Gerrit R. J. Melles

A surgical technique for posterior lamellar keratoplasty.

PURPOSE To design a surgical technique for transplantation of posterior corneal tissue, while leaving the recipient anterior cornea intact. METHODS In human cadaver eyes, and in a cat and monkey model, recipient eyes had an 8.0-mm limbal incision made with a diamond blade set to 50% of central pachymetry. A stromal pocket was created across the cornea, and a 6.0-mm diameter posterior lamellar disc was excised. A donor posterior disc was implanted into the recipient opening, and the limbal incision was sutured. The procedure was evaluated with keratometry, biomicroscopy, endothelial (supra)vital staining, and light microscopy. RESULTS In human cadaver eyes, post-operative astigmatism averaged 1.2 D (SD, +/- 0.6 D). Posterior transplants showed an intact endothelial cell layer with 1.0% (SD, +/- 1.2%) of cell death. In the animals, six (75%) eyes had clear transplants 2 weeks after surgery; one of these eyes later developed an allograft rejection. Two (25%) eyes showed corneal decompensation, because of inverted implantation of the donor disc. Microscopy showed minimal scarring at the donor-to-host interface and a normal wound-healing response at the posterior stromal wound edges. CONCLUSION In experimental models, posterior lamellar keratoplasty can be performed through a limbal incision and a mid-stromal pocket. The procedure may be a potential alternative in the surgical management of corneal endothelial disorders.

A technique to excise the Descemet membrane from a recipient cornea (Descemetorhexis)

Objective: To describe a technique for excision of the Descemet membrane (DM) from the recipient eye for preparation of a recipient stromal bed in posterior lamellar keratoplasty. Methods: In 10 human eye bank eyes and 3 patients, recipient eyes had a 5.0-mm scleral tunnel incision made extending 1.0 mm into the peripheral cornea at the 12 o’clock surgical position. The anterior chamber was completely filled with air, and a reflective glide was placed through the incision onto the iris, to better visualize DM. A 9.0-mm mark was made onto the corneal epithelium to outline the area from which the Descemet membrane was to be removed. With a custom-made scraper, the DM was then carefully stripped off the posterior stroma by loosening the membrane at the 6 o’clock position and pulling it toward the incision at 12 o’clock. The excised DMs were evaluated by light and electron microscopy. Results: In all recipient eyes, DM could be easily and completely removed from the posterior corneal stroma. Microscopy showed isolated DMs without stromal tissue elements. Conclusion: With the technique described, DM can be excised in a controlled fashion without damaging the posterior corneal stroma, to quickly create a recipient stromal bed before implantation of a donor posterior lamellar disk in posterior lamellar keratoplasty.

A new surgical technique for deep stromal, anterior lamellar keratoplasty

AIMS To describe a new surgical technique for deep stromal anterior lamellar keratoplasty. METHODS In eye bank eyes and sighted human eyes, aqueous was exchanged by air, to visualise the posterior corneal surface−that is, the “air to endothelium” interface. Through a 5.0 mm scleral incision, a deep stromal pocket was created across the cornea, using the air to endothelium interface as a reference plane for dissection depth. The pocket was filled with viscoelastic, and an anterior corneal lamella was excised. A full thickness donor button was sutured into the recipient bed after stripping its Descemet’s membrane. RESULTS In 25 consecutive human eye bank eyes, a 12% microperforation rate was found. Corneal dissection depth averaged 95.4% (SD 2.7%). Six patient eyes had uneventful surgeries; in a seventh eye, perforation of the lamellar bed occurred. All transplants cleared. Central pachymetry ranged from 0.62 to 0.73 mm. CONCLUSION With this technique a deep stromal anterior lamellar keratoplasty can be performed with the donor to recipient interface just anterior to the posterior corneal surface. The technique has the advantage that the dissection can be completed in the event of inadvertent microperforation, or that the procedure can be aborted to perform a planned penetrating keratoplasty.

Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery

A capsulorhexis may be difficult to perform in the absence of a red fundus reflex. Using 0.1 mL of trypan blue 0.1% to stain the anterior capsule in 30 patients with a mature cataract enabled us to visualize the capsulorhexis during phacoemulsification. No adverse reactions were observed up to 12 months after surgery. Trypan blue staining of the anterior capsule appears to be a safe technique to facilitate the performance of a capsulorhexis in the absence of a red fundus reflex.

Transplantation of Descemet's membrane carrying viable endothelium through a small scleral incision.

Purpose. To design a technique for transplantation of the Descemets membrane (DM) as a carrier for its endothelium, while maintaining the low-astigmatic recipient anterior corneal curvature. Methods. In a human eye bank eye model, recipient eyes (n = 15) had a 5.0-mm scleral tunnel incision made, extending 1.0 mm into the peripheral cornea. A 9.0-mm-diameter Descemeto rhexis was created, i.e., a circular portion of DM was stripped from the posterior stroma. With use of a custom-made inserter, a 9.0-mm-diameter donor DM carrying autologous donor endothelium was brought into the anterior chamber and positioned against the recipient posterior stroma. The procedure was evaluated by keratometry, endothelial vital and supravital staining, and light microscopy. Results. Mean postoperative astigmatism was 1.0 D (±0.6 D). Implanted donor DM showed an intact endothelial cell layer, with 3.4% (±1.1%) dispersed focal cell death. Microscopy showed normal endothelial cell morphology and complete apposition of the donor DM against the recipient posterior stroma. Conclusions. DM can be transplanted in vitro with acceptable damage to the donor endothelium and with little induced astigmatism.

Donor tissue preparation for Descemet membrane endothelial keratoplasty

PURPOSE: To evaluate a technique for preparing a donor Descemet membrane carrying autologous endothelium for transplantation in Descemet membrane endothelial keratoplasty (DMEK). SETTING: Netherlands Institute for Innovative Ocular Surgery, Rotterdam, The Netherlands. METHODS: A 9.5 mm diameter DM carrying autologous endothelium was stripped from 10 corneoscleral rims that had been organ cultured for 1 week. The endothelial cell density (ECD) was evaluated with light microscopy before and immediately after DM was stripped and during 4 additional weeks of organ culture. RESULTS: The mean ECD was 2701 cells/mm2 ± 302 (SD) before and 2719 ± 322 cells/mm2 immediately after DM was stripped and declined from 2604 ± 352 cells/mm2 after 1 week to 2190 ± 768 cells/mm2 after an additional 4 weeks of organ culture (n = 10). Typical “endothelial streaks,” ie, linear cellular disruptions observed immediately after DM was stripped, showed complete regeneration after the second culture period. CONCLUSIONS: Descemet grafts for transplantation in DMEK procedures can be surgically prepared from organ‐cultured corneal rims and stored for an additional 3 weeks with acceptable endothelial cell loss. Because the donor tissue can be dissected directly from organ‐cultured corneoscleral rims, donor preparation for DMEK can be readily accessible to most corneal surgeons.

Endothelial keratoplasty: DSEK/DSAEK or DMEK--the thinner the better?

Purpose of review Endothelial keratoplasty has been adopted worldwide as an alternative to penetrating keratoplasty in the treatment of corneal endothelial disorders. Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) may be the current standard, whereas Descemet membrane endothelial keratoplasty (DMEK), that is, isolated transplantation of Descemet membrane, may allow further improvement of clinical outcome. Recent findings DSEK/DSAEK may still have three major challenges: suboptimal visual acuity and relatively slow visual rehabilitation, limited accessibility due to required investments in equipment or the purchase of predissected tissue, and a drop in donor endothelial cell density in the early postoperative phase. Although DMEK may allow much quicker and (near) complete visual rehabilitation as well as easier logistics in donor preparation, the surgical technique may initially require more training to obtain consistent outcomes. Summary Compared with DSEK/DSAEK, DMEK may have higher clinical potential with 75% of cases reaching 20/25 or better (≥0.8) within 1–3 months. Furthermore, preparation of isolated Descemet grafts does not require large investments and may increase overall donor tissue availability. Hence, corneal surgeons may consider ‘to make the switch’ from DSEK/DSAEK to DMEK.

Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy: review of the first 50 consecutive cases

Purpose:To evaluate the clinical outcome and complications of Descemet membrane endothelial keratoplasty (DMEK), using Descemet-stripping endothelial keratoplasty (DSEK) as a back-up procedure, in the management of Fuchs endothelial dystrophy.Design:Non-randomised prospective clinical study.Methods:The first fifty consecutive eyes that underwent DMEK, that is, transplantation of an isolated donor Descemet membrane carrying its endothelium, for Fuchs endothelial dystrophy were evaluated. In all eyes, the best-corrected visual acuity (BCVA) as well as the endothelial cell density (ECD) was measured before and at 6 months after surgery, as clinical outcome parameters.Results:Ten patients required a secondary DSEK for failed DMEK. In the remaining 40 DMEK eyes, 95% had a BCVA of ⩾20/40 (⩾0.5) and 75% ⩾20/25 (⩾0.8) at 6 months after surgery. ECD averaged 2618 (±201) cells/mm2 before, and 1876 (±522) cells/mm2 at 6 months after surgery (n=35). When the outcomes of DMEK and secondary DSEK procedures were combined, 94% reached a BCVA of ⩾20/40 (⩾0.5) and 66% ⩾20/25 (⩾0.8) (n=47), and ECD averaged 2623 (±193) cells/mm2 before, and 1815 (±578) cells/mm2 at 6 months after surgery (n=43).Conclusion:With DSEK as a back-up procedure, DMEK may provide relatively quick and complete visual rehabilitation in a majority of patients operated on for Fuchs endothelial dystrophy. Endothelial cell survival may be similar to earlier types of (lamellar) keratoplasty. Early graft detachment was the main complication in this first series of DMEK surgeries for Fuchs endothelial dystrophy.

Sutureless, posterior lamellar keratoplasty: a case report of a modified technique

Purpose. To describe a technique for sutureless, posterior lamellar keratoplasty. Methods. The procedure was performed for a case of pseudophakic bullous keratopathy. Through a 5.0-mm, self-sealing scleral tunnel incision, a stromal pocket was dissected across the cornea, just above Descemets membrane. An 8.5-mm diameter posterior lamellar disc, consisting of posterior stroma, Descemets membrane, and endothelium, was transplanted without suture fixation. Results. One week after surgery, the best spectacle corrected visual acuity (BSCVA) was 0.8 (20/25), with S −1.5 and C −1.0 × 85°. After 1 year, the posterior transplant was clear and in position, and the BSCVA was 0.8 with S −1.5 and C −1.75 × 80°. Pachymetry measured 0.60 mm. Endothelial cell counts averaged 1390 cells/mm2. Conclusion. Sutureless, posterior lamellar keratoplasty may be an effective new surgical approach for managing corneal endothelial disorders.

Visual Rehabilitation Rate After Isolated Descemet Membrane Transplantation: Descemet Membrane Endothelial Keratoplasty

OBJECTIVE To evaluate visual rehabilitation after Descemet membrane endothelial keratoplasty (DMEK) in the management of corneal endothelial disorders. METHODS In this prospective, nonrandomized, clinical study, DMEK was performed in a first group of 35 consecutive patients with either Fuchs endothelial dystrophy or bullous keratopathy. The Descemet membrane was stripped from the recipient posterior stroma with the anterior chamber completely filled with air. Using a 3.0-mm clear corneal incision, an organ-cultured donor Descemet roll 9 to 10 mm in diameter was inserted into the recipient anterior chamber, positioned on the posterior stroma, and secured by completely filling the anterior chamber with air for 45 to 60 minutes. RESULTS Ten eyes had preexisting ocular disease or an early graft detachment. In the remaining 25 DMEK-treated eyes, best-corrected visual acuity was 20/40 (Snellen notation, 0.5) or more in 18 eyes (72%) within 1 month. At 3 months, best-corrected visual acuity was 20/40 (0.5) or more in 23 of 25 eyes (92%) and 20/25 (0.8) or more in 15 of 25 eyes (60%). CONCLUSIONS In most cases, DMEK results in functional visual rehabilitation within 1 to 3 months. Overall, visual recovery after DMEK may be faster and more complete than with other techniques for (lamellar) keratoplasty for treatment of corneal endothelial disorders. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00521898.