Just as a pair of glasses needs to be clear and clean, so do the lenses sitting near the front of our own eyes. Yet with age, it appears almost inevitable they will at some point begin to get cloudy with the formation of cataracts. According to the National Institutes of Health (NIH), over half of people 80 years old either have cataracts or have already had cataract surgery; some estimates put the rate higher yet. Cataracts can also develop in infants and other young people from severe infectious or allergic conditions. In fact, there are numerous types and causes of cataracts known to medicine. Fortunately, most are rare – except those coming with age.
The lens is jam-packed with proteins called crystallins. As the name implies, they should be crystal clear, and they are as long as they’re all lined up properly. With age or appropriate perturbation, though, some proteins lose their proper structure, giving them a tendency to clump together – doctors say they are ‘denaturing’. This is essentially the same process as the clear fluid of a raw egg turning white as it cooks – just not nearly so fast!
In addition to cloudiness, cataracts can cause yellowing of the vision and a loss of distinguishing between blues and greens. There may be a decline in the contrast seen with shades of differing brightness. Lights often begin to have a glare or halo around them, due to the scattering effect of the cataracts. Oddly enough, given that we virtually always use our eyes together, cataracts typically develop in one eye sooner than in the other. Go figure!
The most common environmental factor contributing to cataract formation is excess exposure to the sun’s ultraviolet (UV) rays. Hence wearing UV-blocking sunglasses can help stave off their development, as can simply wearing a hat in the sun. High blood pressure increases the risk of developing cataracts or of developing them sooner. They are also one of the many, many complications of diabetes.
The human eye lens is in fact generally sensitive to high energy forms of radiation, such as from radioactive substances and cosmic rays of outer space. Cataracts are extremely common in former astronauts and even some pilots spending thousands of hours at very high altitudes, where cosmic radiation is not blocked by the atmosphere. In fact, doctors predict the incidence of cataracts in the general, earth-bound population will increase, due to thinning of the ozone layer caused by certain pollutants!
Because cataracts develop slowly, the cloudiness of vision they cause is possible to ignore or put up with for a while. Left untreated, however, cataracts will become worse to the point of blinding a person. This is still a fairly common cause of blindness around the world.
Research in the past decade with the natural antioxidant L-carnosine in eye drops has been very promising, reducing some of the symptoms of cataracts or slowing down their progression. This is a naturally occurring molecule normally found in our brain and muscle. Its use for cataracts is not yet endorsed by main stream medicine, which is conservative about such things. A bit more research clarifying doses and responses can change such a stance.
Historically the most common treatment for cataracts has been surgical removal and replacement with an artificial lens. This is in fact the most common surgical procedure done in the US and many other countries, with very low rates of complications. It may well remain the best option for treating many cataracts, depending on their severity and response to other options.