What is Cataract?
A cataract is a clouding of the lens of the eye.
It is a cloudy or opaque area in the normally clear lens of the eye. For people who are developing cataracts, looking through the cataract is like looking out a frosty or foggy window.
Cataracts can make it more difficult to read or drive a car, especially at night.
Cataracts usually develop in people over age 55, but they can also occur in infants and young children or as a result of trauma or medications. Usually, cataracts develop in both eyes, but one may be worse than the other.
Cataracts will not go away on their own. Without proper intervention, they can worsen and may lead to total vision loss.
Clouding of the lenses
Lenses are the nearly transparent structures that sit right behind the pupils in your eyes. Their main purpose is to focus and direct light rays onto the retina at the back of the eye.
In order for us to see clearly, our lenses need to be clear. As we age, however, protein can build onto them, and turn them cloudy.
Cataracts generally form very slowly. At first, they don’t disturb eyesight. Gradually, however, the clouded areas on the lenses become larger and denser causing sight to worsen. Signs and symptoms of a cataract may include:
- blurred vision
- sensitivity to light (seeing a glare or ‘halos’ around lights)
- reduced night vision
- fading or ‘yellowing’ of colours
- Frequent changes in eyeglass prescription
When the cataracts impair your vision or interfere with your usual activities, cataract surgery is usually recommended. Fortunately, cataract surgery is generally a safe, effective procedure.
Types of cataract
There are three main types of cataract, named for their location in the lens:
1. Nuclear Cataracts
Nuclear sclerotic cataracts is the most common type of cataract. ‘Nuclear’ refers to the clouding of the central portion of the lens (nucleus) and ‘sclerotic’ means ‘hardening’ of the lens.
2. Cortical Cataracts
These cataracts start on the outside edge of the lens and form lines that then move towards the centre, like the spokes of a wheel.
3. Posterior Subcapsular Cataracts
The posterior subcapsular cataract is the clouding of the back of the lens, beneath the membrane that holds the lens in place.
Causes of cataracts
In Australia, over 700,000 people are affected by cataracts. Most cataracts are due to age-related changes in the lens of the eye, other factors can contribute to the development of cataracts, including:
- Eye trauma
- Family history
- Excessive sun and UV ray exposure
- Heavy alcohol use
Congenital and infantile cataracts
Cataracts can present at birth or develop in early infancy. It is very rare. Researchers estimate it occurs in approximately two out of every 10,000 births.
When a baby is born with a cataract it is called a ‘congenital cataract.’ If a cataract develops in the first six months of life, it is known as an ‘infantile cataract.’ A common cause of congenital cataracts in babies is heredity. Sometimes, the cataracts in the baby can be traced to an infection of measles or rubella in the mother in the first trimester of pregnancy.
How to reduce the risk of cataracts
Things you can do to reduce your risk of cataracts:
- Stop smoking
- Reduce your alcohol use
- Wear sunglasses and a hat whenever you are outside for eye protection from the sun
- Eat a well-balanced diet
- Have a regular eye examination, particularly if you are over 60
What to expect at the optometrist
Cataracts are most commonly diagnosed by an eye doctor (optometrist). Your Eyecare Plus optometrist will be able to perform an eye exam to check for cataracts.
Your eye doctor will look at the appearance of your eye during the eye exam.
During your eye exam your eye doctor may examine your eye with a slit lamp, which will show the location and pattern of the cataract.
Based on that information, your optometrist will discuss treatment options and possibly refer you to an ophthalmologist for cataract surgery.
Cataract surgery, also called ‘lens replacement surgery,’ is one of the most frequently performed eye surgery procedures performed by an ophthalmologist, in the world. It is simple and low-risk. During the eye surgery, the patient’s cloudy lens is replaced with a clear intraocular lens (IOL). Most IOLs are made of silicone or acrylic. The entire procedure takes about thirty minutes and is performed in a day surgery or a hospital.
Once the cataract has been completely removed with surgery, it does not return.
Are cataracts inevitable?
Cataracts are a natural part of the aging process. Although they are not inevitable, most of the figures suggest that, if you live long enough, the risk of developing cataracts is high. About 30% of people in Australia over the age of 50 have age-related cataracts. For people over the age of 80, the prevalence of cataracts is about 80%. The prevalence of cataracts in Indigenous Austraians is five to six times higher than non-Indigenous Australians in those aged over 60.