In a majority of cases, cataracts form as individuals grow older. In fact, it has been suggested that by the time a person reaches 30 years old, the beginning stages of cataracts formation has already begun, although it may take up to another half a century for the cataracts to be fully developed and in need of medical intervention.
Statistics show that by age 75, 70% of Americans may have cataracts which cause problems with everyday activities. Besides age, a second leading cause of cataracts is diabetes which is also the number one reason for blindness in adults between the ages of 20 and 74.
Diabetes and obesity have both been associated with early onset of cataracts formation. The problem could possibly lie with the excess sorbitol, a byproduct of high blood sugar - glucose, found in the blood of diabetics. The sorbitol may collect in the lens of the eye and promote cataracts development. Although scientists are not positive on the relationship between obesity and cataracts, the fact remains that there is an increased chance of developing cataracts if an individual is overweight and, even more alarming, the risk doubles if the person is obese, as defined by a body mass index (BMI) measurement. 11
Other risk factors for the development of cataracts include lifestyle behaviors such as smoking and the excessive use of alcohol. Male smokers who go through 20 cigarettes or more per day have a two fold increase in their risk of developing cataracts and for women, smoking 35 cigarettes or more a day increases the risk by approximately one half. 11 More than likely, smoking raises cataracts formation risk due to the higher quantity of free radicals floating around in a smoker's body. A second reason may relate to the inability of a smoker's body to shuttle enough nutrients to the lens where they are used for proper, routine maintenance. Over time, without the correct minerals and vitamins, the lens (especially the proteins of the lens) begins to deteriorate.
Long term use of corticosteroids has come under attack for its relationship to cataracts occurrence, too. In one particular study, 80% of patients on a prolonged treatment regimen of oral prednisone of 15 mg a day went on to develop cataracts. In the past, it was thought that inhaled corticosteroids were safe to use, however, a recent study published findings of a 50% increase of nuclear cataracts and a 90% greater occurrence of posterior subcapsular cataracts in those patients using inhaled corticosteroids versus the group not using the steroids. This study is especially important for asthmatic patients to take into account if prescribed inhaled corticosteroids. In many cases, however, the benefit-risk ratio must be studied by both patient and doctor.
In a final note on corticosteroids, topical application to the eyelids and corticosteroid eye drops may also increase the risk of developing cataracts later in life.
Injuries to the eye, also known as traumatic cataracts formation, can occur from blunt or penetrating trauma as well as exposure to alkaline chemicals. Sometimes cataracts will develop soon after the trauma and in other cases may not show up until many years later. Prior eye surgery has also been shown to increase the risk of cataracts formation.
Those with a family history of cataracts run an increased risk of developing cataracts as do people that had developmental delays as a child, or were premature at birth. Being HIV positive, or of African-American heritage are both associated with a higher than normal risk of cataracts occurrence.
Finally, prolonged exposure to UV light from sunlight or even from x-rays, can increase the chance of cataracts formation. This type of cataracts is known as a radiation cataracts.