Hi there, my name is Dr. Theresa Cooney.

And I am a comprehensive ophthalmologist and

cornea specialist at the Kellogg Eye Center.

And today, I'm going to be talking to you about capsular tension rings.

So this is an introduction, capsular tension rings are made of PMMA,

a plastic material with a circular open loop ring.

These are meant to,

Stabilize the zonular apparatus through centrifugal forces.

Once they're inserted into the eye, into the capsular bag, they can expand and

centrate that capsular bag, supporting weak zonules and

recruiting tension from stronger zonules.

This in turn will provide intraoperative support for both preoperative or

intraoperative zonular defects.

And it can also provide long-term postoperative intraocular fixation.

It's also thought to potential lead to less and

more symmetric capsular phimosis or contraction.

So looking back at the history of these rings, back in 1999,

Hara et al published article where they discussed a closed silicone ring,

but this ring did not adapt to various bag sizes.

In 1993, Legler et al published an article where they talked about the first

capsular tension ring that was designed for humans specifically.

This was an open PMMA ring with eyelets on both ends.

And this has since been marketed by Morcher.

And we'll be talking more about that later.

In 1994, Nagamoto and Bissen-Miyajima implanted

an open 12.5mm PMMA ring into a cadaver eye.

In 1998, Cionni and his coworkers

started using modified capsular tension ring which we will discuss later.

In 2002, Dr. Ahmed used a capsular tension segment for the first time.

So what are indications for capsular tension rings.

The most common indications are for zonular issues.

These issues most commonly includes pseudoexfoliation, traumatic zonulysis,

iatrogenic zonular damage often incur during the surgery, Marfan syndrome,

homocystinuria, hypermature cataracts, high myopia, and

post-vitrectomy and/or filtration surgery eyes.

It can also be used if there was significant contralateral postoperative

capsular phimosis to prevent it in the eye that your operating on.

Less common indications include iris defects from things such as aniridia,

intraocular neoplasms that have been excised leading some large defects as well

as congenital lens colobomas.

Other indications that are less common include retinitis pigmentosa,

Weil-Marchesani syndrome, and microspherophakia.

So what are the criteria for implanting capsular tension rings?

First of all, it would be mild zonular instablity as opposed to moderate or

severe zonular instability.

What this means is that you could have less than not more than 4 clock hours of

zonulolysis or mild generalized zonular weakness.

And how this can be ascertained as to whether there is some mild phacodonesis or

shaking of the lens when you examine the eye.

Slight lens movement during the anterior capsulorrhexis creation or

mild anterior capsulorrhexis ovalization during creation of the capsulorrhexis.

So a person who would have good indications for

capsular tension ring placement would be someone with pseudoexofoliaton with a mild

floppy capsular bag.

Contraindications would be like I said moderate or more advanced zonulopathy.

So having more than four o'clock hours of zonular problems and

having a capsular bag that anteriorly radializes or posteriorly tears.

So you need to have an intact capsule.

Because what can happen is the capsular tension ring can provide further extension

or breakage of the capsular bag.

So there are two major design types of the capsular tension rings on

the market currently.

The first one is the one that I've highlighted up here.

It's the Morcher ring also called the Reform Ring and

it is manufactured by Alcon.

It has three different sizes or types.

The first one is a type 14.

This is 12.3mm, and can compresses to 10mm.

And it's basically meant for eyes that have axial lengths < 24mm.

The most common Morcher ring is the type 14C Morcher ring.

It is 13mm, it compresses to 11mm.

And it basically is meant for axial lengths of 24 to 28mm,

which is the majority of the eyes that we operate on.

The third type is a type 14A Morcher ring.

This is 14.5mm, it compresses to 12mm.

And this is more rigid design from myopic guys that have an extra length of > 28mm.

So not used all that frequently.

The second design which has come out more recently is the design that I have up here

which is the Henderson ring.

This is also made by Morcher and

it comes in a single size of 12.29 ring that compresses to 11mm.

So pretty similar to the type 14C Morcher ring that I have listed above.

What they claim is that it has enhanced flexibility and breakage resistance.

And that these eight equally spaced indentations that you see along the edge

of the ring here allow for easier nuclear and cortical material which can sometimes

be difficult when you have to insert a ring at the beginning of a case.

Another ring is the Ophtec ring.

This is made by StabilEyes AMO, and this is a 12mm ring that compresses to 10mm.

And they also have a 13mm ring that compresses to 11mm.

But these don't tend to be used as frequently as the Morcher rings.

So the device size,

how do you decide what is the best ring to put into a person's eye?

This is basically often based on capsular bag dimensions.

Basically, you want a larger ring for a larger capsular bag.

The capsular bag typically positively correlates with both the corneal diameter.

So what you want to do is measure the white to white diameter.

And then that would basically approximate the compressible diameter of the CTR.

And you also want to look at the axial length.

You usually are going to need a larger capsular ring size in more highly myopic

eyes as I described earlier.

It's most effective to have the ring ends to overlap when you're done so

the diameter should exceed that of the capsular bag.

Many surgeons prefer a larger implant.

So the most common ring like I told you before is a 13mm

ring that compresses to 11mm.

Because if the ends do not overlap,

the gap should be opposite the area of zonular dehiscence.

So when is the best time to insert a capsular tension ring?

It really can be in sort of any time during the case.

It can be inserted into the capsular bag or best after a good hydrodissection.

If you have to insert it before phacoemulsification,

the pros would be that you'd have improved nuclear stability for

phacoemulsification during the procedure.

So this is helpful for patients with pseudoexfoliation or

who have known preoperative zonular issues.

However, the cons would be that's more difficult with a mature lens

to have this capsular tension ring, and to remove the nucleus, and

you can have higher risk of further iatrogenic damage during the case.

There's also increased difficulty removing cortical material during the case.

And if the capsular tear were to occur, there is a risk that the ring

could move posteriorly into the vitreous and that would have to be retrieved later.

You can also decide to do it after phacoemulsification.

However, if you think you might need it earlier on the case during

phacoemulsification or cortex removal, there's also an option of putting iris

hooks to support the capsular bag to give you additional support during the surgery.

However, there is a risk of the iris hooks could become dislodged and

then you could subsequently get some additional capsular tears.

But the optimal timing of the insertion is to do it as late as safely possible, and

do it any time there's loss of zonular integrity.

So what is the technique?

Initially, they used to insert this with two hand technique using forceps.

Tying forceps were used to inject the capsular tension ring through the wound

and the second instrument was used to help direct the insertion.

And I will now show you a video that will describe to the more common technique

currently which is the injector technique.

So basically, the video just showed you a depiction of what the technique is, but

now I'll verbally tell you about it.

So there's an injector called the Geuder injector and it's a one hand technique.

Basically, viscoelastic is used to lubricate the ring

when it's placed on the surface of its container.

The injector hook is then used to engage an eyelet at the trailing end of the ring,

then used to withdraw the ring inside the injector.

The injector is then placed to the temporal third corneal incision or

the scleral incision whichever you used, and is aimed into the capsular

bag after viscoelastic has been placed into the capsular bag of safe.

The ring is released slowly under the anterior capsular rim.

And the leading edge should be directed against the quadrant of zonular issues so

that the implantation is to proceed clockwise.

The reason for this is you want to push loose equatorial portions of

the capsular bag against the sulcus during the ring introduction, preventing

further zonular damage and preventing herniation of vitreous into this area.

Once the entire ring is secured inside the capsular bag,

the injector is then rotated 90 degrees clockwise.

And then posteriorly to disengage the eyelet of the trailing edge of the ring,

and then remove from the eye.

A few pearls for insertion of these capsular tension rings.

It's very important to have a good, but gentle hydrodissection.

If you inject for your hydrodissection too vigorously,

you could have further issues in terms of further zonular damage as well as causing

additional issues with the capsular bag.

And this can be done with either balanced salt solution or viscoelastic.

You want to circular complete curvilinear capsulorrhexis.

And you want to aim for one that is a 5 to 5.5mm size.

Again, if there's any defects in the capsular bag whether they be posterior

defects or anterior realizations of your capsulorrhexis,

it's not safe to use a traditional capsular tension ring.

You want to use low settings on your phaco machine.

So low vacuum, low aspiration, and

low irrigation to try to prevent further disruption of the weak zonules.

Chopping is probably one of the better ways to do these cases.

And this avoid excessive zonular stress as well as the excessive spinning sometimes

you acquire with some other techniques.

However, I would recommend that you avoid peripheral chopping initially.

And finally, you want to slow irrigation and aspiration.

You want to strip tangentially towards the area of zonular dehiscence.

Complications I can see.

Intraoperatively.

Again, you can create further zonular damage and

then you have to reassess the situation at that time.

As I mention also, the capsular tension ring can become dislocated.

And if there's insufficient support in the capsular bag or by the zonules,

the capsular tension ring can actually fall into the back of the eye.

One way to prevent this from happening is to place a 10.0 prolene safety suture

through leading eyelet so that it can be retrieve more readily.

Postoperative complications can include subluxation or

dislocation of the capsular tension ring at any time.

And this is a bigger risk when there's more severe or more progressive zonulysis.

So again, it's very important to decide during the case how much zonular

damage there is.

You can also get posterior capsular opacification from these.

But it's actually thought that there might be less opacification that occurs when

using a capsular tension ring.

And finally, some patients are prone to capsular phimosis or contraction.

And there may also be reduced incidence of this compared

to when you don't use a capsular tension ring.

A few other options, there is something called a modified capsular

tension ring which is introduced by Cionni as I discussed earlier.

Basically, this has one to two fixation eyelets as you can see over here on

the side of the ring that you can fixate anterior to the capsulotomy.

And these fixation eyelets are then secured to the sclera and

provide additional support to the capsular tension ring.

So this allows scleral suture fixation of the capsular bag, but

you must have an intact anterior capsulorrhexis and a posterior capsule,

again, to be using these.

There's also something called a capsular tension segment and

that was introduced by Dr. Ahmed as I mentioned earlier.

And for these types of segments, you may have disruption of your capsule.

And this is used for

maximal intraoperative support with scleral fixation.

You can place more than one of these as needed.

Basically, this chart at the end here, compares the different types of capsular

tension, segments, and rings that are available, and tells you what the pros and

cons are to both of them.

So basically, a continuous curvilinear capsulorrhexis is required for

a capsular tension ring and a modified capsular tension ring, but not for

a capsular tension segment.

It's difficult to place a capsular tension ring and

a modified capsular tension ring prior to lens removal, but possible and

easier to place a capsular tension segment just because they're smaller.

The only ones that can be used with anterior capsular tears and

posterior capsular rents are the capsular tension segments.

The capsular tension ring can be used with less than 4 clock

hours of zonular dialysis.

Or as the capsular tension segment and

modify capsular tension ring can be used to > 4 clock hours.

Again similarly, for those cases I have progressed on your zonulysis,

a capsular tension ring should not be used, but

a modified capsular tension ring and capsular tension segment can be used.

These latter two devices can also be used as sclera fixated sclera.

One of the things both the capsular tension ring and

modified capsular tension ring are pretty easy to remove from the eye if necessary

whereas the capsular tension segment is not as easy to remove.

And finally, the capsular tension ring and modified capsular tension ring make

cortical removal a little bit difficult because of the bulkiness of them.

Whereas the capsular tension segment is less bulky and it's there for

easier to remove cortical material.

And this is just some of the references that I used for this presentation.

04.03 - Capsular Tension Rings (13:07)

Introduction to Cataract Surgery

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