How is cataract surgery performed?
Cataract surgery involves the removal of the cloudy lens from the eye, and insertion of an artificial lens implant (intraocular lens) in its place.
Cataract surgery is performed as Day Surgery (the patient returns home the same day). Patients will usually be admitted to hospital at least 2 hours prior to surgery, as the preparation process is intensive, mostly involving the instillation of frequent eye drops to prepare the eye for surgery.
Type of Anaesthesia:
Cataract surgery is usually performed under local anaesthetic with twilight sedation. This means that the eye is thoroughly numbed with eye drops plus an injection (around the eye, not into the eye), and an additional sedative is given to relax the patient, often to a near-sleepy state. This results in an experience that should be entirely pain-free and comfortable. It is also impossible for the eye to “view” what is going on during the operation.
Occasionally a general anaesthetic will be recommended, if it will improve the safety or comfort of the surgery. For example, patients who are extremely claustrophobic, anxious, or unable to lie flat and still for the duration of the operation, may require a general anaesthetic. They should still be able to return home the same day.
Cataract surgery is generally a quick operation, taking on average 10 mins to complete. During the surgery, incisions are made in the cornea (“clear window” of the eye) to get into the eye, and a round incision is made into the capsular bag holding the cataract. The cataract is then carefully incised and broken up into small pieces using ultrasonic technology (sound waves), and these pieces then aspirated from the eye. An intraocular lens implant is then inserted into the now-empty capsular bag, which will allow clear focused vision. Cataract surgery is, in the vast majority of cases, a suture-less procedure (no stiches are used)
An eye patch is placed on the eye after surgery, and worn overnight.
After the surgery:
Patients will be observed on the ward after surgery for approximately 1-2 hours, and allowed to eat and drink. Patient should expect to spend an entire half-day (whole morning, or whole afternoon) in hospital for their entire cataract surgery.
Patients will remove their eye pad on waking the next day, and begin applying their prescribed postoperative eye drops.
Patients will also attend DrThen’s rooms for a check-up the following day after surgery, to ensure there are no problems and that they are comfortable.
What is Laser-Assisted Cataract Surgery?
The intraocular lens implant
A variety of lens implants are now available to insert during cataract surgery. As well as replacing the natural lens of the eye, they also allow the correction of pre-existing refractive errors in the eye, such as short-sightedness (myopia), long-sightedness (hyperopia) and astigmatism.
This means that many patients will be less dependant, or even completely free from, spectacles for certain distances after cataract surgery.
Choosing the right implant:
Prior to cataract surgery, highly sophisticated equipment is used to measure the parameters of the eye (length, curvature, depth etc) in order to calculate the power and prescription of the lens implants required for each surgery. This is called ocular biometry.
The types of implants available include:
Monofocal lens –
These have one focal length, meaning they are made to only focus for one set distance.
If a distance monofocal is inserted in both eyes, they will provide clear distance vision without glasses, but the patient will need to wear glasses for near vision.
A monofocal lens may also be placed to provide distance vision in one eye, and near vision in the other eye. This is called Monovision. For patients able to tolerate this, it may allow freedom from glasses for both distance and near vision. A contact-lens trial prior to surgery may be required to see if patients are suitable for this option.
Multifocal lens –
These have multiple focal lengths, meaning they are made to focus at different set distances. They reduce dependence on spectacles for distance, intermediate and near vision in many patients. However, they do have limitations in that glasses may still be required for certain set distances and tasks. They may also have potential adverse effects including poorer quality of vision in dim light conditions, and more glare and haloes at night, compared to monofocal lenses. Dr Then will discuss with patients whether they may be suitable for multifocal lenses.
Toric lens –
These lenses correct astigmatism. They may be monofocal or multifocal lenses.
What are the benefits of cataract surgery?
The aim of cataract surgery is to improve the symptoms caused by cataracts. Mostly this translates to better vision for the individual patient.
As the cataract can never recur, this improved vision should be maintained for many years to come.
The success of cataract surgery in improving vision is very high. If there are no other problems in the eye, many patients achieve close to perfect vision (20/20 vision.)
However, it is important to remember that other problems in the eye can also reduce vision with age (eg. Macular Degeneration). If these problems are also present, they may limit the final visual outcome after cataract surgery. Dr Then will always identify and discuss this with you prior to surgery.
2. Freedom from spectacles.
Depending on the type of intraocular lens that is implanted in the eye, patients may enjoy freedom from spectacles for certain distance, intermediate and near activities after cataract surgery.
A variety of lens implants are now available, including Monofocal (generally for distance vision), Toric (for the treatment of astigmatism), and Multifocal (for distance, intermediate and near vision) lenses. Combinations of Monofocal lenses can also be used to achieve functional distance and near vision without glasses (“monovision”). With such a choice of lenses, it is important that every patient is counseled as to the right lens choice for them, as there are potential limitations and side- effects with various lenses. Dr Then will thoroughly discuss the appropriate lens choice for each patient.
The risks of cataract surgery
Cataract surgery is generally considered safe and low-risk. However, no surgery is completely risk-free.
Common risks include:
- Increase in glare or light sensitivity after surgery.
- Worsening or new onset of dry eye symptoms after surgery (Click here to read about Dry eye)
- Haloes or starburst around night lights
- Floaters more apparent in vision
Uncommon or rare risks include:
- Rupture of the capsule holding the lens during surgery
- Severe infection
- Severe swelling of the cornea (window of the eye)
- Retinal tears or detachment
- Worsening of pre-existing macular degeneration (conversion of dry to wet MD)
Even though these complications may occur, it is very rare for them to result in severe or permanent visual loss, particularly if they are detected and treated appropriately.