What is a cataract?
by Naz Ahmed, optometrist at AJ Spurrett Opticians, Blackburn
A cataract is a common eye disease in which the clear lens of the eye becomes cloudy or opaque, causing a decrease in vision. Most cataracts are related to ageing and are very common amongst older people.
You may be asking – what is the lens? The lens, which is located behind the pupil, is a clear part of the eye that helps focus light, or an image, onto the retina. The retina is the light-sensitive tissue at the back of the eye. In a healthy 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, such as with a cataract, the image you see will be blurred. The extent of the visual disturbance is dependent upon the degree of cloudiness in the lens.
A cataract can occur in either or both eyes. Individuals with a cataract in one eye usually go on to develop a cataract in the other eye as well. Cataracts are not contagious, so cannot be spread from one eye to another or from person to person. Cataracts do not cause the eye to produce tears abnormally. They are not painful and don’t make the eye itchy or red.
What causes cataracts?
The lens lies behind the pupil and works much like a camera lens focussing light onto the retina at the back of the eye. The lens also adjusts the eye’s focus which allows us to see clearly both close up and far away. The lens is made of mostly water and protein. The protein is arranged in such 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, causing blurred vision, which makes it harder to see.
What are the risk factors for cataracts?
Advanced age is a significant risk factor for the development of cataracts. Research suggests other risk factors include:
Certain diseases (e.g. diabetes)
Genetic illnesses (e.g. Downs Syndrome)
Personal behaviour (smoking, alcohol use etc.)
The environment (prolonged exposure to ultraviolet sunlight, trauma to the eye)
Medication use (e.g. oral corticosteroids)
How will I know I have a cataract?
You may not notice any symptoms in the early stages of the cataract developing. As a cataract becomes more advanced, decrease in the clarity of vision which cannot be fully correctable with glasses, is noticed.
The most common symptoms are:
Cloudy or blurry vision
Colours seem faded
Glare – headlights, lamps or sunlight may appear too bright.
Frequent changes in your glasses or contact lens prescription.
A cataract is diagnosed through a routine eye examination by your optometrist. Tests are carried out and the eye examined thoroughly, including a visual acuity test, an examination of the back of the eye and measurements of your eye pressure. Your optometrist will examine your entire eye for evidence of any other eye disease which may be compromising your vision.
How fast does a cataract form?
Cataracts tend to generally ‘grow’ slowly, so vision gets worse gradually. Over time, the cloudy area in the lens may get larger and seeing becomes more difficult. Your vision may get duller or blurrier. The rate of cataract ‘growth’ can be dependent on the risk factors that you are exposed to.
The clear lens may also slowly change to a yellowish/brownish colour, adding a brownish tint to vision. Over time, increased tinting may make it more difficult to read and perform other routine activities. This type of gradual change in the amount of tinting does not affect the sharpness of the image transmitted to the retina. If you have advanced discoloration, you may not be able to identify blues and purples. For example, you may be wearing what you believe to be a pair of black socks, only to find out from friends that you are wearing purple socks.
Can you get rid of a cataract naturally?
Everyone, if they live long enough, will develop cataracts. Unfortunately there is no scientifically proven method that prevents the inevitable. However, progression of cataracts can be slowed by:
• Avoiding large amounts of ultraviolet light. When you are exposed to the sun, wear UV-protection sunglasses. Wearing a hat with a brim to block UV sunlight may also help
• If you smoke, stop! If you don’t smoke, don’t start!
• Following a healthy diet – researchers recommend eating green leafy vegetables, fruits and other foods high in antioxidants
• Avoiding trauma to either eye
Ideally if you are over 60 you should have a comprehensive eye exam at least once every two years. In addition to cataract, your optometrist can check for signs of age-related macular degeneration, glaucoma, and other vision disorders. Early treatment for many eye diseases may save your sight.
Are there different types of cataract?
Yes. Although most cataracts are related to ageing, there are other types of cataract:
Secondary cataract – which can form after surgery for other eye problems, e.g. glaucoma
Traumatic cataract – which 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
Radiation cataract – which develop after exposure to some types of radiation
Cataracts can be classified by the location within the lens, degree of clouding of the lens or by the cause of the cataract. A cataract may be mild, moderate or severe. It may be early or advanced. If the lens is totally opaque it is termed a ‘mature’ cataract.
How is a cataract treated?
The symptoms of early cataract can be effectively managed by your optometrist by either changing your glasses, reading in brighter lights and wearing anti-glare glasses and sunglasses.
Using magnifying lenses for close work and reading fine print may also be helpful.
Many cataracts are not too bothersome, causing few symptoms. In that situation, no surgical treatment is necessary.
However, the only true treatment for cataract is surgical removal of the cloudy lens and replacing it with a new artificial lens – called an intraocular (IOL) lens.
A cataract needs to be removed only when vision loss interferes with your everyday activities, such as driving, reading or watching TV. You and your optometrist can make this decision together.
Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery.
If you choose surgery your optometrist will refer you to a specialist ophthalmologist to remove the cataract. If you have cataract in both eyes that require surgery, the surgery will be performed on each eye at separate times, usually 6-8 weeks apart (also dependent on hospital waiting times in your area). There is usually no harm in waiting for a longer period between the two operations unless it is causing you visual problems.
What are the risks of cataract surgery?
As with any surgery, cataract surgery poses risks such as infection and bleeding. Displacement of the IOL lens, glaucoma and retinal detachment are also possible complications. Fortunately, with modern surgical techniques, all these complications are rare and usually can be managed.
Talk to your optometrist about these risks to make sure cataract surgery is right for you.
What happens before surgery?
Approximately two weeks before surgery you will have what is known as a Pre Assessment. The specialist nurse/ophthalmologist at the hospital or clinic will do some tests. These tests include measuring the curve of the cornea and the size and shape of your eye. This information helps the ophthalmologist choose the right type of IOL for you. You may have some drops put in your eye to dilate your pupils, if so, you will be advised not to drive. You may wish to have a relative or friend accompany you.
The nurse/ophthalmologist will happily address any questions you may have. Feel free to write a few questions down beforehand if you feel you may forget (I know I would!)
What happens during surgery?
Cataract surgery is usually performed as a day-case outpatient procedure under local anaesthesia. On the day of the procedure drops will be put in your eye to dilate your pupils and anaesthetise your eye. The area around your eye will be washed and cleansed.
The operation itself usually lasts less than an hour and is almost painless.
After the operation a patch may be placed over your eye. You will rest for a while and the medical team will watch for any problems. Most people who have cataract surgery can go home the same day. You will need someone to drive you home.
You will be given eyedrops to use to help healing and decrease the risk of infection. You will be informed how to use your eyedrops, how often to use them and what effects they can have. You will need to wear an eye shield or glasses to help protect your eye
Is my eye removed?
No – your eye is never removed for the procedure! This is a popular and bizarre myth!
What happens after surgery?
Itching and mild discomfort are normal after cataract surgery. Some fluid discharge is also common. Your eye may be sensitive to light or touch. If you have more than mild discomfort your doctor can suggest treatment. After one or two days moderate discomfort should disappear.
When you are home, try not to bend from the waist to pick up objects off the floor. Do not lift any heavy objects. You can walk, climb stairs, and do light household chores. In most cases, healing will be complete within 8 weeks. You will have scheduled eye examinations after this period to check on your progress and be given a prescription for new glasses if required.
Can I drive after cataract surgery?
You can return quickly to many everyday activities, but your vision may be blurry. The healing eye needs time to adjust so that it can focus properly with the other eye.
Your optometrist will conduct an eye examination and check your vision. They can advise you then if your vision is within the legal driving standards, whether that be without the need for glasses or in some cases a prescription for driving may still be necessary. If you have any concerns whether you are safe to drive always check with your optometrist.
Can problems develop after surgery?
Frequently, within months to years after surgery, the thin capsule that encloses the IOL becomes cloudy and may blur your vision. You may have the sensation that the cataract is returning because your vision is becoming blurry again. This process is termed posterior capsular opacification (PCO) or a ‘secondary cataract’. To restore vision a laser is used in the clinic to painlessly create a hole in the cloudy capsule. This outpatient procedure is called a YAG laser capsulotomy. This procedure takes only a few minutes in the clinic and vision usually improves immediately.
Cataract surgery is the most common operation performed in the UK, with a high success rate in improving your eyesight. Like any other surgical procedure the important thing to remember is to make an informed decision and understand the limitations to the outcome of surgery.
You can consult with your optometrist at any stage of your decision making, all we want is for you to be able to see well and we will do our utmost best to make this happen for you.