Freeing and Removing an IOL

removing an IOL can be tricky.  first you have to free the IOL from its capsular adhesions.  then you have to get it out.  here i will share a few tips on removing IOLs.

freeing the IOL from the capsule.  The ease of IOL removal is mostly dependant on how long the IOL has been in the bag.  IOLs which have been in the bag for a few weeks are very easy to free from the bag.  IOLs that have been in the bag for years can be very hard to remove.  Removing an IOL with an intact posterior capsule is far easier than when the patient has had a YAG capsulotomy. 

the first step is to somehow get a visco dissection plane started between the IOL and the capsule.  I like to use dispersive OVD especially when the posterior capsule is not intact.  with IOLs that have been in place for a while i like to use a 27 gauge needle attached to viscoat and use the sharp end to get under the capsule and then inject the viscoat. then i will sometimes use the Duet micro forceps (as shown in the video) to lift the capsule to get a canula under for more viscodissection.  I also like to use a flat hydrodissction cannula for visco dissection as the flat surface makes it easier to get between the capsule and the IOL.  most of your attention should be directed to freeing up the haptics with viscodissection.  If the posterior capsule is intact the viscoat will often track around the optic and free it from it posterior attachments. after the capsular adhesions are freed try to spin the IOL clockwise to allow the haptics to spin free.  sometimes the haptics are just too stuck and must be cut to free separately or are even left in the bag.




removing the IOL can be done through a small incision (refolding or cutting) or by extending the incision to the size of the optic.

The high index of refraction acrylic IOLs (eg. MA60, SA 60) can be refolded within the eye either using the folding forceps or the henderson technique.   The standard refolding technique uses a paracentesis across from the main wound (3.5 mm) to introduce a spatula to place under the optic while using an open IOL insertion forcep above the optic in the anterior chamber.  while lifting with the spatula and coming down on top of the optic with the open insertion forceps the IOL can be folded inthe anterior capsule.  once folded  the optic is simply removed through a 3.5 mm or so wound   please use lots of OVD during this process.  refolding the IOL only works well with thin acrylic IOLs likem the SNWF, SA60, MA60 and in my hands is virtually impossible with thick acrylic IOLs like the AR40 and the slippery IOLs like the silcon three piece IOLs.   see video of refolding. 




The henderson (bonnie henderson boston ma) technique for folding soft IOLs such as the IQ single piece acrylic is very slick.   dr henderson's technique is to simply pull on an externalized haptic (with 0.12 or similar toothed forcep) while pushing on the optic 180 degrees across from the wound (inside the eye) with a hook (eg. Kuglen) amazingly the IOL folds itself and pops out of the eye.   see video. 



There a few ways to cut an IOL to get the optic small enough to remove through a small incision.   One classic technique is to only cut about 2/3 through the IOL and make what looks like a Pac Man and rotate the IOL out through the wound as shown in the video.


You can also cut the IOL completely in half or into thirds and bring out the pieces.  i like to use the Osher mildly serrated cutter from Duckworth and Kent as shown in this video.  you can usually keep the IOL from flopping around too much by holding the externalized haptic with this cutter.    if you are in a bind you can even use Vanna scissors to cut the IOL.



i also think the Duet forceps and IOL cutters can be handy to cut IOLs and haptics.  you can use the Duet forceps through a paracedntesis to stop the IOL from flopping about and hitting the cornea.  both the cutter and the forceps can pass through a paracentesis.  here the Duet system forcep is used to hold an IOL while cutting in the video.

Iris Prolapse

Iris prolapse can create problems during surgery and can lead to iris damage which can be dysfunctional.

Iris prolapse typically comes from a wound which is too short or from an iris which is floppy and/or poorly dilated.  The actual prolapse of the iris usually occurs during hydrodissection and can create transillumination defects, loss of iris tissue, iridodialysis, and hyphema.   It is important for eye surgeons to know how to preserve the iris when prolapse occurs and i suppose, more importantly, to prevent it from occuring in the first place.


     

Wound too short.  When the wound is too short one of the best options to prevent iris prolapse is to simply close the short wound and move to another site.  Often however moving to another site is difficult as the brow, a bleb, or the surgeons handedness get in the way of this solution.   A nice simple solution is to place a single iris hook under the incision to pull the iris under the incision preventing prolapse.  If the pupil is also small it can be useful to place 4 hooks in a diamond configuration with one hook under the wound to both prevent iris prolapse and to open the small pupil.  Iris rings such as the Malyugin ring can be used also but if the wound is very short the iris can still prolapse with the ring. 

Floppy iris.  When the patient is at risk for a floppy iris (intraoperative floppy iris syndrome) from an alpha blocker (especially Flomax or tamsulosin) or some other cause (eg ischemia ) it may be best to prevent iris prolapse with iris hooks or a Malyugin ring especially if the pupil is small.  The most common time for iris prolapse is during hydrodissection when the fluid wave passes around the lens and out the eye taking the iris out too.  Excessive and especially dispersive viscoelastic can make hydrodissection more risky for iris prolapse.  I like to remove viscoelastic above the lens prior to hydrodissection to help prevent this complication.   Gentle rocking of the lens will help to release trapped fluid behind the lens which will lower the pressure and deepen the anterior chamber.

Repositing the iris.  When iris prolapse occurs the emphasis should be on preserving the iris and preventing further prolapse.  The first step following prolapse is to use the paracentesis to remove fluid pressure from within in the eye which is pushing the iris out.  Then using a viscoelastic cannula gently reposit the iris.  After the iris is back into position consider placing an iris hook under the wound to keep the iris from further prolapse.   below you will find a video showing these techniques  Rarely, iris prolapse willl occur when you face posterior pressure from a choroidal hemorrhage, choroidal effusion, or misdirection of aqueous.

References:

Chang DF, Braga-Mele R, Mamalis N, Masket S, Miller KM, Nichamin LD, Packard
RB, Packer M; ASCRS Cataract Clinical Committee. ASCRS White Paper: clinical
review of intraoperative floppy-iris syndrome. J Cataract Refract Surg. 2008
Dec;34(12):2153-62. 

Chang DF. Use of Malyugin pupil expansion device for intraoperative
floppy-iris syndrome: results in 30 consecutive cases. J Cataract Refract Surg.
2008 May;34(5):835-41.

Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with
tamsulosin. J Cataract Refract Surg. 2005 Apr;31(4):664-73.

converting to ECCE

Conversion to ECCE often comes at a difficult time. The lens is about to fall south, the vitreous has prolapsed and the surgeon is stressed. 

Understanding the steps and process of conversion to ECCE is essential and study before the crisis will help soothe the stress when this inevitable process occurs. We will cover several areas: identifying patients at risk for the need for conversion to ECCE, indications for conversion, conversion from topical to sub-tenon’s, wound preparation, expressing the lens material, closure of the wound, placement of the IOL, post operative issues and a brief section on anterior vitrectomy. For more detailed instructions please refer to: http://webeye.ophth.uiowa.edu/eyeforum/tutorials/Cataract-ECCE/Cataract-Surgery-Complex-Conversion-Extracaps-ECCE.htm

One of the most important parts of the pre-operative process for cataract patients is to assess the difficulty factors that may lead to conversion to ECCE or otherwise complicate the procedure. You may want to add operative time to your schedule or ask for additional equipment. You may want to change to a superior limbal wound which facilitates conversion to an ECCE rather than a temporal clear corneal incision. You may want to do a retrobulbar block rather than topical anesthesia as the case may last longer or is more likely to become complicated. Or you may want someone more experienced to do the case. for more detail on dkifficulty factors please see: http://www.medrounds.org/cataract-surgery-greenhorns/2005/09/chapter-1-assessment-difficulty.html

Conversion to ECCE is indicated when phacoemulsification is failing. Sometimes this is due to a very hard lens which does not submit to ultrasound or a lens that is hard enough that the surgeon is concerned that the required ultrasound energy will harm a tentative cornea, e.g. Fuchs’ endothelial dystrophy or posterior polymorphous dystrophy (PPMD). Sometimes one will convert to ECCE when an errant capsulorhexis goes radial especially with a hard crystalline lens when the surgeon is concerned that the risk of dropping the lens is too great with continued phacoemulsification. Rarely now with Trypan Blue dye, a surgeon will choose to convert to ECCE when the anterior capsule is hard to see and capsulorhexis must be completed with the can opener technique. More often the conversion is indicated when the crystalline lens is loose from weak zonules or a posterior capsule tear which make phacoemulsification less safe than extending the wound and removing the residual lens material. Indications for conversion to ECCE include: Hard crystalline lens or unstable endothelium, Radial tear in anterior capsule with hard lens, Poor visualization despite Trypan dye,

Posterior capsular tear, and Zonular dialysis.

Converting to subtenon’s anesthesia. Often we convert cases from topical clear corneal to ECCE. While the ECCE can be done under topical it is usually more comfortable and safer to give additional anesthetic which is typically a sub tenon’s injection of bupivicaine and lidocaine. This will provide some akinesia and additional anesthesia. There is usually subconjunctival hemorrhage and if the injection is made too anterior it can cause chemoisis and ballooning of the conjunctiva. The steps of the sub tenon’s injection are shown in the video below(1):

A major decision step when converting to ECCE is to either extend the existing wound or close and make another. The ECCE will require a large incision of from 9-12 mm which is closed with suture. The decision to extend the existing wound or make a new wound hinges on several factors: location of the original wound, size of the brow, past surgical history, and possible need for future surgery.

Making a new incision during conversion is identical to that for a planned ECCE. The original incision is closed with a 10-O nylon suture. The surgeon and microscope are rotated as the surgeon should sit superior. The steps to make a new superior incision are:

• Conjunctival peritomy of about 170 degrees
• Use 64 or crescent blade to make limbal groove with a chord length of 11mm
• Bipolar cautery for hemostasis
• Use keratome to make initial incision starting in groove into AC
• Extend initial incision to full length of groove (with scissors or knife)
• Safety sutures are preplaced usually 7-O vicryl

Extending an existing incision can be tricky and the technique is different for scleral tunnels compared to clear corneal incisions. However in both cases the original extension is brought to the limbus. In the case of an original scleral incision the incision is brought anterior to join the limbus on either end before extending along the limbus for a chordlength of about 11mm. In the case of an existing corneal incision the corneal incision is brought posterior toward the limbus before extending the wound along the limbus for a chord length of about 11mm. When iris hooks are being used in a diamond configuration the wound can be extended to preserve the sub-incisional hook and the large pupil(2). The steps include:

• Conjunctival peritomy of about 170 degrees,
• Use 64 or crescent blade on either side of the existing wound to make a limbal groove with a chord length of 11mm
• Bipolar cautery for hemostasis
• Use Crescent to bring existing scleral wound anterior or existing corneal wound posterior to join limbus
• Extend initial incision to full length of groove (with scissors or knife)
• Safety sutures are preplaced usually 7-O vicryl.

One has to be far more careful when removing the nucleus during the typical conversion to ECCE which comes along with vitreous loss. First the anterior capsule must be large enough to allow the nucleus to express which may require relaxing incisions in some cases. When the zonules are weak or the posterior capsule is torn the lens cannot be expressed with fluid or external pressure as is often done with a planned ECCE with intact capsule/zonlules. After any vitreous is removed, the lens must be carefully looped out of the anterior chamber with minimal pressure on the globe. If the posterior capsule and zonlues are in tact than the lens can be expressed as described with a planned ECCE.

Placement of the IOL IOL selection with ECCE conversion depends on the residual capsular complex(3,4). The key to IOL centration is to get both of the haptics in the same place: either both in the bag or both in the sulcus.

When the posterior capsule is intact following a conversion to ECCE the anterior capsular opening is usually poorly defined which can make bag placement difficult. If the anterior capsule and thus the bag is well defined, then place a single piece acrylic IOL without folding it directly and gently into the bag using kelman forceps.

When the posterior capsule is intact and the anterior capsule is poorly defined then place a 3 piece IOL in the sulcus such as a large silicone IOL or the MA50 acrylic by placing these directly and unfolded into the sulcus with kelman forceps. Make sure that both haptics are in the sulcus.

When the posterior capsule is damaged, if enough anterior capsule and posterior capsule is left to support the IOL, define the sulcus with viscoat and place the IOL directly in the sulcus. Make sure both haptics are in the sulcus. If the IOL does not seem stable then place McCannel sutures to secure the IOL to the iris or remove and replace with an AC IOL (don’t forget to place a PI with vitrector).

When the capsule is severly damaged and cannot support an IOL then place the IOL in the anterior chamber. Use kelman forceps to place the IOL, then secure the chamber, and use a sinsky hook to place the AC IOL into its final position. (don’t forget to place a PI with vitrector).

Postoperative care for patients following conversion from phaco to ECCE is a bit more complicated and focuses on preventing cyctoid macular edema and limiting induced astigmatism. Often the care is very similar to that of a planned ECCE with about 3 post operative visits one the same day or next, one a week later, and one about 5-6 weeks later. Depending on the amount of astigmatism the patient may require several visits to sequentially remove sutures to eliminate induced astigmatism.

References

1. Oetting, TA, Cataract Surgery for Greenhorns, Available at http://medrounds.org/cataract-surgery-greenhorns.%20accessed%20September%209, 2007

2. Dupps WJ Oetting TA, Diamond iris retractor configuration for small-pupil extracapsular or intracapsular cataract surgery. J Cataract Refract Surg Vol 30(12):2473-2475

3. Chang DF, Oetting TA, Kim T, Curbside Consultations in Anterior Segment Surgery, Slack Inc, Thorofare NJ, 2007

4. Henderson BA, Essentials of Cataract Surgery, Slack Inc, Thorofare NJ, 2007

Pearls for Small Pupils

I use three techniques to manage small pupils:  stretching, iris hooks, and the Malyugin ring.

Pupil stretching used to be one of the main ways that I would force mydriasis.  This is really a good technique if you have posterior synechiae or if the patient has been on Pilocarpine chronically.  However, more and more I am avoiding using pupil stretching techniques because it is contraindicated in patients that are on Flomax (or other alpha blockers) as it can lead to even more problems with iris prolapse.  Compounding this problem is the reality that so often patients cannot remember having been on Flomax (or their other medications).  Because my practice is concentrated at our VA Hospital here in Iowa City, I have a lot of patients who have been on either Flomax or junior varsity versions of this alpha blocker in the past (Hytrin, Cardura, saw palmetto…) and so if they have a small pupil I just assume that have had Flomax.  I also think pupil stretching should be avoided in patients with shallow chambers, as there is a tendency for iris prolapse in those patients as well.  

The technique that I use for pupil stretching is to use two Kuglen hooks -- one through the paracentesis and the other through the main wound.  The hook through the paracentesis grabs the pupil and pulls it towards the paracentesis and then the other hook pushes 180 degrees across from the paracentesis to stretch the pupil.  The stretch is held for a few seconds and it is not uncommon that you will notice some hemorrhage along the pupil.  This is a good thing as it shows that there has been some change in the pupillary sphincter.  Following stretching of the pupil, you need to use a dispersive viscoelastic which is highly viscous to help push the pupil open.  There is really only one highly cohesive dispersing viscoelastic for me -- Viscoat; although others, such as Healon D and Vitrax, may be available in your area.  I like to place the Viscoat in a circular pattern, around and around, to gently push the pupil out.  You often find that at first you didn’t think there was much effect from the pupil stretch, and then after adding the Viscoat in this fashion, you gain enough mydriasis to safely proceed with surgery.    

I will also caution you that during hydrodissection, the fluid wave can catch the dispersive viscoelastic, pulling the iris with it out of the eye, producing prolapse of the iris.  As such, I recommend that you remove the viscoelastic over the lens, before hydrodissection, either using the automated irrigation/aspiration unit or use a syringe with BSS to wash out some Viscoat.  This will reduce the likelihood of iris prolapse during hydrodissection.  However, you just need to be careful during hydrodissection to avoid iris prolapse. 

Iris hooks are a great technique for the small pupil and I use them often, although I don’t use them as often as I used to as I am transitioning some to the Malyugin ring, which I will discuss below.  Iris hooks are great for shallow chambers, they are great for complex cases where you might have to convert to a large incision extracapsular procedure or if you have to use complicated suturing of IOLs or Cionni rings during the case which would make an internal device such as a Malyugin ring more difficult.  I usually avoid iris hooks if there is a bleb present, because it is sometimes hard to work around the bleb and you have to be very careful not to damage the bleb.  They are also harder when there are narrow lid fissures because the hooks get in the way of the lids, and so I tend to avoid them in that situation.  

The way I like to use iris hooks, I described in a paper with Louis Omphroy.¹ In this technique, we use a diamond configuration of the hooks such that there is one hook under the main incision, one across, and then one hook 90 degrees to either side of the wound.  This creates, relative to the incision, a diamond configuration of the iris.  I like to use a 27 gauge needle, a Grieshaber knife, or a 75 blade to make the four paracenteses for the iris hooks.  You want to make these as posterior as possible and you want to make them short and angled slightly down, such that the hook, when it is placed in the eye, is aimed towards the iris.  I like to place the hooks before I add viscoelastic so that the chamber is not so deep that it makes it very difficult to grab a hold of the iris.  After placing the hooks, then I add viscoelastic and make the incision just anterior to one of the hooks.  I tend to use a Kelman McPherson and a straight tie to place the hooks as shown in the video below.

I like the Malyugin ring and use it most of the time now for small pupils.  The Malyugin ring comes in two sizes; one with an internal diameter of 6.2 mm and the other with an internal diameter of about 7 mm.  The Malyugin ring is great in patients that are on alpha blockers such as Flomax².  It is great in patients that have narrow lid fissures because it does not involve any external manipulation to the eye and so you don’t have to have proptosis or great exposure.  I would recommend avoiding the Malyugin ring if you think you are going to convert to an extracap as this is very difficult with the ring as opposed to being relatively easy when using iris hooks.  I would avoid the Malyugin ring when using other intraocular hardware such as Cionni rings or suturing inside the eye, as the Malyugin ring can get in the way (relative to iris hooks) when doing these complex procedures.   

The Malyugin ring is placed with a special inserter into the eye and the leading eyelet is engaged onto the iris and then one toes down a bit as the ring is pushed further in, trying to engage the lateral eyelets as well.  Very often, only one of the two lateral eyelets is also engaged in the initial insertion process.  The trailing eyelet often is very difficult to disengage from the inserter without introducing a hook through the paracentesis to push the ring slightly to the side to allow the inserter to exit the eye.  I tend to use a Kuglen hook to subsequently place the eyelets that were not initially engaged with the inserter; a Lester hook can also be used or Sinskey hook.  

Retraction of the Malyugin ring is probably the trickiest thing.  You want to first disengage the leading eyelet which is across from the wound and then you want to disengage the leading eyelet and T it up slightly to the side and anterior.  Use plenty of viscoelastic so that you don’t engage the IOL during this process and that so that the cornea is safe.  The inserter is then placed in the eye slightly to the side of the eyelet, but over the ring, and then is turned such that the hook is over the entire eyelet and then pulled back and engaged onto the eyelet and pulled back into the inserter.  It is most important that you not completely retract the ring into the inserter, as funny things happen when you do this.  As shown in the video below, odd things will happen if you try to totally retract the ring, so just pull it back so that it is just thin enough to come back through the wound and pull it out of the eye. 

There are two choices for the Malyugin ring; one which is 6.2 mm in internal diameter which is useful for most cases, but if the pupil starts off big or if you are going to use a particularly large IOL, then I would recommend using the 7.0 mm Malyugin ring.  We tend to stock both in the operating room here, and use the smallest ring that you can to get the job done.  The advantage of the smaller ring is that it is easier to insert and easier to retract, and the advantage of the larger ring is that you can use it when the pupil starts off bigger.  

 

References: 

1.  Oetting TA, Omphroy LC.  Modified technique using flexible iris retractors in clear corneal cataract surgery, Cataract Refract Surg 2002;28(4):596-8.

2.  Chang DF.  Use of Malyugin pupil expansion device for intraoperative floppy-iris syndrome: results in 30 consecutive cases, Cataract Refract Surg 2008;34(5)835-41.