What Is A Cataract?
A cataract is a clouding of the lens in the eye. It is the most common cause of vision loss or blindness in people over age 40.
The lens is a clear part of the eye behind your iris (the coloured part of your eye, usually brown or blue) that helps us to focus light, or an image, on the retina - very much like a camera lens. This process helps us to see via a complex mechanism.
The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred, clouded, misty or faded. It may not even be seen at all!
Who Is Affected?
Currently, cataracts are the main cause of blindness in the world. They are responsible for over 51% of world blindness, affecting more than 20 million people globally with many of them in developing countries, like Nigeria. As the population ages, more than 30 million people are expected to have cataracts by the year 2020.
What Are The Types Of Cataracts?
Cataracts develop slowly over several years which explains why it is commoner in older in people but it can be found in all ages. A cataract can be found in one or both eyes. It cannot spread from one eye to the other. It also cannot be spread from one person to the other. There are three (3) types of cataracts described due to their position on the lens:
- A subcapsular cataract occurs at
the back of the lens. It is commonest in diabetics.
- A nuclear cataract forms in the
central area of the lens.
- A cortical cataract starts in the periphery of the lens and works its way to the centre in a spoke-like fashion ? like the wheels of a bicycle.
Cataracts may also be described with their nature or degree of growth. This is called maturity. Consequently, a cataract covering a large area of the lens is called mature or complete cataracts while a developing cataract yet to reach the whole area of the lens is termed immature or partial. A hypermature cataract has a leaky liquid surface. Cataracts may also remain largely the same for several years (referred to as stationary) or continue to grow (referred to as progressive).
What Causes Cataracts?
Ageing is the commonest cause of cataracts. This is because the natural lens has proteins which degrade over time. The lens is also less flexible as we age. However, there are certain conditions that increase the possibility of you developing cataracts. These conditions include the following:
- Cataracts may form in response to a change
or disease process in the body. These are called secondary cataracts. These
can form after surgery for other eye problems, such as glaucoma. They can also
develop in people who have other health problems, such as diabetes mellitus.
Cataracts are sometimes linked to steroid misuse.
- Cataracts can develop after an eye injury, usually
a few years after the injury.
- Some babies are born with cataracts or
develop them in childhood, often in both eyes. These are usually due to
infections such as Rubella affecting the mother before the birth of the baby.
- Cataracts can develop after exposure to some types of radiation.
Cataracts are not genetic and cannot be passed from parents to their offspring. However, cataracts may be seen as part of the symptoms of some genetic diseases (e.g. Down?s Syndrome). They are formed from the deposition of protein pigments in clumps on the lens.
What Are The Symptoms Associated With Cataracts?
If you have cataracts in one or both eyes, you may experience some following. The extent or severity of these symptoms depends on the stage or maturity of the cataract.
- Blurry vision. The sight is misty and
cloudy. You may feel like your glasses are dirty and need cleaning, even when
- Colours that seem faded or look a little
more washed out than they should be.
- Double vision. Images may begin to become doubled
in your field of vision. This may cause problems with reading, driving or recognizing
the faces of people.
- Frequent prescription changes for your
- Glare and new onset light sensitivity -
headlights, lamps or sunlight may seem too bright, causing you discomfort when
you look directly at them. You may also see a halo around lights.
- Night blindness. There is an increased
difficulty in seeing at night when you have cataracts.
- People affected by cataracts may be moody and keep to themselves due to their increasing loss of independence
While it is quite visible to other people when you have cataracts, other conditions may seem like cataract due to the similarities between them. If you think you have a cataract, see an eye doctor for an exam to find out for sure. Your doctor may also use special instruments to look at the front and back of your eye under magnification.
How Can One Prevent The Development Of Cataracts?
Besides advancing age, there are risk
factors for cataract which can be managed to reduce the onset and severity of
symptoms as well as the progression of cataract. Preventing cataracts is an
active process that you need to pat specific and wilful attention to. These
- Properly control your blood sugar and blood
pressure if you are diabetic and/or hypertensive. Adhering to your lifestyle
changes and/or medications will help prevent or reduce the risks of developing a
- Wear appropriate eye wears to shield the
eyes from ultraviolet radiation from sunlight and other sources especially
if you are often outdoors in the sun or work near radiation sites.
- Keep fit and maintain a healthy weight.
Obesity has been linked to the development of cataracts.
- Quit Smoking. Cigarette smoking increases
the possibility of developing cataracts, among other things. If you smoke,
endeavour to quit.
- Use steroid-containing medications only on
doctor?s orders. Drug misuse will hasten or lead to the development of
- Protect your eyes from trauma in sports and
avoiding physical violence. Sustaining facial injuries especially if the eyes
are affected may cause eye injury and the development of cataracts.
- Reduce your alcohol consumption.
- Eat more fruits and include vegetables in your meals.
How Is Cataract Treated?