This article is more than 5 years old. Information may no longer be current.
A ‘blue IOL’ presents a rare surgical challenge during corneal transplantation
Click Here to Manage Email Alerts
Corneal transplantation has progressed from deep lamellar endothelial keratoplasty to Descemet’s stripping automated endothelial keratoplasty to Descemet’s membrane endothelial keratoplasty. In the process, the donor disc has progressively decreased in thickness to about 15 µm for DMEK, with donor Descemet’s membrane of 8 µm to 10 µm and corneal endothelium of about 5 µm. Placing it in perspective, the cling wrap used to seal food items is about 12.5 µm. Such decreased donor tissue thickness, a 97% reduction, introduces complexities to corneal transplantation never before seen in the anterior segment surgical arena.
Corneal stroma, when used in donor tissue, introduces rigidity to the donor disc, facilitating surgical handling in donor tissue preparation and manipulation within the recipient anterior chamber. In short, stroma ensures a surgeon-friendly experience in procedures such as DSAEK.
When the donor corneal stroma is eliminated, the flimsy Descemet’s membrane can easily be torn during donor tissue preparation. Moreover, lacking any memory, the tissue rolls on itself tube-like along the longitudinal axis, exposing the endothelium on the outside surface. The absence of stromal tissue in the donor disc compels the surgeon to shift gears from a hands-on DSAEK procedure to a hands-off DMEK procedure. This requires the surgeon to rely mostly on fluidics and forced fluid injection within the recipient anterior chamber to unroll the donor Descemet’s membrane before air-assisted attachment to the recipient cornea.
Unfortunately, the donor Descemet’s membrane can dive into linear and nonlinear paths of least resistance when subjected to forced fluid injection. It can potentially pass through a large peripheral iridectomy or iris defect; absence of the iris in aniridia; or absence of a posterior capsule in aphakia, a scleral-fixated posterior chamber IOL or any situation in which there is an absence of structural divide between the anterior and posterior segment. In these cases, the donor Descemet’s membrane can plunge into the posterior segment in the blink of an eye, beyond the reach of a corneal surgeon.
Figure 1. Intraoperative photo showing a cataract and corneal edema associated with Fuchs’ corneal dystrophy (left). Circular mark is made on the corneal surface using the John DMEK corneal marker (ASICO) (right).
Figure 2. The donor Descemet’s membrane is detached as a single circular disc, avoiding any radial tears.
Images: John T
In this column, I describe for the first time the “blue IOL,” which can be a surgical setback during DMEK.
Case history
An 81-year-old Caucasian woman presented with symptoms of blurred vision in her left eye secondary to cataract and Fuchs’ corneal dystrophy, with endothelial decompensation and stromal edema (Figure 1). She wanted nonpenetrating corneal transplantation with cataract surgery. After discussing it with the patient, I elected to perform a triple procedure: DMEK, phacoemulsification and posterior chamber IOL implantation in the involved eye.
Surgical technique
Combined DMEK and cataract surgery (Figures 1 to 9) are performed under monitored anesthesia care with topical 2% lidocaine jelly. An 8-mm circular mark made on the corneal epithelial surface serves as a guide during Descemet’s membrane manipulation. Using a John Dexatome spatula (ASICO), a descemetorrhexis is performed with Healon (sodium hyaluronate, Abbott Medical Optics), and the disc of Descemet’s membrane is detached and removed. Care is taken not to touch the inner stromal surface during Descemet’s membrane removal. The point of instrument contact is always on the folded Descemet’s membrane. Damage to the corneal stroma must be avoided in order to maintain a pristine interface, which contributes to improved postoperative vision.
Figure 3. The donor Descemet’s membrane is seen within the recipient anterior chamber.
Phacoemulsification is performed, a foldable acrylic posterior chamber IOL (Alcon) is placed in the posterior capsular bag, and Miochol (acetylcholine chloride, Bausch + Lomb) is used to constrict the pupil. An inferior peripheral iridectomy is performed. Following Healon removal, the wound is closed with a single 10-0 nylon suture.
Next, the donor Descemet’s membrane is detached as a single circular disc, avoiding any radial tears (Figure 2). Trypan blue staining ensures easy identification of the donor Descemet’s membrane within the recipient anterior chamber (Figure 3). Fluidics are used to unfold the donor Descemet’s membrane (Figure 4).
Figure 4. Fluidics are used to unfold the donor Descemet’s membrane.
Composite intraoperative photographs show the donor Descemet’s membrane moving toward the pupil, diving into the pupillary space and completely disappearing from the anterior chamber (Figure 5). The donor Descemet’s membrane passes around the peripheral aspect of the posterior chamber IOL, reaching its final resting position between the posterior chamber IOL and the posterior capsule and resulting in a “blue IOL.”
A “blue IOL” is a sign of an intraoperative setback, with no easy access to the donor Descemet’s membrane (Figure 6). Additionally, pulling on the membrane will tear it and make the donor tissue more difficult to remove.
Figure 5. Composite intraoperative photos show the donor Descemet’s membrane moving toward the pupil, diving into the pupillary space and completely disappearing from the anterior chamber. The donor Descemet’s membrane passes around the peripheral aspect of the posterior chamber IOL, reaching its final resting position between the IOL and the posterior capsule, resulting in a “blue IOL.” Notice that staining helps identify the location of the Descemet’s membrane.
Figure 6. The “blue IOL” is clearly visible with a pie-in-the-sky appearance, a difficult surgical setback because the donor Descemet’s membrane is trapped between the posterior chamber IOL and the posterior capsule with no easy access. Additionally, pulling on the membrane will tear it and make the donor tissue more difficult to remove.
Figure 7 displays the intraoperative steps of a no-touch technique, using fluidics and gentle movement of the posterior chamber IOL to redeliver the trapped Descemet’s membrane from the posterior chamber into the anterior chamber through the pupil as an intact disc, without tearing the donor tissue. The anterior chamber-delivered donor Descemet’s membrane is then unrolled and attached to the recipient cornea in a uniform manner without any folds, as confirmed by intraoperative slit lamp examination.
Figure 7. Intraoperative steps demonstrating the no-touch technique, using fluidics and gentle movement of the posterior chamber IOL to re-deliver the trapped Descemet’s membrane from the posterior chamber position behind the IOL to the anterior chamber through the pupil as an intact Descemet’s membrane disc without tearing the donor tissue.
Figure 8 shows a clear and compact cornea with a well-positioned posterior chamber IOL and a round pupil 1 year and 10 months after the DMEK triple procedure. In figure 9 corneal OCT at 1 year and 10 months shows uniform integration of the donor Descemet’s membrane and healthy endothelium with the recipient cornea. Central corneal thickness is 559 µm.
Figure 8. Slit lamp photograph 1 year and 10 months after the DMEK triple procedure shows a clear and compact cornea with a well-positioned posterior chamber IOL and a round pupil.
Figure 9. Corneal OCT 1 year and 10 months after DMEK shows uniform integration of the donor Descemet’s membrane and healthy endothelium with the recipient inner corneal stroma with a central thickness of 559 µm.
Confocal microscopy performed 1 year after the procedure showed an endothelial cell count of 2,083/mm2, representing a 12% cell loss compared to the preoperative donor endothelial cell count of 2,369/mm2. It is important to note that preoperative and postoperative cell counts are performed by different examiners in different locations, the eye bank and the physician’s office, using different technology, specular microscopy at the eye bank and confocal microscopy at the physician’s office.
Surgical pearls, comments
1. Keep the donor Descemet’s membrane in the central region of the anterior chamber while unfolding the membrane.
2. Avoid DMEK when there is no structural barrier to prevent the donor membrane from going into the posterior segment.
3. Constrict the pupil before introducing the donor Descemet’s membrane into the anterior chamber.
4. Use a gentle fluid injection technique to unfold the donor Descemet’s membrane.
5. Stain the donor Descemet’s membrane with trypan blue for easy identification.
6. Close the entry wound with a 10-0 nylon suture immediately after introduction of the donor Descemet’s membrane into the recipient anterior chamber.
7. The pupil often will not constrict as well in a triple procedure in which the pupil is first dilated as when DMEK is performed as a standalone procedure.
This case challenged the surgeon when the donor Descemet’s membrane landed between the posterior chamber IOL and the posterior capsule, because this membrane cannot be pulled from that location with forceps. Any mechanical pulling of the flimsy Descemet’s membrane will result in tearing the tissue, further complicating the procedure. Additionally, if the Descemet’s membrane is not stained with trypan blue, it is very difficult to identify the tissue location once it disappears from the anterior chamber. Surgeons performing DMEK should be aware of the rare intraoperative setback of a “blue IOL” during DMEK.
References:
- Busin M, Patel AK, Scorcia V, Galan A, Ponzin D. Stromal support for Descemet’s membrane endothelial keratoplasty. Ophthalmology. 2010;117(12):2273-2277.
- Dapena I, Ham L, Droutsas K, van Dijk K, Moutsouris K, Melles GR. Learning Curve in Descemet’s Membrane Endothelial Keratoplasty: First Series of 135 Consecutive Cases. Ophthalmology. 2011;118(11):2147-2154.
- Laaser K, Bachmann BO, Horn FK, Cursiefen C, Kruse FE. Descemet membrane endothelial keratoplasty combined with phacoemulsification and intraocular lens implantation: Advanced triple procedure. Am J Ophthalmol. 2012;154(1):47-55.
For more information:
- Thomas John, MD, is a clinical associate professor at Loyola University at Chicago and is in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at 708-429-2223; email: tjcornea@gmail.com.
- Disclosure: John receives a small royalty from ASICO Inc.