CATARACT - What you need to know!
Has your overall vision become gradually hazy or dim, without any noticeable eye pain? Do colours appear dull, less vibrant than before?
It might be a Cataract.
What is a Cataract?
The word Cataract is derived from the Latin word "Cataracta" meaning "waterfall". A cataract is simply a "clouding" of the natural lens in your eyes, it affects your vision, like looking through a "waterfall".
It is a natural process associated with age especially adults aged 55 years and above. As light passes through the cloudy lens, it is diffused or scattered. This results in blurred or defocused vision. A cataract generally should be removed to provide better and clearer vision.
Most cataracts are highly treatable. Cataract surgery is one of the most common surgeries performed in Singapore with most patients experiencing improved vision if there are no other eye conditions present.
A cataract can occur in either or both eyes. It cannot spread from one eye to the other.
What is the Lens?
The human lens, made mostly of protein and water, can become clouded. It is so clouded that it keeps light and images from reaching the retina.
Usually the lens is a clear part of the eye that helps to focus light, or an image, on to the retina. The retina is the light-sensitive tissue at the back of the eye. (Please see diagram on the right)
In a normal eye, light passes through the transparent lens focusing 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.
CAUSES & RISK FACTORS
What causes Cataracts?
As we age, some of the protein in our lens 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.
Who is at risk for cataract?
The risk of cataract increases as you get older. Clouding starts in a small area and over time, the cataract may grow larger and cloud more of the lens making it harder to see. Most Singaporeans older than 55 years have cataracts.
Other risk factors for cataract include:
- Medical Conditions
Diabetes and other systemic diseases, glaucoma, and metabolic abnormalities can cause cataracts.
- Physical Injuries
Commonly called traumatic cataracts. A blow to the eye, great heat or cold, chemical injury, exposure to radiation (usually associated with radiation therapy for cancer patients), and other injuries can lead to cataract formation.
- Ultraviolet Radiation (UVA or UVB)
Prolonged exposure to sunlight is believed to speed the development of cataracts.
- Oral Steroids and Other Medications
Oral steroids (such as prednisone), the gout medication allopurinol, the breast cancer drug-tamoxifen, the heart medication amiodorone, and the long-term use of aspirin have also been associated with cataracts.
- Personal Behaviour
Studies indicate that smokers and alcoholics are twice more likely to develop cataracts than non-smokers and non-alcoholics. Quitting smoking can reduce the risk for developing cataracts.
Are there other types of Cataract?
Yes. Although most cataracts are related to aging, there are other types of cataract:
- 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 prolonged 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.
SYMPTOMS & DETECTION
What are the symptoms?
The most common symptoms of a cataract are:
- Cloudy or blurry vision
- Problems with light sensitivity. These can include headlights that seem too bright at night; glare from lamps or very bright sunlight; or a halo around lights
- Colours that seem faded
- Poor night vision
- Double or multiple visions (this symptom sometimes goes away as the cataract grows)
- Frequent changes in your eyeglasses or contact lenses
These symptoms also can be a sign of other eye problems. You should have an eye check-up if you have any of the above problems.
How is a Cataract detected?
Cataract is detected through a comprehensive eye examination which includes:
- Visual Acuity Test
- Slit Lamp examination
- Dilated Fundus Examination
Other tests may be done in certain circumstances for more complex cases.
Cataract Surgery can provide better vision for a happier life
Being diagnosed with a cataract need not be an alarming event. In fact, when you understand what a cataract is, how it will be removed, and the life-changing benefits cataract surgery can bring, you'll likely wish you'd had the procedure sooner.
A cataract can progress until eventually there is a complete loss of vision in your eye, and neither diet nor laser treatment will make a cataract go away. LASIK eye surgery cannot treat a cataract.
However, a cataract surgery can help restore your vision, long before you experience loss of vision significant enough to interfere with your daily activities.
After successful cataract treatment, your vision will be clearer, brighter, and sharper than it's been for long time.
Getting Ready for Cataract Eye Surgery
Cataract surgery is one of the safest, most effective types of surgery. It's also one of the most successful. After deciding that you will have cataract surgery, measurements will be taken of your eye to determine the proper power of the new replacement lens called an Intraocular Lens, (or ‘IOL' for short) that will be placed in your eye during surgery.
What IOL to Choose for Cataract Eye Surgery? The ‘IOL' will be implanted in the eye to replace the eye's natural clouded crystalline lens during cataract surgery.
- Monofocal lenses provide corrective power in only one segment of your visual range (typically distance vision). Monofocal lens can have astigmatic correction as well (Toric IOLs).
- Multifocal lenses are designed to correct a range of vision - near through distance.
- Accommodative lenses are designed to move within the eye to allow some range of focus from near to far.
Each lens has it advantages and disadvantages, and there will always be a "best" lens for you and your lifestyle.
The same view with a cataract
Courtesy NIH National Eye Institute
How will it feel?
Cataract surgery is an outpatient procedure. You'll spend about 6 hours at the hospital. Because your eyes will be treated with an anaesthetic, you should feel little or no discomfort.
After the surgery, you'll be required to rest for a few hours. Then, the very same day, you can go home. Within the next 24 hours, you will be seen for a post-operative check-up. Drops will be prescribed to guard against infection and to help your eyes heal.
For a few days, you will wear a clear shield, usually at night to prevent you from rubbing your eye.
When should I seek treatment?
The decision to proceed with cataract surgery is very personal.
With modern medical technology, cataracts are routinely treated safely and effectively using microsurgical techniques. Today, cataract extraction is one of the most successful surgical procedures-about 99 percent of all cataracts surgical procedures result in improved vision.
During the early stages of cataract development, more frequent changes in your eyeglass prescription may be sufficient to restore adequate vision. Surgery should be considered when the reduced vision caused by cataracts begins to interfere with normal daily activities such as reading and driving, even when corrective glasses are used. Although the potential risks of surgery must be weighed against its potential benefits, delaying surgery can lead to accidents when driving as well as personal injury such as falls. In addition, the surgical removal of advanced cataracts is more difficult than the removal of moderately dense cataracts.
Things that indicate you need Cataract surgery:
- You do not feel safe driving because of difficulty reading signs, glare from lights at night, or other visual disturbances.
- You do not see well enough to do your best at work.
- You do not see well enough to do the things you need to do at home.
- You do not see well enough to do things you enjoy, such as reading, sewing, or playing golf.
- Because of your poor vision, you may bump into things, stumble, or fall.
- Because of your poor vision, you are not as independent as you would like to be.
- You cannot see as well as you would like to see, even with your glasses.
- Your eyesight bothers you a lot.
Types of Cataract Surgery
The most common and advanced cataract surgery technique is Phacoemulsification or "Phaco" for short.
The first step of Phaco is a small incision at the edge of the cornea. An opening is made in the membrane that surrounds the cataractous lens. This thin membrane is called the capsule.
Next, a small ultrasonic probe is inserted through the opening in the cornea and capsule. The probe's vibrating tip breaks up or "emulsifies" the cloudy lens into tiny fragments that are suctioned out of the capsule by an attachment on the probe tip.
After the lens is completely removed, the probe is withdrawn leaving only the clear (now empty) bag-like capsule, which will act as support for the intraocular lens (IOL).
Phacoemulsification allows cataract surgery to be performed through a very small incision in the cornea. Stitches are seldom needed to close this tiny entry, which means that there is less discomfort and quicker recovery of vision than with other surgical procedures.
Small incisions do not change the curvature of the cornea like larger ones that were required with older surgical techniques. This allows for more rapid rehabilitation of vision and possibly less dependence on glasses for good distance vision.
After removal of the cataract-damaged lens, an artificial intraocular lens (IOL) is implanted. Made from soft acrylic or solid medical-grade silicone, IOLs are folded so they can be implanted with a small injector, which uses the same incision through which the phaco probe was inserted at the beginning of the procedure.
As the IOL is implanted, it unfolds and anchors itself behind the eye's pupil within the remaining clear capsule. The IOLs to be implanted are selected based on power calculations made before surgery.
The phaco probe emulsifies the cataract and removes the resulting fragments.
The replacement for the cataract-damaged natural lens, the intraocular lens (IOL), is positioned in the capsular bag of the eye.
Throughout the procedure, most patients are drowsy, relaxed, and feel no pain.
Extracapsular Cataract Extraction
A less common method of cataract surgery is extra-capsular cataract extraction (ECCE). This procedure, which was developed before phaco, is often used for removal of very advanced cataracts that may be too hard to break up using phaco or in patients who have multiple eye conditions that render phaco a less desirable surgical option.
ECCE requires a larger incision than phaco, perhaps 10 to 12 mm long, at the top of the cornea so the cataract can be removed in a single piece.
Visual recovery may be slower after ECCE than phaco and there may be more discomfort because of the larger incision and sutures that are required to close it.
Once the cataract is removed, an IOL is implanted in the eye. Given that a larger incision has been made to remove the cataract-damaged natural lens, the surgeon has the option of inserting a non-foldable IOL made from a medical-grade Plexiglas-like material or a foldable material as discussed above.
The Wonder of Cataract
When your cataract has been removed it may seem like a wonder. All the things you couldn't see clearly are bright, clear, and vivid again. In fact, many patients will tell me that they haven't seen life so clearly in years.
Once you see how good the world looks, you'll be so joyful - like millions of others just like you — that a cataract is one thing you can live without.
There are risks with any surgical procedure. During your examination Dr Tan will discuss with you the various options, risks and benefits of your Cataract procedure.