Cataracts typically begin forming in your 40s, though most people won’t notice any vision changes until their 60s or later. The process is gradual: proteins in the eye’s lens slowly break down over decades, and by the time clouding becomes noticeable, the changes have been underway for years. Globally, about 8 in 100 adults over 60 have cataracts significant enough to affect their vision.
How Cataracts Develop by Decade
The lens of your eye contains some of the longest-lived proteins in your body. Unlike most tissues, the lens doesn’t shed and replace its cells. The proteins you’re born with are the same ones you’ll have at 80, and they accumulate damage the entire time. Small chemical changes begin in your 20s and 30s, but they’re far too minor to affect vision.
By your 40s, those protein changes become detectable on a detailed eye exam, even if you feel perfectly fine. This is when early lens changes start showing up in a meaningful portion of the population. A large cross-sectional study in Central India found that about 36% of cataract cases were in the 40 to 59 age group, while the majority, 54%, were between 60 and 79. That pattern holds broadly across populations: the 40s mark the beginning, and the 60s and 70s are when cataracts become a dominant eye health issue.
The progression isn’t sudden. You might go a full decade with a slowly developing cataract and never realize it. Many people first notice symptoms in their mid-to-late 60s, when the clouding finally becomes dense enough to interfere with reading, driving at night, or distinguishing colors.
What Actually Happens Inside the Lens
Your lens is made almost entirely of tightly packed proteins called crystallins. For the lens to stay clear, these proteins need to remain precisely folded and evenly distributed. Over time, several types of spontaneous chemical damage accumulate and disrupt that structure.
The most common change is a process where the building blocks of these proteins flip into a mirror-image shape. Once that happens, the protein can’t fold correctly anymore, and the change is essentially permanent. Other damage includes proteins losing small chemical groups (which changes their charge and makes them clump together), proteins bonding to each other in ways they shouldn’t, and proteins breaking apart at weak points in their chain. Oxidative damage also plays a key role, particularly in the lens core, where protective antioxidants decline with age.
None of these changes happen overnight. They’re the cumulative result of decades of normal chemistry. Once enough proteins in a region of the lens become misfolded or clumped, they scatter light instead of transmitting it cleanly. That scattering is what you eventually perceive as blurry, hazy, or washed-out vision.
Earliest Symptoms to Watch For
The first sign of cataracts isn’t usually blurriness. It’s often a subtle loss of contrast, where things look slightly faded or washed out, or increased sensitivity to glare. Oncoming headlights at night may seem to have halos or streaks. Colors may look less vivid than they used to. These changes can be present even when a standard eye chart still shows good visual acuity, which is why people sometimes feel something is “off” before their eye doctor flags a problem.
Posterior subcapsular cataracts, which form at the back of the lens, tend to cause the most noticeable early symptoms. They’re particularly associated with glare problems and reduced contrast sensitivity. Nuclear cataracts, which form in the center of the lens, sometimes cause a temporary improvement in near vision (sometimes called “second sight”) before overall vision worsens. Cortical cataracts, forming around the edges, may not cause symptoms at all until they grow inward.
Cataracts That Don’t Follow the Typical Timeline
Not all cataracts are age-related. Some people are born with them. Congenital cataracts are typically detected through a red reflex screening shortly after birth, with a follow-up exam at 6 to 8 weeks. When present, timing matters enormously: surgery for a cataract in one eye is generally recommended by 6 weeks of age, and for cataracts in both eyes, by 8 weeks. The visual system is still developing rapidly during this period, and a cloudy lens left in place can permanently impair the brain’s ability to process images from that eye. This critical window of visual development extends to about age 9 or 10.
Eye injuries can also trigger cataracts at any age. After blunt trauma to the eye, about 13% of affected individuals develop a cataract, typically within two weeks of the injury, though it can take up to several months. These traumatic cataracts generally respond well to surgery.
Certain medications, particularly long-term corticosteroid use, can accelerate cataract formation. Diabetes is another significant risk factor. People with diabetes often develop cataracts earlier and more rapidly than their peers, because elevated blood sugar alters the chemistry inside the lens.
Who Is at Higher Risk
Women develop cataracts at higher rates than men. Global data from 2021 shows a prevalence rate of about 8,300 per 100,000 among women over 60, compared to 7,080 per 100,000 among men. Hormonal differences, longer average lifespans, and potentially greater cumulative UV exposure in some populations all contribute.
Geography and income level also matter. South Asia and Oceania have the highest cataract rates in the world, roughly seven to eight times higher than high-income regions like Japan, Australia, or Western Europe. This gap reflects differences in UV exposure, access to eye care, and the availability of surgery. In wealthier countries, cataracts are removed long before they cause serious disability, so fewer people live with advanced disease at any given time.
Slowing the Process Down
You can’t stop lens proteins from aging, but you can reduce how fast the damage accumulates. UV radiation accelerates several of the chemical changes that cloud the lens, so wearing sunglasses that block UVA and UVB rays is one of the most straightforward protective steps. This is especially important if you spend significant time outdoors.
Smoking roughly doubles your risk of cataracts compared to nonsmokers. Quitting at any age reduces further damage. A diet rich in colorful fruits and vegetables provides antioxidants that support lens health, though no supplement has been proven to prevent cataracts outright. Managing blood sugar if you have diabetes, and avoiding unnecessary corticosteroid use when alternatives exist, also helps delay onset.
When Cataracts Need Treatment
A cataract diagnosis doesn’t automatically mean surgery. Many people live with early cataracts for years, managing with updated glasses prescriptions, better lighting, and anti-glare lenses. Surgery becomes the conversation when cataracts interfere with activities that matter to you: reading, driving, working, or recognizing faces.
There’s no universal vision score that triggers surgery. Most decisions are based on how much your daily life is affected. Some insurers require visual acuity of 20/50 or worse, or documented glare problems, before covering the procedure. But the clinical standard is functional: if your cataracts are limiting what you can do, surgery is appropriate.
Cataract surgery is the most commonly performed surgery in the world, and outcomes are overwhelmingly positive. The clouded lens is removed and replaced with a clear artificial one. Most people notice dramatically improved vision within days, and serious complications are rare.