We’ve created an extensive to guide to answer all your questions relating to cataracts, including causes, symptoms, treatment, and the on-going research into cataracts.
What Is A Cataract?
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to ageing; cataracts are very common in older people.
A cataract can occur in either or both eyes. It cannot spread from one eye to the other.
There are many different types of cataracts. Not all cataracts cause symptoms. If a cataract causes no symptoms, it can usually be left alone. If symptoms, such as blurred vision, occur then cataracts can be treated very successfully with surgery.
The Lens
The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye.
In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain. 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.
What Causes Cataracts?
The lens lies behind the iris and pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye where an image is recorded. The lens also adjusts the eye’s focus, letting us see things clearly both up close and far away. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.
But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.
As you become older, you might also find that the lens begins to acquire a brownish shade. If you have advanced lens discolouration, you may not be able to identify blues and purples.
Cataracts are associated with the sun and so are far more common in areas of the world such as India and Africa. Other causes include injury, diabetes, smoking, certain drugs, and some ocular diseases.
Whilst cataracts are commonest in older people, they can occur at any age. Some children are born with cataracts, this is known as congenital cataracts.
Cataract Symptoms
The most common cataract symptoms are:
• Cloudy or blurry vision
• Colours seeming to fade
• Glare, headlights, lamps, or sunlight might appear too bright. A halo may appear around lights
• Poor night vision
• Double vision or multiple images in one eye.
• Frequent prescription changes
Because cataracts normally develop very slowly over many years, most people don’t notice the gradual deterioration in their vision until it starts to interfere with their daily activity, or it is spotted by their optometrist.
Different Types of Cataracts
• Secondary Cataract: Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
• Traumatic Cataract: Cataracts can develop after an eye injury, sometimes years later.
• Congenital Cataract: Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
• Radiation Cataract: Cataracts can develop after exposure to some types of radiation.
How Is A Cataract Detected?
Cataracts are detected through a comprehensive eye exam that includes:
• Visual Acuity Test: This eye chart test measures how well you can see at various distances.
• Dilated Eye Exam: Drops are placed in your eyes to widen, or dilate, the pupils. Your optometrist uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems.
• Tonometry: An instrument measures the pressure inside the eye.
How Are Cataracts Treated?
The most effective treatment for cataracts is an operation to remove the cataract and replace the cloudy lens with a clear artificial implant.
The lens of each eye should be clear in order for your eyes to work properly. When glasses no longer improve your vision, the only way to restore your vision is by having the cataract removed by surgery.
The Cataract Operation
Cataract surgery is one of the most common and quickest surgeries performed today. Modern cataract surgery, called phacoemulsification, is usually performed under local anaesthetic as a day case procedure. During the surgery, a tiny incision is made into the eye and the lens removed with an ultra-sound probe. The capsule of the lens is left behind and this is used to house the new lens implant. The whole procedure takes between 15 and 20 minutes and the visual recovery is very quick with most patients noticing improved vision within a matter of days.
Lens Implant Types
Each patient and each eye are different. Measurements are taken prior to surgery, called biometry, to establish the correct lens power for the individual eye. Lens implants also come in different types. The two major categories of lens implants are:
Monofocal Lenses
The vast majority of patients have this lens type put in. These provide good distance vision, but glasses are required for close work.
Multifocal Lenses
These lenses offer a high probability of achieving glasses independence, providing patients the ability to see far as well as to read without glasses.
However, patients can experience a reduction in contrast sensitivity, especially in dim lighting, as well as halos and glare around lights at night.
The pre-operative preparations for patients interested in multifocal lens implants are more involved than when monofocal lenses are being used, a wider range of issues need to be discussed, and the post-operative management is more intensive. These are the major reasons that these lenses are not offered on the NHS.
Current Cataract Research
The National Eye Institute is conducting and supporting a number of studies focusing on factors associated with the development of age-related cataracts.
These studies include:
• The effect of sunlight exposure, which may be associated with an increased risk of cataracts.
• Vitamin supplements, which have shown varying results in delaying the progressions of cataracts.
• Genetic studies, which show promise for better understanding cataract development.
