December 2016

 

COVER FEATURE

 

Highlights from ESCRS 2016

New techniques for cataract surgery complications


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer

 
   
Positioning of both capsules

Positioning of both capsules in the lens groove

Bag-in-the-lens

Bag-in-the-lens solution for PCO Source: Marie-José Tassignon, MD, PhD

Grooved, capsulorhexis- centered IOLs eliminate some of cataract surgery’s most elusive complications

Cataract surgery with IOL implantation is the most common ophthalmic surgical procedure, estimated at 20 million per year worldwide. Roughly 30% of uncomplicated cataract surgical outcomes are complicated by posterior capsular opacification (PCO) within 5 years after surgery,1 impacting visual acuity, contrast sensitivity, and visual alignment. While a number of surgical techniques have been shown to reduce PCO to varying degrees and durations of time, such as continuous curvilinear capsulorhexis (CCC), cortical clean-up, and anterior capsule polishing, only bag-in-the-lens (BIL) IOL implantation boasts 100% PCO elimination.

Cataract specialists Marie-José Tassignon MD, PhD, University Hospital Antwerp, Antwerp, Belgium, and Samuel Masket, MD, Advanced Vision Care, Los Angeles, and clinical professor of ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, shared their expertise with grooved capsulorhexis-centered IOLs at the 2016 European Society of Cataract and Refractive Surgeons (ESCRS) annual meeting.

Posterior capsular opacification

The bag-in-the-lens IOL and its specially developed surgical implantation technique have proven effective in providing stable vision without PCO in a wide variety of patients, including pediatric and toric patients, for almost 10 years. As opposed to the conventional lens-in-the-bag approach to cataract surgery, BIL involves both an anterior and a posterior rhexis, a specially grooved IOL, and a uniquely effective capsular tuck technique. In an interview with EyeWorld, Dr. Tassignon, the technique and IOL inventor, shared her wealth of experience on the subject. “I think many ophthalmologists are not aware of the impact and the power of the lens epithelial cells and how they can act to decenter the lens. About 10 years ago, I set out to get rid of capsular opacification, which meant that I needed to limit the capsular healing process, brought about by these cells after cataract surgery, to the periphery of the capsular bag. On the one hand, PCO on the central posterior capsule impedes vision, while on the other hand, the irregular growth of epithelial cells and their fibrotic reaction cause capsule contraction, which can decenter the IOL. These different healing mechanisms are a very important principle,” she said.

Dr. Tassignon created the BIL IOL (Morcher, Stuttgart, Germany) with a novel feature: a groove at the equator of the optic, designed to fit into the carefully sized capsulorhexis, receiving the cut ends of both the anterior and posterior capsular rhexis ridges. “Both the anterior and posterior capsule are positioned within the lens groove. This has proven more than 10 years to limit Soemmering’s ring to the capsulorhexis rim with no effect on vision or IOL position. Newer grooved lenses that make use of an optic groove to tuck the anterior capsule leaf do not have a solution for PCO,” she said.

Tucking in both the anterior and posterior capsule edges allows a permanently symmetrical periphery of the capsular bag. Although the capsule bag refills with lens epithelial cells after cataract surgery/IOL implantation, it occurs symmetrically and prohibits any cells from migrating behind and potentially changing the position of the lens. The capsular bag healing process is associated with capsular contraction, loss of elasticity, loss of transparency, and the stretching of zonular fibers. Dr. Tassignon chalks up the prevention of PCO growth behind the IOL to the cutting and tucking of the posterior rhexis, as removing the tissue behind the IOL precludes the growth of cells in the Berger space.

Position

Unlike most other IOLs, positioning the BIL IOL is independent of the capsule bag, as its design has nothing to do with the traditional placement of haptics into the bag. Most haptics have a 12 to 13 mm total diameter, meaning that the lens position will be affected by the area the haptics take up within the capsular bag, causing a slight tilt. The final position of the IOL in the eye is influenced by the edges of the haptics and optic zone, the contact area of the capsular bag with the IOL, and the size of the anterior rhexis. The BIL IOL gives the surgeon the freedom to choose the best place to perform capsulorhexis for ideal lens centration. With respect to the visual axis, Dr. Tassignon thinks that her IOL design has everything to do with the excellent visual results she obtained with the BIL IOL, again owing to its independence of the capsular bag. In an examination of BIL centration and visual outcomes conducted in 180 eyes of 125 patients, she demonstrated that surgeon-controlled BIL centration was predictable and remained unchanged 6 months and 1 year after cataract surgery. In the study, the geometric center of the IOL, as measured by red reflex slit lamp photography, was compared with the geometric center of the pupil and the limbus. It concluded that capsular bag healing had no influence on BIL IOL centration over time.2

“The pupil is not necessarily in the middle of the mathematical center of the limbus. For instance, the more myopic the patient, the more the pupil will be decentered nasally. That means that to center the IOL properly, you would need to use the pupil. However, you cannot change the position of the IOL according to the pupil when implanting traditionally. Traditional implantation is based on the capsule, and because it is not centered behind the pupil, IOLs will end up decentered. This may not be a big problem when implanting monofocal lenses, but it is a problem when dealing with complex lenses like toric or multifocal IOLs. However, using BIL, the surgeon can choose where to center the lens,” she said.

She noted that although BIL implantation allowed a certain flexibility of IOL placement, the options were not limitless as the capsule needed to maintain its structural integrity. Nonetheless, in a series of toric IOL implantations that based IOL centration on patients’ pupillary entrance using Purkinje reflexes of the surgical microscope light, Dr. Tassignon demonstrated 82% astigmatism correction in 52 eyes of 35 patients using spherotoric BIL IOL implantation.3 “When you put a toric element in your lens, you are correcting a corneal problem on the lenticular plane, at the distance of approximately 4 mm from where the problem is occurring. You have to take a good look at the problem and at the architecture of the cornea. This may not always be possible using traditional IOL implantation,” she said.

Keep it simple

According to Dr. Tassignon, ophthalmic surgeons do not always need to use sophisticated methods and machinery to produce a perfectly sized and centered anterior capsulorhexis with accurate, reproducible results. She recommended the use of a ring caliper for reliable rhexis sizing and centration, at low cost. She explained, “I am a big advocate of trying to avoid the booby trap of paying excessive amounts of money to use difficult and complex devices, like the femtosecond laser, that may play a role in imprecise corneal measurements. In the end, the comfort of pressing a button cannot replace the excellent results achieved with more simple techniques. We have to think about cost and use machinery thoughtfully. I try to apply all the knowledge I have accumulated over 33 years of experience, and I find that simple devices and techniques allow a perfect, well-centered IOL implantation.” Dr. Tassignon is expecting the first prototype of a diffractive version of the BIL IOL, which is the first IOL to incorporate diffractive elements onto the posterior side of a lens where the posterior capsule cannot play a role in reducing the diffractive pattern since it is not present.

Negative dysphotopsiaCataract surgery article summary

It seems that the concept of capturing the lens with the anterior capsule can be of benefit against other in-the-bag traditional cataract surgical complications. According to observations from recent case studies, the updated anti-dysphotopic 90S IOL (Morcher) could eliminate the occurrence of negative dysphotopsia (ND), a temporal dark crescent reported by cataract patients following uncomplicated cataract surgery. “The evidence seems to suggest that the final common pathway for ND is any ‘in-the-bag’ IOL with the anterior capsulotomy edge overlying the optic,” Dr. Masket said during his presentation at the ESCRS meeting. “Therapy or prevention of ND involves placing the lens anterior to the capsule or a portion of the lens anterior to the capsule, which can be accomplished using a method referred to as reverse optic capture.” In a presentation of 55 eyes requiring management or prevention of ND, Dr. Masket reported that reverse optic capture (ROC) was successful in 19 of 20 eyes that experienced ND for more than 6 months following cataract surgery. Moreover, 20 of 20 fellow eyes of symptomatic patients had primary ROC, which successfully prevented ND. Other strategies for managing ND included exchange of the IOL from bag to sulcus, which relieved ND in six of seven eyes. Bag to bag exchanges, however, for a lens of different design or material failed to help in all four cases. Piggyback lenses were successful in eight of 11 eyes. These last results mirrored outcomes from a previous trial conducted by Dr. Masket in which he found that piggyback IOLs and ROC were the most successful approaches to eliminating ND in a retrospective case series of 14 patients/12 eyes experiencing ND after uncomplicated cataract surgery with in-the-bag IOL implantation.4

Dr. Masket said that negative consequences with primary ROC were noted in second eye implantations, i.e., non-symptomatic fellow eyes, as early post-surgical fibrotic PCO necessitated capsulotomy. Also, the long-term sulcus placement of an add-on lens was thought to be associated with decentration and iris chafe.

The Morcher 90S IOL was designed by Dr. Masket in part to simulate ROC in order to prevent ND. At this time, approximately 60 of the IOLs have been implanted in limited clinical trials. The 90S IOL has an equatorial groove designed to capture the anterior capsulotomy. The IOL design allows a small segment of the optic to overlie the capsule and the haptics to be placed inside the capsule bag, Dr. Masket explained. The first 39 eyes received an initial version of the 90S IOL. Of these patients, femtosecond laser was used to create the anterior capsulotomy in 29 of 39 eyes, which measured 4.8 to 4.9 mm in size. Capsule block was experienced in three of 29 eyes, from fluids trapped behind the capsulotomy. In two eyes, the IOL failed to capture the anterior capsule. There was no case of ND (0/39) or iris chafe (0/39) in this series. The anterior capsulotomy must be appropriately sized and placed; an automated or guided capsulotomy is the best approach.

Going back to the drawing board, Dr. Masket edited the lens design to include fenestrations that could allow the passage of fluids and prevent capsule block. “The challenge at this point was to design a lens that could handle all these issues, still fill the capsule bag, have a portion of the optic anterior to the capsulotomy, and allow fluids to pass through the capsulotomy and prevent blockage. We modified the lens to have fenestrations, which would allow the surgeon better manipulation to bring the optic into the capsular remnant, and allow egress of fluid from the capsule bag, precluding capsule block,” he explained. None of the eyes implanted with the original or modified 90S IOL developed ND, proving that having the optic anterior to the capsule will eliminate ND, Dr. Masket said. “While ND continues to plague some of our patients, we think we have a better understanding of the mechanisms and the prevention of it,” he said.

In addition to preventing ND, there are a number of advantages that accrue when the IOL is fixated by the anterior capsulotomy as in the case of the BIL and Morcher 90S IOL. The capsulotomy supported IOL has very stable fixation, and the same IOL may be used with an open posterior capsule, such as with posterior capsule tears. There can be no capsule contraction and decentration because the capsule is captured in the rigid lens. There will be no tilting of the IOL optic and, toric IOLs will not shift axis. Moreover, there can be perfect centration and more predictable ELP. “If one can center the capsulotomy on the visual axis, one can also eliminate higher order aberrations induced by the lens,” Dr. Masket said.

References

1. Schaumberg DA, et al. A systematic overview of the incidence of posterior capsule opacification. Ophthalmology. 1998;105:1213–21.

2. Verbruggen KH, et al. Intraocular lens centration and visual outcomes after bag-in-the-lens implantation. J Cataract Refract Surg. 2007;33:1267–1272.

3. Tassignon MJ, et al. Clinical results after spherotoric intraocular lens implantation using the bag-in-the-lens technique. J Cataract Refract Surg. 2011;37:830–4.

4. Masket S, et al. Pseudophakic negative dysphotopsia: Surgical management and new theory of etiology. J Cataract Refract Surg. 2011;37:1199–1207.

Editors’ note: Drs. Masket and Tassignon have financial interests with Morcher.

Contact information

Masket: sammasket@aol.com
Tassignon: Marie-Jose.Tassignon@uza.be

New techniques for cataract surgery New techniques for cataract surgery
Ophthalmology News - EyeWorld Magazine
283 110
220 173
,
2017-04-12T14:23:33Z
True, 12