Failing to wear sunglasses in sunlight causes cataracts in old age
the verdict
CONTESTED PARTIAL
refutedsupported
the weight of evidence
3 sources for · 1 against
Evidence sources partially connect prolonged UV exposure to an increased risk of cataracts and suggest sunglasses may help mitigate that risk, while other clinical data report no observed association between sunlight exposure and senile cataracts.
If you're experiencing any of these symptoms, it's crucial to consult an eye care professional for a comprehensive eye examination and proper diagnosis. Causes of Cataract
Cataracts develop when the clear lens of the eye becomes cloudy, impairing vision. Several factors can contribute to the formation of cataracts. These include:
- Age: Age-related changes in the lens structure are the most common cause of cataracts. As people age, the proteins in the lens can clump together, causing cloudiness and opacity. - UV Radiation: Prolonged exposure to ultraviolet (UV) radiation from sunlight over the years can increase the risk of developing cataracts. Protecting your eyes from UV rays with sunglasses that block UVA and UVB rays may help reduce this risk. - Diabetes: People with diabetes are at a higher risk of developing cataracts due to changes in the metabolism of glucose within the eye, which can lead to clouding of the lens. - Smoking and Alcohol Consumption: Smoking and excessive alcohol consumption have been linked to an increased risk of cataracts. The exact mechanisms are not fully understood, but they may contribute to oxidative stress and damage to the lens.
A cataract is a cloudy area in the lens of the eye that impairs vision. How fast a cataract develops depend on the type and one or both eyes may be affected by the condition. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and difficulty seeing at night. This may result in difficulty driving, loss of independence, and decreased ability to perform everyday tasks. Poor vision caused by cataracts may also result in an increased risk of falling and depression.
Cataracts are most commonly due to aging but may also be caused by trauma to the eye, radiation exposure, conditions present from birth or complications from other conditions. Risk factors include diabetes, longstanding use of corticosteroid medication, obesity, other eye conditions, dietary deficiencies, smoking tobacco, prolonged exposure to sunlight and alcohol use. Cataract formation is primarily driven by oxidative stress and aging. Over time, the systems within the eye that keep the lens clear don't work as well, leading to the lens clouding. Diagnosis is typically made through an eye examination, including testing vision at various distances, slitlamp microscopy, and retinal examination. Slit-lamp examination provides further details on the characteristics, location, and extent of the cataract. An ophthalmoscope or a slit lamp with special lenses can be used to evaluate the retina. Sometimes the eye will be dilated before examination to give a better view of the retina. There are many types of cataracts, differentiated by where in the lens the clouding occurs. The three most common types of cataracts are nuclear, which affect the center of the lens, cortical which affect the outer part of the lens, and posterior subcapsular which develop at the back of the lens.
As of 2025, there is no proven way to prevent or delay the development of age-related cataracts. However, risk factors such as alcohol use, smoking, and ultraviolet exposure can be controlled. Early on, the symptoms may be improved with glasses. If this does not help, surgery to remove the cloudy lens and replace it with an artificial lens is the only effective treatment. Cataract surgery is not readily available in many countries, and surgery is needed only if the cataracts are causing problems and generally results in an improved quality of life.
As of 2020, around 12 to 15 million people worldwide are blind due to cataracts and over 200 million have some level of visual impairments due to the condition. Cataracts remain the single most common cause of blindness. The prevalence of cataracts across all ages is 17.2%, with the most common types being nuclear and cortical cataracts. Cataracts become more common with age and are more common in women. Most individuals with cataracts live in lower income countries, with South Asia having the highest rates of cataract induced blindness. Access to cataract surgery varies around the world and those in low- and middle-income countries have lower rates of surgical treatments. In these regions cataracts are responsible for up to 50% of blindness, compared with only about 5% in high-income countries.
Age: aging is the main risk factor for the development of cataracts
Genetics: those with relatives who have cataracts, as well as individuals with specific genetic conditions are more likely to develop cataracts
Ultraviolet (UV) radiation: longterm UV exposure from the sun can damage lens proteins leading to a higher risk of cataracts
Smoking: toxins from cigarette smoke cause damage to the lens leasing to an increased risk of cataracts
Alcohol use: chronic alcohol use contributes to lens damage and has been associated with heightened cataract risk
Diabetes: high blood sugar levels may lead to sorbitol building up in the lens leading to an increased risk of developing cataracts
High blood pressure: associated with heightened risk of cataracts
Obesity: metabolic and vascular complications of obesity puts an individual at a higher risk for cataracts
Medications: chronic corticosteroid usage along with phenothiazine, antidepressants, miotics, and statins can increase the risk of cataracts
Diseases: cataracts can develop as a result of other eye disorders such as chronic anterior uveitis, pseudoexfoliation syndrome, acute congestive angle-closure glaucoma, severe nearsightedness (high myopia) and some inherited disorders (Marfan syndrome, Down syndrome, myotonic dystrophy, Alport syndrome, retinitis pigmentosa, late-onset retinal dystrophy, or neurofibromatosis type 2)
Eye injuries: injuries to the eye can cause cataracts directly after the trauma or years later
Radiation: exposure to ionizing radiation damages the lens cells, raising the risk of developing cataracts
Diet: deficiencies of antioxidants, minerals, and
Sunlight, skin sensitivity, and senile cataract. This study explores the association between sunlight exposure and senile cataract, taking into account such individual differences as skin sensitivity to sunlight and the use of sun-shielding devices, i.e., sunglasses and hats. A case-control study was conducted among 160 matched pairs of subjects between October 1, 1984 and June 1, 1985 at the University of Iowa Hospitals and Clinics in Iowa City, Iowa. Cases were selected from among all patients admitted for inpatient or outpatient cataract surgery who were at least 40 years old. Controls were selected from among those waiting for a friend or relative who was attending one of the ophthalmology clinics. Controls were matched to the cases on a 1:1 basis on sex and age (+/- one year). No association was observed between history of sunlight exposure and senile cataract.
Protecting the eye from ultraviolet A radiation during photochemotherapy. Except for the skin, the eye is the only organ that is continuously exposed to solar radiation, including longwave ultraviolet irradiation (UVA). Since 8-methoxypsoralen (8-MOP) remains not only in the skin but also in the lens of the eye after 8-MOP + UVA (PUVA) treatment, wearing protective goggles just during the UVA irradiation is insufficient. It is wise to shield the eyes for several hours after 8-MOP ingestion, to avoid or reduce possible long-term side effects such as cataract formation. Adequate eye protection from UVA after PUVA can be provided by sunglasses that filter out the appropriate UVA spectrum from the sunlight. Nearly all the commercially available sunglasses are colored, which reduces the intensity of the visible light reaching the eye. In such cases, the diameter of the pupil can remain dilated, which it would not without sunglasses. However, the UVA intensity remains the same. As a result, more UVA can reach the lens. In this study, new uncolored glasses are evaluated and compared with commercially available sunglasses (all colored) to determine their UVA transmission.
Sunglasses: are they necessary in Christchurch? Concern over potential eye injury from sunlight prompted this study to see if the levels of sunlight in Christchurch posed a particular risk to our population's eyes, whether the populace was aware of any risk and whether effective sunglasses were freely available to the public. While there has been a 4% to 9% increase in UV radiation since 1969 due to global ozone depletion, no firm evidence was found that focal ozone depletion was a particular problem in New Zealand. Christchurch residents were poorly informed about the ocular hazards of sunlight. A questionnaire completed by 200 adults disclosed 32% were unaware of the particular danger of UV light and only 3% knew that snow blindness, eclipse burns and cataracts could all be caused by sunlight. Fifty-four sunglasses were analysed for labelling and for transmission characteristics of their lenses. The standard of labelling of the sunglasses was poor with only 53% making reference to UV transmission characteristics and only three pairs stating that they adhered to the New Zealand Sunglass Standard.
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