15 Endothelial Keratoplasty Including Pre-Descemet Endothelial Keratoplasty with Glued Intraocular Lens Glued intraocular lens (IOL) was introduced in 2007 as a technique for sutureless scleral fixation of the IOL via transscleral haptic tuck in patients with absent or deficient capsular support.1,2,3,4,5,6,7,8,9,10,11,12,13 This may be done as a primary procedure during cataract extraction in case of posterior capsular rupture (PCR) and deficient capsule or as a secondary procedure in an aphakic patient. It may also be used for closed chamber translocation of a malpositioned or subluxated three-piece IOL. However, many of these patients who need primary or secondary glued IOL implantation have already undergone complicated cataract surgery with an inability to implant an IOL in the bag during the cataract extraction. Therefore the chances of endothelial damage and the consequent need for a keratoplasty are also higher in these patients. Depending on the severity of endothelial damage and corneal scarring the patient may require either a penetrating keratoplasty (PK) or an endothelial keratoplasty (EK). Glued IOL may be combined with PK when there is associated stromal scarring. The PK can be done with the help of a femtosecond laser. The advantages of glued IOL with PK as compared to other forms of secondary IOL fixation are the relatively short open-sky time as well as the sturdy fixation of the IOL. In patients with predominantly endothelial damage, EK may be performed instead of PK. The advantages over PK include a closed chamber technique with faster visual recovery, better vision quality, less induction of irregular astigmatism, decreased chances of rejection, and fewer surface and suture-related problems. There is also likely to be less postoperative refractive surprise with EK as compared to PK. Glued IOL can be combined with Descemet stripping automated endothelial keratoplasty (DSAEK), Descemet membrane endothelial keratoplasty (DMEK), or pre-Descemet endothelial keratoplasty (PDEK). It may also be done as a staged procedure, with the glued IOL performed first and EK in a second sitting. In aphakic eyes, a loss of bicamerality of the eye leads to posterior migration of the air bubble used for attaching the EK graft. This increases the risk for a consequent postoperative partial or total graft detachment, forward bowing of the iris, iris–graft touch, graft dislocation into the vitreous, and so on, all of which can necessitate secondary procedures, such as refloating, rebubbling, vitrectomy, anterior chamber (AC) formation, and so on, in turn increasing graft endothelial cell loss. An effective compartmentalization of the eye can be obtained through the glued IOL technique. The glued IOL offers advantages of posterior chamber IOL placement, ease of centration, scleral fixation, as well as stable and sturdy fixation without pseudophakodonesis. It is therefore our preferred technique when combining with EK unlike AC IOL placement, which has disadvantages of decreased AC space, iris-fixated IOLs (which require intact iris all around), as well as sutured scleral-fixated IOL (which has disadvantages of greater pseudophakodonesis and greater difficulty in centration) (► Fig. 15.1, ► Fig. 15.2, ► Fig. 15.3). The procedure is started as a conventional glued IOL. An AC maintainer or a trocar AC maintainer is inserted. Conjunctival flaps and lamellar scleral flaps are made 180 degrees apart. Sclerotomies (20/22 gauge) are made under the scleral flap ~ 1 mm from the limbus. This is followed by a limited 23-gauge vitrectomy through the sclerotomies followed by glued IOL implantation. The haptics are tucked in the Scharioth pockets, and the flaps may be glued down. As the posterior capsule is unlikely to be intact, there is still a chance of posterior migration of air that is injected into the AC for graft support. Migration of air behind the IOL leads to insufficient support for the graft with consequent graft detachment. It is therefore imperative to have a good iris–IOL diaphragm separating the anterior chamber from the vitreous cavity. Therefore, when combining a glued IOL with EK, the sclerotomy should be made slightly closer to the limbus than usual in order to decrease the potential gap between the iris and the IOL. At the same time, an iridoplasty should be done to obtain a round pupil that overlaps the IOL optic all around. Once this is done the adequacy of air fill is checked by turning off the infusion and checking for the air fill. If inadequate, the pupil may need to become smaller or the IOL may need to come closer to the iris. A well formed iris–IOL diaphragm prevents air from going back into the vitreous cavity and allows good postoperative support for the graft. Once the air fill is found to be adequate, air is attached to the AC maintainer (ACM) through an air pump, and host descemetorhexis is performed. The EK graft is then injected into the AC, unfolded, and floated up using air. In cases with subluxated or dislocated three-piece IOL needing EK, a closed chamber translocation of the subluxated IOL into a glued IOL may be done using the handshake technique. This is followed by iridoplasty, if required, and EK. Fig. 15.1 Pre-Descemet endothelial keratoplasty (PDEK) with glued intraocular lens (IOL) (Part 1). (a) Pseudophakic bullous keratopathy. Note the corneal haze and a single-piece, nonfoldable posterior chamber IOL in the anterior chamber (AC). (b) AC maintainer fixed. One can also fix a trocar AC maintainer or a trocar cannula in the pars plana. Two sclera flaps created 180 degrees apart and a 20/22-gauge sclerotomy created with a needle 1 mm from the limbus. (c) After vitrectomy, the haptics are grasped with glued IOL forceps and externalized using the handshake technique. (d) One should be careful when externalizing the haptics because this is a single-piece, nonfoldable IOL. If the haptic breaks the IOL can be explanted and replaced with a three-piece IOL. (e) Scharioth pocket created with a 26-gauge needle and haptics tucked within them. (f) Pupilloplasty done. Fig. 15.2 Pre-Descemet endothelial keratoplasty (PDEK) with glued intraocular lens (IOL) (Part 2). (a) Type 1 big bubble is created. The PDEK can be performed in one sitting with the glued IOL. It is better to do in two steps so that the glued IOL heals well and a month later PDEK is performed. Another advantage is that donor corneas are not readily available and one can do the glued IOL and wait for a good donor cornea to do the PDEK. (b) Air pump–assisted PDEK. The air pump is connected to the trocar anterior compartment (AC) maintainer or AC maintainer so that air is continuously flowing inside the AC. If one is doing PDEK with glued IOL in one sitting it is better to have a trocar cannula in the pars plana with fluid being passed inside and an AC maintainer or a trocar AC maintainer in the AC passing air. This way there will not be any hypotony and one can control the amount of fluid being passed inside the eye. (c) Descemetorhexis. (d) The PDEK graft is injected inside the AC and unrolled with the help of endoilluminator-assisted PDEK. (e) The graft is attached. (f) Glue is applied. Fig. 15.3 Pre Descemet’s Endothelial Keratoplasty (PDEK) with glued IOL (Part 3) (a) Pre op (b) One day post op (c) Anterior segment OCT shows an attached graft. Cases with a malpositioned single-piece IOL requiring explantation or an AC IOL need an enlargement of the wound followed by explantation of the IOL. This is followed by the technique already described. Construction of a scleral tunnel for IOL explantation or a 3 mm L-shaped scleral tunnel incision gives very good wound closure and excellent AC stability. A potential complication that may occur on combining a glued IOL with EK is the risk for hypotonous and subsequent graft detachment in the postoperative period. Hypotony can lead to detachment of the EK graft from the eyelids pushing on the cornea with normal lid movements. This risk can be decreased by making sure that the globe is adequately pressurized at the end of surgery. As noted, this is done by achieving an adequately tight air bubble in the AC. If the globe still feels hypotonic, air is injected through the pars plicata into the vitreous cavity with a 30-gauge needle under direct visualization of the needle tip in the vitreous cavity. At the conclusion of surgery, it should also be ensured that the sclerotomies are well sealed by the scleral flaps using fibrin glue. All corneal incisions should be leakproof and may also be sealed using fibrin glue to avoid any postoperative leakage of aqueous or escape of air, which could increase the risk of detachment. Patients undergoing the procedure therefore need to be watched more closely after surgery to look for any evidence of partial or total graft detachments and taken for rebubbling if required. A properly positioned IOL and a good iridoplasty decrease the chances of the graft slipping into the vitreous cavity during surgery. However, this possibility should be kept in mind, and care should be taken to avoid any inappropriate fluidics, which may cause a graft drop. Descemet stripping endothelial keratoplasty (DSEK) can be combined effectively with glued IOL. The glued IOL is put in place and followed by iridoplasty, host descemetorhexis, insertion, and flotation of the DSEK graft. DSEK has disadvantages of causing more induced hyperopia as compared to DMEK and PDEK but may be preferred in cases with an incomplete iris–IOL diaphragm, large-sector iridectomies, or traumatic/congenital aniridia. The standard DSAEK graft or the ultrathin DSEK graft may be used. The DSEK graft may be inserted using the taco technique with forceps, Busin glide, Tan EndoGlide (Angiotech), or suture pull-through technique. DSEK is a partial-thickness corneal graft operation in which the inner endothelial layer is replaced. Two partial-scleral-thickness flaps approximately 2.5 by 2.5 mm are made 180 degrees opposite to each other. An ACM is introduced in the inferior quadrant. A circular mark is placed on the patient’s corneal surface, and it serves as a guide for removal of the recipient Descemet membrane. The anterior chamber is entered through a peripheral stab incision, and the Descemet membrane is scored and detached as a single disc. It is important not to damage the inner surface of the patient’s cornea during this step of the Descemet membrane removal because the inner corneal stroma will form half of the donor–recipient interface. A sclerotomy wound is created with a 20-gauge needle ~ 1 mm away from the limbus beneath the scleral flaps, and the entire glued IOL surgery is performed until the haptics are tucked into the scleral pockets. An inferior peripheral iridectomy is performed to prevent postoperative air bubble–associated pupillary block glaucoma attack. The ACM helps to maintain the AC throughout the surgery. The use of viscoelastic is deterred because it is important not to leave residual viscoelastic in the AC; it is thought to potentially hamper good adhesion between the donor corneal disc and the recipient corneal stroma. Next, the donor cornea is mounted within an artificial AC and pressurized. Manual dissection is used to remove the anterior corneal stroma. The dissected donor corneal tissue is then placed with the epithelial side down, and trephination is carried out from the endothelial side using a disposable trephine. The diameter of the trephine matches the diameter of the circular mark placed on the corneal epithelium of the recipient cornea made at the beginning of the procedure. The donor disc is about 150 εm thick. A small amount of viscoelastic is placed on the endothelial surface of the donor corneal disc. The donor corneal disc is then introduced into the AC with a taco-fold technique using a forceps, or it is inserted using a surgical glide or an inserter in its unfolded or partially folded state. Once within the AC, the donor disc is attached to the recipient’s inner corneal stroma using a large air bubble. The donor–recipient interface is formed between donor and recipient corneal stroma. The donor disc is then centered to the recipient cornea using the pre-placed epithelial circular mark. A wait of ∼ 10 minutes facilitates initial donor recipient corneal disc adherence. Postoperatively, the patient is asked to lie flat in the recovery room for about an hour and also to lie flat for the most part during the first postoperative day. Gerritt Melles described DMEK, which refers to transplantation of the Descemet membrane with endothelium.14,15 It has advantages over DSAEK with respect to visual quality, absence of hyperopization, and lower rates of graft rejection. The DMEK graft may be harvested directly by the operating surgeon or may be ordered from the eye bank. The submerged cornea using backgrounds away (SCUBA) technique, as described by Art Giebel, is used to harvest the DMEK graft.16 It is more easily harvested from older donor corneas due to weaker attachments in older corneas between the Descemet membrane and overlying stroma. Corneas younger than 40 are therefore generally not suitable for DMEK. The DMEK graft is more fragile than the DSAEK and PDEK grafts and is more likely to tear during graft preparation and manipulation if handled inappropriately. Extreme care in handling should therefore be exercised. Glued IOL implantation and air fill check are followed by host descemetorhexis and DMEK graft implantation. Perception of light and IOP are checked, and the patient maintains a supine position for 24 hours (► Fig. 15.4). In patients with compromised endothelium (► Fig. 15.4a) it has a tremendous potential for faster recovery. The recipient corneal dissection in DMEK is similar to the above two procedures, resulting in the exposure of the patient’s uncut inner corneal stroma. An inferior peripheral iridectomy is performed as in DSEK and DSAEK procedures. The donor Descemet membrane is scored, partially detached under fluid, and trephined from the endothelial side. A Sinskey hook is used to lift up the edge of the cut Descemet membrane. Once an adequate edge is lifted, a nontoothed forceps is used to gently grab the Descemet membrane at its very edge and the graft (► Fig. 15.7b) is separated from the underlying stroma in a capsulorhexislike circumferential manner. The Descemet membrane with the healthy donor corneal endothelium is removed as a single donor disc without any donor corneal stroma. Hence there is no need for an artificial AC or a microkeratome in the donor tissue preparation. This donor Descemet membrane/endothelial complex is stained with a vital dye, such as trypan blue, for visualization. An ACM is introduced, and all the steps of glued IOL surgery are followed consecutively, beginning from 180-degree-opposite scleral marking to the externalization and tucking of haptics (► Fig. 15.4c, d). The graft is then carefully loaded into a Visian ICL injector (Staar Surgical) (► Fig. 15.4e) with the cartridge tip held occluded with a finger. It is then injected gently into the AC by plunging the soft-tipped injector, taking care not to fold the graft. Wound-assisted implantation is avoided, and the ACM flow is titrated carefully to prevent backflow and extrusion of the graft through the incision. The default shape of the donor disc is a coiled circular tube. This donor disc is then uncoiled using fluidics, and the surgeon must avoid for the most part any direct instrument contact to the donor endothelium. Proper orientation is essential prior to attaching the donor Descemet membrane to the exposed recipient bare corneal stroma. The graft orientation is then checked, and it is unfolded gently using a small air bubble as described by Melles. Once unfolded, an adequately tight air bubble is injected under the graft to float it up against the stroma (► Fig. 15.4f). Fibrin glue is finally used to seal the lamellar scleral flaps, conjunctiva, and clear corneal incisions.
15.1 Introduction
15.2 Glued IOL with Penetrating Keratoplasty
15.3 Glued IOL with Endothelial Keratoplasty
15.4 Principles of Combining Glued IOL with Endothelial Keratoplasty
15.5 Glued IOL with Descemet Stripping Endothelial Keratoplasty
15.6 Glued IOL with Descemet Membrane Endothelial Keratoplasty
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