Jessica T. Lie

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.

Standardized ‘no-touch’ donor tissue preparation for DALK and DMEK: harvesting undamaged anterior and posterior transplants from the same donor cornea

Purpose:  To describe a standardized ‘no‐touch’ harvesting technique of anterior and Descemet membrane (DM) grafts for use in deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK), which provides undamaged anterior and posterior corneal grafts.

More efficient use of donor corneal tissue with Descemet membrane endothelial keratoplasty (DMEK): two lamellar keratoplasty procedures with one donor cornea

Since 1998, we have published several techniques for endothelial keratoplasty, popularised as deep lamellar endothelial keratoplasty (DLEK), Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and Descemet membrane endothelial keratoplasty (DMEK).1–3 All of these techniques potentially provide the possibility of using a single donor cornea for more than one recipient: because only the posterior corneal layers are used in endothelial keratoplasty, the remaining anterior cornea may potentially be used in an anterior lamellar keratoplasty procedure. With the advent of DMEK, for which Descemet membrane with its endothelium is stripped from a donor corneo-scleral rim to subsequently become transplanted, the complete donor stroma is left intact for other different transplantation purposes,4 including a “full-stromal-thickness” deep anterior lamellar keratoplasty (DALK). However, the preparation of thin Descemet grafts may …

Bowman Layer Transplantation to Reduce and Stabilize Progressive, Advanced Keratoconus

OBJECTIVE To evaluate the clinical outcome of mid-stromal isolated Bowman layer transplantation, a new surgical technique to reduce and stabilize ectasia in eyes with advanced keratoconus, to postpone penetrating keratoplasty or deep anterior lamellar keratoplasty, and to enable continued daily contact lens wear. DESIGN Prospective, nonrandomized cohort study at a tertiary referral center. PARTICIPANTS Twenty-two eyes of 19 patients with progressive, advanced keratoconus not eligible for ultraviolet cross-linking. INTERVENTIONS The mid-stroma was manually dissected and an isolated donor Bowman layer was positioned within the stromal pocket. MAIN OUTCOME MEASURES Before and up to 36 months after surgery (mean follow-up, 21±7 months), best spectacle-corrected visual acuity (BSCVA), best contact lens-corrected visual acuity (BCLVA), Scheimpflug-based corneal tomography measurements, endothelial cell density, biomicroscopy, refraction, and intraoperative and postoperative complications were recorded. RESULTS Two surgeries were complicated by an intraoperative perforation of Descemet membrane; no other intraoperative or postoperative complications were observed. Maximum keratometry decreased on average from 77.2±6.2 diopters (D) to 69.2±3.7 D (P < 0.001) at 1 month after surgery and remained stable thereafter (P ≥ 0.072). Mean BSCVA improved from 1.27±0.44 logarithm of the minimum angle of resolution units before surgery to 0.90±0.30 logarithm of the minimum angle of resolution units 12 months after surgery (P < 0.001), whereas BCLVA remained stable (P = 0.105). Mean thinnest-point pachymetry increased from 332±59 μm before surgery to 360±50 μm at the latest follow-up (P = 0.012), and no change in endothelial cell density was found (P = 0.355). CONCLUSIONS With isolated Bowman layer transplantation, reduction and stabilization of corneal ectasia was achieved in eyes with progressive, advanced keratoconus. Given the low risk for complications, the procedure may be performed to postpone penetrating or deep anterior lamellar keratoplasty.

Midstromal Isolated Bowman Layer Graft for Reduction of Advanced Keratoconus: A Technique to Postpone Penetrating or Deep Anterior Lamellar Keratoplasty

Midstromal implant of an isolated Bowman layer graft is a new approach to reduce ectasia in eyes with advanced keratoconus. The procedure should postpone penetrating or deep anterior lamellar keratoplasty. Ten eyes of 9 patients with progressive, advanced keratoconus and contact lens intolerance underwent the procedure with no intraoperative adverse events. Throughout the study period, we observed no complications related to stromal dissection and/or the Bowman layer graft. Maximum corneal power decreased from a mean (SD) of 74.5 (7.1) diopters (D) before to 68.3 (5.6) D after surgery (P = .002). Hence, implant of an isolated Bowman layer graft may offer a safe and effective new technique to reduce ectasia in eyes with advanced keratoconus, potentially allowing continued long-term contact lens wear. The low risk of complications may render the procedure suitable as a treatment to postpone penetrating or deep anterior lamellar keratoplasty in cases with impending contact lens intolerance and/or corneal scarring (clinicaltrials.gov Identifier: NCT01686906).

Isolated Bowman layer transplantation to manage persistent subepithelial haze after excimer laser surface ablation

In a 21-year-old patient with persistent dense subepithelial haze after photorefractive keratectomy, unresponsive to retreatment, a stromal flap, 9.0 mm in diameter and approximately 60 microm in thickness, was excised and an unsutured 9.0 mm donor Bowman layer was transplanted onto the stromal bed. The corrected distance visual acuity improved from 20/40 (0.5) before surgery to 20/18 (1.2) with a scleral-supported contact lens 2 months after transplantation. With optical coherence tomography, the transplanted Bowman layer was seen as a fine white line bordering the anterior host stroma. No recurrence of stromal haze was seen throughout the 6-month follow-up. Isolated Bowman layer transplantation may be a new technique for the management of anterior stromal opacities or complicated epithelial wound healing such as persistent corneal haze after excimer laser surface ablation.

Case Report of Quarter-Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy.

Purpose: To describe a further modification of Descemet membrane endothelial keratoplasty (DMEK), using a quarter of an untrephined full-size donor Descemet membrane (DM) sheet (“Quarter-DMEK”). Methods: A 58-year-old patient underwent Quarter-DMEK for Fuchs endothelial dystrophy in his pseudophakic right eye, with a single quadrant of a full-size, 11.5-mm-diameter DM graft. Results: Best-corrected visual acuity improved from 20/50 (0.4) before surgery to 20/40 (0.5) at 1 day, 20/30 (0.7) at 1 week, 20/25 (0.8) at 1 month and 20/20 (1.0) at 3 months after surgery. Central endothelial cell density decreased from 2700 cells/mm2 before surgery to 1551 cells/mm2 at 1 week, 1104 cells/mm2 at 1 month, and 846 cells/mm2 at 3 months after surgery. Pachymetry returned to normal values within the first month. No complications were observed. Conclusions: Quarter-DMEK may give fast visual rehabilitation within the first month similar to visual outcomes after circular DMEK or semicircular DMEK (hemi-DMEK). If long-term endothelial cell density would prove acceptable in a larger number of cases, quarter-DMEK may have the potential to quadruple the availability of donor endothelial tissue for endothelial keratoplasty.

Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty: An Updated Review

Purpose: To provide an overview of the current literature on donor tissue preparation for Descemet membrane endothelial keratoplasty (DMEK). Methods: A comprehensive database search without date restrictions was performed in PubMed and in The Cochrane Library in May, 2017. Keywords included Descemet membrane endothelial keratoplasty, corneal transplantation, graft, harvest, dissection, preparation, endothelial cell, and endothelial cell density. Articles aiming to describe or evaluate a technique for DMEK graft preparation were considered eligible and were included in this review. Results: A graft dissection technique that provides consistent tissue qualities and a low risk of preparation failure is essential for surgeons and eye banks preparing DMEK tissue. Various techniques have been described aiming to facilitate DMEK graft dissection, including manual dissection, pneumatic dissection, and hydrodissection. All show a trend toward a no-touch technique, for example, without direct physical tissue manipulation during tissue harvesting, as a potential ideal approach to minimize graft damage. Conclusions: An overview of the current harvesting techniques available for DMEK may benefit corneal surgeons and eye banks in choosing the best approach for each specific user.

Quarter-Descemet membrane endothelial keratoplasty (Quarter-DMEK) for Fuchs endothelial corneal dystrophy: 6 months clinical outcome

Background/aim To assess the clinical outcome of the first series of Quarter-Descemet membrane endothelial keratoplasty (Quarter-DMEK), a potential hybrid technique between ‘descemetorhexis only’ and conventional, circular DMEK. Methods Prospective interventional case series at a tertiary referral centre. Twelve eyes of 12 patients with central Fuchs endothelial corneal dystrophy underwent Quarter-DMEK, that is, transplantation of one quadrant of a full-diameter DMEK graft, and were evaluated for best-corrected visual acuity (BCVA), endothelial cell density (ECD) and complications up to 6 months postoperatively. Results At 6 months postoperatively, all eyes reached a BCVA of ≥20/40 (≥0.5), 11/12 (92%) of ≥20/25 (≥0.8) and 6/12 (50%) of ≥20/20 (≥1.0). Mean central ECD decreased from 2867 (±161) cells/mm2 before to 1255 (±514) cells/mm2 at 1 month, 1058 (±455) cells/mm2 at 3 months and 968 (±427) cells/mm2 at 6 months after surgery. Rebubbling was performed in 4/12 eyes (33%) within the first two months. Conclusions Quarter-DMEK may be a feasible procedure that allows for visual outcomes similar to conventional, circular DMEK. The relatively large drop in ECD within the first month may have resulted from more extensive endothelial cell migration and/or measurement error (at the graft edges). If longer-term outcomes would resemble those of conventional DMEK, Quarter-DMEK may potentially quadruple the availability of endothelial grafts.

Floating device for donor corneas in organ culture

Aim: To introduce a new floating device for donor corneas to avoid accumulation of debris onto the endothelial surface during organ culture and to facilitate handling of the tissue during preservation and surgery. Methods: From 11 donors, one randomly chosen cornea was stored in organ culture attached to a floating device, while the contralateral cornea was attached to the lid of the phial by a suture (“hanging by suture”). Endothelial cell density (ECD) was evaluated prior to tissue storage and after 2–3 weeks of culture. Furthermore, we compared ECD in a larger group of corneas sent off for transplantation with the device (n = 281) to a historical group of control corneas “hanging by suture” (n = 444). Results: There was no significant difference in ECD between corneas attached to the floating device or “hanging by suture” (n = 11; p⩾0.1). Similarly, no different ECDs were observed between corneas sent off for transplantation with the device (n = 281) and the historical group of control corneas “hanging by suture” (n = 444) (p⩾0.1). Conclusion: The use of the floating device may not affect tissue quality. Since its introduction, the use of the device has been uneventful and greatly facilitated tissue handling.