31 Intraocular Lens Exchange with an Open Posterior Capsule An intraocular lens (IOL) exchange can be challenging enough with an intact capsular bag, but an IOL exchange in a eye that has undergone a previous yttrium-aluminum-garnet (YAG) laser capsulotomy presents the surgeon with a totally different set of surgical challenges. There are many circumstances, however, in which a patient may need an exchange IOL when the posterior capsule is open. This chapter discusses a step-by-step surgical technique for successful IOL removal and exchange in the face of an open posterior capsule following a YAG laser capsulotomy. Acrylic single-piece IOLs are currently the predominant lenses of choice for cataract surgery. Multifocal lens in particular carry a risk of visual dissatisfaction in some patients.1–3 Identifying the root cause of postoperative visual disturbance is critical before considering an IOL exchange.4,5 However, once it is determined that an IOL exchange is necessary to improve visual function, generally the sooner the surgery is performed, the easier the lens removal will be. In many cases, a YAG laser capsulotomy may have already been performed to help resolve the patient’s vision complaints. Once a YAG laser capsulotomy has been performed, many surgeons may not attempt to remove an IOL due to the increased risk of complications. These risks may include zonular lysis from the stress induced by removing the haptic, the risk of dislocation and subluxation of the IOL or parts of the IOL into the vitreous chamber, and difficulty inserting a secondary IOL. Corneal endothelial damage with prolonged postoperative corneal edema is also a concern. In addition, a planned vitrectomy must be anticipated when removing an IOL with an open capsule. The longer an IOL remains in the capsular bag, the greater the tendency for fibrosis of the haptics between the anterior and posterior capsule. The IOL design will also have an impact on the ease or difficulty of an IOL disinsertion from the capsular bag. If the haptics of the IOL have an expanded terminal bulb, fibrosis around the bulb may make it more difficult to extricate the lens from the capsular bag. A successful strategy when approaching these cases must meet high expectations of an excellent vision outcome for the patient with resolution of the vision problems associated with IOL. A good technique must enable the following: The surgery is initiated with two 1.5-mm secondary corneal limbal incisions placed on each side of the meridian parallel to the insertion of the haptics to the optic. These incisions should be oriented perpendicular to the meridian of where the primary incision will be placed. They should be marked with a radial keratotomy (RK) marker to ensure their accurate placement. The function of the secondary incisions is as follows: After the two secondary incisions have been created and an intracameral anesthetic has been injected, a high molecular weight cohesive viscoelastic should be injected into the anterior chamber. A cohesive viscoelastic is essential and should not be substituted for a dispersive viscoelastic. It is important that the viscoelastic remain in the anterior chamber throughout the surgery. The viscoelastic must endure the IOL manipulation, bisection, and removal, and a vitrectomy, and as well as the insertion of the new IOL. The primary purposes of the cohesive viscoelastic are as follows: A small-gauge, blunt-tip spatula introduced through the secondary incision can be used to bluntly dissect the anterior capsule off of the perimeter of the IOL. Alternatively, the blunt-tip cannula can be attached to a cohesive ophthalmic viscosurgical device (OVD), and a gentle viscodissection can be performed. Dissection of the anterior capsule generally is easier if the IOL exchange is performed within 6 months of the implantation, but the anterior capsule generally can be readily dissected from an acrylic IOL optic years after the implantation. Once a separation of the anterior capsule has been achieved, the spatula can be swept 360 degrees to free the optic from the capsule. The capsule can also be dissected away from the proximal haptic–optic junction, but the distal haptic in the equatorial capsular bag should not be disturbed. As long as the distal haptics remain fibrosed in the peripheral capsule, care should be taken to avoid any stress to the zonules. Avoid any manipulation of the distal haptics at this stage of the surgery. It is important not to exert any forces that result in centripetal displacement of the distal haptic (Fig. 31.1). Note that IOLs with holes at the haptic–optic junction such as the EnVista (Bausch and Lomb, Rochester, NY) may make separation of the anterior and posterior capsular adhesions more demanding. After the IOL optic and the anterior capsule have been lysed of all adhesions from the peripheral areas of the IOL optic, the spatula is then placed under the lens optic and advanced across the posterior surface of the IOL. If using the viscodissection technique, OVD can be injected between the optic and the vitreous to elevate the optic and push the vitreous more posteriorly. The optic and the optic–haptic junction can now be displaced upward into the anterior chamber above the plane of the anterior capsule. The displacement should be enough to angle the haptics upward, exposing the optic–haptic junction above the plane of the anterior capsule while being careful not to displace the distal haptics centripetally from the equatorial the capsular bag. The primary incision should not be the first incision created, and its construction should be delayed until the IOL is ready to be removed. The incision size should be between 2.4 and 2.7 mm. The primary purposed of this incision are as follows: Following the anterior displacement of the acrylic IOL, the primary incision can be created. The primary incision for an IOL exchange is best placed slightly posterior to the limbus and advanced onto the cornea from the limbus. Entry into the anterior chamber should be a biplanar to create a self-sealing wound. A more posterior incision enables enlarging the wound intraoperatively, if necessary, with minimal impact on the induction of astigmatism. The ideal wound placement should be 90 degrees from the meridian of the haptic–optic junction. This provides access to disengage and remove the haptics from the capsular bag. If there is a clear corneal temporal incision present, it is recommended to avoid reopening the original incision, as irregular healing may create unpredictable astigmatism (Fig. 31.2).
Step 1: The Secondary Incisions
Step 2: Viscoelastic
Step 3: Dissect Adhesions from the Anterior Capsule and the Intraocular Lens
Step 4: Displace the Optic of Intraocular Lens Anteriorly
Step 5: Create the Primary Incision
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