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Cataract Surgery | Feb 2013

Is IOL Explantation Necessary?

A series of case studies and recommendations.

IOL Explantation: Time for a New View and a New Name?

By Charles Claoué, MA(Cantab), MD, DO, FRCS, FRCOphth, FEBO, MAEM
I consider the term IOL explantation an acceptance of the pre-Ridley era truism that ophthalmologists remove foreign bodies but do not implant them. The word explantation implies that an unexpected catastrophe has occurred, and that the Irish dictum, “to get there, I would not start from here,” applies. This word has acquired pejorative overtones in ophthalmic usage; so has time come for change?

Polypseudophakia—more than one IOL in an eye—has been an accepted practice for about 20 years. Initially used for extreme refractive errors when a single IOL could not provide enough optical power, the technique can also be used to correct refractive surprises. However, surgeons found that implanting a standard IOL in a different anatomic position than intended for the lens design caused complications such as pigment dispersion, glaucoma, hyperopic defocus from the contact area when two biconvex IOLs were used, and pupil capture. Today in Europe, three companies manufacture supplementary IOLs with platforms specifically designed for sulcus placement. I do not believe that the term piggyback should be used for these IOLs, as these platforms are different from the older generation of piggyback IOLs; the term duet procedure is preferred.

CASE REPORT

Mrs. N is the 52-year-old wife of a patient who was delighted by the correction of his preoperative moderate myopia after bilateral cataract surgery. She presented requesting bilateral refractive lensectomy. A lifelong gaspermeable contact lens wearer, Mrs. N’s BCVA was 20/40 with a manifest refraction of +13.25 -0.75 X 70 in her right eye and 20/32 with +13.00 -1.00 X 90 in her left.

After 6 weeks of contact lens abstinence, axial length in her right and left eyes was 16.60 and 16.71 mm, respectively. Use of multiple second- and third-generation biometry formulas and requests for advice from several eminent colleagues produced IOL powers ranging from 44.50 to 52.50 D. Despite extensive chair time and detailed counseling, Mrs. N was adamant that she wanted to proceed with surgery. Because current EU legislation precludes the sale of such high-power IOLs, primary duet implantation—a single procedure combining inthe- bag IOL implantation with supplementary sulcus IOL implantation—was the preferred option.

Following full informed consent, Mrs. N elected to have immediate sequential bilateral cataract surgery under general anesthesia. I implanted a 40.00 D C-flex IOL (Rayner Intraocular Lenses Ltd.) into the capsular bag of each eye and 9.50 D and 8.50 D Sulcoflex IOLs (Rayner Intraocular Lenses Ltd.) into the sulcus of the right and left eyes, respectively (Figure 1). Preoperatively, bilateral Nd:YAG iridotomy was performed. The procedure was uneventful; however, low scleral rigidity was noted.

At follow-up, BCVA was 20/40 bilaterally with refractions of -3.50 D and -2.50 D in her right and left eyes, respectively. From my perspective, Mrs. N’s outcome was suboptimal, but she was utterly delighted because this was the first time that she could see anything at any distance without optical aids. She was adamant that she did not want any further surgery.

DISCUSSION

Let us conceptualize what could be done for Mrs. N. In normal practice, eyes with refractive errors are normally treatable with surface ablation or femtosecond LASIK with a high degree of predictability. Given Mrs. N’s extreme hypermetropia, however, a lens-based solution was appropriate. Had only a single IOL been implanted in the capsular bag, IOL explantation and exchange or supplementary IOL implantation would be options to correct her refractive surprise.

What struck me in this case was that it would be easy to exchange just the supplemental IOL. Because the anterior chamber depth could be measured accurately and the supplementary IOL power is an easy vergence calculation, this is a highly attractive option. There is no risk to the capsular integrity, and the IOL is so thin that it does not need to be cut for explantation—just dialed into the anterior chamber and pulled through the wound before implanting the new IOL. This procedure is not particularly high risk if prophylactic intracameral cefuroxime is used.

Given current biometric limitations for eyes with high ametropia, it is probable that similar eyes would benefit from a primary duet procedure, especially because a refractive surprise is most likely in these cases. A modern supplementary IOL allows postoperative refractive manipulation. I purposely avoid using the word explantation because the removal (or exchange) was either planned or recognized as a possibility for overall management. The term I prefer is duet deconversion because, in some circumstances, an eye is converted from polypseudophakia to pseudophakia.

This duet deconversion technique can be considered in several potential scenarios, such as an eye that requires silicone oil for a retinal detachment repair (which becomes hypermetropic depending on what type of silicone oil was injected). If oil removal is uncertain, a supplementary IOL can be implanted simultaneously with the injection of silicone oil; subsequent duet deconversion can be performed if the oil is later removed. Another example is patients who require spectacle independence but are concerned about potential halos from multifocal IOLs. A presby-duet procedure—a monofocal IOL targeted for emmetropia implanted in the capsular bag and a plano/multifocal supplementary IOL implanted in the sulcus—can provide patients with good vision after neural adaptation.

However, for the small minority who prefer absolute presbyopia, duet deconversion by removing only the supplementary IOL results in what we would call a monofocal refractive lensectomy. Lastly, pediatric cataract cases can benefit from a duet deconversion procedure, as -2.00 D—the approximate ideal refractive outcome to minimize amblyopia in childhood—produces unacceptably high myopia later in life when the IOL is left in the eye. On the other hand, after implanting a capsular-fixated IOL powered for adult emmetropia and a supplementary IOL with the remaining power as part of a primary duet procedure, the supplementary IOL could be removed (duet deconversion) when the child grows up.

CONCLUSION

Modern supplementary IOLs available in Europe have uncovered numerous therapeutic options, including the treatment of negative dysphotopsia. Use of these IOLs can be categorized into four procedures, which are detailed in Table 1.

I recommend duet deconversion as nomenclature to explain the opportunities offered by supplementary IOLs. Compared with the language planned IOL exchange/removal, duet deconversion does not imply the same pejorative overtones. Such thinking will allow surgeons and patients to appreciate the full potential of modern supplementary IOLs.

I expect some other professionals will have reservations; however, I am reminded that professionals built the Titanic but amateurs built the Ark.

Charles Claoué, MA(Cantab), MD, DO, FRCS, FRCOphth, FEBO, MAE, is a Professor of Ophthalmology at Queen’s Hospital, BHR University Hospitals NHS Trust, London, and at the University of Pretoria Department of Ophthalmology and Ufa Eye Research Institute. Professor Claoué states that he is a consultant to Rayner Intraocular Lenses Ltd. He may be reached at tel: +44 020 8852 8522; e-mail: eyes@dbcg.co.uk.

Think or Sink

By Brian C. Little, MA, FRCS, FRCOphth
A 76-year-old Italian woman came to my practice in the summer of 2006 with a dense unilateral cataract in her right eye. She spoke very little English (but better than I spoke Italian) and was accompanied by her son, who spoke a bit more English than his mother, although not a great deal.

I slowly elicited a history of previously poor vision in her right eye, and the story for amblyopia sounded fairly compelling. The UCVA in her right eye was hand movements, with accurate light projection in all four quadrants. BCVA in the left eye, which had an early cataract, was 20/40. There was no history of eye trauma nor any sign of afferent pupillary defect. The cataract was white, dense, and stable and could not be refracted.

Optical biometry revealed a normally dimensioned left eye, but the axial length in the right eye was 34 mm, which, at that time, was one of the longest eyes I had ever seen. This axial length discrepancy also explained the amblyopia on the basis of high anisometropia.

I informed the patient and her son about the limited visual potential of her right eye and the increased risks of surgery with a white cataract. She was keen to go ahead with surgery, which I performed under local anesthesia, thankfully without any complications. Intraoperatively, I noted that her anterior segment was of surprisingly normal dimensions, considering her extreme myopia, with a stable iris-lens diaphragm. However, we know from experience that this can sometimes be the case even in very large eyes.

At her first postoperative visit, the patient was delighted with the result. Despite improving from her preoperative vision of hand movements to only 20/200, she was aware of the vision in this eye being significantly brighter and clearer. When I looked at her right fundus, I was surprised to see that it looked quite normal and had no myopic features. I arranged for her to be refracted at her next visit a couple of weeks later, when she would be finished with her drops. The refraction was straightforward but somewhat shocking: +13.00 -0.75 X 100 = 20/20. This is my personal record for target refraction errors, which I hope to never beat. How on earth did this happen?

Before going into the whys and wherefores, it is best to cover the principles underlying her immediate management. The same three actions are required in any such situation: apologize, explain, and support. Be concerned, and take an active interest in the progress of the case and its outcome. This involves making friends with your mistakes and taking responsibility by avoiding excuses, denial, and silence. Remain accessible and available, and keep in touch with the patient. No one is likely to sue someone they like, so treat your patients in the way you would prefer to be treated.

The source of error in this case was a wildly aberrant axial length reading from relying on optical biometry in a white cataract. This was not questioned, as it fit the story (in fact, incorrect story) of amblyopia. So, having explained the situation to the patient and her son, the next step was to sit down and discuss the options for visual rehabilitation with a refractive error of +13.00 -0.75 X 100. This level of hyperopic correction is not possible using laser refractive surgery, which leaves four other options: (1) the zero option of simply retaining the anisometropic status quo; (2) contact lens correction, which she was not keen on; (3) piggyback sulcus IOL implantation; and (4) lens exchange with endocapsular implantation of a posterior chamber IOL.

Understandably, the patient wanted some time to make her decision, saying that, for the moment, she would prefer to avoid further surgery. She delayed her return for 3 months, during which time she had undertaken discussions with the rest of her family. The original implant was a three-piece hydrophobic acrylic IOL (AcrySof MA60; Alcon Laboratories, Inc.), and, on examination, although the IOL was inside the capsular bag, it was decentered by about 1 mm. The likely cause of this was the crimping of one of the polypropylene haptics during implantation. This effectively took option No. 3 off the table, as a piggyback IOL on top of a decentered implant would not be a good idea. After further discussion, the patient selected option No. 4, endocapsular lens exchange.

LENS EXCHANGE SURGERY

In principle, there are three steps to lens exchange surgery: (1) get the original lens out of the bag, (2) get the lens out of the eye, and (3) get the new lens into the bag. For a video of this case of lens exchange surgery, visit eyetube. net/?v=fowiz. All three of these steps must be executed without damaging the corneal endothelium, iris, or capsular bag. In order to achieve this, it is necessary to use copious amounts of OVD and the appropriate instruments, which should ideally include coaxial anterior segment forceps and a pair of suitable IOL cutters to bisect the lens. For this case, I used Osher IOL scissors (Bausch + Lomb/ Storz), which work very well, although by current standards they are now large to use through an unenlarged sub-3-mm wound. I currently favor the coaxial Packer-Chang IOL scissors (MicroSurgical Technology), which are excellent.

The time from the patient’s original cataract operation to the lens exchange surgery was 4 months. Over this period, it was expected that the capsular leaves had stuck together, although not inseparably.

The first challenge was to get under the edge of rhexis, which was well apposed to the optic of the implant. I tried using a chisel-ended instrument that had been specifically designed for this purpose, but the wedge of the tip was not thin enough to get under the edge of the rhexis. Therefore, I abandoned this approach and used a straight-shafted ring manipulator (Duckworth & Kent Ltd), which inserted easily under the almost-exposed edge of the decentered optic. I usually use Healon 5 (Abbott Medical Optics Inc.) for these procedures, as its pseudoplasticity and retentive properties are useful. Healon 5 was injected into the bag behind the implant to achieve viscoseparation of the capsular leaves and expansion of the whole bag.

Fortunately, the polypropylene haptics of three-piece acrylic IOLs are nearly always easy to get out of the bag, even after a year or more, using plenty of OVD and gently dialing them out bimanually. I used the ring manipulator and an iris repositor to do this. With the lens dislocated into the anterior chamber and sitting fairly central, I bisected it using the Osher scissors through a 4-mm scleral tunnel placed about 2 mm back from the limbus. It is important to apply counterpressure on the opposite edge of the optic to avoid the lens being squeezed forward out of the jaws of the scissors. This can be done using a Sinskey hook, a chopper, or the versatile ring manipulator, as in this case. Both halves of the lens are removed, preferably using notched or toothed forceps for a secure grip.

I advise against the use of the so-called Pac Man technique for IOL removal. With this approach, the optic is cut only halfway across its diameter, and the lens is then pulled out of the eye by traction and rotation. The Pac Man technique is potentially hazardous, with likely iris and corneal trauma from the forces required and the uncontrolled acrobatics of the implant as it is removed.

I previously removed three-piece IOLs by refolding them in the eye, but doing this I encountered a disaster, in which a high-diopter IOL slipped under force when refolding and caused a major intraocular bleed. There is nothing more persuasive than personal experience to change one’s practice.

An option that I now favor is implanting the secondary IOL into the bag underneath the dislocated original implant before removing it from the eye. There is plenty of space to safely do this in most pseudophakic eyes, and it provides secure protection of the posterior capsule during cutting and removal of the original implant.

By this stage, the pupil had shut down, so I put in four iris hooks to allow adequate exposure and clear visibility of the rhexis and capsular bag. With the bag fully inflated with OVD, I swept the fornices with an iris repositor to ensure that there was no peripheral closure of the bag that might decenter the new implant.

I then injected the new lens into the bag and, confident that it was sitting centrally, removed the iris hooks and OVD from the eye, securing the conjunctiva over the unsutured scleral tunnel using a single 10-0 nylon stitch.

CONCLUSION

This type of surgery requires careful systematic planning and execution. Applying the appropriate techniques and using the correct instruments, it is not particularly difficult to achieve consistently satisfactory results.

Brian C. Little, MA, FRCS, FRCOphth, is a Consultant Surgeon at Moorfields Eye Hospital in London. Dr. Little states that he has no financial interest in the products or companies mentioned. He may be reached at e-mail: brianlittle@blueyonder.co.uk.

Patient Satisfaction After Lens Exchange

By Daniela M.V. Marques, MD, PhD; and Frederico F. Marques, MD, PhD
A 64-year-old woman presented for consultation 1 year after cataract surgery due to an unacceptable refractive result. Her past ocular history was unremarkable except for this procedure.

On examination, UCVA was counting fingers in her right eye, improving to 20/25 with an unexpected manifest refraction of -6.75 D of sphere, and 20/200 in her right eye, improving to 20/40 with manifest refraction of -3.00 -0.50 X 100. Slit-lamp examination revealed a clear cornea with a quiet anterior chamber in both eyes. In her right eye, a one-piece IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc.) was well centered in the capsular bag with 360° anterior capsular fibrosis and no posterior capsular opacification (Figure 2); a grade 1+ nuclear cataract was noticeable in her left eye. Intraocular pressure and fundoscopy were unremarkable in each eye, and keratometry readings were regular (44.90 45.50 X 64 right eye and 44.50 45.60 X 1 left eye). Additionally, in her right and left eyes respectively, pachymetry was 410 and 418 μm and axial length measured with ultrasound immersion was 23.80 and 23.60 mm.

We discussed possible solutions with the patient, including contact lens prescription, supplementary IOL implantation, and IOL exchange with distance or near monovision. We decided that IOL exchange was the best option, optimizing the lens power for distance vision.

The procedure was performed under peribulbar anesthesia. First, we created a paracentesis using a 15° blade and a near clear corneal incision using a 2.75-mm blade. After filling the anterior chamber with a dispersive ophthalmic viscosurgical device (OVD), we inserted a Y-hook and dissected the adhesions between the anterior capsular rim and the anterior IOL optic, a maneuver that was difficult due to the extensive fibrosis. Once the adhesions were released, we used the Y-hook to lift the rim while introducing a 30-gauge flat cannula underneath it to viscodissect the anterior and posterior capsules. After expanding the capsular bag uneventfully, we inserted a Sinskey hook to manipulate the IOL and Buratto forceps to liberate the inferior haptic. Thus the entire lens could be elevated into the anterior chamber.

The superior haptic was strongly adhered to the capsular equator, and, during the maneuvers to release it, an iatrogenic zonular dialysis of approximately 2 clock hours occurred. Based on this complication, we decided to amputate the haptic using Vannas scissors through the main incision, and this was accomplished without complication. Then we rotated the IOL until the remaining uncut haptic was externalized.

After performing a contralateral paracentesis 180° from the main incision, we introduced the Sinskey hook underneath the IOL to create counterpressure while using the Buratto forceps to fold the IOL against the hook. After confirming a good fold, we released the hook and removed the folded IOL safely from the eye through the main incision. Subsequently, we implanted a three-piece hydrophobic acrylic IOL into the capsular bag, positioning the superior haptic 90° apart from the residual amputated haptic to achieve good centration and stability. At the end of the procedure, we initiated irrigation and aspiration to remove the OVD using a two-compartment technique and closed the incisions with the aid of stromal edema (Figure 3). For a video demonstration of the procedure, visit eyetube.net/?v=dilon.

On the first postoperative day, the patient was happy, there was minimal corneal edema, and her UCVA was 20/40. One week later, BCVA improved to 20/20 with a manifest refraction of 0.00 -0.50 X 110. Once the patient was happy with the outcome of her right eye, we performed standard cataract surgery on her fellow eye. The procedure was uneventful, and the patient achieved excellent visual acuity on the first postoperative day with a UCVA of 20/25 and a stable manifest refraction (-0.25 -0.50 X 80 yielding 20/20) by the seventh postoperative day.

Daniela M.V. Marques, MD, PhD, is a Medical Director at the Marques Eye Institute in São Paulo, Brazil, and a Medical Collaborator in the Research Department of the Cataract Sector of the Federal University of São Paulo. Dr. Marques states that she has no financial interest in the material discussed in this article. She may be reached at tel: +55 11 99252 1925; e-mail: dradaniela@marqueseye.com.br.

Frederico F. Marques, MD, PhD, is a Medical Director of the Marques Eye Institute in São Paulo, Brazil, and a Medical Collaborator in the Research Department of the Cataract Sector of the Federal University of São Paulo. Dr. Marques states that he has no financial interest in the material discussed in this article. He may be reached at tel: +55 11 98292 3082; e-mail: drfrederico@marqueseye.com.br.

Strategies for IOL Explantation

By Abhay R. Vasavada, MBBS, MS, FRCS
A 50-year-old man who underwent cataract extraction with in-the-bag IOL implantation 10 years prior presented with sudden decreased vision that he first noticed 6 months earlier. The patient had undergone cataract surgery for a posterior polar cataract, during which a posterior capsular rupture occurred. The posterior capsular support was judged to be adequate for in-the-bag IOL implantation, and a one-piece AcrySof IOL (Alcon Laboratories, Inc.) was implanted in the capsular bag at that time. The patient was doing well but was lost to follow-up 1 year after cataract surgery.

On presentation, the patient’s visual acuity was 20/100. Slit-lamp examination revealed aphakia in the pupillary area. The IOL could not be seen initially at the slit lamp but was later observed in the anterior vitreous in a supine position. The margin of the original posterior capsular rupture could be clearly visualized, and the anterior chamber was free of any vitreous (Figure 4).

The patient was counseled regarding explantation of the dislocated IOL with possible fixation of another IOL. The surgical strategy was to perform pars plana vitrectomy, explant the one-piece IOL, and fixate another IOL depending on the available anterior capsular support.

First, 23-gauge pars plana vitrectomy was performed using the Infiniti Vision System (Alcon Laboratories, Inc.) For a video of this procedure, visit eyetube.net?v=belis. Vitrectomy was performed with the following parameters: cut rate, 2,500 cpm; vacuum, 300 mm Hg; aspiration flow rate, 25 cc/min; and irrigation bottle height, 50 cm H2O. Thorough vitrectomy was performed to ensure that the IOL was free of all surrounding vitreous. Using a bimanual technique and microincisional grasping forceps, the IOL was gently brought out into the anterior chamber. A dispersive OVD (Viscoat; Alcon Laboratories, Inc.) was injected in the anterior chamber to coat the corneal endothelium. A temporal clear corneal incision of 2.4 mm was fashioned. The IOL was explanted using a special wire loop passed through the A-cartridge (Alcon Laboratories, Inc.). This device, developed by Dr. Arup Bhowmick of Kolkata, India, enables reverse folding of the IOL: that is, it allows the entire IOL to be folded back into the cartridge and removed through a very small incision.

Once the IOL was explanted, the anterior capsule support was assessed and judged to be adequate for sulcus IOL fixation. A three-piece AcrySof IOL (Alcon Laboratories, Inc.) was implanted in the sulcus, and the optic was captured through the anterior capsulorrhexis margin. At the end of the procedure, preservative-free triamcinolone acetonide was injected in the anterior chamber to detect the presence of any residual vitreous.

At 1 month postoperative, the patient had achieved a BCVA of 20/30, and the IOL was stable and centered in the eye. He maintained the same IOL centration and stability at 1.5 years postoperative (Figure 5).

The take-home pearls from this case are several. First and foremost, the extent of subluxation or dislocation of the IOL should be assessed. Preoperatively, the presence of vitreous in the anterior chamber and the extent of residual anterior and posterior capsular support should be assessed. Intraoperatively, adequate vitrectomy should be performed to ensure that the IOL is free of all coating vitreous. It is also advisable to use an appropriate IOL explantation strategy that is the least traumatic to the eye. Finally, the surgeon should perform a critical assessment of the available capsular support and then choose the best site for IOL implantation and fixation.

Abhay R. Vasavada, MBBS, MS, FRCS, is Director of the Iladevi Cataract & IOL Research Centre, Raghudeep Eye Clinic, Memnagar, Ahmedabad, India. He acknowledged no financial interest in any product or company mentioned herein. Dr. Vasavada may be reached at +91 79 7492303; e-mail: shailad1@sancharnet.in.

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