A cataract is a clouding of the natural lens inside your eye, causing blurry vision that worsens over time. It happens when proteins in the lens clump together and block light from passing through clearly. Cataracts are extremely common: roughly 8 out of every 100 people over 60 have them, and more than half of people over 80 either have cataracts or have already had surgery to remove them.
What Happens Inside the Lens
Your eye’s lens sits just behind the iris (the colored part) and works like a camera lens, focusing light onto the retina at the back of your eye. The lens is made of water and specialized proteins called crystallins, arranged in precise layers that keep it perfectly transparent.
Over time, those proteins can become damaged, unfolding and sticking together in clumps. When that happens, tiny patches of the lens turn opaque instead of clear. Light scatters instead of passing straight through, and your vision gets hazy or washed out. Several things drive this process: oxidative damage from UV light and cigarette smoke, dehydration of lens tissue that forces proteins into irreversible contact with each other, and the simple accumulation of decades of wear. Genetic mutations can also change the shape of crystallin proteins, exposing sticky surfaces that trigger clumping much earlier in life.
Types of Cataracts
Not all cataracts form in the same part of the lens, and the location affects which symptoms you notice first.
- Nuclear cataracts form in the center of the lens. The nucleus slowly yellows and hardens over years, progressing from hazy white to yellow to brown. This is the most common age-related type. Early on, a nuclear cataract can actually improve your near vision temporarily (sometimes called “second sight”) before distance vision deteriorates significantly.
- Cortical cataracts start in the outer layers of the lens and work inward, often appearing as white, wedge-shaped streaks. They tend to cause problems with glare.
- Posterior subcapsular cataracts form at the back surface of the lens. They can develop faster than other types and are especially linked to long-term steroid use, diabetes, and prior eye injury. They often interfere with reading and cause noticeable halos around lights at night.
Symptoms to Watch For
Cataracts develop gradually, so you may not notice anything at first. The earliest sign for many people is slightly blurred or foggy vision that doesn’t fully correct with glasses. As the cataract progresses, you may experience fading or yellowing of colors, making the world look more washed out than it used to. Halos or starbursts around lights at night are common, and glare from headlights or bright sunlight can become bothersome enough to affect driving.
Some people find themselves needing brighter light to read, or they notice that their glasses prescription keeps changing. With a nuclear cataract, near vision may temporarily sharpen before overall vision declines. If colors look increasingly brownish or you’re struggling in low light, those are signs the cataract is advancing.
What Raises Your Risk
Age is the biggest factor. Subtle lens changes can begin as early as 40, but vision-impairing cataracts typically don’t develop until after 60. Beyond aging, several things accelerate the process:
- UV exposure: Years of unprotected sun exposure damage lens proteins over time.
- Smoking: Smoking doubles or triples your risk by creating oxidative stress that directly harms lens proteins.
- Diabetes: Elevated blood sugar causes the lens to swell and speeds up protein changes that cloud vision. People with diabetes tend to develop cataracts earlier and faster.
- Steroid use: Long-term corticosteroids, whether taken orally, inhaled for asthma, injected, or used as eye drops, increase the risk of posterior subcapsular cataracts. Higher doses and longer use carry greater risk.
- Eye injury or surgery: Past trauma, chronic inflammation, or previous procedures like glaucoma surgery can damage the lens.
- Family history: If parents or siblings had cataracts, you’re more likely to develop them, and potentially earlier.
- Heavy alcohol use: More than two standard drinks per day is linked to increased risk.
- Obesity and high blood pressure: Both contribute through inflammation and changes in blood flow to the eyes.
How Cataracts Are Diagnosed
An eye doctor can spot a cataract during a standard dilated eye exam using a slit lamp, a microscope with a thin beam of light that lets them view the lens in cross-section. This reveals the exact location and density of any clouding. Nuclear cataracts appear as a hazy, yellowed, or brownish core. Posterior cataracts are identified using a technique called retroillumination, where the doctor shines light through the pupil and looks for dark shadows against the bright reflection from the retina. The exam also helps rule out other causes of vision loss, like glaucoma or macular degeneration.
Surgery: What to Expect
Cataracts don’t require immediate surgery. Many people manage early cataracts with updated glasses, better lighting, and anti-glare sunglasses. Surgery becomes worth considering when blurry vision starts interfering with daily activities like driving, reading, or working.
The procedure itself is one of the most commonly performed surgeries in the world. It’s done as an outpatient procedure, typically under local anesthesia (numbing drops or an injection around the eye). The surgeon makes a tiny incision, uses ultrasound vibrations to break the clouded lens into small pieces, removes the fragments, and inserts a clear artificial lens in its place. The incision is small enough that it usually seals on its own without stitches. The entire process takes roughly 15 to 30 minutes per eye.
Choosing a Replacement Lens
The artificial lens (called an intraocular lens, or IOL) stays in your eye permanently. You have several options:
- Monofocal lenses provide sharp vision at one distance. Most people choose distance correction and then use reading glasses for close-up tasks. These are the standard choice and produce the fewest side effects.
- Multifocal lenses have built-in zones for near and far vision, similar to bifocal glasses. They reduce dependence on reading glasses but can cause glare and halos, especially at night. They’re generally not recommended for people who already have vision loss from conditions like glaucoma or macular degeneration.
- Toric lenses correct astigmatism in addition to replacing the clouded lens. People with moderate to high astigmatism tend to be happiest with these.
If night driving is a big part of your routine, a monofocal lens may be the safer bet, since multifocal lenses can create glare and halos in dim lighting that some people find distracting.
Recovery Timeline
Full recovery typically takes about four weeks, but most people notice improved vision within a few days. Things may look blurry immediately after surgery, and that’s normal. Vision sharpens gradually over the following days and weeks. You’ll go home the same day after being monitored for 15 to 30 minutes.
During recovery, you’ll use prescribed eye drops and need to avoid getting water, soap, or shampoo in the eye. Rubbing or pressing on the eye is off-limits. You’ll wear sunglasses outside and an eye shield while sleeping. Your surgeon will give you specific guidance on when you can drive, exercise, swim, bend over, lift heavy objects, and return to work. Most restrictions lift within the first few weeks.
Reducing Your Risk
You can’t fully prevent age-related cataracts, but you can slow the process. Wearing sunglasses that block UV rays is one of the simplest protective steps, since cumulative sun exposure directly damages lens proteins. Quitting smoking removes one of the largest modifiable risk factors. Managing blood sugar carefully matters for anyone with diabetes.
Diet plays a role too. People who get the most lutein and zeaxanthin, nutrients found in leafy greens like spinach and kale, have a significantly lower risk of developing cataracts. Vitamin C, found in citrus fruits and peppers, is linked to lower cataract risk as well. Zinc deficiency has been connected to cloudy lens changes and poor night vision; good sources include meat, shellfish, and legumes. None of these nutrients will reverse a cataract that’s already formed, but they appear to help protect the lens over the long term.