As people age health problems become more and more prevalent. Cataracts and Macular Degeneration are the two most common age-related eye problems, causing vision loss in populations over 65 years of age.
60% of those between 65 and 74, and 91% of those aged 75 and higher show evidence of cataract development. 10% of those between 65 and 74, and 30% of those aged 75 and higher are likely to develop Age-Related Macular Degeneration.
A cataract is a clouding of the lens of the eye. The lens gradually becomes opaque, causing vision loss. Early on, this may manifest as myopia, or an inability to perceive blue colours properly. In later stages the lens swells, then shrinks, which can lead to total loss of transparency, and blindness. The senile form of cataracts may be caused by long-time exposure to ultra-violet light, or by complications from diseases such as diabetes or hypertension. Cataracts can also be an effect of trauma, a side effect of corticosteroids, or it can be caused by exposure to radiation.
Age-Related Macular Degeneration, or AMD, takes two forms: Wet and Dry. Wet AMD occurs when abnormal blood vessels grow beneath the macula and leak. This displaces the macula, causing vision loss. Dry AMD is atrophy that causes photoreceptor loss in the centre of the eye. AMD risk factors include genetic factors, exposure to blue light, race, smoking, dietary insufficiencies, oxidative stress, hypertension, and obesity.
Treatment of Cataracts
Although it’s believed that preventive measures such as wearing sunglasses and taking vitamin supplements may help prevent cataracts, the only accepted treatment is surgical. There are two types of surgery; the most commonly performed is extracapsular cataract extraction, or ECCE. In this procedure the lens is removed, but the lens capsule is left intact. Sometimes sound waves are used to break up the lens before extraction. A plastic lens is then inserted. Sometimes these can be multifocal, so that the patient can decrease dependency on glasses. The operation usually only requires a local anaesthetic, and patients can go home the same day.
Is There A Connection Between Cataract Surgery and AMD?
There has been some concern that cataract surgery may accelerate progression of AMD in elderly patients. Several studies have concluded that there is no cause for alarm, although recent large population studies have shown that there may be very slightly increased odds of vision loss due to AMD after cataract surgery.
It may be that the two diseases simply develop along similar pathways, and that regardless of whether or not one has had cataract surgery, one will develop AMD. It may also be that the AMD was present pre-surgery, and was masked somewhat by the cataract. But some researchers feel that removal of the cataract results in higher exposure to blue light – which in turn hastens the progression of AMD.
Supplementing with carotenoids may help to lessen this effect. Wearing blue light blocking sunglasses after cataract surgery is also recommended. A new blue light blocking plastic lens for implementation during cataract surgery is currently in development.
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