In this article
According to the Royal National Institute of Blind People (RNIB), cataracts affect around 2.5 million people aged 65 or over in the UK. The prevalence of cataracts increases with age and almost 30% of people over the age of 65 in the UK have them. Worldwide, this condition is the leading cause of blindness and estimates suggest that cataracts cause half of all cases of blindness in the UK. In this article, we’ll tell you all about cataracts.
What are cataracts?
Cataracts are a common eye condition in which the lens of the eye becomes cloudy, leading to a decrease in vision. The lens is the clear structure that helps to focus light onto the retina, which sends the visual signals to the brain. When this lens becomes cloudy with cataracts, this interferes with the transmission of light, leading to visual impairment.
Due to the cloudy or opaque lens, vision becomes hazy because the light that enters the eye is scattered or blocked. Besides reduced vision, there are other visual disturbances associated with cataracts.
- Reduced visual acuity: The cloudy lens makes seeing finer details and sharp edges more difficult.
- Light sensitivity: With a cloudy lens, you might be increasingly sensitive to bright light, making it uncomfortable to be in sunlight or bright environments.
- Difficulty with night vision: Cataracts can cause glare or halos around lights in the dark. This makes it harder to see at night.
- Changes in colour perception: The cloudiness of the lens can affect a person’s perception of colour, causing them to appear faded or with a yellow tint.
- Double vision: Sometimes cataracts cause double vision in the affected eye.
Cataracts can affect one or both eyes. They can develop slowly over time or they can occur rapidly. Though they’re more common in older adults, they can occur in younger people, especially where there is a family history of the condition.
It’s important to have regular eye examinations to detect cataracts early and prevent vision loss.
Types of cataracts
There are several types of cataracts that affect the eye.
The most common types include:
1. Nuclear cataracts: These cataracts occur in the centre of the lens and are often associated with ageing. They can also cause near-sightedness (myopia) or changes in colour perception.
2. Cortical cataracts: These cataracts start at the edge of the lens and gradually extend inward toward the centre, forming wedge-shaped opacities. They may cause problems with glare and light scatter.
3. Posterior subcapsular cataracts: These cataracts form at the back of the lens, directly behind the lens capsule and can cause rapid vision changes, including difficulty reading and sensitivity to bright light.
4. Congenital cataracts: These are cataracts that are present at birth or develop during childhood. They may be caused by genetics, infection or other factors.
5. Traumatic cataracts: These cataracts may develop after an eye injury or as a result of surgery.
6. Secondary cataracts: These cataracts may develop as a complication of other eye conditions, such as uveitis, glaucoma or diabetes.
What causes cataracts?
The exact causes of cataracts aren’t always clear but there are several factors that are believed to contribute to their development.
The most common factors that can lead to cataracts include:
- Age: Cataracts are more common in older people and a person’s risk will increase with age.
- Genetics: Family history of cataracts can increase the likelihood of a person developing the condition.
- Diabetes: A diagnosis of diabetes means cataracts are more likely.
- UV radiation: Prolonged exposure to ultraviolet radiation either from the sun or other sources can cause cataracts.
- Trauma: Eye surgery or injuries can cause cataracts to develop.
- Medications: Long-term use of certain medicines like corticosteroids can cause cataracts to develop in some people.
- Other health conditions like high blood pressure (hypertension) or obesity can increase the chances of developing cataracts.
- Lifestyle factors: Smoking and consuming excessive amounts of alcohol can increase a person’s risk of developing cataracts.
Who is at risk of cataracts?
Cataracts can affect anyone, but certain factors can increase the risk of developing them. If you have a family member who has cataracts, you’re more likely to get them yourself. Secondly, if you are diabetic, obese, smoke or consume alcohol in excess, you’re at a greater risk. Besides these factors, you can be at a greater risk of cataracts if you take long-term medications like corticosteroids, statins, antipsychotics, beta-blockers and diuretics, or you have been exposed to prolonged periods of ultraviolet radiation.
It’s worth mentioning that the benefits of any medications will usually outweigh the risks of developing cataracts and you shouldn’t stop taking medication without consulting a healthcare provider.
Finally, ageing is one of the biggest risk factors – and one that no one can avoid!
Signs of cataracts
The signs and symptoms of cataracts can vary depending on the type and severity of the cataract.
Some common symptoms include:
- Blurry or cloudy vision: This is often the first sign of a cataract, and it can make driving, reading and seeing objects clearly more difficult.
- Light sensitivity: With cataracts, you’re more sensitive to bright lights and you might notice halos around lights.
- Difficulty seeing in the dark: Cataracts make seeing at night or in the dark more difficult.
- Fading or yellowing of colours: With a cataract, you might see colours as less vibrant or they may have a yellow tinge.
- Double vision: Double vision can occur with cataracts as it will affect how light passes through the lens. This can cause two images to be seen rather than one.
- Frequent changes in prescriptions: When cataracts develop, they cause changes in your glasses prescription. This might mean you need new glasses or contact lenses more frequently.
How are cataracts diagnosed?
Cataracts are usually diagnosed following a comprehensive eye examination conducted by an optician or ophthalmologist.
The following tests might be used:
Visual acuity test
This test measures how well you can see at different distances using an eye chart. This is a simple and non-invasive test and is usually performed as a part of a routine eye test. It is commonly used to detect refractive errors like near-sightedness (myopia), farsightedness (hyperopia) and astigmatism as well as cataracts.
During a visual acuity test, the patient will be asked to read symbols and letters on an eye chart at a standard distance. The letters become smaller and the optician will record the smallest letters you can see.
Visual acuity is typically expressed as a fraction. The top number represents the distance at which the chart is viewed (this is usually 20 feet/6 metres) and the bottom number represents the distance at which a person with normal vision can read the same line of letters. For example, if you can read the line of letters at 20 feet that a person with normal vision can read at 40 feet, your visual acuity would be recorded as 20/40. Normal vision is 20/20.
Dilated eye exam
This is a comprehensive examination that uses eye drops to dilate the pupils to allow a better view of the inside of the eye. During a dilated eye exam, the retina, optic nerve and other eye structures will be checked for signs of disease.
The drops take around half an hour to take effect and the dilation usually lasts a few hours. During this time, a person’s vision will likely be blurry and they may be more sensitive to light. Patients are recommended to bring sunglasses to wear afterwards.
After the drops have taken effect, the doctor will use a special magnifying lens to examine the inside. This can be uncomfortable but it isn’t usually painful. There may be other instruments used that measure the pressure inside the eyes too.
Slit lamp exam
This test uses a special microscope to look at the front of the eye. The doctor will examine the cornea and iris as well as the lens.
During this test, the patient sits in front of the slit lamp machine and places their chin on a rest. The doctor will use a joystick to move the lamp around and adjust the focus. A thin beam of light is directed onto the front of the eye to illuminate the different structures that are being examined. The doctor can adjust the height and width of the beam to get a better view.
This test is used to diagnose corneal abrasions, glaucoma, macular degeneration and other conditions as well as cataracts.
If a doctor detects a cataract, they will monitor its progression and prescribe glasses, if needed, to help improve vision. For severe cases, the doctor might recommend surgery to remove the clouded lens and replace it with an artificial lens.
Treatments for cataracts
The primary treatment for cataracts is surgery to remove the cloudy lens and replace it with an artificial intraocular lens (IOL). Cataract surgery is a safe and effective procedure that is usually done on an outpatient basis, meaning the patient can go home the same day.
Before surgery, there will be a local anaesthetic given to make the eye numb before surgery. Some patients can be given a sedative if necessary to help them to relax.
During surgery, a small incision will be made in the front of the eye in the cornea. It’s usually around 3 millimetres long.
The surgeon will use a small instrument to create a circular opening in the front of the lens capsule (the thin membrane surrounding the natural lens). This is called a capsulotomy.
A probe will then break up the lens using high-frequency ultrasound waves or laser. The pieces of lens will then be removed through the incision by suction. This is called phacoemulsification.
An artificial lens is then implanted to replace the lens and provide clear vision. After this, the small incision will be closed with tiny sutures or self-sealing incisions.
After surgery, patients will usually need to use eye drops to prevent infection and reduce inflammation. They will also need to avoid some activities like heavy lifting or rubbing their eyes to allow the eye to heal.
Sometimes cataracts might not need to be removed immediately, particularly if they are not causing significant problems with vision. In these cases, the doctor might monitor the cataracts and recommend surgery if they start to interfere with daily activities.
Unfortunately, there are no non-surgical treatments or medications that can cure cataracts or prevent their development.
Can cataracts be prevented?
There are no specific ways to prevent cataracts. However, there are steps people can take to reduce the risk of them developing.
- Protecting eyes from UV radiation. This means wearing sunglasses that block UV.
- Don’t smoke. Smoking has been linked to cataracts developing and so refraining from smoking can help to prevent them.
- Eating healthily. Eating a diet that’s rich in fruits and vegetables might help reduce the risk of developing cataracts. Vitamins A, C and E are especially important.
- Managing other health conditions well. Certain conditions like diabetes can increase a person’s risk of developing cataracts. Ensuring the correct management of this condition can help to reduce the risk of cataracts.
- Getting regular eye tests. Eye tests can help detect cataracts in their early stages, which means you can monitor their progression. This is particularly important for those over 60.
It’s important to note that while these steps might help to reduce your risk of developing cataracts, they can’t guarantee that you won’t develop them. Cataracts are a natural part of the ageing process and, in some cases, they might still develop despite taking steps to reduce the risk.
Final thoughts on cataracts
Cataracts are not life-threatening but they can interfere with the quality of a person’s life and can cause blindness. If a person has an elevated risk of cataracts either through family history, a medical condition or taking certain medication, it’s a good idea to lead a healthy lifestyle and avoid smoking and obesity, which further increase the risk.