Roughly one in six adults worldwide has some form of cataract at any given time. A large systematic review and meta-analysis covering populations across multiple continents put the age-standardized prevalence of any cataract at about 17 percent, though the number climbs steeply with age and varies considerably by region and sex.1PubMed Central. Global and regional prevalence of age-related cataract: a comprehensive systematic review and meta-analysis That single figure, however, papers over enormous differences depending on how old you are, where you live, and what other health conditions you carry.
The Numbers Are Growing Fast
Cataracts are not just common; they are becoming more common. Between 1990 and 2021, the total number of people living with cataracts worldwide rose from about 42 million to over 100 million, an increase of roughly 138 percent.2PubMed Central. Global, regional, and national burden of cataract: A comprehensive analysis and projections from 1990 to 2021 Part of that surge reflects population growth and aging demographics. People are living longer in most parts of the world, and longer lives mean more time for lens proteins to degrade. The age-standardized prevalence rate also ticked upward over that period, from about 1,145 to 1,181 per 100,000 people, which suggests that aging alone does not explain the entire trend.
How Age Changes the Picture
Age is the single strongest predictor of cataracts, and the leap between decades is dramatic. In the well-known Beaver Dam Eye Study, which tracked thousands of adults in Wisconsin over years of follow-up, the cumulative incidence of nuclear cataract was only about 3 percent in people who started the study between ages 43 and 54. Among those aged 75 and older, that figure jumped to 40 percent.3JAMA Ophthalmology. Incidence of Age-Related Cataract: The Beaver Dam Eye Study Cortical cataracts followed a similar curve, rising from about 2 percent to 22 percent, while posterior subcapsular cataracts went from roughly 1 percent to 7 percent across the same age range.
Those three types refer to where in the lens the clouding develops. Nuclear cataracts form in the center, cortical cataracts start at the edges and work inward like wheel spokes, and posterior subcapsular cataracts appear at the back surface. A person can have more than one type at once, and the types respond differently to risk factors and progress at different speeds. The point for anyone wondering about their own odds is straightforward: if you are in your 40s or early 50s, your chance of having a clinically noticeable cataract is low. If you reach your late 70s or beyond, the odds flip. By that age, cataracts are more the rule than the exception.
Why Women Are Affected More Often
Across every large dataset that has looked at the question, women consistently have higher cataract rates than men. A global analysis comparing age-standardized disability rates found that women had meaningfully higher burdens than men in both 1990 and 2015, and the gap widened with age.4JAMA Ophthalmology. Association of Sex With the Global Burden of Cataract This is not simply a matter of women living longer and therefore accumulating more age-related disease. Population-based studies that compare men and women of the same age still find that women have a higher prevalence of lens opacities, especially cortical cataracts.5PubMed. Gender and cataract–the role of estrogen
One plausible explanation involves estrogen. Estrogen has antioxidant properties and appears to protect lens proteins from oxidative damage. After menopause, when estrogen levels drop sharply, the lens loses some of that protection. The epidemiological pattern fits: the sex difference in cataract rates is modest among younger adults and grows substantially in older age groups, tracking the timeline of menopause.
Risk factors also play out differently by sex. A large study tracking cataract diagnoses found crude incidence rates of about 35 per 10,000 person-years in women compared with 29 in men. Interestingly, certain risk factors weighed more heavily for one sex than the other. Alcohol consumption and unemployment carried greater cataract risk in men, while high blood pressure and metabolic syndrome contributed more to risk in women.6Review of Contact Lenses. Sex-Specific Risk Factors Identified in Cataract Development
What Happens Inside the Lens
The lens of the eye needs to be transparent so light can pass through it cleanly. That transparency depends on crystallin proteins, which are arranged in an extremely orderly fashion inside lens fiber cells. Unlike most cells in the body, these fiber cells shed their internal machinery early in life and never replace their proteins. The crystallins you are born with are essentially the same ones you have at 80. Over decades, oxidative stress slowly damages them, causing the proteins to misfold and clump together into aggregates that scatter light instead of transmitting it.7PubMed Central. Dimerization of natively folded molecules drives misfolding and aggregation in Cys-depleted variants of cataract-associated human lens γD-crystallin That scattering is what produces the characteristic clouding of a cataract.
Hydrogen peroxide and other reactive molecules inside the lens accelerate this process. Researchers have demonstrated that exposing crystallin proteins to oxidative stress in the lab causes them to form fibril-like aggregates, essentially recreating the early stages of cataract formation in a test tube.8PubMed. Inhibiting H(2)O(2)-Induced Aggregation of Human γD-Crystallin with Nanoformulations of Polyphenols Specific mutations in crystallin genes can also make the proteins less stable and more prone to aggregation, which is why some people develop cataracts much earlier than others.9PubMed Central. Cataract-Associated New Mutants S175G/H181Q of βΒ2-Crystallin and P24S/S31G of γD-Crystallin Are Involved in Protein Aggregation by Structural Changes
Risk Factors That Push the Odds Higher
Age is the dominant risk factor, but it is far from the only one. Several modifiable and non-modifiable factors can accelerate crystallin damage and move someone’s cataract timeline forward by years or even decades.
Diabetes
People with diabetes face a clearly elevated risk. Both how long a person has had diabetes and how well their blood sugar has been controlled matter. Longer disease duration and higher average blood sugar levels are each independently associated with increased cataract risk.10PubMed Central. Risk Factors for Cataracts in Patients with Diabetes Mellitus The mechanism involves excess glucose in the lens being converted into sorbitol, a sugar alcohol that draws in water and disrupts the orderly protein arrangement. One encouraging note: in younger people with diabetes, improving metabolic control has been shown to partially reverse early lens changes, though this does not appear to work once cataracts are firmly established in older adults.11PubMed Central. Cataract in diabetes mellitus
Ultraviolet Light Exposure
UV radiation from sunlight is one of the better-established environmental causes of cataracts. A systematic review and meta-analysis of observational studies found that people with the highest UV exposure had substantially elevated odds of developing cataracts compared with those who had the lowest exposure. When studies compared extreme high versus low exposure groups, the pooled odds ratio was over six-fold.12Bioscientia Medicina : Journal of Biomedicine and Translational Research. Occupational and Environmental Ultraviolet–Sunlight Exposure, Including Outdoor Agricultural Work, and the Risk of Cataract: A Systematic Review and Meta-Analysis of Observational Studies Outdoor agricultural workers, construction laborers, and anyone who spends long hours in direct sunlight without eye protection carry an outsized share of this risk. This is one of the few cataract risk factors where a simple intervention, wearing sunglasses that block UV-A and UV-B, is cheap and genuinely effective.
Alcohol
Heavy drinking raises cataract risk. A meta-analysis of ten studies found that heavy alcohol consumption was associated with about a 26 percent increased risk of age-related cataracts compared with non-drinkers or light drinkers. Moderate drinking showed a marginally non-significant trend toward lower risk, but the evidence was inconsistent across studies.13PubMed. Different amounts of alcohol consumption and cataract: a meta-analysis A large Japanese case-control study added granularity to this picture, showing that cataract risk climbed with both drinking frequency and total lifetime consumption, with the threshold for significantly increased risk appearing earlier in women than in men.14Scientific Reports. Alcohol use patterns and risk of incident cataract surgery: a large scale case–control study in Japan
Steroid Medications
Long-term use of corticosteroids, whether oral, inhaled, or even intranasal, is a well-known risk factor for posterior subcapsular cataracts specifically. Systemic steroids have the strongest association, but case reports document cataracts developing in patients on prolonged intranasal steroid use as well.15PubMed. Bilateral posterior subcapsular cataracts associated with long-term intranasal steroid use This is relevant for the millions of people who use steroid inhalers for asthma or steroid nasal sprays for allergies. The risk generally depends on dose and duration, and short courses or low-dose topical use carry far less concern than years of daily high-dose therapy.
Where You Live Matters
The global average of roughly 17 percent conceals enormous geographic variation. Countries with low levels of human development bear a much heavier burden of cataract-related blindness and vision loss. Age-standardized rates of disability from cataract inversely correlate with a country’s development index, meaning the poorest countries consistently have the highest rates of cataract-related blindness, severe vision loss, and moderate vision loss.16PubMed Central. Socio-economic disparity in visual impairment from cataract
This gap is driven less by differences in who develops cataracts and more by differences in who gets them treated. In wealthy countries, cataract surgery is routine and widely accessible. In many lower-income countries, the resources and infrastructure for broad cataract surgery programs simply do not exist, particularly in rural areas.17PubMed Central. Cataract Surgery in Low-Income Countries: A Good Deal! The result is that millions of people in sub-Saharan Africa, South Asia, and parts of Southeast Asia live with treatable blindness. The irony is that cataract surgery is one of the most cost-effective interventions in all of medicine, returning years of productive vision for a relatively modest investment per procedure.
Cataracts in Children and Young Adults
While cataracts are overwhelmingly a condition of aging, they can occur at any age. Congenital cataracts are present at birth or develop in early infancy, and pediatric or juvenile cataracts appear during childhood. The causes are quite different from age-related cataracts. Genetic mutations account for a significant share of congenital cases, with dominant inheritance patterns being common. Intrauterine infections and metabolic diseases also contribute.18PubMed Central. Prenatal Ultrasound Diagnosis and Prognosis Analysis of Fetal Congenital Cataract Some congenital cataracts are associated with systemic conditions, including Down syndrome, cerebral palsy, and prematurity.19PubMed Central. Histopathological findings of anterior lens capsule in pediatric cataract
Congenital cataracts are rare, affecting roughly 1 to 6 per 10,000 live births depending on the population studied, but they are disproportionately important because they can permanently impair visual development if not caught early. The visual system in infants is still forming its neural connections, and a lens that blocks light during the first months of life can lead to amblyopia that no later surgery can fully correct. This is why newborn eye screening is standard practice in many countries.
Can You Lower Your Risk Through Diet?
The lens’s main enemy is oxidative stress, so it makes intuitive sense that antioxidant-rich diets might offer some protection. The evidence, while not bulletproof, does lean that direction. A systematic review examining the relationship between diet and age-related cataracts found that dietary patterns high in antioxidants were associated with substantially lower cataract risk. Omega-3-rich dietary patterns also showed a protective association.20PubMed Central. Influence of Diet, Dietary Products and Vitamins on Age-Related Cataract Incidence: A Systematic Review
In practical terms, this means eating plenty of fruits, vegetables, and fish may slow the onset of cataracts, although how much protection it provides is hard to quantify from observational studies alone. The challenge is that people who eat well also tend to exercise more, smoke less, and have better access to healthcare, making it difficult to isolate diet’s independent contribution. Vitamin supplements, particularly vitamins C and E, have been studied in randomized trials with generally disappointing results. The protection, to whatever extent it exists, seems to come more from whole dietary patterns than from individual supplements.
Beyond diet, the modifiable risk factors discussed earlier, especially UV protection, smoking avoidance, blood sugar management, and moderate alcohol consumption, represent the most actionable steps for delaying cataracts. None of them will guarantee prevention, but they can meaningfully shift the timeline.
Surgery and the Access Gap
Cataract surgery is the only cure once a cataract has formed. No eye drops, medications, or lifestyle changes can reverse established lens clouding. The surgery itself is remarkably effective and one of the most frequently performed procedures in the world. It involves removing the clouded natural lens and replacing it with a clear artificial one. Modern phacoemulsification, which uses ultrasonic vibration to break up the old lens through a tiny incision, produces consistently good visual outcomes.21Surabaya Medical Journal. Overview of visual acuity improvement in postoperative cataract patients using a monofocal lens and phacoemulsification techniques
The global picture of surgical access, however, is starkly unequal. Cataract surgical rates range from as low as 36 per million population in some countries to over 12,800 per million in others, and average surgical coverage in most countries sits at about 50 percent or lower.22PubMed. Global prevalence of cataract surgery That means roughly half of people who need the surgery worldwide are not getting it. In wealthy nations, the constraint is often personal choice or mild cataracts that have not yet progressed enough to justify surgery. In lower-income settings, the barriers are more fundamental: too few trained surgeons, too few equipped facilities, and costs that are out of reach for people living on very low incomes.
What Happens After Surgery
Even after successful cataract removal, a related problem can develop. Posterior capsule opacification, sometimes called a secondary cataract, occurs when residual lens cells on the capsule left behind during surgery grow and become cloudy. The term “secondary cataract” is somewhat misleading because the original cataract does not grow back. Instead, the thin membrane that once held the natural lens becomes opaque over months or years.
This is the most common complication of cataract surgery, and it involves the remaining lens cells undergoing a transformation into scar-like tissue.23PubMed Central. ErbBs in Lens Cell Fibrosis and Secondary Cataract The good news is that the fix is simple. A brief outpatient laser procedure called a YAG capsulotomy can clear the clouded membrane in minutes with minimal risk. Most people notice an immediate improvement in vision afterward. It is a one-time treatment and recurrence is uncommon.
How Cataracts Get Graded and Tracked
One reason cataract prevalence numbers can vary between studies is that there is no single universal threshold for when a lens qualifies as having a “cataract.” Grading systems have evolved over decades, with the most widely used clinical system classifying lens opacities by type and severity using standardized photographic comparisons.24PubMed. Cataract grading systems: a review of past and present An eye with mild nuclear sclerosis might be classified as a cataract in one study and as a normal aging change in another, which is part of why prevalence estimates range from the mid-teens to above 30 percent depending on the cutoff used.
Newer imaging technologies, including optical coherence tomography and automated analysis of fundus photographs, are pushing toward more objective grading. These tools can detect early lens changes before a human examiner would call them clinically significant. As these methods become more widespread, reported cataract prevalence may actually increase, not because more people are developing cataracts, but because earlier and subtler cases are being captured. For someone looking at prevalence statistics and wondering how to interpret them, this measurement issue is worth keeping in mind. The percentage depends partly on where you draw the line between an aging lens and a cataract, and that line is not as firm as you might expect.