implant.
The procedure takes about 10 to 15 minutes per eye. You receive numbing drops so you do not feel pain, though you may feel pressure or see light and movement. The surgeon makes a small incision in the front of your eye, breaks up the clouded lens using ultrasound (a technique called phacoemulsification), and removes the pieces. Then they insert a folded artificial lens through the same small incision, where it unfolds and stays in place permanently.
After surgery, your eye will feel scratchy or irritated for a few days. You will use antibiotic and anti-inflammatory eye drops for several weeks to prevent infection and reduce swelling. Most people notice improved vision within a few days, though it can take up to a month for vision to stabilize completely. You will need to avoid strenuous activity, heavy lifting, and getting water in your eye for about a week. Driving restrictions vary, but many people can drive again within a few days if their vision is clear enough and their eye doctor approves.
Complications are rare but can include infection, bleeding, swelling, or problems with the artificial lens. Your eye doctor will monitor you closely in the weeks after surgery to catch any problems early.
Insurance coverage and what cataract surgery costs
Medicare covers cataract surgery when the procedure is medically necessary — meaning the cataract is causing vision loss that affects your daily activities. You pay the Part B deductible (currently $226 per year, though this amount changes annually) and 20 percent of the approved cost after that. If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be lower.
Most private insurance plans cover cataract surgery when it is medically necessary. Check your plan documents or call your insurance company to learn your deductible and coinsurance amount. Some plans require prior authorization before surgery, meaning your eye doctor must submit paperwork to the insurance company for approval before the procedure.
If you do not have insurance, the cost of cataract surgery varies widely by location and surgeon, typically ranging from $3,000 to $6,000 per eye. Some surgeons offer payment plans or discounts for uninsured patients. Ask about costs upfront and whether your eye doctor's office can help you find financial resources.
The artificial lens implant itself is included in the surgery cost. However, if you choose a premium lens designed to reduce your need for glasses after surgery (such as a multifocal or toric lens), there may be an additional out-of-pocket charge not covered by insurance, typically $500 to $2,000 per eye.
Preventing cataracts or slowing their development
You cannot prevent age-related cataracts entirely, but you can slow their development. Protect your eyes from UV light by wearing sunglasses that block 99 to 100 percent of UVA and UVB rays whenever you are outdoors, even on cloudy days. A wide-brimmed hat adds extra protection. Control diabetes if you have it — keeping blood sugar in your target range significantly slows cataract formation. Do not smoke — smoking roughly doubles the risk of cataracts. Limit alcohol — heavy drinking is linked to earlier cataracts.
Eating a diet rich in antioxidants — found in leafy greens, colorful vegetables, berries, and nuts — may help protect your eyes, though research on whether specific foods prevent cataracts is still ongoing. If you take corticosteroid medications, work with your doctor to use the lowest dose necessary and for the shortest time possible, and have regular eye exams to catch any changes early.
Frequently Asked Questions
Can cataracts come back after surgery?
No. Once the clouded lens is removed and replaced with an artificial one, a cataract cannot form in that eye again. However, the membrane that holds the artificial lens in place can become cloudy months or years later — a condition called posterior capsular opacification. This is easily treated with a quick laser procedure in your eye doctor's office that takes just a few minutes.
Will I still need glasses after cataract surgery?
Most people still need glasses for reading or close work after surgery, even if they did not before. Your eye doctor will measure your eye after surgery to determine the right lens implant power. Standard implants are set for distance vision, so reading glasses are usually needed. Premium lens implants can reduce or eliminate the need for glasses, but they cost more and are not covered by insurance.
What if I have cataracts in both eyes — do I have surgery on both at once?
No. Surgeons operate on one eye at a time, usually waiting one to two weeks between surgeries. This allows the first eye to heal and gives you a chance to see how well the surgery worked before operating on the second eye. It also reduces the risk that a complication in one eye will affect the other.
Can I drive if I have a cataract?
It depends on how much the cataract is affecting your vision. If your vision is clear enough to read a standard eye chart and you do not have significant glare problems, you may be safe to drive. However, if a cataract is causing blurred vision, difficulty seeing at night, or severe glare from headlights, you should not drive. Talk to your eye doctor about whether it is safe for you.
Is cataract surgery painful?
No. Your eye is numbed with drops before surgery, so you should not feel pain — only pressure or a sensation of movement. Some people feel mild discomfort or scratchiness for a few days after surgery as the eye heals, which is managed with prescribed eye drops and over-the-counter pain relievers if needed.