Rénuka S. Birbal

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 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.

Simple technique for graft insertion in Descemet-stripping (automated) endothelial keratoplasty using a 30-gauge needle

&NA; We describe a needle insertion technique for graft insertion in Descemet‐stripping (automated) endothelial keratoplasty (DSEK/DSAEK). A folded donor posterior corneal disk is inserted through a 5.0 mm scleral tunnel incision over a plastic glide using a 30‐gauge needle. The technique enables safe and easy graft insertion without vertical or horizontal compression of the donor tissue, causing minimal trauma to the donor endothelium and/or host structures.

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.

Validity of Bowman layer transplantation for keratoconus: visual performance at 5-7 years

more retinal harm than red laser pointers (Xu et al. 2016). Safety-regulated hand-held lasers have a power output of <5 milliwatts (mW). One retinalinjury-implicated green laser had an output of 42 mW (Raoof et al. 2014). Laser-induced maculopathy may resemble macular dystrophy (Zhang et al. 2016), and children may be reluctant to admit to the mechanism of injury delaying the diagnosis (Raoof et al. 2014). Development of CNV is a rare but serious complication. In our case, CNV was treated successfully with intravitreal anti-VEGF with no reactivation during 4-year follow-up. The outer retina partially recovered over the years, and the boy kept driving licence vision in both eyes, but will require lifetime ophthalmological monitoring for CNV. We wish to raise awareness of the danger of imported laser ‘toys’ of uncertain safety classification.

Bowman layer transplantation in the treatment of keratoconus

Several treatment options corresponding to the grade of keratoconus have been established. These are ultra-violet corneal crosslinking and intracorneal ring segments for mild to moderate keratoconus, and penetrating keratoplasty or deep anterior lamellar keratoplasty for the more advanced cases of keratoconus.Bowman layer transplantation was developed as a procedure for patients with advanced, progressive keratoconus. The technique consists of transplanting an isolated donor Bowman layer into a mid-stromal pocket of a keratoconic cornea resulting in corneal flattening and stabilization against further ectasia. Thus, it aims at corneal stabilization in eyes with advanced keratoconus, and enabling continued contact lens wear for normal visual functionality. By being a sutureless procedure and using an acellular graft, it potentially avoids commonly known suture and graft-related complications of penetrating or deep anterior lamellar keratoplasty.The treatment seems to be a promising option in the management of advanced keratoconus in order to postpone or prevent a more invasive corneal surgery, while minimizing the risk of complications and allowing less stringent surveillance and less intensive medical therapy.

Clinical feasibility of using multiple grafts from a single donor for Quarter-DMEK

in the operating theatre 1 day before surgery. All DSAEK surgeries were performed in the same manner by one surgeon (AI). Concurrent phacoemulsification was performed in patients with cataract. Patients were planned for examination after 1, 3, 6, 12 and 24 months with visual acuity, refraction, Scheimpflug tomography (Pentacam HR, Oculus, Germany), whole eye scatter measurement (OQAS, IQ Medical, Australia) and anterior OCT (Spectralis, Heidelberg Engineering, Germany). The study followed the Helsinki declaration, was approved by the local ethics committee, and all patients gave informed consent to participate in the study. After 1 month, six patients had been treated with FSDSAEK and five patients had received UT-DSAEK. Due to large observed differences in the clinical outcome, no further patients were recruited, and after 3 months, the study was suspended. Graft dislocation occurred in all patients after FS-DSAEK and was managed with rebubbling. In two patients, rebubbling had to be repeated twice. After graft adhesion, all grafts in both groups gradually became clear and thin, although the interface continued to have noticeable haze in all FS-DSAEK patients. No patients with UT-DSAEK had graft dislocation. All patients with FS-DSAEK had significantly poorer clinical outcome than UT-DSAEK patients as seen in Table 1. After 3 months, visual acuity was approximately 2.5 times worse after FS-DSAEK, Pentacam densitometry at the interface was 1.4 times higher, and OQAS whole eye scatter was approximately 2.5 times higher after FS-DSAEK than after UTDSAEK. Graft thickness in FSDSAEK was close to the intended thickness of 110 lm which was slightly more than in UT-DSAEK. Posterior back-surface regularity as measured with Pentacam posterior higher-order aberrations was similar in the two groups. Endothelial cell count was not possible due to interface scatter. In conclusion, the Ziemer LDV Z8 was able to cut planar grafts with a thickness very close to the intended. However, the clinical study had to be aborted prematurely due to poor outcome in FS-DSAEK treated patients with very high rebubble rate (100%) and very poor visual outcome due to increased scatter at the interface. Whether optimizations in laser energy and pattern eventually will improve the outcome of FS-DSAEK sufficiently to allow clinical use remains to be examined.

Asymmetrical endothelial cell migration from in vitro Quarter-Descemet membrane endothelial keratoplasty grafts

To investigate in vitro central and peripheral corneal endothelial cell (EC) migration from Quarter–Descemet membrane endothelial keratoplasty (Quarter‐DMEK) grafts.

Minimizing Graft Preparation Failure in Descemet Membrane Endothelial Keratoplasty

Purpose: To report the failure rate of 2 graft preparation techniques for Descemet membrane endothelial keratoplasty (DMEK) and to evaluate how to minimize graft preparation failure. Methods: Retrospective, nonrandomized study at an eye bank specialized in graft preparation for lamellar keratoplasty. For 1416 donor corneas, the DMEK graft preparation failure rate was evaluated for 2 different techniques, technique I: “Standardized traditional technique” (n = 341) and technique II: “Standardized no-touch technique” (n = 933), and for grafts that were converted from technique II to technique I during preparation (n = 142). Results: The overall failure rate averaged 3.9% (55/1416): 7.0% (24/341) for technique I and 2.9% (31/1075) for technique II (P < 0.05). Tissue preparations which were converted from technique II to technique I failed in 13.4% (19/142), whereas for grafts that were entirely prepared by technique II, the failure rate was only 1.3% (12/933). The endothelial cell density decrease (before compared with after preparation) did not differ for both techniques (1.1% vs. 0.2%, P > 0.05). Conclusions: Various DMEK graft preparation techniques may provide failure rates of <4%. A “no-touch preparation” approach (technique II) may combine good graft quality (completely intact endothelial cell layer, ie, negligible preparation-induced endothelial cell density decrease) with low risk of dissection failure, leaving the possibility of conversion to “traditional preparation” (technique I) as a backup method.