IOL exchange is a useful technique in a variety of circumstances, and it should be part of all refractive cataract surgeons' armamentarium. Our case involves a 65-year-old man who had undergone uneventful, sequential, bilateral phacoemulsification and the implantation of diffractive multifocal IOLs. Several months after surgery, he developed glaucoma in his right eye with an arcuate scotoma and nerve fiber layer defect that had not been present preoperatively. He could no longer tolerate multifocal vision in this eye. After a lengthy discussion regarding the risks of explanting the lens, the patient strongly requested an IOL exchange.
SURGICAL TECHNIQUE
The basic principles of an IOL exchange involve a
thorough preoperative evaluation of the position of the
patient's IOL, the capsular bag, and the type of lens
implanted at the time of the original surgery. The surgical
plan can then allow for an IOL exchange.
The first and probably most important step in an IOL exchange is to examine the capsular bag. The surgeon should pay attention to the size of the anterior capsulotomy and the degree to which it covers the PCIOL. He or she should look for pseudophacodonesis, which would suggest zonular weakness. The surgeon should also evaluate the posterior capsule for tears or a previous YAG capsulotomy, as either will require changes in the surgical technique and dramatically increase the risk of vitreous loss.
The length of time that the IOL has been in the eye also plays a role in the safety and efficacy of an IOL exchange. In general, the longer the lens has been in situ, the more difficult it is to replace. We perform specular microscopy preoperatively to evaluate the health of the corneal endothelial cells.
In this case, the patient had received a single-piece AcrySof Restor lens (Alcon Laboratories, Inc., Fort Worth, TX) 9 months earlier. The eye had also undergone a previous YAG capsulotomy. With this in mind, our surgical plan included the potential for lost vitreous and the possibility that the new lens might be placed in the sulcus or the capsular bag.
METHODS
The patient's pupil was maximally dilated. At the time
of surgery, a 2.65-mm incision was created, and a
1.2-mm stab incision was made at the 9-o'clock position.
The eye was filled with a cohesive viscoelastic. An
attempt to open the capsular bag with a dispersive viscoelastic
on the blunt viscoelastic cannula was unsuccessful,
because the capsular bag had shrink-wrapped
around the IOL—a common problem. For this reason, a
30-gauge needle was inserted between the capsular bag
and the IOL, and then a dispersive viscoelastic was used
to inflate the capsular bag and dissect it away from the
lens (Figure 1). The AcrySof Restor IOL has an acrylic
haptic with a bulbous dilation, which generally encourages
adhesion of the capsular bag to the haptic in this
area. The surgeon therefore paid special attention to the peripheral insertion of the haptic into the capsular
fornix and used a dispersive viscoelastic to open up this
area. In most cases, viscodissection is helpful. In cases
where the haptic is more fibrosed, it can be cut and left
in place after removal of the optic.
At this point, the lens could be removed. A dispersive viscoelastic placed behind the IOL tamponaded the vitreous face in the area of the open capsulotomy. The lens was then “pea-podded” into the anterior chamber and out of the capsular bag (Figure 2). With a singlepiece acrylic lens, it is best to lift the lens straight up rather than to rotate it circumferentially. In contrast, with a three-piece lens that has Prolene haptics, rotation is preferable for an IOL exchange.
The surgeon inserted a monofocal IOL into the eye beneath the multifocal lens after it was in the anterior chamber. In our experience, the anterior chamber is more than deep enough to safely allow the implantation of a second lens. The surgeon placed the threepiece monofocal aspheric IOL in the capsular bag and rotated it into position. Inserting the second IOL into the eye before removing the first lens allowed the latter to tamponade the vitreous face and dramatically reduce the risk of vitreous loss upon the original IOL's removal. A small degree of vitreous loss occurred that would have been significantly greater had the monofocal lens not been in place. Once the monofocal lens was well positioned, the surgeon grasped the multifocal IOL from the side using a Mackool Lens Removal System (Impex, Inc., Staten Island, NY). He used the scissors to cut the lens to 90% of its length. Next, he grasped the haptic and rotated half of the lens out of the wound. The lens was then rotated 90º, after which the trailing half of the lens was rotated out of the eye. Finally, with the haptics in the sulcus, the surgeon captured the optic behind the capsulotomy to ensure the IOL's centration.
The surgeon instilled Miochol-E (Novartis Ophthalmics, Inc.) into the eye to make certain that there was no vitreous loss or adhesions. Postoperatively, the patient followed an aggressive topical nonsteroidal and corticosteroid therapy to reduce the risk of inflammation and cystoid macular edema. The patient had a two-line improvement in BCVA and, more importantly, a subjective improvement in his quality of vision. The IOL exchange is an important procedure in the armamentarium of the refractive cataract surgeon.
A video of this case is available at http://eyetube.net/?v=hogis.
Allon Barsam, MD, MRCOphth, is a corneal, cataract, and refractive surgery fellow at Ophthalmic Consultants of Long Island in Rockville Centre, New York. He acknowledged no financial interest in the products or companies mentioned herein. Dr. Barsam may be reached at abarsam@hotmail.com.
Zachary A. Davis is affiliated with Ophthalmic Consultants of Long Island in Rockville Centre, New York. He acknowledged no financial interest in the products or companies mentioned herein.
Eric D. Donnenfeld, MD, is a professor of ophthalmology at NYU and a trustee of Dartmouth Medical School in Hanover, New Hampshire. Dr. Donnenfeld is in private practice with Ophthalmic Consultants of Long Island in Rockville Centre, New York. He is a consultant to Abbott Medical Optics Inc., Alcon Laboratories, Inc., and Bausch + Lomb. Dr. Donnenfeld may be reached at (516) 766-2519; eddoph@aol.com.
