Cataracts develop in the sensitive lens of your eye as opaque clumps of tissue. Since the lens focuses light into crisp images, just like a camera lens, this causes a particular loss of vision. Symptoms include dimness, selective blurriness, night blindness, double vision, yellowish or grey colors, or blocked regions of view. Cataracts form in old age, or can accompany other diseases such as diabetes. When diagnosed early, they are surgically removed with a high rate of success.
Light enters our eye through the pupil, travels through the lens, and lands on our retina in a focused, clear, colored picture. The lens is susceptible to accumulating lumpy strands of protein as we age. This collection interferes with exact focus and color in an image. Although cataracts are not a cloud, growth, or infection, they can still be compared to smearing oil on a camera lens. Looking through the camera, you would see blurred, obstructed, or shaded sections in your field of view because the grime has scattered the light.
Although the risk for cataracts is extremely high in those individuals aged above 50, they are not the first stage in total blindness in both eyes. Cataracts seriously compromise common activities, like driving at night, watching television, or even walking in unfamiliar territory, but they do not always get progressively worse until you cannot see at all. Accurate diagnosis by an ophthalmologist can separate your vision problems from diseases of the retina, optic nerve, cornea, or brain that might be caused by unrelated eye conditions like macular degeneration or glaucoma. Consult your physician at the first sign of vision loss.
Since 70% of people older than 75 have at least one cataract, early diagnosis is the most important part of the healing process. Mild cases can be temporarily treated with a different eyeglass prescription, or simple lifestyle changes such as only driving during the day and stop watching television. A permanent solution is cataract surgery under local anesthetic. While you should discuss the risks of surgery with your health care provider, this common procedure has a 95% success rate.
Signs and symptoms of cataracts include:
Clouded, blurred or dim vision
Increasing difficulty with vision at night
Sensitivity to light and glare
Seeing "halos" around lights
Frequent changes in eyeglass or contact lens prescription
Fading or yellowing of colors
Double vision in a single eye
At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye's lens and you may be unaware of any vision loss. As the cataract grows larger, it clouds more of your lens and distorts the light passing through the lens. This may lead to signs and symptoms you're more likely to notice.
Make an appointment for an eye exam if you notice any changes in your vision. If you develop sudden vision changes, such as double vision or blurriness, see your doctor right away.
Treatment for age-related cataracts may not be needed if:
you have no symptoms
your sight is only mildly affected
In the early stages of a cataract, your vision may be improved with stronger glasses, or by using a brighter light when you read, for example. However, the improvement may not last long.
Surgery is the only way to treat cataracts that become more severe.
Your optometrist (a specialist who examines eyes and tests sight) or GP will probably recommend treatment if your loss of vision affects your usual daily activities. For example, if cataracts affect:
your ability to look after yourself or someone else
your driving
going out
seeing people's faces
your work
reading
Cataracts are treated by having surgery to remove the cloudy lens in your eye. In most cases, the natural lens is replaced with an artificial, clear plastic lens. This is called an intraocular implant or intraocular lens (IOL).
Most cataract operations in the UK are carried out under local anaesthetic, as keyhole surgery, where a very small incision (cut) is made. You will probably be admitted as a day patient (day case), which means that you will not need to stay in hospital overnight.
The most common cataract operation is called phacoemulsification, and is sometimes referred to as phaco extracapsular extraction. Cataracts cannot be treated with laser surgery (when beams of energy are used).
Before having cataract surgery, your GP or optician will refer you to an ophthalmologist or an ophthalmic surgeon (medical doctors who specialise in eye conditions and their treatment). They will assess your eyes and your general health. This is called a pre-operative assessment.
During the assessment, your eyes will be measured. The artificial lens that will replace your natural lens can then be prepared. An appointment will probably be made for your operation to take place during a separate visit.
Just before the operation, drops to dilate (widen) your pupil (the black circle in the middle of your eye) will be put into your eye. You will also be given a local anaesthetic that will prevent you feeling any pain during the procedure. This may be applied to your eye as drops, although sometimes an injection in the tissue around the eye may be used.
Once the anaesthetic takes effect, you will not be able to feel anything. While the operation is taking place, all you will be able to see is a bright light. You will not be able to see what is happening.
Different types of replacement lens are available. These include:
fixed strength lenses (monofocal), which are set for one level of vision, usually distance vision
multifocal lenses, which allow two or more different strengths, such as near and distance vision
accommodating lenses, which allow the eye to focus on both near and distant objects, in a similar way to the natural human lens
Your ophthalmologist will discuss with you which type of lens will suit you.
During the operation, your ophthalmologist will make a very small incision (cut) in the surface (cornea) at the front of your eye. Your ophthalmologist will then insert a tiny probe through this cut. The probe breaks up the cloudy lens into tiny pieces using ultrasound (high frequency sound waves). The tiny pieces will then be sucked out of your eye.
Once this is done, your ophthalmologist will insert an artificial, clear plastic lens through the incision. The lens sits in a little 'pocket' called the lens capsule to keep it in place. The lens is folded when it is inserted, and once it is in position it is allowed to unfold.
The operation usually takes 15 to 30 minutes, although sometimes it can take slightly longer.
Two other operations may be performed to remove age-related cataracts, although these are much less common. They are:
manual extracapsular extraction
intracapsular extraction
In manual extracapsular extraction, the ophthalmologist makes a slightly larger cut in the eye. The lens is removed in one piece, rather than being broken up by ultrasound.
During intracapsular extraction, the lens capsule is removed, as well as the lens. A replacement plastic lens is then sewn into the eye. In some cases, special (aphakic) glasses or contact lenses may need to be worn instead. Intracapsular extraction is rare in the UK.
The vision of most people who have cataract surgery improves almost immediately. However, it may take a little time to settle down completely. The incision (cut) in the eye's surface is so small that it usually heals by itself, although sometimes a small stitch may be needed.
Your ophthalmologist will probably advise you to take it easy, for example, by:
avoiding sports and any vigorous activities
not rubbing your eye
not getting soapy water in your eye, for example, while taking a shower
wearing a pad over your eye to protect it
When the operation has been completed, your plastic lens will be set up for a certain level of vision. After the operation, you may need to wear glasses in order to see objects that are:
far away (distance vision)
close to you (near vision)
If you wore glasses previously, your prescription will probably change. It will take several weeks after the operation for your vision to settle down before your optometrist can give you a new prescription.