Eye Care

What Is Cataract Surgery?

Originally published May 22, 2025

Last updated May 22, 2025

Reading Time: 4 minutes

A woman sits in an optometrist's office with her eye in a medical machine.

Cataracts can cause vision loss — and even blindness — unless a patient gets surgery. Fortunately, cataract surgery is safe, common and highly effective.

Many eye conditions can be corrected with glasses, contact lenses or medication, but a few common conditions require eye surgery once they advance beyond a certain point. One of the most common is cataract, a clouding of the eye’s lens that occurs naturally as we age.  

“When you’re young, the lens of your eye is crystal clear, but as we age, or in certain medical conditions, the lens turns cloudy,” says Kristina Voss, MD, an ophthalmological surgeon with the USC Roski Eye Institute, part of Keck Medicine of USC. “This clouding scatters light and causes lack of focus, loss of contrast and in time an overall loss of vision.” 

Ophthalmologists will often prescribe glasses to help with the condition, but sooner or later surgery is almost always necessary. Dr. Voss shares what happens during the procedure, what patients can expect and what the recovery process is like.  

What are cataracts? 

As people get older, proteins in the lens of the eye start to break down and clump together, forming clouds that will eventually obscure the person’s vision. 

A cataract often starts to develop when a person is as young as 45-50 years of age, but it develops slowly. In fact, most adults start to show symptoms at age 70.  

That said, it can happen at any age. “I’ve performed cataract surgery on 90-year-olds and, while rare, on 20-year-olds,” Dr. Voss says. 

Who’s most likely to develop cataracts? 

There are several risk factors that can make cataracts more likely or likely to develop sooner:  

  • Ultraviolet light exposure from the sun can damage the lens, causing the proteins to break down at a younger age. 
  • Diabetes can lead to cataracts by damaging blood vessels in the eye. 
  • Smoking also damages the eye’s blood vessels. It also causes oxidative stress, an imbalance of free radicals and antioxidants that leads to cell damage, which in turn encourages cataracts to develop. 
  • Eye injuries that damage the lens can eventually lead to cataracts. 
  • Certain medications, such as corticosteroids, can encourage the development of cataracts.  
  • Genetic predisposition is a factor that cannot be controlled, but patients who know they have it can minimize their risk by wearing sunglasses outdoors and maintaining a healthy lifestyle. 

What is the treatment for cataracts? 

When symptoms first appear, they can be mitigated with glasses for a time. However, the only truly effective treatment is a surgery that replaces the damaged lens with an artificial one. Dr. Voss counsels patients not to worry — the procedure is safe, quick and relatively painless. 

“The anesthetic approach is known as MAC, for monitoring anesthesia care,” she says. “This is the type of anesthesia known for providing a ‘happy twilight.’ Patients are usually awake but calm and relaxed enough to not care that they’re having eye surgery.” 

The only discomfort patients feel is a mild burning sensation from the numbing eye drops that are also used, and this typically lasts about 10 seconds.  

“Otherwise, most patients actually describe it as pretty enjoyable,” Dr. Voss says, explaining that the mechanics of the procedure result in the patients having a kaleidoscopic view of what’s happening.  

“They see a myriad of colors, but they don’t see anything sharp coming at them. It’s all too close and blurred,” Dr. Voss says. 

During the procedure, tiny incisions are made in the cornea. Next, the cloudy lens is cut up and removed via suction, and an acrylic lens is implanted in its place.  

“It goes in folded, then unscrolls across the eye and rests perfectly where the original lens used to live,” Dr. Voss says.  

And it all takes between 15 and 20 minutes.  

What is recovering from cataract surgery like? 

“Once the cataract surgery is done, patients typically feel good, aside from a little occasional irritation,” Dr. Voss says. “People might see a bit of a glare or a halo for the first 24 hours, but that goes away.” 

Patients may also notice that the eye is red or watery, but this is also normal and should clear up fairly soon.  

“The best thing about recovery for patients is how quickly their vision clears up and knowing that the effects are permanent,” Dr. Voss says. “Barring any complications, you only need to have the surgery once to see better for the rest of your life.” 

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Kate Faye
Kate Faye is an editor and writer for Keck Medicine of USC.