Cataracts

What are cataracts?

Cataracts occur when the lens, the small transparent tissue inside the eye, scatters light. This makes makes the eye appear cloudy or milky to others, and prevents you from seeing clearly or even at all. Cataracts are the leading cause of blindness worldwide.

What are the different types of cataracts?

The commonest type of cataract is age-related cataracts (ARC). There are three main types of age-related cataracts: nuclear sclerotic, cortical and posterior subcapsular. There are also different types of congenital or childhood cataracts.

On top of this, you might hear different terms that describe the location and appearance of cataracts, such as cortical cataracts and lamellar cataracts.

What causes cataracts?

Age is the main factor in developing cataracts - they are most common in people over 60. But not every older person gets cataracts, and many centenarians do not develop cataracts.

Some of the proteins that make up the lens of your eye are made before you are born. These proteins can become damaged with age, which causes them to scatter the light that we use to see. The lens then appears “cloudy” because of this scattering of light.

The biggest influence on whether we get age-related cataracts is our environment, health and how we live our lives. Factors that can increase your chances of developing cataracts include:

• A family history of cataracts
• Eye injury
• Diabetes
• Drinking alcohol
• Eye surgery – for example to treat glaucoma or another eye condition
• Kidney dialysis
• Long-term use of certain medications, such as steroids
• Other eye conditions – such as retinitis pigmentosa, glaucoma or uveitis
• Radiation exposure – such as sunlight or X-rays
• Smoking

Childhood cataracts are usually caused by inherited gene mutations. Cataract was the first human disease to be identified as “autosomal dominant” in humans. In autosomal dominant inheritance, someone with the condition has a 50% chance of passing the mutated gene, and the disease, to each of their children. 

What are the signs and symptoms of cataracts?

You might not have any symptoms at first, but cataracts will eventually affect your vision as they gradually get worse over time. As cataracts can affect each eye differently, you might notice different vision in one eye compared to the other.

• Blurred or hazy vision – which may appear ‘washed out’, with less contrast between black and white. This is the main symptom of cataracts.
• Double vision – seeing objects in duplicate.
• Difficulties with colour vision – which may look faded, altered or more yellow.
• Glare – difficulty seeing in the presence of bright light and lamps sunlight. Or headlights seem too bright.
• Halos – seeing halos around lights.
• Problems with night vision – difficulty seeing well at night.

Concerned about your eyesight or that of a loved one? Make an appointment today with an optician to get it checked out. Even if your vision seems fine, get your eyes tested every two years. An eye test can spot some eye conditions and early treatment might be able to stop them getting worse. 

How are cataracts diagnosed?

Cataracts can be detected by an optometrist during a regular eye test, and can sometimes be spotted before they have started to affect your vision. If they spot cataracts you may be referred to an opthalmologist (hospital eye doctor) for more tests. 

Are cataracts serious?

Cataracts can make it gradually more difficult to carry out everyday activities, such as driving, reading, recognising faces or watching TV. They gradually get worse over time.

Cataracts are not painful but can cause blindness if left untreated. 

For older people, visual impairment such as cataracts increases the risk of other health issues, because of the increase in the risk of trips and falls and the complications of those.

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What are the treatments for cataracts?

Cataract surgery is currently the only way to effectively treat cataracts. It involves removing and replacing the inside of the lens with a new artificial plastic lens (an intraocular lens, or IOL) to restore your vision, and it's one of the most common surgical procedures in the UK. 

It's recommended once cataracts affect your eyesight and quality of life. 

There are two alternative approaches – the “lens in the bag” and the “bag in the lens”. For children, the bag-in-the-Lens has significant advantages, and in adults, it also helps prevent PCO.

You should be given an opportunity to discuss the options available to you at the pre-assessment appointment by the clinical team responsible for your treatment.

What does cataract surgery involve?

You'll need various tests to be done before surgery can be done, including an eye exam to determine the optical requirements of the intraocular lens to be implanted. If you wear contact lenses, these must be removed before the eye exam. The ophthalmological team responsible for your treatment will organise a pre-assessment appointment, where you'll get all the information you need for the eye exam and for the operation.

Cataract surgery for adults is usually carried out as a day surgery procedure, and usually takes 30 to 45 minutes.

NHS patients are usually offered monofocal lenses optimised for either near or distance vision, although some patients may be given other options for the lenses to be implanted. The pre-assessment meeting will explain the risks and benefits of different options.

You'll usually be recommended to wait at least three days before returning to work after the surgery. You can ask the doctor for advice about going back to work when you have the pre-assessment meeting.

Will both eyes be treated at once?

If a you have cataracts in both eyes and a low risk of complications, it may be recommended that both eyes are treated on the same day. This will be discussed at the pre-assessment meeting. Otherwise, surgery is usually done 6 to 12 weeks apart to allow one eye to recover at a time.

Can cataracts be treated without surgery?

Surgery to replace a cataract is currently the only available clinical option. Some people decide to delay surgery and have regular check-ups to monitor their cataracts and the impact on their sight, before deciding to have surgery.

What are the risks of cataract surgery?

Cataract surgery is a common, safe and effective type of surgery, although there are risks. The pre-assessment meeting is an excellent opportunity to discuss these risks.

These can include blurred vision, some loss of vision, and detached retina – where the thin layer of tissue at the back of the eye becomes loose.

There is a very small risk of permanent sight loss due to the operation (one person in 1,000 experiences this).

The biggest risk is the development of posterior capsule opacification (PCO), which then requires laser treatment to correct it. It is important to discuss the risk of PCO, as well as any other risks that you are worried about, at your pre-assessment meeting with the team responsible for your cataract treatment.

PCO is caused by the lens cells that remain after surgery growing to cover the replacement lens and the lens sac, scattering the light and preventing it from reaching the retina. 

PCO usually occurs two to five years after the initial cataract surgery in adults.

What happens after cataract surgery?

After cataract surgery, you should be able to see things clearly, and your colour perception and contrast sensitivity should be restored or even better than you remember them. 

Most people will need to wear glasses for some tasks after surgery, such as reading. Once the eye has completely healed, you might need a new prescription for glasses or contact lenses.

You can help yourself by following these dos and don'ts:

• Do use eye drops as prescribed: Eye drops after cataract surgery can prevent infection and aid recovery.
• Do take time to heal: Avoid strenuous activity, and rest for the first two or three days following the operation. Consultants can advise on this further.
• Do protect your eyes from bright lights: Wear sunglasses and allow time for your vision to adjust to the extra brightness due to the more efficient, new lens.
• Do use a protective eye shield, or glasses outside: Use your eye shield for at least a week following the procedure. This is especially important during the night, to avoid rubbing your eyes in your sleep.
• Don’t drive home after the surgery
• Don’t wear eye makeup for at least a week after the operation: Particles from eye makeup can cause an infection or inflame the wound, delaying the healing process. All eye makeup must be removed before the operation, for the same reasons.

The ophthalmological team will advise further on dos and don’ts after surgery.

What can help cataracts?

Having regular eye exams can help to spot when cataracts first appear and then to monitor their progression. If youor cataracts are at an early stage and the symptoms are mild, small changes such as a stronger prescription or contact lenses and brighter reading lights may help.

There are no proven ways to prevent developing cataracts. There are a few lifestyle changes that might help reduce the risk:

• Protecting the eyes from the sun – wearing high-quality sunglasses and a wide-brimmed hat can help protect your eyes from ultraviolet (UV) damage.
• Quit smoking - smoking is bad for your general health and your eyes. When it comes to cataracts, smoking is a risk factor you can control.
• Managing your health conditions – if you have diabetes, keep your blood sugar under control. People with diabetes are more prone to cataracts.
• Reducing alcohol intake – drink alcohol in moderation, as there is some evidence that excessive drinking can increase the risk of cataracts.
• Healthy diet – eat a variety of healthy foods rich in vitamins and antioxidants, including fruits and vegetables, leafy greens, nuts and whole grains.

What research is there into cataracts?

Whilst the original discovery by Harald Ridley that plastic lenses could be used to replace lenses clouded by cataracts was a step forwards in the treatment of cataract, the common complication of cataract surgery called ‘posterior capsule opacification’ still needs to be solved.

Other key topics in cataract research include advanced genetic studies, developing a non-surgical treatment for preventing or delaying cataracts, the development of stem cell and gene therapy approaches combined with lens regeneration to replace artificial plastic lenses, the application of the latest genetic and proteomic technologies to make the multimorbidity connections that will take disease treatment and prevention to a new level.

These key topics will represent the advances in the treatment of cataract and human disease. That's why we're funding projects in these areas.

See our research projects