Conversion to extra-capsular cataract extraction (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.

Patients at risk for conversion to ECCE: One of the most important parts of the pre-operative process for cataract patients is to assess the factors increasing surgical difficulty 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. In some situations, the pre-operative risk factors make you consider inviting someone more experienced to do the case.

Difficulty Factors (in decreasing order of importance)¹

• Zonular Laxity (pseudoexfoliation-PXF, history of trauma, Marfan’s syndrome, etc.)
• Rock hard lens (red or black lens)
• Pupil size (why is it small? PXF, diabetes s/p laser, central posterior synechiae - CPS, floppy from tamsulosin/Flomax)
• Cannot lay flat for very long (eg. chronic obstructive pulmonary disease - COPD, claustrophobia, tremor, severe obesity)
• Big brow limiting superior access
• Narrow angle limiting anterior chamber (AC) space
• Predisposition to corneal decompensation: (e.g. Fuch's dystrophy or corneal guttata, PPMD, hard nucleus)
• Poor red reflex white/black cataract making continuous curvilinear capsulorhexis (CCC) difficult
• Past surgery such as existing trab or past pars plana vitrectomy (PPVx)
• Predisposition to exposure: eg: botox, past lid trauma, diabetes mellitus (DM)
• Anticoagulants (e.g., warfarin/Coumadin, asparin)
• Monocular patient

Table 1: Difficulty Factors

Factor	Time	Equipment/Anesthesia
Zonular Laxity	Double	Iris retractors available to hold capsule Capsular Tension Ring (CTR) Ready for sutured IOL Ready for ICCE (e.g., Cryo) Consider retrobulbar block (RB) Consider sup. limbal wound
Rock Hard Lens	Add 50%	Consider planned ECCE Consider sup. limbal wound w/ PE Consider RB
Small Pupil	Add 50%	Stretch pupil (only if no Flomax) Consider iris retractors Consider RB
Flomax	Add 50%	Strongly consdier iris retractors Consider single iris retractor Consider RB
Poor Red Reflex	Add 50%	Trypan blue stain Consider RB Consider sup. limbal wound
Big Brow	Add 25%	Consider sup/inf. bridal sutures Consider RB to give proptosis
Narrow Angle	Add 25%	May need iris hooks for prolapse Consider smaller phaco tip Frequent dispersive ocular viscoelastic device (OVD)
Predisposition to corneal decompensation	0%	Use BSS+; phaco chop Arshinoff shell w/ OVD Consider conversion to ECCE
Existing Trabeculectomy bleb	0%	Avoid fixation ring Avoid conj. manipulation Always suture wound
Prior vitrectomy (PPVx)	0%	Possible CTR Use caution during I/A
Cannot lay flat	0%	Consider general anesthesia (or at least MAC)
Anticoagulant use	0%	Use topical anesthesia (avoid injection risks)
Monocular patient	0%	Use topical anesthesia for faster rehabiliation Try to forget about the monocular status (minimize anxiety)
(modified from Oetting, Cataract Surgery for Greenhorns, http://medrounds.org/cataract-surgery-greenhorns)

Indications for conversion: 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. A surgeon may choose to convert to ECCE when the anterior capsule is hard to see and capsulorhexis must be completed with the can opener technique (however, with the use of Trypan Blue stain this is less commonly indicated). 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
• Zonular dialysis

Converting to sub-Tenon’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 outlined below:¹

• Prepare 3cc syringe with equal parts of 2% lidocaine/0.75% bupivacaine
• Place lacrimal canula (or Masket canula) with gentle curve to approximate that of the globe
• Pick a quadrant for the block (best to go for a lateral quadrant to avoid oblique muscles)
• Have the patient look away from the chosen quadrant to increase exposure
• Use .12 forceps to retract conjuctiva
• Make small incision down to sclera with Wescott scissors
• Redirect Wescott scissors with curve down and bluntly dissect through quadrant
• Dissect past the equator (similar to using Stevens tenotomy scissors in peds/retina)
• Use .12 Forceps for counter traction
• Place canula through incision and direct past the equator before injecting
• The local anesthetic should flow easily and cause little chemosis -- If not, redissect with the Wescott scissors to get more posterior
• Use 2-3 cc of the local mixture

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 7-0 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

• 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 blade 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 7-0 Vicryl)

Removing the lens: 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 (see below), the lens must be carefully looped out of the anterior chamber with minimal pressure on the globe. If the posterior capsule and zonlues are intact then the lens can be expressed as described with a planned ECCE.

Removing lens with intact capsule complex:

• Mobilize the lens (physically with cystotome or with hydrodissection--be careful)
• Lens removed w/ lens loop or w/ counter-pressure technique
• Wound is closed with safety sutures and additional central Vicryl suture
• Cortical material is removed using I/A device (either automated or manual)
• Instill ophthalmic viscoelastic device (OVD)
• Lens is placed in the posterior chamber
• Wound is closed with 10-O nylon and Vicryl sutures are removed.
• OVD is removed

Removing lens with vitreous present:

• Mobilize lens with Viscoat canulla (tip lens so that wound side is anterior)
• Slip lens loop under lens, "toe up" the instrument, remove lens
• Wound is closed with safety sutures and additional central vicryl suture
• Anterior vitrectomy (see below)
• Cortical material is removed using dry technique or anterior vitrector
• Instill ophthalmic viscoelastic device (OVD)
• Lens is placed in the sulcus or in the anterior chanber
• Wound is closed with 10-O nylon and Vicryl sutures are removed
• OVD is removed

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 posterior iridectomy with the 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 Sinskey hook to place the AC IOL into its final position. (don’t forget to place a peripheral iridectomy with the vitrector).

Post-operative issues: Post-operative care for patients following conversion from phaco to ECCE is a bit more complicated and focuses on preventing cystoid macular edema (CME) 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 or next day, 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 while eliminating induced astigmatism.

First post-operative visit: This visit is often on the same afternoon (4-6 hours following surgery) or the next morning with the primary emphasis to check the IOP, look for wound leaks, and scan for residual lens material or vitreous in the anterior chamber. Certainly most wound leaks should be sutured, but if the AC is not formed closing these is mandatory. Residual nuclear material should be removed in the next few days if present but residual cortical material will often dissolve away with little inflammation. You would expect poor vision in the 20/200 range due to astigmatism and edema. The anterior chamber should be formed and typically has moderate cell (10-20 cells/hpf with 0.2 mm beam). If the IOP is less than 10 mmHg, search carefully with a high index of suspicion for a leak using Seidel testing. If the IOP is in the 10-29 range, then everything is probably okay unless the patient is a vasculopath, in which case your upper limit of IOP tolerance should be lowered. If the IOP is in the 30-39 range consider aqueous suppression. If the IOP is >40 than consider aqueous suppression and "burping" or "bleeding down" the IOP through the paracentesis or an anterior chamber tap. The IOP should be rechecked 60-90 minutes later to ensure success with your treatment. Look at the fundus to rule out retinal detachment (RD) and choroidal effusion or hemorrhage. Typically patients are placed on prednisolone acetate 1% 1 drop 4 times a day (QID), cyclogyl 1% 1 drop 2 times a day (BID), and an antibiotic 1 drop QID for the next week.

Week 1 post-operative visit: The vision and pressure should dramatically improve in patients over the next week after a case that was converted to ECCE. The vision should be in the 20/100 range with pinhole improvement to around 20/50. The vision is usually limited by residual edema and astigmatism. In a study of our ECCE cases, we found about 7.0 diopters of cylinder at the one week visit. You should expect very little inflammation and document that no RD exists. Search for residual lens material in the anterior segment and posterior pole. You can discontinue the cyclogyl and the antibiotic. Slowly taper the prednisolone acetate (e.g., 1 gtt QID for 7 more days, then 1 gtt three times a day [TID] for 7 days, then 1 gtt BID for 7 days, then 1 gtt QD for 7 days), then discontinue. If the patient is at risk for cystoid macular edema (CME), as is possible with vitreous loss, then you should keep on prednisolone at the higher frequency (e.g., QID) and start a non steroidal (like topical ketorolac or equivalent 1 gtt QID) until the next visit 4 -6 weeks later.

Week 5 post-operative visit: The vision should continue to improve as the astigmatism settles and the cornea clears further. The eye should be comfortable. The vision should be in the 20/80 range, improving to 20/40 with pinhole. In our study the astigmatism induced by ECCE sutures was about 5.0 diopters at the incision. The anterior segment should be quiet and the IOP normal (unless the patient is a "steroid responder"). Consider CME as a possibility in patients where conversion was required as these cases are often long and can involve vitreous loss. Evaluate as clinically indicated by exam or history with optical coherence tomography (OCT) or flourescein angiography (FFA).

By this point in the recovery, the main issue is astigmatic control with suture removal. Use keratometry, refraction, streak retinoscopy, or topography to guide your suture removal. If the keratometry is 45.00 @ 90, and 40.00 @ 180, then look for tight sutures at around 90 degrees (12 o'clock) that are causing 5 diopters of cylinder. You can take only one suture at 5 weeks, but by the 8 week evaluation, you could consider 2 sutures removed at a time. The plan is to remove a suture and see how the cornea settles. When the astigmatism is less than about 1.0 to 1.5 diopters you should stop suture removal and correct any residual astigmatism with refraction. Use antibiotic drops prophylactically for a few days after each suture removal. After this visit you should consider the following choices with each visit (don’t waste too much time thinking about other possibilities and remember not everybody is going to be 20/20):

1. pull a stitch (i.e. cylinder at axis of stitch is greater than 1.0 to 1.5 diopters on manifest refraction [MRx])
2. give glasses (i.e. no stitch to pull or cylinder is less than 1 on MR)
3. get FFA or OCT because you suspect CME

Anterior Vitrectomy. Converting to ECCE is almost always accompanied by vitreous. Sometimes the conversion comes when the lens is too hard and the capsule is intact but most often it seems conversion comes when the zonules or capsule releases the vitreous into the reluctant hands of the anterior segment surgeon. We will cover the causes and signs of vitreous prolapse and the principals of anterior vitrectomy in various situations.

Causes of vitreous prolapse. The vitreous either comes around the zonules or through a tear in the posterior capsule. Posterior capsular tears are caused commonly by 1) anterior tear extending posteriorly – most common, 2) posterior tear – secondary to phaco needle or chopper being too deep, 3) during manipulation with the I/A instrument, or 4) a pre-existing injury (e.g., posterior polar cataract, iatrogenic from PPVx, or from penetrating lens trauma). Zonular problems are often pre-existing (e.g., from trauma, PXF, or Marfan’s syndrome) but can also be iatrogenic from forceful rotation of the lens or pulling on the capsule during I/A.

Signs of vitreous prolapse. Thefirst sign of vitreous prolapse is denial. Something seems wrong but you can’t quite pin point the issue. At first you deny that an issue exists but soon it becomes clear. More tell-tale signs of vitreous prolapse include 1) deepening of the chamber, 2) widening of the pupil, 3) lens material no longer centered, 4) lens particles no longer come to phaco or I/A, and 5) the lens no longer rotates freely. When you suspect vitreous prolapse you should place dispersive OVD into the eye before removing the phaco needle or I/A and can check the wound with a Weck-Cel (or similar arrow sponge) for vitreous.

Basic Principles of anterior vitrectomy. The key to a successful anterior vitrectomy is to control the fluidics of the eye. The first step is to close the chamber. This is often hard when you have converted to an ECCE as the wound is large. However you must close the wound so that the only exit point for fluid is the aspiration/cutting device. Separate the irrigation device from the aspiration/cutting device so that you can create a pressure differential such that the vitreous is encouraged to go to the aspiration/cutter. The final important point is to cut low and irrigate high. If you can place the irrigation device in the anterior chamber above the aspiration/cutter down near the plane of the posterior capsule than the vitreous will leave the anterior chamber.

Close the chamber Separate the irrigation and cutter Cut low - Irrigate high

In general the bottle height should be low – just high enough to keep the AC formed and not so high to push fluid and possibly vitreous out from the eye. The cutting rate should be as high as possible when cutting vitreous and low when cutting cortical lens material. We will separately discuss early-, mid-, and late-case vitreous loss below.  

Vitreous Presenting early in case –while most of crystalline lens is in eye: This is the worst time for vitreous to prolapse and one should strongly consider converting to ECCE. The steps to consider are outlined below:¹

• If topical do sub-Tenons injection (as described above)
• Consider closing the temporal incision with 10-0 and make separate incision with peritomy superiorly especially (as discussed above)
• Use dispersive viscoelastic to lift lens up near the wound and to displace vitreous more posterior.
• May need Weck-Cel vitrectomy to clean up if the vitreous is very prolapsed
• Use lens loop to remove lens (as described above)
• Have Wescott scissors ready when looping out lens to cut vitreous
• Close with 3 each of 7-0 Vicryl safety sutures (one at center and one on either side 3 mm away, allowing for removal of center suture to place 6 mm IOL)
• May need to add some 10-0 nylon at wound edges to be sure it is watertight
• Anterior vitrectomy (as discussed above separate asp/cutter from irrigator)
• Dry removal of residual cortical material with syringe on 27 gauge cannula
• Use J-cannula or paracentesis if needed for sub-incisional material
• Consider staining with Kenalog (see below)
• Place IOL if possible in sulcus (adjust power) or use an AC IOL (don’t forget peripheral iridotomy)
• Miochol to bring pupil down—seats sulcus IOL, peaked pupil helps to detect vitreous

Vitreous Presenting mid case – while removing cortical material: This seems to be the most common time for vitreous loss. Often one will get the posterior capsule just as the last nuclear fragment is taken. Of course there is no reason to convert to ECCE in this case. The following steps are useful:¹

• Place viscoat in area of tear or dialysis before removing instruments
• Make separate 1 or 1.5 mm incision for anterior vitrectomy
• Separate irrigation (through paracentesis) and asp/cutter (through larger paracenetesis)
• May need to suture original wound to keep chamber formed
• Irrigate high and cut/suck low – creates a pressure gradient to push the vitreous back
• Settings low vacuum 100 range, low bottle height 50 range, max cut rate
• Try to get some of the residual cortical material
• Dry removal of residual cortical material with syringe on 27 gauge cannula
• Use J-cannula or paracentesis if needed for subincisional material
• Consider staining with kenalog (see below)
• Place IOL if possible in sulcus or AC (if AC don’t forget peripheral iridotomy)
• Miochol to bring pupil down

How to deal with Vitreous Presenting late in the case – while placing IOL: This is the least problematic and least common time to loose vitreous. The main issue is to make sure the IOL is stable while attending to the vitreous and then to secure a proper IOL in either the AC, sulcus, or bag:¹

• Place viscoat in area of tear or dialysis before removing instruments
• Make separate 1 or 1.5 mm incision for anterior vitrectomy
• Separate irrigation (through paracentesis) and asp/cutter (through larger paracenetesis)
• May need to suture original wound to keep chamber formed
• Irrigate high and cut/suck low – creates a pressure gradient to push the V back
• Settings low vacuum 100 range, low bottle height 50 range, max cut rate
• If the sulcus can support an IOL, then
  • Move existing 3-piece IOL into sulcus
  • Replace an existing single-piece IOL with-3 piece IOL in the sulcus
  • Consider anterior capsule capture of optic if CCC is round and centered
• If the tear in the posterior capsule is round and secure
  • Place viscoat in hole
  • Gently place single piece IOL into the bag (be very careful with 3-piece lens in bag)
• Miochol to bring pupil down

Staining the Vitreous with Kenalog: Scott Burk at Cincinatti Eye described using Kenalog off-label to stain vitreous that had prolapsed into the anterior chamber⁵ link to Facebook video. As Kenalog is not approved by the FDA for this indication and as some retnal surgeons have had sterile (and even infectious) endophthalmitis from using Kenalog, its use is controversial. However it is a very useful adjunct to anterior vitrectomy. The method for mixing the triamcinolone (Kenalog) to dilute 10:1 and to wash off the preservative follows:

• TB syringe to withdrawn 0.2 ml of well shaken triamcinolone (40mg/ml)
• Remove the needle and replace with a 5 (or 22) micron syringe filter (Sherwood Medical)
• Force the suspension through the filter and discard the preservative filled vehicle
• The Kenalog will be trapped on the syringe side of the filter
• Transfer the filter to a 5 ml syringe filled with balanced salt solution (BSS)
• Gently force the BSS through the filter to further rinse out preservative
• Repeat rinsing a few times
• Place a 22 gauge needle on the distal end of the filter
• Draw 2 ml of BSS into the syringe through the filter to resuspend the Kenalog
• The Kenalog (now without preservative and dilute 10:1) will stain vitreous strands white

References

1. Oetting, TA, Cataract Surgery for Greenhorns, Available at http://medrounds.org/cataract-surgery-greenhorns. accessed September 9, 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.
5. Burk SE, Da Mata AP, Snyder ME, Schneider S, Osher RH, Cionni RJ. Visualizing vitreous using Kenalog suspension J Cataract Refract Surg. 2003 Apr;29(4):645-51.