Descemet Stripping Automated Endothelial Keratoplasty Donor Research Articles

Visibility of the Retina Through an Air-Filled Anterior Chamber During Simultaneous Vitrectomy and Descemet's Stripping Automated Endothelial Keratoplasty.

PurposeTo describe the visibility of the retina through an air-filled anterior chamber during simultaneous pars plana vitrectomy (PPV) and Descemet’s stripping automated endothelial keratoplasty (DSAEK), and to discuss the technical challenges of a fluid-air exchange under such conditions.MethodsSix eyes from 6 patients with coexisting bullous keratopathy and posterior segment problems such as vitreous opacity, retained silicon oil, intraocular lens subluxation, or aphakia underwent simultaneous PPV and DSAEK. In all cases, after completion of 25-gauge PPV with/without flanged intrascleral intraocular lens fixation, DSAEK donor tissue was inserted into the anterior chamber. Air was then injected into the anterior chamber to attach the donor graft to the back surface of the host cornea. At this point, the visibility of the retina was evaluated using endoillumination and a wide-angle viewing system.ResultsIn all cases, visibility of the retina through an air-filled anterior chamber, with the DSAEK donor attached, was sufficient to perform a fluid-air exchange.ConclusionOur clinical observations of such rare but clinically important conditions indicate that simultaneous PPV and DSAEK is possible with fair visualization of the posterior segment including the retina.

Hybrid Descemet Membrane Endothelial Keratoplasty (H-DMEK): results of a donor insertion pull-through technique using donor stroma as carrier

AimTo evaluate the outcomes and complications of hybrid Descemet membrane endothelial keratoplasty (H-DMEK) using a Descemet stripping automated endothelial keratoplasty (DSAEK) pull-through donor inserter and donor stroma as carrier.MethodsThis was...

Surface quality and endothelial cell viability after femtosecond laser-assisted donor lenticule preparation for endothelial keratoplasty - An in-vitro study.

Purpose:To compare surface quality and endothelial cell viability of descemet stripping automated endothelial keratoplasty (DSAEK) donor lenticules prepared with femtosecond laser (FSL) or microkeratome (MK).Methods:Experimental ex-vivo evaluation of 15 DSAEK donor lenticules prepared from optical quality donor corneas using 200 KHz FSL (9 eyes) or MK (6 eyes). Surface quality and smoothness of the cut were assessed using atomic force microscopy and endothelial cell viability was assessed using transmission electron microscopy.Results:Mean lenticule thickness was 121.89 ± 17.13 μm in FSL group and 112.67 ± 5.89 μm in MK group (P = 0.33). Average roughness of stromal surface (RMSavg) [FSL- 30.51 ± 4.55 nm, MK-22.37 ± 1.83 nm; P = 0.02] and root mean square roughness (RMSrough) [FSL-31.39 ± 5.75 nm, MK-23.08 ± 0.40 nm; P = 0.012] was significantly more in FSL group. Increased granular and linear irregularities were observed in the FSL group. Endothelial cell disruption was more in FSL group (FSL- 29.49 ± 6.91% MK-13.28 ± 3.62%; P < 0.001) with decreased mean nucleus length (FSL-5.56 ± 0.17 μm, MK-7.52 ± 0.65 μm; P < 0.001).Conclusion:Automated MKs are still the standard of care for donor lenticule preparation and MK-assisted donor lenticules have smoother surface with less endothelial cell disruption than FSL. Further research is mandatory before FSL platforms can be considered a viable alternative to the MK.

Factors Influencing Graft Endothelial Cell Density after Descemet Stripping Automated Endothelial Keratoplasty.

Purpose:To determine the factors that influence the endothelial cell density (ECD) of donor grafts after Descemet stripping automated endothelial keratoplasty (DSAEK).Methods:This retrospective, interventional case series comprised 77 eyes of 64 patients who underwent DSAEK. Confocal microscopy was performed at the final follow-up examination to evaluate the endothelial cell count, cell morphology, and graft thickness. Univariate and multiple linear regression analyses were used to investigate recipient-, donor-, surgical-, and postoperative related variables capable of influencing graft endothelial cell counts after DSAEK.Results:The mean patient age was 62.3 ± 15.6 years; patients were followed-up for 26.2 ± 20.9 months postoperatively. Forty-six eyes (59.7%) underwent stand-alone DSAEK; 31 eyes (40.3%) underwent DSAEK combined with cataract surgery. The donor trephination size was 8.0 ± 0.21 mm. The mean donor age was 30.4 ± 11.2 years, and the mean preoperative endothelial cell density was 3127.4 ± 315.1 cells/mm2, which decreased to 1788.6 ± 716.5 cells/mm2 postoperatively (P < 0.001). The mean postoperative central graft thickness was 102.4 ± 31.6 μm. Univariate analysis revealed that postoperative ECD was significantly associated with death to preservation time (P = 0.046), graft thickness (P = 0.016), follow-up duration (P = 0.005), and graft non-attachment (P = 0.049). Multiple regression analyses identified graft thickness (β = 10.62, P = 0.003) and follow-up duration (β = -22.09, P = 0.001) as the significant characteristics influencing postoperative ECD.Conclusion:The primary predictors of ECD after DSAEK were graft thickness and duration of follow-up. Surgeons’ requests for ultrathin DSAEK donor grafts to improve visual outcomes might not have the desired postoperative outcome with respect to ECD.

Hypoxia and the Prolyl Hydroxylase Inhibitor FG-4592 Protect Corneal Endothelial Cells From Mechanical and Perioperative Surgical Stress.

To determine whether hypoxia preconditioning can protect corneal endothelial cells from mechanical stress and perioperative procedures mimicking Descemet stripping automated endothelial keratoplasty (DSAEK). Preconditioning was delivered by 2 hours of 0.5% oxygen incubation in a hypoxia chamber or by exposure to the prolyl hydroxylase inhibitor FG-4592, which prevents hypoxia-inducible factor-1 alpha degradation. Damage to whole corneas was produced by brief sonication. To mimic use with DSAEK, FG-4592-preconditioned and control donor corneas were dissected with a microkeratome, and the posterior donor button was pulled through a transplant insertion device (Busin glide). The area of endothelial damage was determined by trypan blue staining. In all cases, hypoxia preconditioning or incubation with FG-4592 protected corneal endothelial cells from death by mechanical stress. Hypoxia-preconditioned human and rabbit corneas showed 19% and 29% less cell loss, respectively, relative to controls, which were both significant at P < 0.05. FG-4592 preconditioning reduced endothelial cell loss associated with preparation and insertion of DSAEK grafts by 23% relative to the control (P < 0.01). These results support the hypothesis that preconditioning by hypoxia or exposure to FG-4592 improves corneal endothelial cell survival and may also provide protection during surgical trauma.

Augmentation of corneal graft tissue with UV‐riboflavin crosslinking: a pilot study in glaucoma drainage device patients

PurposeGlaucoma drainage device (GDD) surgery has gained popularity, with outcomes equivalent to trabeculectomy in some studies. However, erosion of the tube through the overlying conjunctiva may occur in 5–10% of patients. Donor cornea tissue has been utilized as a patch graft for GDD surgery, with positive short‐term results. We report interim results of an ongoing pilot study to determine the feasibility and safety of utilizing the anterior lenticule from Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) corneas, with augmentation by corneal crosslinking.MethodsProspective study of 10 patients undergoing GDD surgery. The anterior corneal lenticule (300–350 μm) from a DSAEK donor tissue was placed epithelial side down in a well, and allowed to soak in riboflavin solution (Vibe‐X, Avedro) for 15 min. Then 8 mW/cm2 ultraviolet irradiation was applied for 15 min, for a total energy of 7.2 J/cm2. The tissue was then bisected and placed in Optisol GS media at 4°C. When ready to be implanted, the tissue was sutured over the glaucoma device, then covered with recipient conjunctiva as per the usual technique. Representative sections were examined with H&amp;E and Masson Trichrome histological stains. Intraoperative and postoperative findings and complications were documented, with all subjects reaching the 3 month visit of an anticipated 36 month study.ResultsAfter 15 min the grafts demonstrated complete saturation with riboflavin. Histology revealed no apparent demarcation line, supporting a full‐thickness treatment effect. There were no intraoperative complications, no postoperative infections, and no unexpected surgical difficulties.ConclusionsUV‐riboflavin crosslinking of corneal tissue appears to be a safe modification of GDD surgery, and warrants ongoing study.

Visualization of precut DSAEK and pre-stripped DMEK donor corneas by intraoperative optical coherence tomography using the RESCAN 700.

BackgroundTo report the feasibility of intraoperative spectral domain optical coherence tomography (OCT) using the RESCAN 700 for the visualization and evaluation of precut Descemet’s stripping automated endothelial keratoplasty (DSAEK) and prestripped Descemet’s membrane endothelial keratoplasty (DMEK) donor tissue.MethodsPrecut DSAEK (n = 11), prestripped DMEK (n = 4) preserved in a viewing chamber were examined by intraoperative OCT. Wholly intact donor corneas for penetrating keratoplasty (PK) (n = 8) were also examined as controls. The obtained images were analyzed qualitatively for characteristics of each type of donor.ResultsFor each type of donor, characteristic images were consistently obtained by intraoperative OCT in both the front and back views through the viewing chamber. In wholly intact donors for PK, appearance of normal corneal curvature and stromal texture with high reflectivity of epithelium and endothelium cell layers were clearly visualized. In precut DSAEK donors, precut lines were characteristically visualized in addition to the intact donor cornea images. In prestripped DMEK donors, identical OCT images to the intact donor cornea were noted when observed from the anterior surface. However, peripheral partial detachments of Descemet’s membrane were characteristically observed in all prestripped DMEK donors when viewed from the back of the viewing chamber.ConclusionRapid visualization and rough evaluation of donor tissues for PK, precut DSAEK and prestripped DMEK donor corneas by intraoperative OCT was consistently possible through the viewing chamber. Therefore, this device may be used as an alternative of AS-OCT when the eyebank does not have their own AS-OCT. Although the peripheral detachment in DMEK donors are quite common and clinically non-problematic in DMEK donor quality and subsequent DMEK surgeries, it may be useful to distinguish between wholly intact PK donors and prestripped DMEK donors, enabling to prevent mix-ups of donors, especially when several different types of keratoplasties are scheduled in a same day in one operating theater.

Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study.

The aim of this study was to evaluate different factors that affect Descemet stripping automated endothelial keratoplasty (DSAEK) donor graft lenticle adhesion to the recipient cornea. This experimental study included 10 eye bank recipient corneas and 10 donor DSAEK lenticles. Recipient corneas were mounted on an artificial anterior chamber (AC), whereas donor lenticles were placed beneath the host cornea. Using optical coherence tomography and imaging software, the interface gap (IG) between the donor and recipient cornea was quantified to evaluate the effect of variations in AC air fill pressure, AC air fill duration, corneal massage, and corneal venting incisions on DSAEK donor graft lenticle adhesion. Different intraocular pressures (IOP) under air for the same time intervals, do not significantly correlate with the IG; nevertheless, it was noticed that the IG decreases as the IOP increases. With respect to the magnitude of AC IOP, there was no statistically significant difference when comparing 10 mm Hg with 30 mm Hg and assessing IG (P = 0.4). Complete air-fluid exchange resulted in significantly higher IG when compared with AC air bubble of 10 and 30 mm Hg that was sustained for 1 hour (P < 0.05). Furthermore, corneal surface massage did not facilitate DSAEK graft adhesion (P = 0.59). Finally, paracentral venting incisions followed by interface fluid aspiration seemed to significantly decrease the IG (P = 0.014). Corneal venting incisions and higher AC IOP values seem to facilitate DSAEK donor graft lenticle adhesion to the recipient cornea.

Descemet Stripping Automated Endothelial Keratoplasty Using Infant Donor Tissue

The purpose of this study was to report the outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) surgery using infant (2 years and younger) donor tissue. Retrospective interventional case series of 3 patients. All 3 patients in this series had good visual outcomes and clear DSAEK grafts. The average endothelial cell count (ECC) from infant donors was very high (4239 cells/mm(2)). Similarly, the average postoperative ECC was also high (3359 cells/mm(2)) with a mean endothelial cell loss of 20.9% at 11-month follow-up. One patient remarkably had an ECC of 4065 cells per square millimeter at 1-year follow-up with a net endothelial cell loss of only 13.3%. No difficulties were noted using infant donor tissue, including the intraoperative use of the Moria microkeratome to prepare the DSAEK donor, insertion of the donor graft, or with air-bubble management. Using infant donor tissue for DSAEK surgery is safe and may be preferable, particularly for younger patients. The higher preoperative endothelial cell densities in infant donor tissue should improve graft survival and long-term maintenance of corneal transparency provided that surgery-related endothelial cell loss is minimized.

Retrephination of Eccentric Donor Graft for Descemet Stripping Automated Endothelial Keratoplasty

We describe a technique of intraoperative eccentric retrephination of Descemet stripping automated endothelial keratoplasty (DSAEK) donor graft to avoid the presence of epithelium on the graft lenticule. Trephination of the DSAEK graft may prove to be very challenging for surgeons, especially when flap diameter is small; this can result in an eccentric trephination and the presence of epithelium on the graft. Insertion of epithelium with DSAEK donor graft into the anterior chamber could result in epithelial ingrowth and downgrowth, complications that may lead to poor visual outcomes, graft detachment, and anterior chamber angle closure. A second eccentric retrephination is a simple and easy-to-perform intraoperative surgical step that could avoid the presence of corneal epithelium on the DSAEK donor graft.

The Use of Polarization Filters to Detect the Edge of the Descemet's Stripping Automated Endothelial Keratoplasty(DSAEK) Graft

Purpose:To report the technique of combining the two different polarization filters to detect the flap edge of the corneoscleral tissue before trephining the Descemet's stripping automated endothelial keratoplasty (DSAEK) tissue.Methods:A human DSAEK donor tissue was prepared with mechanical microkeratome and the tissue on the cutting block was brought under the microscope. The liner, circular, or the combination of these two polarization filters was placed between the tissue and the microscope. The tissue images were taken with digital camera under either of 3 settings.Results:The combination of circular and linear polarization filters enabled us to recognize the edge of the flap more easily than others.Conclusion:This simple system with polarization filters was effective in clear visualization of the flap edge during DSAEK tissue preparation. These features may significantly enhance safety of various surgical procedures, in addition to DSAEK tissue preparation.

Descemet-stripping Automated Endothelial Keratoplasty (DSAEK)

To qualitatively assess the endothelial damage on Descemet-stripping automated endothelial keratoplasty (DSAEK) donor tissue resulting from a gentian violet marking pen. An in vitro model was used, by using corneoscleral rims, DSAEK quality corneal donor tissue, and a gentian violet marking pen. After making a mark on the stromal side of a microkeratome-prepared DSAEK corneal button to confirm appropriate orientation of the donor tissue after insertion into the anterior chamber, the corneal tissue was returned to Optisol GS solution for 1 hour. A vital dye assay was used to identify devitalized and necrotic endothelial cells with alizarin red S and trypan blue. Corneal donor tissue evaluated with the gentian violet marking pen showed positive trypan blue staining, limited to the area marked with the gentian violet ink. Marking the DSAEK donor stromal surface with a gentian violet marker damages the endothelium. Surgeons should limit the size of the mark or use an insertion technique that avoids confusion about orientation of the donor cornea.