Cataract Surgery


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WHY IS CATARACT SURGERY NECESSARY?

Cataract surgery is performed for patients whose vision is affected by cataract.

The lens is the middle window inside the eye that focuses light entering the eye. As you age, your lens becomes gradually more cloudy – this is called a cataract. As the cataract progresses, you may experience worsening vision and increasing glare.

During cataract surgery, the cloudy lens inside your eye is removed and replaced with an artificial clear lens implant. The lens implant remains in the eye permanently.

(Image adapted from the internet)

Improvements in cataract surgery techniques mean that surgery can be performed at any stage when the cataract affects daily life. There is no need to wait for the cataract to ‘ripen’.



WHAT DOES CATARACT SURGERY DO?

Cataract surgery is a surgical procedure which involves:

● Making a few incisions (less than 3 mm in length) in the eye.
● Removing the cataract, usually with ultrasound phacoemulsification), and
   not with laser as commonly believed.
● Implanting the artificial clear lens.
● Very occasionally, stitching of the incisions may be necessary.

(Image adapted from the internet)

Femtosecond laser assisted cataract surgery is a technique that utilizes laser to perform some of the steps, but the rest of the operation and outcome remain essentially the same.



WHAT TESTS ARE NEEDED BEFORE CATARACT SURGERY?

A-scan biometry will be performed to determine the strength of the lens implant that best suits your eye. This is performed before surgery, usually at your first clinic visit.

If you wear contact lenses, you must leave them out for at least 4 weeks before having the scan.

You may also require the following tests:
● OCT scan of the macula (central part of the retina) to detect any macular
   problems, such as age-related macular degeneration (AMD).
● Topography scan of the cornea (front window of the eye) to detect any
   corneal irregularity, such as in keratoconus.

Previous laser vision correction with excimer laser (such as lasik or PRK) affects the calculations that are used to determine the strength of lens implant to be inserted into your eye.

Lens implant selection is therefore not as accurate and you may end up having unpredicted long-sightedness or short-sightedness after surgery. This can be corrected with glasses or contact lenses but sometimes further surgery may be required.



WHAT ARE THE POTENTIAL RISKS?

Cataract surgery has a success rate of around 98%. Most complications can be treated, although sight-threatening complications may occur rarely (less than 1 in every 1000). These can sometimes occur even if the operation has been carried out perfectly.

Risks during surgery:

● Bleeding into the eye. If severe the operation may be discontinued, and
   will need to be completed on another day.
● Damage to other parts of the eye, including the capsule holding the lens.
   This will prolong the surgery and your eye may take a few months to
   recover instead of just a few weeks.
● Part of the cataract falling into the back of the eye (dropped nucleus).
   This may require another operation to remove the cataract fragment from
   the back of the eye (vitrectomy).

Risks after surgery, where treatment does not involve another procedure:

● Bruising of the eye or eyelids. This is quite common.
● Allergy to the post-surgery eye drops, causing redness and irritation of
   the eye and eyelid.
● High pressure in the eye. The pressure can sometimes be elevated in the
   first few days after surgery. This tends to settle without any issues or
   treatment. However, if the eye pressure remains persistently high, it can
   be treated with pressure lowering eye drops.
● Fluid at the central part of the retina (macular edema). This is usually mild
   and settles with a course of anti-inflammatory eye drops. Occasionally, it
   can be severe and cause reduced vision in the long term.

Risks after surgery, where treatment requires another procedure:

● Wrinkling of the bag that holds the lens implant in place (posterior
   capsular opacification). This blurs the vision and can be easily treated with
   laser (laser capsulotomy).
● Cloudiness of the front window of the eye (corneal decompensation). This
   usually recovers with time but sometimes the cornea remains cloudy
   causing persistent vision blurring. If this happens, corneal graft surgery
   will be required.
● Lens implant dislocation. This can be treated with surgical repositioning.
● Unpredicted long-sightedness or short-sightedness (refractive surprise).
   This can usually be corrected with glasses or contact lenses. However if
   severe, surgical exchange of the lens implant can be considered.
Detachment of the retina. This can be treated with retinal detachment
   surgery (vitrectomy).
● Infection inside the eye (endophthalmitis). This is the most serious
   complication and may cause permanent sight loss despite treatment
   with antibiotics and surgery.



WHAT ARE THE OPTIONS FOR VISION AND GLASSES?

Standard (monofocal) lens implants:

The artificial lens implant that will be inserted in your eye is only able to provide focus at one distance. You will need to choose your preferred vision outcome following cataract surgery: distance vision in both eyes, close vision in both eyes, or monovision.

● Distance vision: Most people aim for good distance vision. If you choose
   this option, you will need reading glasses and may still need glasses for
   fine focusing in the distance.
● Close vision: Some people prefer good close vision, especially if they like
   to read or embroider without glasses. If you choose this option, you will
   need glasses for distance.
● Monovision (distance vision in one eye and near vision in the other):
   Some people want monovision to try and minimize the need for glasses. If
   you choose this option, you may find it difficult to adjust, as only one eye
   is used at a time. You may still need glasses for some tasks such as
   computer work or night driving.

If you are considering monovision, it is a good idea to have a trial with contact lenses first – this can be discussed and organized with your local optometrist.

(Image adapted from the internet)


Multifocal lens implants:

Multifocal lens implants are lenses that aim to correct vision for both near and distance. They do not work for all patients and may cause some visual quality problems such as glare and reduced contrast sensitivity. These problems can be difficult to correct with glasses and often require surgical exchange of the lens implant.

Toric lens implants:

Astigmatism occurs when the eye is shaped more oval rather than round. Light rays entering the eye is not uniformly focused onto the retina, thus reducing the sharpness of your vision. The amount of astigmatism in the eye can be reduced by a toric lens implant, but not by a standard lens implant. The aim is to improve your vision so that you reduce the need for distance glasses (reading glasses will still be needed).

The surgery is the same as standard cataract surgery apart from having to rotate the toric lens implant to the correct position (angle) for your eye after insertion. A standard lens implant does not need to be rotated to a specific position or angle.

There are some risks with toric lens implants:
● A toric lens implant may not fully correct the astigmatism and you may still
   need glasses for distance. Further correction of this remaining
   astigmatism may not be possible.
● If complications occur during cataract surgery, it may not be possible to
   insert a toric lens implant, and a non-toric, standard monofocal lens
   implant may inserted instead.
● The toric lens implant can rotate and a second operation may be needed
   to rotate the toric lens implant back into position for best vision, with the
   additional risk of further surgery.

It is not possible to guarantee absolute accuracy. Sometimes, patients may still require moderately strong glasses following surgery despite correctly taken measurements and uncomplicated surgery.



WHAT SHOULD I EXPECT?

Cataract surgery is a hospital-based day case procedure performed under local anesthetic. The operation is usually performed one eye at a time.

Before surgery:

On the day of your procedure, please take all your usual medications unless otherwise advised. You will need to fast for at least 6 hours before your procedure. You will not be able to drive home on the day of the procedure, so you will need to arrange for someone to take you home. Please allow at least 3 to 4 hours in the hospital.

Before the cataract surgery, you will receive the following:
● Eye drops to dilate the pupil. These can take up to 30 minutes to work.
● Cannula inserted into a vein, usually at the back of your hand.
● Eye drops to numb the eye prior to the anesthetic injection.
● Local anesthetic injection around your eye to fully numb the eye.

During surgery:

To reduce the risk of infection, povidone iodine antiseptic is used to clean your eye and eyelashes, a sterile drape will cover your face, and a sterile clip will keep your eyelids open.

You will be awake during surgery, but you should not feel any pain. If you feel discomfort or pain, additional local anaesthetic can be given. It is normal to notice bright lights or colours, hear buzzing and beeping sounds, and feel cold water running down your ear.

(Image adapted from the internet)

You will need to lie relatively still for up to 45 minutes for the operation. At the end of surgery, you may feel a sting due to an injection.

After surgery:

After cataract surgery, a pad and shield will be placed over your eye. The pad and shield can be removed the next day, and you can start your normal postoperative eye drops, usually a steroid anti-inflammatory eye drop (Prednisolone or Dexamethasone) and an antibiotic (Chloramphenicol) 4 times daily for 3 to 4 weeks. You will need to continue your other usual eye drops (if any).

Over the next few days, you may experience blurriness, discomfort, sensitivity to light, and blood around the eye. This will gradually improve with the eye drops. You may take paracetamol to help control any discomfort. It can take a week or two before you notice any improvement in your vision.

You will usually be reviewed 2 to 4 weeks after cataract surgery. There is no need to be seen the next day unless there is a specific reason to do so.

Around 4 to 6 weeks after surgery, you can see your optometrist for new glasses to further sharpen up your focus.

Please contact the clinic immediately if you experience pain or a sharp drop in vision.




Learn more about cataract surgery

Learn more about the techniques of cataract surgery

Learn more about the steps involved in cataract surgery

Learn more about what to expect with cataract surgery

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Return to: Vision & Eye Health



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