Cataract & Cataract Surgery

 

What is a cataract?

 

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are verycommon in older people. By age 80, most people, either have a cataract or have had cataract surgery.A cataract can occur in either or both eyes. It cannot spread from one eye to the other.

 

What is the lens?

 

The lens is a clear part of the eye that helps to focus light, or an image, on the retina.The retina is the light-sensitive tissue at the back of the eye.In a normal eye, light passes through the transparent lens to the retina. Once itreaches 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 cloudyfrom a cataract, the image you see will be blurred.

 

What are the symptoms of a cataract?

 

The most common symptoms of a cataract are:

 

• Cloudy or blurry vision.

• Colors seem faded.

• Glare.

• Headlights, lamps, or sunlight may appear too bright.

• A halo may appear around lights.

• Poor night vision.

• Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)

• Frequent prescription changes in your eyeglasses or contact lenses.

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               Normal vision                                    Vision with cataract

 

What happens before surgery?

 

A week or two before surgery, Mr. David will do some tests. These tests may include measuring the curve of the cornea and the size and shape of your eye. This information helps your doctor choose the right type of IOL.

 

 

What happens during surgery?

 

Cataract surgery begins with a very small incision. After the incision has been made, a small instrument is used to create a round opening in the lens capsule. Another instrument, called a phacoemulsification tip, is then inserted through this opening. Phacoemulsification uses high-speed ultrasound waves, vibrating 40,000 times per second, to break the cataract into tiny pieces which are then sucked out of the eye. Ultrasound is currently the most effective method for removing cataracts.Once the cataract has been removed, a lens implant is placed in the lens capsule to replace the focus power of the natural lens.Lens implants are very small ( 6-12mm) and are designed to fit permanently within the lens capsule, where they replace the focusing function provided by the natural lens. They are made of stable polymer plastics which will not be rejected by the eye. Lens implants come in different powers, as do glasses or contact lenses and are selected to improve the eye's focusing ability. Many people discover that lens implants improve their vision and give them greater freedom from their glasses than they enjoyed before they developed cataracts.

 

Is it painful?

 

I commonly use two kinds of anaesthesia - topical anaesthesia and regional anaesthesia.

 

Topical anaesthesia is very popular with many people because no needles are required. Instead, topical anaesthesia simply uses drops which numb the eye. No eye patches are needed and patients usually notice improved vision immediately after surgery.

 

Local anaesthesia involves gently injecting a local anaesthetic into the tissues around the eye. The eye is patched for a few hours and people begin to notice their improved vision by the next day.

 

Topical anaesthesia is now my preferred technique as it offers a quicker recovery with fewer side effects and is completely pain free. The eye is fully anaesthetised but otherwise you are awake during the procedure, which takes about 15 minutes. This means the operation can usually be done as a 'day case', which has many advantages such as shortening the time in hospital and reducing expense for the patient.

 

Local anaesthesia also avoids the post-operative 'hangover' from a general anaesthetic, as well as avoiding the risks of an anaesthetic in patients with, for example, chest problems.

 

The majority of my patients now have their operation done using only anaesthetic drops on the eye (topical anaesthesia), although of course, general anaesthesia is still available for patients who prefer to be completely asleep.

 

Many patients worry that they will see what is happening during the operation. Most patient notice a bright light and vague shapes but you cannot see the actual instruments. Furthermore, although you have to lie fairly still, there is no need to be rigidly immobile; you can adjust your position or even cough or sneeze, provided some warning is given. These days, age or infirmity is no longer a bar to successful cataract surgery.

 

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 and touch. If you have discomfort, Mr. David can suggest treatment. After one or two days, moderate discomfort should disappear. For a few days after surgery, Mr. David will advise you to use eyedrops to help healing and decrease the risk of infection. Avoid rubbing or pressing on your eye.When you are home, try not to bend from the waist to pick up objects on 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 eight weeks. Mr. David will schedule a clinic follow up visit to check on your progress.

 

Can problems develop after surgery?

 

Problems after surgery are rare, but they can occur. These problems can include infection, bleeding, inflammation (pain, redness, swelling), loss of vision, blindness, double vision, swelling of the macula (centre of the retina), bits of the cataract dropping into the back of the eye, retinal detachment and high or low eye pressure. With prompt medical attention, these problems can usually be treated successfully.

 

Benefits of cataract surgery include:

 

• Improved Colour Vision: Colours are brighter and more vivid.

• Greater Clarity of Vision: Vision is crisper and sharper.

• Improved Quality of Life: Studies have shown that people enjoy improved quality of life after successful cataract surgery. Many people can resume driving and activities such as reading, sewing, golf and using a computer are generally easier after cataract surgery.

 

Types of intraocular lens implants

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There are different types of lens implants. 
The intraocular lens (IOL) is the implant used to replace the cataract at the conclusion of surgery. The standard IOL used for cataract surgery done on the NHS is a monofocal lens. A monofocal lens is usually implanted in order to give a person good vision in the distance while intermediate and near work such as looking at a computer screen, looking at a mobile phone screen and reading will require glasses.  You may require spectacles for constant use to sharpen your vision and more so if you have a pre-existing condition such as astigmatism.

Premium lens implants, which Mr. David implants in private patients, include the following

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1. Toric lens implants, which is intended to correct astigmatism.

Astigmatism is caused by an irregular shape of the cornea that gives you some degree of blurred vision at all distances. Toric intraocular lenses give you focused vision at a single distance and also correct your astigmatism so you may not need distance glasses after surgery.

As with standard monofocal lenses, however, you will still need reading glasses to see objects clearly up close. If your degree of astigmatism is too great for a toric IOL to address in full, your doctor may recommend that you have an additional procedure

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If you have astigmatism in addition to cataracts, cataract operation with a toric IOL can often address it, making your vision even clearer after surgery than it was before you developed cataracts. This can also reduce your dependence on glasses or contacts after surgery.

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For patients with astigmatism who would like to correct the refractive defect in distance and near vision at the same time, the ideal solution is the toric multifocal intraocular lenses. 

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2. Extended depth of focus lenses (EDOF lens) which are intended to provide excellent distance and intermediate vision.
EDOF lenses employ a new technology which has recently emerged in the world of lenses. These lenses allow the wearer to increase their range of focus compared to standard Monofocal lenses.
EDOF lenses enable clear vision from far distances to intermediate distances (around an arm’s length). The patient might, however, need to wear reading glasses for close work.

3. Multifocal (trifocal) and Multifocal toric lenses which are intended to eliminate the need for glasses altogether. Multi-focal intra-ocular lenses have special features that give you good near, intermediate and distance vision-all in one lens. 
Multifocal intraocular lenses give you a good chance of living glasses-free for the majority of your activities after cataract surgery.
 

Who are Multifocal Intraocular Lenses for?
With standard monofocal lenses it is possible to achieve good visual acuity for distance after cataract surgery, but near vision becomes blurry.  For this reason, reading glasses are needed with this type of surgery, and many patients are not satisfied.
Multifocal lenses are designed for anyone who would like to enjoy good vision at all distances, ranging from distant to near.  With this solution patients can enjoy good vision without spectacles for all types of tasks, including driving, sports, watching television, using the computer, sewing and reading.

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What are the pros and cons of multifocal lenses?
For many patients, the new quality of life without spectacles is better and more important than the minor optical disadvantages which arise after surgery. Certain activities which have not required the use of spectacles for a long time such as reading, sewing or using a computer can continue to be performed after surgery with a multifocal intraocular lens.  People who are more demanding in this aspect are good candidates for multifocal lens implants.  In any case, it is important to be aware that the use of spectacles may be required for more infrequent, specific tasks.
In some cases, depending on the lens implanted and the post-surgical result, it is true that there may be minor side effects such as glare, halo effect or increase in aberrations.  Over time the neurological system usually adapts to this new situation and the patient will become accustomed, however on occasion these may be persistent.  Adaptation varies according to person and can take a few months.  To ensure total adaptation, if possible both eyes must have been operated on under the same conditions ideally with the same type of multifocal lens implant. 
 

Mr. David will examine your eyes and will discuss with you the different types of premium lens implants and offer you the one that suits you best. 
Mr. David also implants telescopic IOLs to improve vision in people with reduced vision for certain conditions such as macular degeneration.
If you have already had cataract surgery with a monofocal lens implant, it is possible to implant a supplementary lens in front of the existing lens implant to provide the visual and optical advantages that a multifocal lens can offer.

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Please see below for an animated cataract surgery Youtube video by Zeiss Medical Technology

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