GLUED IOL

RATIONALE AND RESULTS

Dhivya Ashok Kumar, MD(AIIMS), FICO, FAICO, FRCS and Amar Agarwal, MS, FRCS, FRCOphth

Glued intraocular lens (IOL) implantation involves the transscleral fixation of a posterior chamber IOL (PCIOL) by intrascleral tucking of the haptics through sclerotomies made 180 degrees apart. Because of the absence of the anchoring sutures and simultaneous use of fibrin glue, this has been termed the glued IOL technique. Introduced by Dr. Amar Agarwal and his colleagues in 2007, the glued IOL technique has been widely performed for various indications.^1,2 The absence of capsular support for placement of an IOL in the capsular bag is the most common indication.^3–6 However, in recent years, there have been numerous modifications in the basic methodology and extension of indications.^7–14 In this section, we would like to present the technique, modifications, and functional and anatomical outcomes of the glued IOL method.

Surgical Technique

Under peribulbar anesthesia, localized peritomies at the desired site of exit of the IOL haptics are made. Two partial-thickness limbal-based scleral flaps about 2.5 x 2.5 mm are created exactly 180 degrees diagonally apart (Figure 40-1). An infusion cannula is inserted through the pars plana or the limbus. For posterior segment cases, the positioning of the infusion cannula should be in the pars plana about 3 mm from the limbus, and for an isolated anterior segment case, an anterior chamber maintainer at the limbus is sufficient. Two straight sclerotomies with a 20-gauge needle are made about 1.5 mm from the limbus under the scleral flaps. This is followed by vitrectomy via the pars plana or anterior route to remove all vitreous traction. A corneoscleral tunnel incision is then prepared for introducing the IOL in the case of a 3-piece nonfoldable IOL or a corneal incision with keratome in the case of an injectable 3-piece foldable IOL.

HANDSHAKE TECHNIQUE

The IOL cartridge is passed into the anterior chamber (Figure 40-2). The glued IOL forceps (MicroSurgical Technology or Epsilon USA) are then passed through the sclerotomy, and the tip of the haptic is grasped (see Figures 40-1 and 40-2). The IOL is then gradually injected into the eye. In an injector with a screwing mechanism, the assistant rotates the injector. The haptic is then held by an assistant or secured with a silicone microbulldog.

The surgeon now flexes the second haptic into the anterior chamber into the jaws of the glued IOL forceps introduced through the second sclerotomy using the handshake technique (Figures 40-1 through 40-5).^3,8 This haptic is then externalized similarly. A scleral tunnel is made with a 26-gauge bent needle on either side at the point of haptic externalization parallel to the limbus. The haptic tips are then tucked into the intralamellar scleral tunnel.

FIBRIN GLUE APPLICATION

When the IOL haptics are well tucked, air is then injected into the anterior chamber, and the fluid from the infusion cannula is turned off. This helps to prevent hypotony and also keeps the area of the glue application dry. The reconstituted fibrin glue (Tisseel) is injected under the scleral flaps. Local pressure is given over the flaps for about 10 to 20 seconds. The corneoscleral wound is closed with 10-0 monofilament nylon in cases using a nonfoldable 3-piece IOL, and in cases with a foldable IOL, the corneal incision may be sealed with fibrin glue. The conjunctiva is closed with the fibrin glue in all eyes.

In some conditions, the surgeon has to implant glued IOL in large eyes with a large white-to-white diameter. If a horizontally oriented glued IOL is performed in large eyes, there may not be enough haptic for intrascleral tuck. Meanwhile, the vertical diameter of the cornea is shorter than the horizontal, and one would get more haptic externalized to tuck and glue. Hence, a vertical glued IOL is preferred with large eyes, including megalocornea or keratoglobus. If the horizontal white-to-white is more than 11 mm, it would be better to do a vertical glued IOL, in which the scleral flaps are made at 12 and 6 o’clock.12

TROCAR ANTERIOR CHAMBER MAINTAINER

Intraoperative fluid maintenance and anterior chamber stability is of utmost importance in all glued IOL surgeries, and a 23- or 25-gauge trocar cannula can be used for fluid maintenance.⁶ It is also safe and easy in the hands of anterior segment surgeons, as one only has to insert the trocar and fixate the infusion cannula. One should always ensure the tip of the infusion cannula is in the vitreous cavity before the infusion is started in a combined posterior segment case and in the anterior chamber in an isolated glued IOL. The direct visualization of the cannula during entrance and exit decreases the risk for complications. Agarwal et al have developed a trocar-based system for anterior infusion—the trocar anterior chamber maintainer.¹² Fluid maintenance helps in maintaining the chamber stability, prevents endothelial damage, maintains the globe integrity, and keeps good control for subsequent intraoperative steps.

GLUED ANIRIDIA IOL

Congenital aniridia and trauma are known to be associated with subluxated cataract or zonular weakness, and in such conditions, a glued iris prosthesis (not approved by the US Food and Drug Administration) can be used. We have used a polymethylmethacrylate (PMMA) aniridia IOL of ocular vision lens style ANI5 (Intra Ocular Care Pvt) for implantation in eyes with iris deficiency.⁷ IOL implantation alone without addressing the iris deficiency may potentially result in a worse functional visual quality due to aberrations induced by light at the margin of the IOL.

During intraoperative posterior capsule rupture with the nuclear remnants sinking into the anterior vitreous, a PCIOL can be used as a scaffold to manage the situation.13 As an immediate measure in such a scenario, a dispersive ophthalmic viscosurgical device (OVD) is injected through the side port and the phaco probe is withdrawn. The nuclear remnants are brought into the anterior chamber using a blunt rod introduced through the side port or by posterior-assisted levitation, then the same steps as described previously are performed.

The glued IOL and the scaffold techniques are thus combined to create an artificial posterior capsule (Figures 40-6 and 40-7). Nuclear fragments are now placed on the IOL optic, OVD is reinjected to protect the endothelium, and phacoemulsification is performed with low settings.

Glued IOL scaffold can be performed for Soemmering ring removal also.¹⁵ The glued IOL scaffold enables a closed-chamber approach with proper placement of an IOL in cases with inadequate sulcus or iris support and allows safe emulsification of the retained nuclear fragments with good visual outcomes. The same technique can be used to remove a Soemmering ring during secondary IOL implantation in aphakic eyes with associated posterior capsule defect following previous pediatric cataract surgery. Vitrectomy is initially performed, then the remnants of the posterior capsule are removed from the visual axis, followed by injection of a glued IOL below the Soemmering ring, and scleral tuck is performed. The Soemmering ring is dislodged from the periphery with a Sinskey hook and brought into the center of the pupil over the surface of the IOL optic, where it is phacoemulsified. The optic of the preplaced IOL acts as a scaffold and prevents dislodgement of Soemmering ring material into the vitreous cavity during emulsification.

A peripheral iridectomy is performed along the base of the scleral flap (Figure 40-8) and beneath a corneal mark at the 180-degree axis for atraumatic haptic externalization in large eyes.⁹

Rationale: Anterior sclerotomy is often performed in large eyes, which shifts the IOL plane anteriorly, often leading to peripheral iris damage during the anterior sclerotomy or haptic externalization. The peripheral iridectomy helps to prevent iatrogenic iris tissue damage during the surgical procedure (Figure 40-9).

CLOSED-CHAMBER HAPTIC REEXTERNALIZATION FOR POSTERIORLY DISPLACED SCLEROTOMY

The glued PCIOL requires externalization of a sufficient length of both haptics to obtain an adequate intrascleral tuck, which is vital for stable IOL fixation. One cause of a decreased length of externalized haptic may be a sclerotomy that is inadvertently placed posteriorly. We described a technique to handle this situation by creating a fresh sclerotomy anterior to the first one, followed by internalizing the haptic and reexternalizing it through the new sclerotomy.¹⁰

Microcornea can be associated with zonular dialysis and subluxated cataract, which can prevent implantation of an IOL in the capsular bag. Glued PCIOLs can be placed in these eyes with less difficulty by following certain intraoperative modifications (eg, customizing haptic trimming, using IOLs with 6.0-mm optic diameters, using foldable IOLs, and maintaining intraoperative closed-globe manipulation). Because a 6.0-mm optic covers almost the entire pupillary zone, the chances of decentration are smaller. With use of a foldable glued IOL and a scleral tunnel incision, suture-induced astigmatism is often minimized (Figure 40-10). Haptic trimming has helped in proper positioning of the IOL (Figure 40-11). In our trial in microcornea, the mean amount of IOL haptic trimmed intraoperatively was 1.54 ± 0.33 mm.¹¹ There was significant correlation between the horizontal corneal diameter and the amount of haptic trimmed (P = .000).

Rationale: Microcornea eyes may require a small diameter IOL, which may not be available. Trimming of the haptics can provide equivalent results in such a scenario.

SILICONE PLUGS FOR NO-ASSISTANT GLUED IOL

Silicone stoppers or tires are the elements that slide onto capsule and iris retractors; they have repeatedly demonstrated the ability to provide grip and remain in place. Fortunately, the central opening of the tires is the right size for fixating an IOL haptic. Once the first haptic is externalized, a silicone tire is placed and adjusted to the length necessary to support the haptic in position. The second haptic is then externalized. A silicone tire is placed on the second haptic if further manipulation or intraocular surgery (such as penetrating keratoplasty or trabeculectomy) is to be done.¹⁶ After the scleral tunnels have been created, the tires are removed one at a time to facilitate threading the haptic into the tunnels.

Rationale: The use of a silicone tire to support an externalized haptic simplifies the procedure of fibrin glue–assisted scleral fixation and obviates the need for trained assistants.

IOL REPOSITIONING OF A DROPPED IOL

Glued IOL can be performed in an eye with a dropped PCIOL. Any 3-piece PCIOL with PMMA or polyvinylidene fluoride haptics can be repositioned via the glued IOL method.¹⁷ There is no need for explantation of the IOL, as the technique of haptic externalization can be performed via the sclerotomy in a closed chamber.

L-FLAP TECHNIQUE OF GLUED IOL

An L-shaped scleral flap has been tried in eyes with a decentered PCIOL where IOL explantation was performed followed by glued IOL.¹⁸ After 180-degree axis marking, conjunctival peritomies were made, followed by framing of 2 partial-thickness scleral flaps along the ink mark. The caliper was set to 3 mm, and the scleral incision was marked. A crescent blade was used to make the tunnel along the L-shaped mark (Figures 40-12 through 40-14). The tunnel was widened anteriorly and to the sides (intrascleral aspect), creating a nearly 6-mm wide tunnel. Infusion was introduced into the eye with the help of a trocar cannula, and a keratome was then used to enter the anterior chamber, creating a broad internal corneal lip. Because the pupil was small, iris hooks were placed to enhance the intraoperative view. The decentered IOL was grasped and explanted, followed by a thorough vitrectomy. A 3-piece IOL was then introduced inside the eye, and a glued IOL procedure ensued, followed by intrascleral haptic tuck and sealing of the flaps with fibrin glue.

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