Lisanne Ham

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.

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.

Endothelial Cell Density After Descemet Membrane Endothelial Keratoplasty: 1- to 3-Year Follow-up

PURPOSE To evaluate donor endothelial cell density (ECD) after Descemet membrane endothelial keratoplasty (DMEK). DESIGN Nonrandomized, prospective clinical study. METHODS From a larger group of patients who underwent DMEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy, complete ECD measurements were available of 26 patients with 6 and 12 months of follow-up, of whom 7 also had 24 months of follow-up. RESULTS For the group with 24 months of follow-up, ECD averaged 2700 (+/- 260) cells/mm(2) before surgery, 2200 (+/- 460) cells/mm(2) at 6 months after surgery, 2050 (+/- 330) cells/mm(2) at 12 months after surgery, and 1780 (+/- 390) cells/mm(2) at 24 months after surgery. For the group with 12 months of follow-up, ECD averaged 2620 (+/- 210) cells/mm(2) before surgery, 1850 (+/- 540) cells/mm(2) at 6 months after surgery, and 1680 (+/- 550) cells/mm(2) at 12 months after surgery. In both groups, the ECD decreased significantly between the preoperative and 6-month measurement (P < .05). CONCLUSIONS Similar to earlier endothelial keratoplasty techniques, DMEK may be associated with a decrease in donor ECD of approximately 25% in the early postoperative phase.

Near complete visual recovery and refractive stability in modern corneal transplantation: Descemet membrane endothelial keratoplasty (DMEK)

OBJECTIVE To report the 6 months results of a large prospective study on Descemet membrane endothelial keratoplasty (DMEK) for management of corneal endothelial disorders. METHODS DMEK was performed in 300 consecutive eyes with Fuchs endothelial dystrophy, bullous keratopathy or previous corneal transplant failure. Best spectacle corrected visual acuity (BSCVA), refractive outcome and endothelial cell density (ECD) were evaluated before and at 1, 3, and 6 months after surgery. Intra- and postoperative complications were documented. RESULTS At 6 months, 98% of eyes reached a BCVA of ≥20/40 (≥0.5), 79% ≥20/25 (≥0.8), 46% ≥20/20 (≥1.0), and 14% ≥20/18 (≥1.2) (n=221). The pre- to 6 months postoperative spherical equivalent (SE) showed a +0.33D (±1.08D) hyperopic shift (P=0.0000). Refractive stability was shown at 3 months after DMEK, i.e. no significant change in SE (P=0.0822) or refractive cylinder (P=0.6182) at 3 versus 6 months follow-up. Donor ECD showed a decrease from 2561 (±198)cells/mm(2) before, to 1674 (±518)cells/mm(2) at 6 months after surgery (n=251) (P=0.0000). The main complication was (partial) graft detachment occurring in 31 eyes (10%). Secondary ocular hypertension was seen in 13 eyes (6%): 6 induced by air-bubble dislocation posterior to the iris and 4 induced by steroids. Secondary cataract requiring phaco-emulsification developed in 3 out of 63 (5%) phakic eyes. CONCLUSIONS DMEK may provide a refractively neutral near complete, rapid visual rehabilitation with ECDs similar to earlier endothelial keratoplasty techniques. This combined with a relatively low complication rate, would indicate that DMEK is a safe and effective treatment for corneal endothelial disorders.

Prevention and Management of Graft Detachment in Descemet Membrane Endothelial Keratoplasty

OBJECTIVE To describe the prevention and management of various types of graft detachment after Descemet membrane endothelial keratoplasty. METHODS In 150 consecutive eyes that underwent Descemet membrane endothelial keratoplasty, the incidence and type of graft detachment were studied at 1, 3, 6, 9, 12, and 24 months after surgery in a nonrandomized, prospective clinical study at a tertiary referral center. Four groups of detachments were identified: a partial detachment of one-third or less of the graft surface area (n = 16; group 1); a partial detachment of more than one-third of the graft surface area (n = 8; group 2); a graft positioned upside down (n = 4; group 3); and a free-floating Descemet roll in the host anterior chamber (n = 8; group 4). RESULTS Partial or complete graft detachment was found in 36 cases (24%), of which 18 (12%) were clinically significant. All 24 eyes with a partial detachment (groups 1 and 2) showed spontaneous corneal clearance, and all but 6 of these eyes (75%) reached visual acuity of 20/40 or better (≥0.5). A reversed clearance pattern and interface spikes were observed in eyes with the graft positioned upside down (group 3). Eyes with a free-floating graft (group 4) showed persistent corneal edema. Detachments were associated with inward folds (12 eyes [33%]), insufficient air-bubble support (7 eyes [19%]), upside-down graft positioning (4 eyes [11%]), use of plastic materials (2 eyes [6%]), irido-graft synechiae (1 eye [3%]), poor endothelial morphology (1 eye [3%]), and stromal irregularity under the main incision (1 eye [3%]); 14 (58%) of the partial detachments were localized inferiorly. CONCLUSIONS Awaiting spontaneous clearance may be advocated in eyes with a partial detachment. Minor adjustments in surgical protocol as well as careful patient selection may further reduce the incidence of graft detachment after Descemet membrane endothelial keratoplasty to 4% or less. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00521898.

Refractive change and stability after Descemet membrane endothelial keratoplasty Effect of corneal dehydration-induced hyperopic shift on intraocular lens power calculation

PURPOSE: To determine the refractive change and stability of the transplanted cornea after Descemet membrane endothelial keratoplasty (DMEK) through a 3.0 mm clear corneal incision. SETTING: Tertiary referral center. DESIGN: Cohort study. METHODS: Subjective and objective refractive data from pseudophakic eyes were obtained before and 3 and 6 months after DMEK. RESULTS: The study comprised 50 eyes, 7 were phakic and 43 pseudophakic. Six months postoperatively, the corrected distance visual acuity was 20/25 (0.8) or better in 38 eyes (74%). The mean increase in spherical equivalent at 6 months (N = 50) was +0.32 diopter (D) ± 1.01 D (SD) (P=.0304) and in refractive cylinder, −0.48 ± 1.02 D (P=.001). Although Scheimpflug imaging showed a stable anterior corneal curvature, the posterior curvature increased from 5.50 ± 0.5 D preoperatively to 6.40 ± 0.4 D at 6 months and pachymetry decreased from 672 ± 82 μm to 540 ± 59 μm, respectively (both N = 32) (both P=.000). CONCLUSIONS: After DMEK, a slight preoperative to postoperative refractive change and stabilization at 3 months occurred that may induce a hyperopic shift that was not the result of the negative lenticule effect of DSEK/DSAEK. Thus, in DMEK, the hyperopic shift may result from a reversal of a preceding myopic shift induced by stromal swelling in endothelial disease. If so, normal intraocular power nomograms apply for cataract surgery before or during DMEK. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Intraocular Graft Unfolding Techniques in Descemet Membrane Endothelial Keratoplasty

OBJECTIVE To define various Descemet graft unfolding techniques in Descemet membrane endothelial keratoplasty. METHODS In a retrospective analysis, the surgical videos of 100 consecutive Descemet membrane endothelial keratoplasty cases with at least 6 months of follow-up were evaluated and categorized. The Descemet graft unfolding methods were categorized into 4 basic techniques and 3 auxiliary techniques. RESULTS All Descemet membrane endothelial keratoplasty surgical procedures could be completed using (a combination of) 4 Descemet graft unfolding techniques: (1) standardized no-touch graft unfolding using a double roll, (2) carpet unrolling while fixating 1 graft edge (Dirisamer technique), (3) small air bubble-assisted unrolling (Dapena maneuver), (4) the single sliding cannula maneuver. Additional maneuvers included turning over the graft when oriented upside down (flushing); manual graft centration with a cannula; and bubble bumping to unfold peripheral inward folds. In 73% of surgical procedures, technique 1 was used, while a combination of techniques was used in 44% and auxiliary techniques in 62%. None of the techniques showed a correlation with the best-corrected visual acuity, endothelial cell density, or postoperative complication rate (P > .10). CONCLUSIONS Descemet membrane endothelial keratoplasty may be further facilitated by using controlled techniques for unfolding the Descemet graft inside the recipient anterior chamber, either as stand-alone techniques or used in various combinations.

Outcomes of Descemet membrane endothelial keratoplasty in phakic eyes

PURPOSE: To determine the clinical outcomes of isolated Descemet membrane transplantation (ie, Descemet membrane endothelial keratoplasty [DMEK]) in phakic eyes. SETTING: Tertiary referral center. DESIGN: Cohort study. METHODS: Phakic eyes from a larger group of consecutive eyes that had DMEK for Fuchs endothelial dystrophy were examined. The examination included corrected distance visual acuity (CDVA), subjective and objective refractions, endothelial cell density (ECD), and intraoperative and postoperative complications at 1, 3, and 6 months. RESULTS: The study enrolled 52 phakic eyes from a group of 260 DMEK eyes. Of the phakic eyes, 69% reached a CDVA equal to or better than 20/40 (≥0.5) within 1 week and 85% reached equal to or better than 20/25 (≥0.8) at 6 months. Compared with an age‐matched control group of pseudophakic eyes, phakic eyes had a similar visual rehabilitation rate, final visual outcome, mean ECD at 6 months (1660 cells/mm2 ± 470 [SD]), minor hyperopic shift (+0.74 diopter), and graft detachment rate (4%). Visual acuity equal to or better than 20/13 (≥1.5) was limited to phakic eyes, suggesting better optical quality with the crystalline lens in situ. Temporary mechanical angle‐closure glaucoma due to air‐bubble dislocation behind the iris was the main complication (11.5%). Two eyes (4%) required phacoemulsification after DMEK. CONCLUSIONS: In phakic eyes, DMEK may give excellent visual outcomes without an increased risk for complications. Visual acuities equal to or better than 20/13 (≥1.5) may indicate that the almost anatomic repair after DMEK is associated with near perfect optical quality of the transplanted cornea. Financial Disclosure: Dr. Melles is a consultant to D.O.R.C. International/Dutch Ophthalmic USA. No author has a financial or proprietary interest in any material or method mentioned.