Lecture: Phacodynamics – Introduction into the Basics

Cataract extraction using Phacoemulsification is the most precise way we currently have to treat cataracts. Small incision Phacoemulsification with intraocular lenses has helped improve visual results with cataract surgery more in the last sixty years than in all of previous history. It has the potential to help patients see well for most or all of their activities with little or no dependence on glasses, and is increasingly available in developing countries. This live lecture describes how it works, with details for settings in different parts of the case, and some cautions in its use.

Lecturer: John E. Downing, MD, FACS, Clinical Professor at Vanderbilt University School of Medicine. In private practice in Bowling Green, KY, USA


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Good morning.
I’m Dr. John Downing.
I’m in Kentucky in the United States.
Very happy to have you join us this morning.
I have been going on missions with Orbis since 1989.
I think it’s a wonderful organization, and Cybersight is making these programs available to lots of people everywhere.
There have been tremendous increases in cataract surgery improvements in the past 50 years.
I started in ophthalmology 51 years ago.
The glasses were not very effective.
Things have really changed a lot since, literally more than in the previous 3,000 years.
A lot of this has to do with the fact that we can use a much smaller incision size.
We’ve gone from having cataract glasses to first contact lenses and then interocular lenses, which are an unbelievable step forward.
People who had surgery before interocular lenses and had to wear glasses, they would be lost or damaged after the first year or surgery, and after that they generally had uncorrected vision, which was 2200 or less.
And cataract surgery has now become a very precise refractive procedure.
How does this work?
First is intraocular lenses, moving the correction from in front of the eyes to inside in natural spots where the natural lens was.
And the invention of phacoemulsification, which allowed us to use small incisions with little induced astigmatism and healing.
We had no way to measure what power lenses we had to use.
Now we can correct many with high accuracy.
Fay co emulsify occasion was developed by Dr. Charles Kelman about 1967.
It’s a small incision ECCE.
We were closing the incision with usually 5 silk sutures.
They were slow to heal.
The healing changed for years.
So, you had to keep changing their prescriptions in their glasses.
Phaco is a minimally invasive closed system where you can get a stable anterior chamber and posterior capsule, but it was developed before its time.
We didn’t have intraocular lenses.
The first lens was implanted in 1951, mixed success, and reported three or four years later.
There had never been an artificial implant that could be placed in the body that worked.
And intraocular lenses were not accepted for more than 20 years.
They were rigid lenses and still required a large incision, so there was very little advantage to doing Phaco.
What did finally make it successful is the small incision induced minimal surgical astigmatism change.
And we had foldable lenses in the mid 70s, and then accurate measurements and calculation formulas.
That’s Dr. Kelman on the right and Henry Mitchell on the left.
Henry was his technician for the first several years. When Dr. Kelman wanted a setting changed, he’s tell Henry, and Henry would dial it into the machine.
This picture was taken at the 25 year anniversary of this invention.
And Dr. Kelman died several years ago, unfortunately.
Henry Mitchell is still going strong.
He works for crest point.
If you happen to be going to the American academy of ophthalmology, stop by crest point and Henry will give you all kinds of stories about Fay co emulsify occasion.
You get predictable good vision, quickly.
And most of the world, it’s the preferred method of cataract surgery because of the advantages.
The disadvantage is it requires expensive equipment, you have problems with maintenance, and you have disposables in most machines where you have ongoing costs with every case.
But it has uses even in poor and developing countries.
In many countries of the world, there’s a marked shortage of ophthalmologists, and the ones there usually don’t do a lot of surgery.
They’re usually in the capital cities.
There’s very little out in the periphery of the country, in the countryside.
That is changing in several countries.
But it can be used to generate income, even in very poor countries.
You may have a country where 90% of the people are very poor, but you have a 10% in almost every country that are middle class or above and want modern care and they’re willing to pay for it.
An example of where this is used is the system in southern Indian.
It was started by Dr. Swamy.
There are at least 45 million people who are blind from cataracts.
He started in 1976 with an 11 bed hospital. The system has grown.
There are now several hospitals that are high volume and high quality.
Most of the surgeries are done with small incision ECCE.
About one thirds of the patients pay, and those patients generate enough income that about two thirds of the patients are done at no charge.
It’s been a self supporting system ever since it started.
There’s a book, “an infinite vision” that tells the story and is well worth reading.
It’s fascinating.
How does phaco work?
You have an Ultrasonic tip that vibrates like a miniature jackhammer.
It moves forward and back.
It does it very fast.
You have to have a cycle rate of 35 to 40,000 cycles per second to overcome inertia, and it only cuts on the forward stroke.
Aspiration has to pull the material back to the tip, and you get another forward stroke very rapidly, and it cuts into small pieces or emulsifies.
The basics of the machine are pretty simple.
You have fluid in flow, you have a bottle, usually, with balanced salt.
And most machines use gravity flow, so the bottle height and port size control the rate of flow in the machine when the valve is open and can let fluid in.
You have an aspiration pump, which pulls material to the tip in the eye, and then pulls the emulsified material on through the eye into a disposal bag.
Vacuum is generated when the material, the tip is occluded. You don’t get any vacuum unless it’s occluded. But once it’s occluded, it helps hold the material on the tip, so you can cut.
The handpiece has an electrical input to cause the vibration.
You have irrigation line, which brings fluid in from the bottle.
It is it goes out through the side ports on the plastic sleeve around the metal tip.
Then when the pump is running, fluid is aspirated through the end of the tip and through the aspiration line.
This is a schematic, basically, of how machines work.
You have a bottle of fluid.
The tubing goes through a pinch valve, and when the pinch valve is open, fluid is irrigated through the tip, through the side ports, and into the eye.
When you have a pump, then, which pulls fluid through the end of the tip, and through the pump and into the disposal bag.
You set the maximum vacuum you want.
There’s a gauge to show how much actual vacuum you’re getting.
You set the maximum phaco power you want, and there’s a gauge that shows how much phaco power you get.
A major advance was the torsion al phaco.
You have side to side sweeping motion instead of forward and back like a jackhammer.
It goes side to side.
So, it doesn’t repel lens material.
It shaves and cuts it on both directions of movement.
It shows longitudinal and torsional.
[Video]>> DR. DOWNING: Without a chattering motion, there’s no need.
Know that PEA is fast.
The efficiency of the torsional tip comes from its action.
In conclusion, let’s compare the differences.
The boring and slicing action of phaco cutting to the shaving action of torsional emulsify .
It is fast and effective.
>> DR. DOWNING: For efficient torsional, you need to use a curved tip.
It sweeps back and forth, and you get a larger sweep that way than if it’s straight.
You control the machine with a foot pedal.
This is the diagram of the foot pedal.
Move your foot off of it, it’s called position zero.
You press down and you’ll hear a click that puts you in a position to flow into the eye.
You’ll hear the pump start running at the next position.
Push down a bit more and you will hear the phaco power coming in.
We normally set the power proportional so it’s how far down into position three you go.
Zero, your foot off of the pedal and nothing is going in or out of the eye.
Position one, you will hear a click and that opens the valve.
It lets fluid flow into the eye, intraocular pressure is going to be equal to bottle height.
But there’s no flow through at that point.
You need a snug fit, but not too tight.
You need a precise incision size to get there.
Foot pedal position two, press down further.
You’ll hear the pump start running.
It adds aspiration, pulls fluid through the eye into the phaco tip and out of the eye.
The flow rate depends on how fast the pump is running, and you set flow rate in mm per minute.
Foot pedal position three, your valve to the bottle is open, so you have inflow.
You have aspiration.
The pump is running.
And position three, going down a little further in the foot pedal, you hear a buzz when you hear phaco power starting.
You pretty much always want to use linear control.
The more you push down, the more power you get up to your preset maximum.
So, I always set it to linear.
You want to use enough pow tore cut the material.
You don’t want to push the lens material away.
If it’s pushing away, you have to increase the power.
You don’t want to stay in phaco for a long time, because it heats up pretty quickly.
I primarily use torsional power with very hard nuclei.
It often helps to use longitudinal along with it, if it’s not cutting or if it’s clogging when you have it in maximum power.
Vacuum level depends on how tightly the tissue is held when the tip is occluded. You don’t get any vacuum unless the tip is occluded.
And vacuum increases proportion ally to.
This rise time.
This is an illustration. In the top one, if you set if you are setting at 20mm per minute, it may take four seconds to get to your maximum. If you double your speed, you should get rise time to vacuum in half the time, in two seconds.
You want to set it fast enough that material moves, but not so fast that it’s jerking, and you get things that you don’t want like the iris or the capsule.
You have different vacuum settings and aspiration rates for different parts of the procedure.
If you’re doing a grooving procedure, you usually don’t need but a little bit of vacuum, 30 to 50mm, but you have to increase it to 200 to 500, sometimes more to hold it on the tip for removal of lens material.
Typically for irrigation aspiration, you have a smaller opening.
You go at 600mmHG typically, for IA.
Something you have to be aware of is surge.
If you’re down to the last pieces, you’re occluded, and you have max vacuum, you have to be very careful, because it can suddenly get pulled in and the vacuum goes from very high to nothing.
And you can get collapse of the chamber and tear a capsule pretty easily.
So, the last bit, you want to be slow and ginger about using a little bit of phaco power at a time.
Some newer machines have what is called active fluidics.
Instead of just depending on bottle height for flow, it actively senses and adjusting to ocular pressure.
This helps to stabilize the anterior chamber and capsule.
It’s a major improvement in safety because you get a much quieter eye and less likelihood of aspirating the posterior capsule inadvertently.
This demonstrates the green line is what typically happens with a gravity feed system.
The reddish line shows that it’s evened out a lot with active fluidics because it senses the pressure in the eye multiple times per second and adjusts it.
As operation rate sets how fast fluid is pulled through the eye.
This, again, depends on what phase you’re in.
You don’t need but about 15 or 20ml per minute.
You can include to 20 to 50 for quadrants.
You want to hold them against the tip more firmly.
You want to adjust the rate, and you watch how the material is moving.
If it’s moving too fast, you want to slow down the aspiration rate.
If it’s jerky.
If it’s not moving fast enough, you can gradually increase your aspiration rate until you can get material coming to your tip in a controlled fashion.
Bottle height with gravity systems determines the flow into the eye, and you have stability of the anterior chamber and posterior capsule.
You have to have an even balance between inflow and outflow.
If you have a problem with the iris or capsule, you want to slow lower the bottle height some and slow down your aspiration rate.
The systems with active fluidics, you set the targeted intraocular pressure, setting it at 55mm is approximately equivalent to 95cm of bottle height, which is usually as high as the average gravity feed system goes.
Again, you want to have an aspiration rate fast enough to keep tissue moving to the tip, but not so fast that you have instability to the chamber.
If it is jerky, slow it down in that case.
Phaco power.
You want to use enough pow tore cut through without pushing it away or moving it, and you only want to cut when you’re in contact with tissue.
If you stay in contact when you’re not, you’ll get heating and can get a wound burn.
If you’re not in contact with lens tissue, go up to position one inflow and aspiration.
Normally if you’re in contact with tissue, you will use a little phaco to bore into a piece of nucleus.
You can hear the sound of the vacuum rise in pitch.
Then use a little phaco pow tore emulsify the tissue.
Normally you are most efficient if you use phaco in short bursts of one or two seconds and then go back to just aspiration.
Once you are in contact with a piece of material and it’s on the tip, stay in position two.
Don’t go back don’t take your foot off the pedal.
If you do, a piece will fall off, and you have to go back down and get it again, which is time consuming and also dangerous.
You have material moving around in the capsule or mag.
Once you have contact with the tissue, the vacuum is building, then you can add enough phaco power to emulsify the pieces.
Short bursts of a second or two are more efficient than always, you go into phaco, back into aspiration, and back into phaco.
You’ll end up using less time, and you’ll be less dangerous as far as overheating.
These settings are going to vary with what you’re doing.
Pre phaco is basically just aspirating the soft material on top of the nucleus.
And how much there is depends on how hard the nucleus is, typically.
Very hard nuclei have little to no.
Soft ones, you’ll have a bit.
Normally you need aspiration, little flow and little vacuum for aspirating on top of the hard nucleus.
You want to leave an edge of epinucleus and cortex.
This gives you an edge for later.
A lot of techniques, you’ll groove the lens and split it.
For grooving, you don’t need very high flow.
You don’t need high vacuum.
You don’t want to occlude the tip.
Use just enough linear power to cut and go through.
You only want to cut moving forward.
When you start back to get another shot at it, go back to position two.
It pulls out what you’ve emulsified and helps cool the tip.
You don’t want to occlude the tip while you’re grooving.
Sometimes you can have a very hard nucleus, and you have trouble grooving it.
You can increase your power.
If you’re in torsional, usually set it at 100% if it still isn’t cutting very well, and some longitudinal.
And it will cut most nuclei.
You can place your second instrument ahead of where you’re grooving to help stabilize the lens or at the equator to hold it to keep from pushing it away.
Most procedures, you start dividing the lens in pieces.
And while you’re learning, a simple technique is to make a deep central groove, split the nucleus into two halves.
If it doesn’t split, you’re not deep enough.
You want to go down until you have an even red reflex all the way across. Then you use your tip and your second instrument to split it.
Once you get it split into two halves, you’re more than half way home. If you don’t get a good split into two halves, you’re going to end up with a plate that’s going to be hard to manage later to manage later.
That first split is very important.
Divide and conquer.
You get your first division, rotate the lens, groove and divide it, so you have an X groove and you have four pieces of the nucleus.
You stay well away from the posterior capsule.
And you don’t have a whole lot of manipulation.
This shows the typical divide and conquer procedure.This is the prephaco where I’m basically just aspirating the soft on top of the hard nucleus.Then I’ll start a groove and watch what the bottom of the groove looks like.
If there’s any gray material, you’re not deep enough.
You have to go down until you get an even red.
Then use the two instruments in the groove to split.
Rotate 90 degrees.
Make your second groove.
You can see the gray material will?
Remember the lens is a lot thicker in the middle, so you have to go deeper there than you do peripherally.
Rotate another 90 degrees.
Make your third groove.
Split it.
You want to split all the way to the middle, so you free up the pieces from each other.
Then you increase your power, vacuum, and aspiration, and emulsify each quadrant.
As you get close to the end, put your second instrument deep to the tip so you don’t aspirate into the cortex with surge at the end.
Epinucleus, if you have it, you don’t need very much of an aspiration for that, and very little phaco power.
Cortex removal is done normally with an irrigation aspiration handpiece.
The vacuum 500 to 600, rate of 50060ml per minute.
And it works best if you do the sub incisional cortex first while the rest of the cortex is helping hold the bag open.
You start sub incisionally and work around.
You separate the infusion and the aspiration can be very handy, particularly if you’re having a problem.
You can manipulate each irrigation and aspiration separately.
You can use a very low vacuum and flow setting if there’s debris on the capsule and aspirate and remove the remainder of the bits of tissue that are on the posterior capsule.
A silicone or plastic tip is safer than a metal tip, if you can get one.
So phaco steps are prephaco, making a groove for most procedures.
Removing the hard nucleus.
Then the epinucleus, it is thicker than cortex but considerably softer than the hard nucleus in most patients. Then in irrigation and aspiration, you remove the cortex, polish the capsule and remove after you put the lens in.
Now you’re going to have problems sometimes. Phaco may stop cutting.
The anterior chamber depth may be unstable.
Tip may clog.
You may not get any aspiration.
You may get a capsule tear.
You definitely will get capsule tears, and you can get wound burns.
If the phaco stops cutting, worry is there a capsule tear?
Is there a vitreous?
You want to make sure that you don’t have a problem with vitreous to the tip.
Fortunately, most of the time you don’t, and you can wiggle the handle a little bit inside and you can see the end of the needle move back and forth.
It’s just loose.
You have to come out of the eye, and tighten or replace the tip.
The anterior chamber is unstable?
That means you have inadequate inflow relative to outflow.
What can cause that?
Bottle may be important.
That’s not uncommon early on.
Maybe you’ll use a lot of fluid.
Or you may have excessive wound leak around the phaco tip.
You won’t have that if you use the correct size so that it’s snug but not too tight but not too loose.
To correct it, figure out what’s wrong and then take care of it.
If the anterior chamber is suddenly very deep when you go in, a common cause is called iris capsule block, where when you pressurize the eye, there’s a block between the iris and anterior capsule.
To correct that, you lift the edge of the iris off the capsule, and the chamber should come back to a normal depth over a few seconds.
But, again, any time anything is not looking right, look for a capsule tear.
If the chamber suddenly gets deep or shallow, look for a capsule tear.
And be careful.
Now if you have maximum vacuum but no aspiration, normally the tip’s going to be clogged.
This is going be more common with very hard nuclei.
You may be able to use a second or two burst and open it.
More often than not you’re going to have to come out of the eye and flush the tip.
Sometimes it can be really clogged, and you have to use the stylet from a spinal needle to get the material flushed out of it.
Make sure it’s flushed and you’re able to aspirate freely.
You will get capsule tears, unfortunately.
And you need to be aware of them.
All of the sudden you’ll notice a very clear area, usually with a pretty straight line on one side or the other.
Natural thing to do is come out of the eye.
Do not do that.
Keep your tip in the eye.
Stay in position one, inflow.
Use viscoelastic to fill the chamber.
When it’s filled, come off of the foot pedal and take out the tip.
You will have to decide what to do to finish the case.
If there’s adequate anterior capsule, usually the best thing to do is go ahead and put in a lens in the sulcus.
It acts as a scaffold and keeps vitreous back and improves the fluidity in the eye.
Usually you will have some cortex at least.
If there’s still hard lens material, you have to do it differently and get everything forward.
You can rotate it.
You push pretty much straightforward and you get it under the iris, over the capsule.
And try to make sure the lens is stable.
You can press over the haptics.
If the optic moves away and springs back, that’s a good sign of stability.
Then you have to worry about getting the rest of the cortex out.
I like the bimanual.
It’s more flexible and you can manipulate it easier.
Work over the IOL as much as you can.
Stay away from the capsule tear, or you’ll get vitreous there, too.
You can also remove the remaining cortex manually, just with some VSS in a 3CCsyringe.
Fill the anterior chamber with viscoelastic.
Pull the plunger.
It’s slower, but it works just fine.
This is a 25-gauge angled canula.
Usually called the gills canula.
I always like to use the myotic when the capsule is broken.
Bring the capsule down.
You want to make sure there’s no good vitreous in any of the wounds. You need to get it free of the main wound or side ports, or you will get inflammation or CME.
Sometimes if you do it this way and you’re very careful, you won’t get loss of vitreous.
Close to 50% of the time, once you are good at recognizing that you have a capsule tear, you do it this time.
I was lucky this time.
Wound burns.
If you use too much phaco power, the tip heats up very rapidly if fluid’s not moving well through it.
You can get a burn with high power very quickly.
Viscoelastic may occlude your tip if you go into phaco without aspirating a little bit before.
Sometimes you can get a wound burn very quickly.
So, irrigate a little bit when you first start.
Don’t use more power for longer than you need to.
Normally as you’re removing the anterior cortex and epinucleus, you will see what you’re aspirating move into the tip.
But sometimes it just gets kind of milky like this.
Hopefully not very often.
It means that it’s not moving into the tip adequately.
And if you look over at the wound, you’re getting some gray haze near the limbus.
I was not aspirating. The aspiration was loose.
I had to take it out and tighten the aspiration line.
Then go back in and this is the way you should see fluid go out of the eye as you’re aspirating it.
Then this is a quick chop technique.
The rest of the case went fine.
But then most of the time when you get a wound burn, the wound will not seal.
And you’ll have to suture it.
And that induces significant astigmatism.
I’m hydrating the stroma and the side port.
And in this case, it happened to seal.
That’s pretty rare.
Sometimes you can be lucky.
This is another case where I was assisting a resident, and he was not going back into position two.
And I was just telling him that, and I realized that he was getting a wound burn.
He came out.
He was able to go ahead and get the rest of the cortex and nucleus out and got a lens in.
But it did not seal.
So, he had to put in sutures, which induces several diopters of astigmatism in that direction.
You need to take out the sutures after two or three weeks, but you will still have significant astigmatism.
The burn shrinks the cornealstroma.
If you have sometimes you’ll get chips stuck in the opening and you can take care of that with a second instrument. If your vacuum doesn’t build, you can have a loose tip or loose aspiration line.
You have to practice using both feet, both hands, your eyes and your ears. One foot for the phaco pedal.
One for the microscope.
Both hands.
One for the phaco tip, one for a second instrument to manipulate.
Your eyes, watch how things are moving.
Stay away from the iris. You have to listen for the sounds and the different functions during the procedure.
Practice as much as you can in a wet lab.
Be aware of what cycle and function you’re in.
Be sure you’re in the right cycle for what you’re trying to do.
Listen for the sounds of each function.
Click to open the valve.
Pump running for aspiration.
Increasing pitch as vacuum builds.
And a buzz to know when you’re having phaco.
In IA, listen for the vacuum to begin to build, then tease it out of the Fornix.
And it works best if you move parallel to the pupil instead of pulling towards the center.
It means a lot less stress. Practice as much as you can.
There are artificial eyes, artificial lens.
It’s very much like learning to play the organ.
Playing the organ also requires coordinating both hands and both feet, watching what you’re doing and obviously listening to what you’re doing.
You want to work in the center of the pupil at the level of the iris as much as possible.
Because the anterior chamber is deepest there, you’re further from the cornea and anterior capsule and it’s less risk of getting a capsule tear.
Or damage to the endothelium.
Make sure you know how the machine works.
You need to know how it sets up.
Most of the time, techs will set it up.
But you need to know proper function and how to troubleshoot it.
If things are not working right, you’re the boss.
You have to figure out what’s wrong and what to do to correct it.
Make sure the staff knows how to set it up and change the settings, but you’re responsible for knowing what to do if it isn’t working right.
You need to know where the vitrector is, and how to set it up and use it because you will need to use it.
Read manuals, watch videos.
There are all sorts of good videos of different techniques on YouTube.
If possible, record your cases.
If you have a problem, you can often see what went wrong and hopefully avoid it in the future.
If it goes well, you can scan through to see what you might improve.
You will probably see a lot of dead time where nothing’s happening.
You can often cut down on that.
It is definitely harder than it looks.
But it’s an elegant and complicated technique.
And it has improved cataract surgery so much over the last 50 years.
It’s made cataract surgery the best refractive procedure that we have.
We can usually help people see well without glasses much or all the time with good measurements, good calculations, and good surgery.
And that’s a lot of fun, folks.
Now, some questions.
And you can I’ll read them, and you can answer on the computer with one, two, three, our four.
[Poll questions] that’s exactly right.
Three quarters of you got it.
That’s good.
Time for question two.
Time for question two.
Decrease the aspiration rate.
Lowering the bottle would make it worse, because you get less inflow.
Phaco power wouldn’t have any effect on how fast material moves. Decreasing the vacuum would have little or no effect .
Question three.
Irrigate before adding any phaco power, it does help some to avoid a capsule tear by keeping the chamber deep.
But the big problem is to make sure fluid is moving through the eye is to make sure to avoid a wound burn.
Question four.
Question four.
It’s usually easier to learn one of the grooving techniques, but chopping techniques usually makes the procedures go faster once you’re familiar with them.
What do you do in glaucoma?
Removing a cataract in a patient with glaucoma often helps improve glaucoma control.
How and when to use pulse and burst modes?
There are different ideas about it.
You can use the fast pulse.
Works usually a little better with softer lenses. Burst often works better with harder lenses.
How to maintain good anterior chamber depth.
We talked about that.
Make sure your inflow balances your outflow.
Increase your bottle height if you’re not getting good chamber depth, decrease your aspiration rate.
How do you save optic nerve from pressure changes during phaco?
Unless they have very advanced glaucoma, you’re not going to have the pressure up that much for that long.
That shouldn’t be a problem.
Increase your bottle height, increase your vacuum and increase power.
You need to know how to remove the lens with a manual extracap.
Are there any standard settings for all machines?
No, unfortunately.
You can use direct chop techniques it says in do you use a technique of direct chop in white or brown?
Brown cataracts, if you’re going to chop, most of the time you can use a vertical chop, but if you’re having the problem you’re going to have to convert and remove manually the lens.
White cataracts, you want to make sure that the anterior chamber has lots of viscoelastic in it.
It’s firm.
Make a small opening in the central capsule.
If you start getting white liquid coming out, aspirate that with your IA.
Try to rock the lens. Remove all the liquid cortex that you can, and you can refill the bag with viscoelastic, and often there’s just a small remaining hard, white nucleus.
Usually at that point you can make a normal sized capsule erectus, and chop usually the small nucleus.
It works really well.
Criteria for selection of a phaco machine.
If you can, get one that has both longitudinal and torsional.
A lot of machines just have longitudinal.
They work perfectly well.
The torsionals are a little more you have a few more choices about different types of lenses.
And it depends on where you are and, you know, how much money you have to spend, what kind of disposables you need.
The best thing, usually, is ask somebody who is doing phaco what they’re using and what they think the advantages or disadvantages are.
My experience is pretty limited as far as types.
I currently am using the AlconCenturion which does have active fluidics, which is wonderful.
I have been on a number of mission trips, I have used an AMO contact, which also works perfectly well.
There are other machines available now.
Look and see what you have.
Try to see what the advantages and disadvantages are for each one.
Pseudo exfoliation in dense lenses. Most of these patients are going to have glaucoma and pupils that don’t dilate well.
Usually they will have a small pupil.
Usually you use iris hooks. Make sure that you have them available.
If the pupil is not dilating well, go ahead and put them down in the beginning of the case.
If it starts coming down, it’s a real problem and something that can happen easily for patients on Flomax and other prostate medication.
Learning to anticipate pupil problems and making sure you can keep it dilated is important.
If the pupil comes down on you, you’re very likely developing a capsule tear.
Posterior polar cataract, that’s very interesting. You have posterior capsule or plaque, and usually the lens material is soft.
Normally what you want to do on those is not hydro dissect, you want to hydro delineate, and you work on those from the center out.
When you get all the harder material from the center, you can viscodissect under the capsule and move material away from the posterior capsule.
There is an excellent video on YouTube about management of posterior polar cataracts.
What phaco mode is best for hard cataracts? You will usually need to use some longitudinal.
Burst mode usually works pretty well.
You will have to see if you can get through it.
If not, you are better off to switch to a manual extract.
Lawrence, do we have other questions?
>> We have about ten Q&A questions, if you want to open those up on your end.
If you click on that.
>> Always available… good question.
>> Good question.
Cybersight, you can ask questions and get a consultant to answer them.
There will be a day or two delay.
If you anticipate a problem before, look it up on YouTube or eyetube.
Most often there are going to be videos that handle the particular problem you have, because we all have similar problems.
Although I have been doing this for a long time, and I keep coming up with new ones.
Which phaco technique would I recommend for beginners?
I have used chop techniques for many years.
Like them.
I think for most people, the simplest way to learn is when I showed the divide and conquer.
Once you’re proficient with that, you can use what’s called the cold stop and chop.
You make a deep central groove, divide the nucleus, and then rotate and chop off pieces around each half.
Then there are also excellent quick chop techniques.
David Chang’s book goes into detail with excellent video.
But you need to get comfortable with a technique that’s reliable.
Type of anesthesia used.
I would there’s really pretty small group of block or I would definitely use block anesthesia until you’re very comfortable and can do cases in less than 30 minutes.
Let’s see.
Let’s go up, I guess.
How does previous refractive surgery complicate power?
You need to know how much correction they had.
There are calculators on ASCRS.org website that are very helpful.
If there’s a new machine called the Aura, where you can measure the refractive power once you get the cataract out and before you put the lens in.
That is really need and usually very helpful if you have it.
But it’s expensive.
We have gotten it.
I had a post myopic patient that my calculation said use 19.
The machine said use the 21, and I used the 21 and it worked.
She would have been hyperopic if I had used the 19.
Whoops. How do you recommend it constructed?
I like a three step wound, starting either slightly clear cornea margin
Or a little bit in.
Make a groove.
Go forward with a carotene in the wound.
Ideally the length or the width of your karat one for your machine.
I use between a 2.2 and a 2.4, so it’s very small tip, so it’s easy to make a square wound, which is by far the strongest.
I do not like corneal incisions. They do not heal well.
Limbal incisions, you can’t open them post op.
Corneal wounds, I have done that post op.
In Africa, we see very dense and hard nucleus. I know that.
If they are black and dark, small incision, manual extra cap is excellent, especially if you operate temporally.
You get much less induced astigmatism.
It doesn’t take long to learn how to do that.
It’s tricky at first.
If you have been used to operating superiorly.
Instead of hydrating wounds, can you inject air?
I don’t think that would work.
You want to make sure that wound is sealed when you end the case.
An air bubble is not going to seal it.
It’s pretty rare, I think, where there would be an indication for an air bubble now.
We used to use them before we had viscoelastic.
What should be done when the ac goes deep?
First thing is, look to see if you have a capsule tear.
If you do, you have to address that by putting in viscoelastic and seeing what you need to do to finish the case.
Look for an IC block, a block between the iris and the ac.
Try lifting the iris off of the capsule, if that’s what it looks like it is.
If it is, it will come forward.
If it doesn’t, it’s probably a capsule tear.
Talked about setting IOP at 55.
That is for a machine with active fluidics.
You set the target IOP if you have active fluidics.
If you have a gravity feed, which is what most machines are, you have to vary the height of the bottle.
To hold the nucleus to do phaco chop.
It often you can hold the harder nuclei better if you use linear.
Burrow in well, let your vacuum build and chop.
And usually that works pretty well.
How do you change from torsional to longitudinal?
Those are just settings on the machine. If you have a machine that has both, there will be one for each.
You can use both together.
That’s pretty good, folks.
>> I think that’s a good place to stop.
There might be one more question, then we can stop.
>> Okay.
Do I recommend to use aspiration for the last segment removal?
If it will aspirate, yes.
And if it won’t, you can often use your second instrument to stuff it in the tip.
Use a little phaco along, and usually you can get it in.
Just don’t use a lot of phaco and let the vacuum get really high before you get that last little bit.
>> All right.
Thank you, Dr. Downing.
>> Thank you.
That was fun.
>> Have a good day, everyone.

November 2, 2017

Last Updated: October 31, 2022

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