Learn about cataracts...
What Exactly ARE Cataracts?
I assume you are reading this because you either have cataracts yourself or a close friend or relative has cataracts and you want to know more about them. Perhaps you’ve seen a doctor or optician already and want to know what cataracts actually are before you get treated, and what the treatment actually involves.
You’re in the right place.
To start from the beginning, as you have probably heard before the eye is similar in many ways to a camera.
Light comes in the front, through the clear layer at the front of the eye, then through the lens and is focused to a sharp image on the back of the eye. The back of the eye (called the retina) is sensitive to light and sends a signal to the brain which makes sense of it as an image, allowing us to “see”.
As you might expect, the lens needs to be perfectly clear to allow light to pass through it and form a sharp and clear image at the back of the eye, and in healthy people this is exactly what happens. But when someone develops a cataract, the lens is no longer perfectly clear but gradually becomes milky white or yellowish in colour.
And this means that the light is no longer focused to a sharp image on the back of the eye but instead becomes scattered as it passes through the lens, making the image dimmer and blurry – rather like looking through a fogged window pane.
graph
The diagrams above show what happens to the light coming into the eye when the lens becomes cloudy.
So a cataract is actually a lens in the eye that has become cloudy.
As you can see the image on the right is out of focus and blurred.
As the blurring gets worse the image becomes less clear, dimmer and the colours become harder to distinguish.
What are the Symptoms of Cataracts?
The people I see in my clinics with cataracts often complain of the following problems with their vision:
- Difficulty in seeing – particularly when driving at night
- “Halos” around bright lights such as street lights
- A “washed out” look to colours
- Getting dazzled by the headlights of oncoming traffic
- Eyes getting tired more easily
- Constantly feeling “as if you need new glasses”
It is important to remember that firstly there are many causes of these symptoms, and that some of them are serious. Also, not everyone with cataracts has all of these symptoms. This is why it is so important to see an expert without delay if you have a change in your eyesight and not to put it off.
The other thing is that cataracts do not simply appear overnight. There are many causes of cataracts and however they are caused, they grow slowly. This means the symptoms they cause appear only slowly too. In fact, people often don’t realise they have cataracts at all: they go and see their optician because they think they need new glasses. Perhaps they are struggling to read the paper or drive at night. And it is only then they find out what the problem is.
Finally, remember that because cataracts grow slowly, so the problems with your eyesight that they cause “creep up” on you slowly too. This is why people sometimes find they stumble and have minor accidents yet don’t realize the problem is they can’t see as clearly as they should.
And this is why I find caring for people with cataracts so rewarding; because they often only find out how poor their vision has become AFTER the problem has been treated. Virtually everyone who has had their cataracts treated is genuinely astonished at the improvement they get in their vision and their quality of life afterwards and wonders how they got by before treatment.
What Causes Cataracts?
Cataracts are extremely common – in fact we probably all know at least one or two people who have had them treated. But what causes them exactly? And why do so many of us develop them?
The commonest cause of cataracts is simply that the lens in the eye “wears out” with time – so-called “age-related degeneration” of the lens in the eye. There are three main causes of this – Nuclear sclerosis, Cortical cataract and posterior subcapsular opacification. The details of these are not important, but what is important is the effect this has on your vision. The lens in the eye becomes murky and hazy and your vision will worsen and over time your vision will deteriorate.
Untreated, patients progressively lose their vision – and that can be very disabling and distressing. But even before that, poor vision can mean people lose confidence in getting out and about in unfamiliar places and stay indoors. Poor vision can mean people socialise less and become withdrawn. And poor vision makes us more likely to fall or injure ourselves in other ways.
That is why the new treatments we have for cataracts are so exciting, and so rewarding: because a simple procedure can give people a whole new lease of life. The magic of seeing someone’s face light up after their cataract operation when they can suddenly see clearly again never fades.
In the pictures below you can see how the eyes of a patient with a cataract appear to the outside world. The picture above is of a normal eye, and in the picture below it you can see how the normally clear lens has become white and cloudy.
