Not everyone develops cataracts, but the odds increase dramatically with age. About 20% of people 65 and older have a cataract, roughly half of those 75 and older do, and by age 80, most people either have cataracts or have already had surgery to remove them, according to the National Eye Institute. So while cataracts aren’t technically universal, they’re close to it if you live long enough.
The reason cataracts are so common is that they stem from the same basic process that ages the rest of your body: proteins breaking down over time. Your eye’s lens contains some of the longest-lived proteins in the human body, and they never get replaced. Decade after decade, those proteins slowly degrade, clump together, and cloud the lens. It’s less a disease than a consequence of biology running its course.
Why Lens Proteins Break Down Over Time
The lens of your eye is built from specialized proteins called crystallins. Unlike most cells in your body, the cells at the center of the lens have no blood supply and no way to swap out damaged proteins for fresh ones. The proteins you’re born with are the proteins you keep for life. Over decades, these proteins undergo a slow, spontaneous chemical breakdown. Their bonds break, their structure warps, and they begin sticking to each other in clumps.
Several types of damage accumulate simultaneously. Chemical bonds between protein chains form permanent cross-links that can never be undone. Proteins change shape through a process called racemization, where the building blocks flip into a mirror-image form the body didn’t originally create. Other proteins simply fragment. As one research team studying lens aging put it, “proteins don’t last forever.” Once enough damage accumulates, the once-transparent crystallins unfold and bind to the fiber cell membranes inside the lens, blocking the passage of light. The lens also gradually picks up yellow and then brown pigment, which is why colors can look washed out or warmer than they used to.
The Three Types of Age-Related Cataracts
Cataracts aren’t a single condition. They’re classified by where in the lens the clouding develops, and each type progresses differently.
- Nuclear sclerotic cataracts form in the center of the lens. The core compresses and stiffens as new layers of lens fiber grow around it over the years. This is the most common type in older adults and tends to progress slowly. It often causes a temporary improvement in near vision (sometimes called “second sight”) before overall vision worsens.
- Cortical cataracts develop in the outer shell of the lens. They typically start as wedge-shaped white opacities around the edges and grow inward. Progression varies widely, from years to just a few months.
- Posterior subcapsular cataracts form at the very back surface of the lens. These tend to appear in younger patients and progress faster than the other types. They’re especially likely to cause glare and difficulty reading.
Many people develop more than one type at the same time, and you can have cataracts progressing at different rates in each eye.
What Cataracts Feel Like Early On
Cataracts usually develop so gradually that you may not notice them at first. Early changes often include increased sensitivity to glare, particularly from oncoming headlights at night. You might see halos around lights or find that colors look slightly faded or yellowish. Reading in dim light becomes harder, and you may need brighter lamps than you used to.
Some people notice they’re changing eyeglass prescriptions more often than expected. Others find that their distance vision worsens while their reading vision temporarily improves (a clue that a nuclear cataract is changing the focusing power of the lens). None of these symptoms are painful, which is part of why cataracts can go undetected for years.
What Speeds Up Cataract Development
While aging is the primary driver, several factors can push cataracts to develop earlier or progress faster.
Diabetes is one of the strongest risk factors. People with diabetes are up to five times more likely to develop cataracts, and they tend to get them at younger ages. Studies have found cataracts are three to four times more prevalent in people with diabetes under age 65 compared to those without. The mechanism involves excess sugar in the bloodstream altering the chemical environment inside the lens, causing the lens fibers to swell and cloud. Young adults with type 1 diabetes are particularly vulnerable to rapid cataract formation.
Long-term use of corticosteroid medications (commonly prescribed for conditions like asthma, arthritis, and autoimmune diseases) also raises the risk, especially for posterior subcapsular cataracts. UV exposure from sunlight accelerates protein damage in the lens, which is why wearing sunglasses that block UV rays offers real protection. Smoking increases cataract risk as well, adding to the chemical stress on lens proteins already under pressure from aging alone.
Can You Slow Down Cataracts With Diet?
You can’t prevent cataracts entirely through diet, but there’s solid observational evidence that certain nutrients help protect the lens. Maintaining a daily vitamin C intake of around 135 mg (roughly two oranges’ worth) appears to benefit lens health. Lutein and zeaxanthin, the pigments found in leafy greens like spinach and kale, are also associated with lower risk. One study found a 42% lower risk of nuclear cataracts in people consuming moderate amounts of omega-3 fatty acids, the kind found in fatty fish like salmon.
B vitamins and multivitamin supplements have shown some association with reduced nuclear cataract risk in observational studies, though the evidence is stronger for food sources than pills. On the flip side, diets high in simple sugars and refined carbohydrates are linked to faster cataract development. Avoiding frequent large servings of sugary drinks and favoring lower-glycemic foods (whole grains over white bread, for instance) is one of the more practical dietary strategies.
When Cataracts Need Surgery
A cataract diagnosis doesn’t automatically mean you need surgery. Many people live with mild cataracts for years using updated eyeglass prescriptions, better lighting, and anti-glare lenses. Surgery becomes relevant when cataracts interfere with daily life: when you can no longer drive safely, read comfortably, or do the activities that matter to you.
The functional benchmark most commonly used is 20/40 vision, the threshold for an unrestricted driver’s license in the United States. Below that level, routine tasks start becoming difficult for most people. But the decision is ultimately based on how much the cataract is affecting your quality of life, not a rigid cutoff.
Cataract surgery is the most commonly performed surgery in the world and one of the most cost-effective medical interventions available. The clouded lens is removed and replaced with a clear artificial one, typically as an outpatient procedure. Vision usually improves within days. Globally, however, access remains uneven: the World Health Organization estimates that one in two people who need cataract surgery worldwide still can’t get it, making cataracts the leading cause of blindness, responsible for 94 million cases of vision impairment.