The glued IOL technique has come a long way since Amar Agarwal, MS, FRCS, FRCOphth, first described it in 2007.1 Since then, we have made modifications and discovered many steps that make it easier and more repeatable. A video available on Eyetube (eyetube.net?/v=kifag) shows a live surgical demonstration of a case of primary aphakia that I tackled using the glued IOL technique. The same principles can be applied in other scenarios as well, such as IOL explantation with glued IOL, closed chamber chamber transposition, exchanging a dropped IOL for a glued IOL, and glued IOL combined with endothelial keratoplasty (EK) or glaucoma surgery. The steps are described in this video.
COMBINED WITH EK
For some time now, in patients with bullous keratopathy who require IOL refixation or exchange, I have used the glued IOL technique in combination with EK, either in the form of Descemet membrane endothelial keratoplasty (DMEK), as described by Gerrit R.J. Melles, MD, PhD,2 or the more recent pre-Descemet endothelial keratoplasty (PDEK), as described by Professor Agarwal.
The PDEK graft differs from the DMEK graft because it includes the pre-Descemet layer (ie, the recently identified Dua layer3), making it more robust and less likely to tear or become damaged during graft preparation and handling. To prepare the PDEK graft, air pressure is used to separate the Dua layer, Descemet membrane, and endothelial complex from the overlying stroma; to achieve this, a type 1 big bubble3 is created in the donor cornea (Figure 1A).
Because the learning curves for DMEK and PDEK are steep, certain special techniques are important when combining one of these procedures with secondary IOL fixation. The most vital step is to obtain effective and stable compartmentalization of the eye to prevent partial or total graft detachment and migration of air behind the iris. This generally occurs in eyes with a malformed (floppy) or incomplete iris. To solve this problem, after fixing the glued IOL, I perform iridoplasty (Figures 1B and 1C). A well-formed, taut iris-IOL diaphragm and a pupil that covers the IOL optic from all sides—thereby completely compartmentalizing and stabilizing the eye—prevents air from traveling posterior to the IOL.
The need for iridoplasty is determined intraoperatively, after implanting the glued IOL and before injecting the DMEK or PDEK graft, by simulating end-of-surgery conditions. I inject a large air bubble into the anterior chamber, as is normally done for apposing a DMEK or PDEK graft, and check the behavior of the bubble. When posterior bubble migration occurs, I perform iridoplasty; when a good, stable air fill is achieved, iridoplasty is not required. The air bubble is then removed, a Descemetorrhexis is performed on the host cornea, and the graft is injected.
I use an endoilluminator, a popular vitreoretinal surgery tool, as an external light source for superior graft visualization and 3-D depth perception. I call these techniques endoilluminator- assisted DMEK and endoilluminator- assisted PDEK (E-DMEK and E-PDEK; Figures 1D and 1E; eyetube.net/?v=utiri), depending on the graft type chosen. I switch off the microscope light and perform surgery with the endoilluminator held obliquely at the limbus, so that light shines into the anterior chamber and onto the graft. The tangential light from the endoilluminator is used to comprehend details of the graft, including its position, morphology, and the orientation of Descemet membrane versus endothelium with respect to overlying stroma.
The angle of incident light can be changed and the probe moved around the limbus to help comprehend the entire graft morphology. As the light is incident from an angle and not vertically, striking 3-D depth perception is obtained secondary to reflexes from the light bouncing off the graft’s edges. Depth perception is also achieved by observing the movement induced in the graft by fluid currents and gentle tapping. The direction of curvature of the graft edges, and therefore graft orientation, is confirmed by tapping the host cornea gently and appreciating the light reflexes. As required, the surgeon can switch between working with the endoilluminator and microscope light, or he or she can use both. However, the best three-dimensionality is obtained with the endoilluminator light alone. In E-DMEK, the graft can easily be oriented the right way up, unfolded, and centered. It is then floated up with air (Figure 1F).
COMBINED WITH GLAUCOMA SURGERY
The glued IOL technique can also be combined with stab-incision glaucoma surgery (SIGS) in patients with coexisting glaucoma. SIGS is a new guarded-filtration technique that I developed to overcome some of the disadvantages associated with trabeculectomy and tunnel trabeculectomy. These include the need for conjunctival peritomy—which can lead to scarring and subconjunctival fibrosis, increasing the risk for failure of filtration—and flap-related problems such as difficult dissection, tearing, laceration, buttonholing, variability in thickness, and suture-related complications.
For video demonstrations of SIGS, visit http://eyetube. net/?v=utole and http://eyetube.net/?v=ovala. A 2.8-mm bevelup keratome is used to create a transconjunctival sclerocorneal tunnel in a single step. The tunnel is then intentionally compromised by punching the posterior corneal lip with a Kelly Descemet punch. A peripheral iridectomy (PI) is required only in certain cases, such as in patients with angle-closure glaucoma, peripheral anterior synechiae, or shallow anterior chamber or when tendency for intraoperative iris prolapse into the SIGS tunnel is seen. Subconjunctival dissection is eliminated, and only the single, 2.8-mm conjunctival cut needs to be sutured. A bleb is created with physiologic hydrostatic ballooning (Figures 2A through 2D).
SIGS can be performed with mitomycin C and combined with other surgeries such as phacoemulsification and penetrating keratoplasty. When combined with the glued IOL technique, basic precautions including a thorough anterior vitrectomy should be taken to avoid an ostial vitreous plug.
The advantages of SIGS include elimination of subconjunctival dissection, thereby decreasing risk of failure from scarring, and minimization of conjunctival scarring, as the single conjunctival incision is only 2.8 mm and located away from the scleral tunnel. Additionally, the hydrostatic bleb elevation facilitates physiologic expansion of subconjunctival drainage channels, and the biplanar nature of the tunnel makes it less likely to seal than a triplanar incision. Furthermore, a controlled leak is obtained with posteriorly directed flow, reducing the chance of overhanging bleb. There is also less chance of postoperative anterior chamber inflammation, and the avoidance of scleral sutures decreases suture-related complications and induced astigmatism. In the extreme event of an expulsive hemorrhage, it is easy to rapidly close the SIGS tunnel (Figures 2E to 2H).
I would like to thank Erik L. Mertens, MD, FEBOphth, for selecting my live surgical video of glued IOL implantation for CRST Europe’s special anniversary edition and also congratulate the team at CRST Europe for the wonderful source of knowledge this publication has become. Lastly, I would like to congratulate Eyetube on its tremendous success, as it has become the go-to video site for ophthalmic videos.
Soosan Jacob, MS, FRCS, DNB, is a Senior Consultant Ophthalmologist at Dr. Agarwal’s Eye Hospital and Eye Research Centre, Chennai, India. Dr. Jacob states that she has no financial interest in the products or companies mentioned. She may be reached at e-mail: dr_soosanj@ hotmail.com.
- Agarwal A, Kumar DA, Jacob S, et al. Fibrin glue-assisted sutureless posterior chamber intraocular lens implantation in eyes with deficient posterior capsules. J Cataract Refract Surg. 2008;34(9):1433-1438.
- MellesGRJ, Ong TS, Ververs B, van der Wees J. Descemet membrane endothelial keratoplasty (DMEK). Cornea. 2006;25:987-990.
- Dua HS, Faraj LA, Said DG, Gray T, Lowe J. Human corneal anatomy redefined:a novel pre-Descemet’s layer (Dua’s layer). Ophthalmology. 2013;120(9):1778-1785.