A Answers (9)
Honor Society of Nursing (STTI) answeredIn some cases, genetic disorders or conditions can contribute to the development of cataracts. However, oftentimes cataracts form as people age without a specific cause. Factors such as eye injuries, long-term exposure to the sun, smoking, and certain medications may all play a role in the formation of cataracts.
Cataracts, a clouding of the lens inside the eye, have multiple causes. Aging is the most common, as the proteins that make up the lens slowly degrade over time. Radiation, such as UV light, microwaves and X-rays, can also cause or contribute to cataracts. Blunt trauma can cause cataracts when the inflammation, swelling and whitening that can happen does not completely resolve. Cataracts are also associated with a number of genetic, metabolic/nutrition and skin diseases. Smoking appears to increase the risk of cataracts. Medications and iodine deficiency can cause cataracts. Some infections, such as varicella and toxoplasmosis or even congenital infections (infections of fetuses before they are born such as rubella or syphilis), can cause cataracts too.
Laura Fine, Ophthalmology, answeredContrary to what some people believe, cataract (clouding of the normally clear lens of the eye) is not caused by a film blanketing the eye, nor is it related to overuse of the eyes. It does not spread from one eye to the other -- although the condition may develop in both eyes.
Aging and accompanying changes in the chemical composition of the lens are the most common causes. Many cataracts develop as an exaggeration of normal aging sclerosis, in which the lens becomes less resilient, less transparent, and often thicker. Fibers in the lens become compressed, and the lens becomes more rigid. Clarity fades as proteins coagulate, or clump together, creating tiny specks or wheel-like spokes in the periphery of the lens. In later stages, the milkiness becomes denser and occurs in the center, making it truly difficult to see. The change in the lens is similar to what happens when you cook an egg white; it goes from clear to opaque. Early on, before cataracts blur vision, they can cause nearsightedness, double vision, or distorted vision.
Although age is the factor most likely to cause cataract, other factors such as family history, eye injuries, use of some medications (particularly corticosteroids), and certain health problems (such as diabetes) can contribute to cataract as well. Several studies have linked cataract with alcohol consumption and smoking. Even if you have smoked for many years, quitting now will help lower the chances of cataracts forming in the future. Long-term exposure to high levels of ultraviolet-B (UVB) rays from the sun is another hazard, and studies have found a greater prevalence of cataract in people who live in areas with considerable sunlight. Wearing sunglasses can help protect eyesight and minimize cataract formation.
A cataract occurs when the lens inside your eye becomes cloudy. Things linked to clouding include:
- Aging (age-related cataracts).
- Overexposure to ultraviolet (UV) radiation, such as from sunlight, tanning booths or sunlamps.
- Diabetes. Diabetes, especially when the blood sugar levels are above the safe range, causes changes in the eye that can result in cataracts.
- Disease inside the eye, such as glaucoma, retinitis pigmentosa, retinal detachment, or long-term uveitis.
- Long-term use of steroid medicines.
- Frequent X-rays or radiation treatments to the head.
- Family history (genetics). A person may inherit the tendency to develop cataracts.
- Vitrectomy. People older than age 50 who have had the vitreous gel removed from their eye (vitrectomy) have an increased risk of cataracts.
- Eye injury. Even though injury-related cataracts are rare, injury is a leading cause of cataracts in children.
- Being born with cataracts (congenital). Some children are born with the condition.
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Normally, the lens of the eye is clear. When a cataract develops, the lens becomes cloudy, similar to a frosted window. Located near the front of the eye, the lens focuses light on the retina at the back of the eye. Light passes through the lens to produce a sharp image on the retina. When a cataract forms, the lens can become so opaque and unclear that light cannot easily be transmitted to the retina.
- Nuclear cataract: A nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes.
- Cortical cataract: A cortical cataract, which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center. Many diabetics develop cortical cataracts.
- Subcapsular cataract: A subcapsular cataract begins at the back of the lens. Individuals with diabetes, high farsightedness, retinitis pigmentosa, or those taking high doses of steroids may develop a subcapsular cataract.
- Other types of cataracts: Although most cataracts are related to aging, there are other types of cataracts including secondary, traumatic, congenital, and radiation cataracts.
- Secondary cataract: Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
- Traumatic cataract: Cataracts can develop after an eye injury, sometimes years later.
- Congenital cataract: Congenital is defined as being present at birth. Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed surgically. Congenital cataracts are uncommon. The causes of congenital cataracts include German measles (rubella) during pregnancy.
- Radiation cataract: Cataracts can develop after exposure to certain types of radiation, including gamma radiation.
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Kelly Traver, Internal Medicine, answered
Cataracts occur due to a change in the chemical composition of the eye's lens, which causes the lens to become cloudy. This condition occurs in most people who live past 70, but frequent exposure to direct sunlight seems to accelerate the process. This condition can easily be treated with surgery to remove and replace the lens.
Michael T Murray, Naturopathic Medicine, answered
Aging-related (senile) cataracts form when the normal protective mechanisms of the eye are unable to prevent free-radical damage. The lens, like many other tissues of the body, depends on adequate levels and activities of antioxidant nutrients and enzymes for its normal protective mechanisms. When it is either overwhelmed by the demand for or deficient in the supply of antioxidant nutrient and enzymes, cataracts form. For example, exposure to cigarette smoke or sunlight increases the risk of cataracts by creating an increased need for antioxidant nutrients and enzymes in the lens of the eye.
Sreedhar Potarazu, Ophthalmology, answered
Cataract is an aged related change to the natural lens of the eye that happens in almost everyone. The increased opacity of the lens can cause vision intitally to be blurred and hazy. One may intially notice seeing haloes around bright lights or glare at night from oncoming headlights as an intial sign. There are some studies to sugest that catracts are are caused by excessive sun exposure and are thus more common in populations who live closer to the equator. Cataracts are treated only when one cannot perform their daily routine because of vision impairment. The treatment of cataract is surgical removal; of the lens with the placement of a lens implant.
American Academy of Ophthalmology answered
The most common type of cataract is related to aging of the eye. Other causes of cataract include:
- Family history
- Medical problems, such as diabetes
- Injury to the eye
- Medications, especially steroids
- Long-term, unprotected exposure to sunlight
- Previous eye surgery
- Unknown factors