The Process of cataract surgery

Results of cataract surgery

Without cataract surgery, the progression of cataract is certain blindness. This is the natural history against which we compare your surgery results.

With surgery the chance of you being blind because of the surgery is less than 1 in 4000 eyes, compared with 100% without surgery.

With surgery almost every patient gains vision compared with their starting vision. Of course this depends on your vision being reduced because of cataract. Most regain 6/6 unaided vision (20/20). We measure the result of any eye surgery with the best pair of glasses on. We call this corrected vision.

Most people are thrilled with the results from cataract surgery. For most patients, vision improvement is experienced immediately or within the first day. Other patient’s vision will clear within the month, occasionally this may take longer. You will still need glasses to achieve best quality vision including reading.

Most patients who have cataract surgery are glad they did. Most patients have improved vision, often the day after surgery, and often without distance glasses. The majority of patients can see in the distance clearly without glasses, such as when driving and watching TV. However, most patients need glasses to read. For most people, the vision has cleared in the first month, but occasionally can take longer.

Sometimes cataract surgery does not improve the vision. This is usually because there is pre-existing disease such as macular degeneration. Retinal disease may not be seen prior to cataract surgery, because the cloudy cataract limits the view. This is why we routinely perform OCT scanning to examine the macula as best we can before surgery.

Some patients want the cataract surgery technique to reduce the need for glasses. We call this “clear lens extraction”. This is usually not the best option for a patient. Please discuss this with your doctor.

The post-operative period

The first day after cataract surgery

After surgery you will have a shield over your eye. Your eye will feel irritated, you may have double vision or a slight discharge (this is treatable with lubrication drops). Your eye shouldn’t ach or throb.

Instructions will be given to you on how to care for your eye and you will be supplied with a month’s duration of drops. The doctor will see you one day after your operation and again over the next month.

Best vision takes time. Both eyes need to be balanced. Your glasses will need updating. It takes weeks or months for the brain to adjust to the new focussing of the eyes.

Often on day one post surgery, the patient will notice improved clarity, vision, improve brightness, improved colour perception. But not always. It always takes a few days for the eye to settle down and for the vision to settle.

The hospital will have given the patient a sheet of post-operative instructions and post-operative drops. On the morning after the surgery we want the patient to remove the eye pad and start the drops.

Some patients experience bruising in the skin around the eye or on the surface of the eye from the anaesthetic needle. This bruising usually settles in four weeks.

We ask the patient to bring the distance glasses to the day-one appointment, so we can push the lens out of the glasses. Usually this lens will no longer be correct for the operated eye. If we cannot push the lens out, then we ask the patient to return to their optometrist one or two days after surgery to push the lens out. The patient goes without a lens initially while the eye recovers from surgery.

After the first eye is done, some patients will experience imbalance between the two eyes. This applies when the refractive error, or the script in the glasses, exceeds 2 dioptres. The problem is that the image created from each eye is a different size and the brain cannot merge the two images from each eye into one image.

This imbalance will prevent a patient from resuming normal activities such as driving. Occasionally it makes the patient feel unsafe. You are better off having one eye blurry, than trying to wear out-of-balance glasses.

Changing the glasses cannot correct this imbalance. The only solution is a temporary contact lens on the eye that has not yet had surgery. In these patients, we ask you to see the optometrist one or two days after the first eye cataract surgery.

We will ask you to return to see us for a check, to measure the result of the first eye surgery, and plan for the second eye surgery. Usually we do this in 1 to 2 weeks.

On the first post-operative day, we also make a plan for the second eye, which almost always needs cataract surgery to balance the two eyes and give best overall quality vision. Usually a plan for both eyes has been made at the first pre-operative appointment.

On the first day, we also remind you to pay attention for serious problems such as infection. At any stage, if the eye becomes increasingly blurry or painful, you must ring and present immediately. The people who have bad outcomes are the people who get worse, and don’t present immediately.

After the second eye is done

Usually the patient does not experience improved vision as rapidly with the second eye, and this is because the patient is comparing it with a good first eye that has already been fixed with surgery.

Sometimes other eye disease will limit the visual result. Usually we wait several weeks before deciding how much the vision is limited by other disease.

We advise patients to return to their community optometrist, usually 4 to 5 weeks after the second cataract surgery is done, to update the glasses, and to continue optometry screening examinations, which are required every year.

After the second eye is done, patients can usually drive without glasses, but they often need to use a temporary pair of reading glasses to get by until they can return to see their optometrist 4 to 5 weeks after the second eye is done.

Patients can usually resume normal activities, such as driving, when they feel safe to do so, when the vision is adequate. Most recreational activities, such as playing golf, can usually be resumed immediately.

There are very few restrictions after eye surgery. Do not rub your eye. Do not wash the surface of your eye with water. Use your drops as instructed.

Otherwise it is "life as normal". You can bend. You can lift. Use common sense to avoid pressure on the eye.

We know other surgeons have greater restrictions for their patients. We also know from our huge experience that most of these restrictions are unnecessary with modern techniques.

When can I drive?

After cataract or lens-replacement surgery, most patients can resume driving within a day or two, when they feel safe to do so. This requires the vision to be "driving standard" or better (6/12 or better) in the operated eye. But it also requires the two eyes to be balanced, with no double vision or ghosting.

Imbalance between the two eyes prevents a patient returning to driving. This often exists after the first eye is done, when patients are waiting for the second eye surgery. This is one of the reasons why we schedule surgery for the two eyes closely, one or two weeks apart. When there is significant imbalance, a temporary contact lenses fitted to the second eye by the optometrist, can sometimes help.

You must not drive unless you feel completely safe to do so, and you are meeting the legal standards to do so.

How do we measure and refocus the eye to determine the power of the intra-ocular lens?

Every eye is different. We cannot measure every eye perfectly every time with the best equipment available.

The only way to accurately measure the power of a lens that a particular eye needs, is to put in a lens of known power, and take measurements. It is not practical to do this for everyone as this means two surgeries.

We use the most advanced machine called the IOLMaster made by the Zeiss optical company. It is very accurate, but not perfect. It is less accurate if you have had previous corneal refractive surgery.

We then plan the “refractive outcome” that we desire for your eye, and this then determines the power of the IOL that we chose.

Despite careful measurements, some patients may have residual refractive error (e.g., slight blurriness or astigmatism) after surgery, which can affect clarity of vision. We call this “refractive surprise”.

Not everyone achieves perfect vision without glasses. The outcome depends on pre-existing eye conditions, lens choice, and healing. Realistic expectations are important.

Refractive Outcomes after cataract surgery

There are several possible refractive outcomes.

Slight myopia. This is the usual plan for the first eye. An eye with slight myopia can still see distance reasonably well, and usually achieve driving standard with out glasses. And the eye can often see at computer distance and some reading, particularly in bright light conditions.
Perfect distance vision, called emmetropia. This is usually the plan for the second dominant eye
Reading vision, or higher myopia. Many patients are naturally myopic, or short sighted, and they like being so. We can retain the myopia and retain the ability to read without glasses, and increasingly patients are choosing this. The disadvantage of retained myopia, is that the eye will need glasses for distance/driving/TV, and there is some delay until the glasses are made by the optometrist (usually 4 weeks)

What is Monovision?

Monovision is a refractive plan for both eyes, where one eye is corrected for distance and the other for near vision without glasses. Some patients already have it, either by design from the optometrist, or by chance, from the way the eyes have naturally developed and focussed.

To work well, it requires your brain to be able to “suppress” the image from each eye, as the images will be different. Wherever you are looking, one eye will be blurry.

It can reduce the need for glasses. It works best when patients already have it and are used to it.

If you do not already have it, we usually do not plan for it. It takes time for your brain to adapt to it, and some patients never learn to tolerate it.

Patients with a history of squint (the eyes are not pointing in the same direction) are usually well suited to monovision, as their brain is already used to a different image from each eye.

Correcting Refractive Error / Refractive Surprise

After cataract surgery, there is ALWAYS some refractive error, regardless of how clearly you perceive your vision.

We correct refractive error with an update of your glasses. Every patient should return to their optometrist 4 weeks after the second eye has surgery to continue optometry care.

It is impossible to accurately measure every eye every time. There is always some residual refractive error. The best analogy is to consider how a telescope is focussed. There is the gross focussing knob, which does most of the work, and there is the fine-focussing knob, which sharpens the image. Cataract surgery and the new IOL is the gross focussing process. Updating Glasses afterwards is the fine-focussing process.

Sometimes after cataract surgery we find that the focussing of the eye is not as we planned. We call this “refractive surprise”. The IOLMaster machine measurements in these cases did not predict the focussing of the eye. There are two potential surgical decisions to make. Firstly, do we adjust the first eye again with further surgery, by doing an IOL exchange? Secondly, how do we modify the surgery for the second eye, on the basis of the result of the first eye? We usually assume that the second eye will behave with the same amount of error as the first eye, but this is not always the case.

If your doctor finds that the focus of the eye is not close to what they were expecting, your surgeon can offer you an IOL exchange. This is when they return you to the operating theatre to take the first IOL out of your eye, and replace it with a newly calculated lens based on your result. This is best done within the first 4 weeks after surgery, before the IOL heals (scars) tightly into the eye.

An alternative to IOL exchange is to place a “piggy-back lens”, called “Sulcoflex”, that can accurately remove the residual optics from the eye. Approximately 0.1% of patients can benefit from these lenses. For most patients, there is an additional cost for this service, which depends on the type of Sulcoflex lens required.

Alternatively, laser refractive surgery can remove the residual refractive error in the optics for you.

It takes time for the eye to heal. You should not judge your vision until the eye has healed. This can take one month or more in some patients.

You can also consider contact lenses, and laser eye surgery (like LASIK or PRK).

After cataract surgery, the focus, or refraction of the eye drifts, regardless of what IOL we use. The size and direction of drift varies between patients, and across time. This is another main reason why most patients end up preferring glasses for best vision later in life.

Have you had Laser corneal refractive surgery already?

This is commonly called PRK, LASIK or SMILE, but there are other terms as well.

All these procedures change the shape of the cornea. Essentially the surgeon takes the glasses and places the lens onto the eye with laser.

These procedures have the disadvantage that THEY MAKE THE PRE-CATARACT MEASUREMENTS OF YOUR EYE UNRELIABLE.

This means that YOU ARE MORE LIKELY TO NEED GLASSES AFTER CATARACT SURGERY, and MORE LIKELY TO NEED A LENS EXCHANGE because of refractive surprise.

If we find that the refractive outcome of your cataract surgery is quite different from the outcome predicted by the IOLMaster, then exchanging the IOL is sometimes required. This is more likely if you have previously had corneal refractive surgery.

Common Problems

Cataract surgery often brings on symptoms of irritation and discharge, and you may need to use lubricating drops and other treatments to control this. Mild discomfort, dry eyes, glare, or halos around lights are common after surgery and usually improve over time. Some patients may experience delayed visual recovery.

Patients experience aches and pains. Often patients feel a foreign body sensation. Sometimes there is bruising in or around the eye. These things are normal.

After cataract surgery, months or years later, the membrane behind the new artificial lens can become cloudy over time, reducing vision and causing glare and haze.

This is called opacification of the posterior capsule. This can easily be cleared away with a short painless laser procedure performed in the consulting rooms, which takes 1 minute and doesn’t require anaesthetic.

The doctor may need to perform this laser soon after the initial surgery to improve your vision, depending on the type of cataract you had. Most patients require YAG laser in the first 5 years after cataract surgery.

Complications

We only offer surgery because, without surgery, you will go blind from cataract. When you read about complications, do not let the fear of the unlikely complication stop you from choosing surgery, as cataract always results in loss of vision and blindness eventually.

The chances of complicated surgery are small. Approximately 1% of people require more intensive post-operative care, and 0.5% benefit from further surgery. Sometimes the ligaments in the eye are not strong enough to support the artificial lens. A different type of lens may be required, placed in a different part of the eye. Most complications can be repaired, and usually the process still improves the vision, but the recovery time may take longer than 3-6 months.

Though rare, complications can include infection, bleeding, retinal detachment, or incorrect lens positioning. Most are treatable, and the overall success rate of surgery is very high.

Complications post-surgery are rare. 2% of people require more intensive post operative care and less than 1% need further surgery to fix surgery complications. Almost no patient ends up worse than before the surgery.

Severe complications occur in 1 in 1000 patients. These include retinal detachments, infection, bleeding in or around the eye, or inflammation that does not go away. Whilst these can be treated, if severe, they can reduce the sight in the eye, and approximately 1 in 5000 patients will be blind from cataract surgery. At any stage after the surgery, if your eye becomes more painful, or your vision more blurry, then you should contact Your Doctor immediately on THE MOBILE NUMBER OF YOUR SURGEON!

Cataract Surgery – there are two techniques

Manual cataract surgery is a 20 year-old technique but has been continually refined by skilled surgeons. It is the Gold-standard technique and is very safe. Our surgeons are very skilled, and have completed over 40 000 manual surgeries. The surgeon performs all the surgical steps by hand. Energy from an ultrasound probe breaks up the cataract. Compared with laser surgery (below), manual surgery is shorter in time, less complicated, results in better vision, and is the preferred method for 95% of eye surgeons. A probe is inserted into the eye and the cataract is sucked out, leaving the supporting capsular bag and ligaments behind. A new artificial lens is placed into this bag. No stitches are required as the wounds self-seal.

Femtosecond laser-assisted cataract surgery (FLACS) was introduced into Australia in 2011. Dr Peter Davies published some of the first data in the world warning about the dangers of FLACS. We showed that FLACS was less safe in our patients and we abandoned the technique in 2013. The majority of the world’s eye surgeons do not offer FLACS to their patients, but a small minority of eye doctors still offer this technique. Extra costs are required to cover the costs of the laser per eye.

FLACS uses laser technology that pre-treats the eye with an additional procedure, prior to the surgeon performing the manual surgery. This is discussed on the last page. Newcastle Eye Hospital abandoned this technology in 2013 because it failed to show any benefit to patients. In fact, it made our results worse. We published our results in a leading eye journal Ophthalmology. Other large studies such as the European Cataract Refractive Study 2015 have found the same result as our study. Most eye surgeons around the world do not recommend laser cataract surgery.

The disadvantages of the laser are:

A ragged cut cataract. We produced electron microscope images here at Newcastle University in 2013. The laser does NOT cut the human cataract cleanly or precisely as was first claimed by industry.
Increased patient cost. FLACS does not meet accepted standards for cost benefit for medical treatment. FLACS is simply not worth the extra cost. This finding was published in Ophthalmology Journal in 2013 and 2016.

Therefore, in 2013 we discontinued offering laser cataract surgery to patients. We have led world opinion in this topic, and currently the majority of eye surgeons do NOT offer laser cataract surgery to their patients.

Truths about cataract surgery

Please consider these facts about eye surgery, and discuss with your surgeon and optometrist.

1. Lens surgery cannot perfectly refocus the eye. We cannot perfectly measure, and therefore correct, the focus of every eye. The artificial lenses used in eye surgery do not change or adjust their focus. Therefore, after surgery, there is always some optical blurring, at difference viewing distances.

2. Sometimes the optical blur, called refractive error, is unacceptable, and we need to change the intra-ocular lens for another power. This is called "refractive surprise". It represents the fact that the focussing of some eyes cannot be predicted by the best technology.

3. Best-quality vision is always obtained with an update of glasses. This applies for all viewing distances. The focus of the eye drifts and changes over time. Therefore, over time, most patients end up having glasses for best-quality vision, both for distance, intermediate, and near viewing.

4. Having said this, most patients can do most visual activities most of the time without glasses. Most of our patients can legally drive without glasses, and many can read in bright light conditions.

5. Most patients achieve best quality vision with single focus intra-ocular lenses. We usually plan to do the non-dominant eye first. In this eye, we aim for mild myopia (short-sightedness). This can help the patient with intermediate and reading vision without glasses. We then measure the first eye, and use the focusing result of the first eye (the refraction) in planning the second dominant eye, usually targeting clear distance vision.

6. The focussing that we aim for is not always what we achieve, because of the variability and inaccuracy of cataract surgery, even when performed by the best surgeon, using the best machines. Eyes are NOT perfectly predictable.

7. The modern multifocal glasses, sometimes called “variable” or “progressive lenses”, are the best way to achieve clear vision for all viewing distances. However some patients cannot tolerate this lens design in their glasses.

8. Single-focus lenses in the eye allow the best-quality vision, achieved with an updated pair of glasses after surgery.

9. For patients wanting to minimise the need for glasses after eye surgery, (which is most of us, let’s be honest), there are various types of intra-ocular lenses designed to do this. There are two basic categories. Firstly, there are bifocal, or trifocal lenses, sometimes also called multifocal lenses. Second, there are lenses called "extended-depth-of-single-focus" (EDOF) lenses. All these lenses reduce the quality of vision, in a way that glasses cannot correct. They reduce the need for glasses, but at the cost of reducing quality of vision. This reduction of quality is most apparent in dim light conditions, such as driving at night. Also to be really technical, they should be called "extended RANGE of focus" - the only true EDOF is a pinhole lens, which we sometimes use in patients with corneal distortion from disease such as keratoconus.

10. When we use these multifocal or EDOF lenses, sometimes patients do not achieve the desired vision, and we need to replace them with single-focus lenses. But we NEVER replace single-focus lenses with multi-focal or EDOF's. Floaters are often more obvious with these lenses, and floater treatment is more likely needed with vitrectomy surgery.

11. All lenses work better in bright-light conditions. In dim light, the vision is always reduced.

12. All surgical methods that aim to reduce the need for glasses after surgery, such as multifocal intra-ocular lenses, have the disadvantage of reducing best-quality vision

13. Sometimes we can focus one eye for distance, and the other eye for near. This is called mono vision. This works best when patients already have this. However, it can fail because one eye is always blurry, where ever the patient is looking. This relies on the brain to ignore the blurry eye. Some patients have this ability, but some (like me!) do not.

14. The best time to try the various refractive outcomes - mono vision, blended vision, multifocal lenses etc - is with contact lenses, BEFORE you develop cataract. See your optometrist to discuss this.

15. Many elderly patients have other eye diseases such as macula degeneration, and blepharitis. In these patients, we always prefer single-focus lenses.

16. Many patients who do not have other eye disease at the time of surgery, will develop other eye disease later on. These patients are better off, had the original eye surgeon used single focus lenses.

17. In the United States of America, eye surgeons are paid considerably more to do surgery with EDOF’s or multifocal lenses. There is a strong international motivation to promote them, which influences the marketing that Australian patients may experience.

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