About Cataracts
Cataracts affect 17% of Americans over the age of 40. Projections indicate that 30 million people will be affected by 2020. An estimated 1.5% of Americans over the age of 40 have macular degeneration, and researchers predict that this number will increase to 3 million by 2020. The cells of the lens in the eye are connected predominantly by connexins 46 and 50. Cataracts are caused by disruption of the lens cells, resulting in the loss of lens transparency. Congenital cataracts as well as the development of cataracts in the aging population are associated with a reduction in connexin function. A number of other eye disorders involves reductions of connexin function in the retina (diabetic retinopathy, macular degeneration), lacrimal gland (dry eye from decreased secretions), and cornea.
A cataract is an opacity that develops in the lens of the eye. Early in the formation of an age-related cataract the optical power of the crystalline lens may be increased, causing near-sightedness (myopia), and clouding of the lens may reduce the perception of blue colors. Cataracts typically progress slowly to cause vision loss and are potentially blinding if untreated. Over time the cataract liquefies to form a milky white fluid and is known as a Morgagnian Cataract, and can cause severe inflammation if the lens capsule ruptures and leaks. Untreated, the cataract can cause glaucoma. Advanced cataracts are liable to dislocation and such posterior dislocations in ancient times were regarded as a blessing from the heavens, because it restored some perception of light.
Cataract derives from the Latin cataracta meaning "waterfall". In Latin, cataracta also had an alternate meaning, "portcullis", which more closely relates to the sense of "obstruction".
Cataracts develop from a variety of reasons: long-term ultraviolet exposure, exposure to radiation, secondary effects of diseases such as diabetes, and advanced age. Genetic factors are often a cause of congenital cataracts. Cataracts may also be produced by eye injury or physical trauma. Exposure to microwave radiation can cause cataracts.
Cataracts are the leading cause of blindness in the world.
In the United States, age-related changes in the lens have been reported in 42% of those between the ages of 52 to 64, 60% of those between the ages 65 and 74, and 91% of those between the ages of 75 and 85. Recent improvements in intraocular lens technology now allow cataract patients to choose implantable lens to create a visual environment in which they are less dependent on glasses.
Prevention of cataracts
Cataracts have no definitively known means of prevention. Wearing ultraviolet-protecting sunglasses may slow the development of cataracts.
Research is weakly positive for the nutrients lutein and zeaxanthin, both connexin-enhancing molecules.
Congenital cataracts are associated with dysfunction of connexin 46 and 50.
It is known that the cells making up the lens of the eye are joined together by connexin molecules and that proper functioning of the lens requires intact and fully functional connexin molecules.
About Macular Degeneration
Macular degeneration is a medical condition predominantly found in elderly adults in which the center of the inner lining of the eye, known as the macula area of the retina, suffers thinning, atrophy, and in some cases, bleeding. This can result in loss of central vision, which causes an inability to see fine details, to read, or to recognize faces. According to the American Academy of Ophthalmology, it is the leading cause of central vision loss (blindness) in the United States today for those over the age of fifty years.
Age-related macular degeneration (AMD) begins with yellow deposits in the central area of the retina.
Advanced AMD has two forms: dry and wet. The wet form of AMD causes vision loss due to abnormal blood vessel growth. Bleeding, leaking, and scarring from these blood vessels cause damage to the photoreceptors (light receiving cells) and rapid loss of vision untreated.
Risk factors for Macular Degeneration (why one gets Macular Degeneration)
Aging: Approximately 10% of patients 66 to 74 years of age will have findings of macular degeneration. The prevalence increases to 30% in patients 75 to 85 years of age.
Family history: The lifetime risk of developing late-stage macular degeneration is 50% for people who have a relative with macular degeneration vs. 12% for people who do not have relatives with macular degeneration, i.e. a fourfold higher risk.
Hypertension: Also known as high blood pressure.
High cholesterol, obesity.
Race Macular degeneration is more likely to be found in whites than in blacks.
The Age-Related Eye Disease Study showed that a combination of high-dose beta-carotene, vitamin C, vitamin E, and zinc reduced the risk of developing advanced AMD by about 25 percent in those patients who have earlier but significant forms of the disease.
Prevention of Macular Degeneration
A 6-year study found that Lutein and zeaxanthin (nutrients in eggs, spinach and other green vegetables) protect against blindness (macular degeneration), affecting 1.2 million Americans, mostly after age 65. Lutein and zeaxanthin reduce the risk of AMD. Foods considered good sources of the nutrients also include kale, turnip greens, collard greens, romaine lettuce, broccoli, zucchini, corn, garden peas and Brussels sprouts.
Beta-carotene, zinc and zeaxanthin are known connexin-enhancing molecules.