Artificial Endothelial Layer Implantation After Multiple Failed Keratoplasties

PURPOSE

Presenting the first case of noncellular corneal endothelial substitute after multiple failed penetrating keratoplasty (PK) and lamellar endothelial keratoplasty.

METHODS

Our case presented with pseudophakic bullous keratopathy after a history of 2 rejected PKs and 1 rejected Descemet stripping automated endothelial keratoplasty. We implanted an artificial endothelial layer.

RESULTS

The implant remained fully attached for a follow-up period of 12 months, and central corneal thickness decreased significantly. The patient reported improvement in her subjective vision, although ocular comorbidities limited the visual potential.

CONCLUSIONS

This new device could serve as an alternative to lamellar endothelial corneal transplantation in cases where tissue rejection has occurred and is highly likely to recur. The technique is simple, and the deswelling effect on the cornea persisted, although the visual results require further validation in patients with a higher visual potential.

Corneal Endothelium Viability Assay Using Trypan Blue Dye After Preloaded Descemet Membrane Endothelial Keratoplasty Graft Preparation

PURPOSE

The purpose of this study was to establish a validated method, consistent with Eye Bank Association of America medical standards, for evaluating endothelial cell loss (ECL) from an entire Descemet membrane endothelial keratoplasty (DMEK) graft using trypan blue dye as an alternative to specular microscopy.

METHOD

Twenty-nine corneas were prepared for preloaded DMEK by a single technician, and the endothelium was stained with trypan blue dye for 30 seconds. The technician estimated total cell loss as a percentage of the graft and captured an image. Images were evaluated by a blinded technician using ImageJ software to determine ECL and compared with endothelial cell density from specular microscopy. Tissue processing intervals were analyzed for 4 months before and after implementation of this method.

RESULTS

For the 29 grafts, there was no statistically significant difference ( t test, P = 0.285) between ECL estimated by a processor (mean = 5.8%) and ECL calculated using an ImageJ software (mean = 5.1%). The processor tended to estimate greater ECL than the actual ECL determined by ImageJ (paired t test, P = 0.022). Comparatively, postprocessing endothelial cell density measured by specular microscopy were higher compared with the preprocessing endothelial cell density (mean = 4.5% P = 0.0006). After implementation of this evaluation method, DMEK graft processing time intervals were reduced by 47.9% compared with specular microscopy evaluation ( P < 0.001).

CONCLUSIONS

Our results show that visual ECL estimation using trypan blue staining by a DMEK graft processor is a reliable and efficient method for endothelial assessment. Unlike specular microscopy, this method achieves comprehensive visualization of the entire endothelium, reduces total time out of cold storage, and decreases total time required to prepare and evaluate DMEK grafts.

Outcomes and Early Complications Using an Endothelium-in Pull-Through Descemet Membrane Endothelial Keratoplasty Technique With Preloaded Versus Surgeon-Loaded Donor Tissue in Fuchs Patients

PURPOSE

This study aimed to compare outcomes and early complications using an endothelium-in pull-through Descemet membrane endothelial keratoplasty (DMEK) technique with preloaded versus surgeon-loaded donor tissue.

METHODS

Data from 163 eyes of 125 patients at the Wilmer Eye Institute diagnosed with Fuchs endothelial corneal dystrophy who underwent DMEK with or without cataract extraction using surgeon-loaded tissue (n = 83) or preloaded tissue (n = 80) were reviewed. Best-corrected visual acuity and early postoperative complications including small graft detachment (less than one third of the graft area), large graft detachment (more than one third), graft failure, and rebubbling were compared.

RESULTS

Baseline characteristics including age, sex, and visual acuity were not statistically different between the groups. Small graft detachment was observed in 18.1% of the surgeon-loaded and 22.5% of the preloaded group ( P = 0.48), whereas large detachment occurred in 12.0% and 5.0%, respectively ( P = 0.11). Among these, rebubbling was performed in 18 (21.7%) in the surgeon-loaded compared with 12 (15.0%) in the preloaded group ( P = 0.27). The rebubbling rate of the combined procedure (cataract surgery and DMEK) was 21.8% and of DMEK alone was 7.7% ( P = 0.048). Primary graft failure occurred in 2 surgeon-loaded cases (2.4%) and 1 preloaded case (1.3%) ( P = 0.58). There was no difference in postoperative best-corrected visual acuity at 1 year (logarithm of the minimum angle of resolution 0.21 ± 0.25 for the surgeon-loaded vs. 0.16 ± 0.16 for the preloaded group, P = 0.23).

CONCLUSIONS

DMEK surgery using preloaded endothelium-in tissue has comparable outcomes with surgeon-loaded endothelium-in tissue. However, there was a trend toward the lower rebubbling rate in DMEK alone compared with combined procedures.

One-year Outcomes of Ultrathin Descemet Stripping Automated Endothelial Keratoplasty Combined with Cataract Surgery in the Korean Population

PURPOSE

To evaluate the refractive outcomes after ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) combined with phacoemulsification and intraocular lens implantation (triple procedure) in the South Korean population.

METHODS

This retrospective observational study included 37 eyes of 36 patients who underwent the UT-DSAEK triple procedure between 2012 and 2021 in a single tertiary hospital. Preoperative and postoperative refractive outcomes and endothelial parameters at 1, 3, 6, and 12 months were observed.

RESULTS

At the final postoperative 12-month period, the average best-corrected visual acuity was 0.4 ± 0.5 in logarithm of the minimum angle of resolution. The mean endothelial cell density at 12 months was 1,841.92 ± 731.24 cells/mm2, indicating no significant endothelial cell loss compared to the baseline (p = 0.128). The mean postoperative central corneal thickness at 12 months was 597.41 ± 86.26 μm. The postoperative mean absolute error at 12 months was 0.96 ± 0.89 diopters (D) and mean error was 0.89 ± 0.97 D.

CONCLUSIONS

The results of our South Korean cohort study on UT-DSAEK triple surgery showed favorable and safe outcomes. Regardless of graft thickness, it should be noted that a hyperopic shift of 1.00 to 2.00 D needs to be considered in the case of UT-DSAEK triple surgery.

Retrospective Study of Preoperative Laser Peripheral Iridotomy Versus Intraoperative Surgical Peripheral Iridectomy in Descemet Membrane Endothelial Keratoplasty

PURPOSE

The aim of this study was to examine the outcomes of laser peripheral iridotomy (LPI) and surgical peripheral iridectomy (SPI) for Descemet membrane endothelial keratoplasty (DMEK) and DMEK with cataract extraction (triple DMEK).

METHODS

This retrospective interventional study included 135 eyes of 135 patients who underwent DMEK alone or triple DMEK. Primary outcomes were graft detachments necessitating rebubbling, repeat grafts, and pupillary block. The secondary outcomes included rejection, cystoid macular edema, uveitis, intraoperative hyphema, visual disturbances, and surgical time.

RESULTS

Thirty-one eyes in the LPI group and 104 eyes in the SPI group were included. Fifty-six eyes had DMEK alone, and 79 had triple DMEK. Visually significant graft detachments occurred in 7 of 31 eyes in the LPI group versus 19 of 104 eyes in the SPI group ( P = 0.61). No statistical significance in DMEK alone versus triple DMEK groups ( P = 0.61 vs. P > 0.99). Two patients in the LPI group and 5 in the SPI group required regraft ( P = 0.66). One (3.2%) experienced pupillary block compared with 5 (4.8%) ( P = 0.99) in the LPI and SPI groups, respectively. Secondary outcomes were similar in both groups ranging from 0% to 3% ( P > 0.99). None had visual disturbances. In DMEK alone, duration of surgery was significantly shorter in the LPI versus SPI group (32.8 vs. 44.1 minutes, P = 0.02).

CONCLUSIONS

This study demonstrated similar outcomes between LPI and SPI, although the LPI group had a shorter duration of surgery when DMEK was performed alone. The remainder of the outcomes demonstrated no statistically significant differences.

Combined or sequential DMEK in cases of cataract and Fuchs endothelial corneal dystrophy-A systematic review and meta-analysis

To compare the outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed after phacoemulsification and intraocular lens (IOL) implantation (sequential DMEK) and DMEK combined with phacoemulsification and IOL implantation (combined DMEK) in patients with Fuchs endothelial corneal dystrophy (FECD) and cataract. Systematic literature review and meta-analysis performed according to the PRISMA guidelines and registered in PROSPERO. Literature searches were conducted in Medline and Scopus. Comparative studies reporting sequential DMEK and combined DMEK in FECD patients were included. The main outcome measure of the study was the corrected distance visual acuity (CDVA) improvement. Secondary outcomes were postoperative endothelial cell density (ECD), rebubbling rate and primary graft failure rate. Bias risk was assessed and a quality appraisal of the body of evidence was completed using the Cochrane Robin-I tool. A total of 667 eyes (5 studies) were included in this review, 292 eyes (43.77%) underwent a combined DMEK, while 375 (56.22%) eyes underwent a sequential DMEK surgery. We found no evidence of a difference between the two groups (mean difference, 95% CI) regarding: (1) CDVA improvement (-0.06; -0.14, 0.03 LogMAR; 3 studies, I2 : 0%; p = 0.86); (2) postoperative ECD (-62; -190, 67 cells/mm2 ; 4 studies, I2 : 67%; p = 0.35); (3) rebubbling (risks ratio: 1.04; 0.59, 1.85; 4 studies, I2 : 48%; p = 0.89); and primary graft failure rate (risks ratio: 0.91; 0.32, 2.57; 3 studies, I2 : 0%; p = 0.86). Of all the 5 non-randomized studies, all (100%) were graded as low quality. The overall quality of the analysed studies was low. Randomized controlled trials are needed to confirm no difference or superiority of one approach in terms of CDVA, endothelial cell count and postoperative complication rate between the two arms.

Comparison of Long-Term Outcomes of DSEK and DMEK in Fuchs Endothelial Dystrophy

PURPOSE

This study aimed to compare the long-term endothelial cell loss, graft survival, and clinical outcomes in patients with Fuchs endothelial dystrophy (FED) after Descemet stripping endothelial keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK) using a standardized surgical protocol.

METHODS

Three hundred and six consecutive DSEK and DMEK grafts of 223 patients with FED performed by 8 surgeons between January 2006 and August 2022 were analyzed. The primary outcome measures were graft survival, endothelial cell loss, and best spectacle-corrected visual acuity.

RESULTS

At 5 years, graft survival was 96% for both DSEK and DMEK eyes. The mean percentage of endothelial cell loss was 57.7 ± 17.1 in DSEK and 56.8 ± 15.2 in DMEK eyes ( P = 0.430). The mean best spectacle-corrected visual acuity was 0.13 ± 0.14 logMAR in DSEK and 0.01 ± 0.18 logMAR in DMEK grafts ( P <0.00001) at 5 years postoperatively. Rebubbling was performed in 7.8% DSEK and 2.1% DMEK grafts ( P = 0.441). Cox regression identified rejection episodes (HR 6.5; 95% CI: 1.70-24.8; P = 0.0062) as a significant contributing factor for graft failure.

CONCLUSIONS

DMEK had superior visual acuity outcomes compared with DSEK in these patients up to 5 years after surgery. At 5 years, there was no significant difference in graft survival or endothelial cell loss between DSEK and DMEK eyes with FED. We propose that our standardized technique reduces the need for rebubbling.

Comparison of efficacy of three gases for anterior chamber tamponade in Descemet's membrane endothelial keratoplasty

PURPOSE

To compare the efficacy of three different gases for intraocular tamponade: 100% air, 10% perfluoropropane (C3F8), and 10% sulfur hexafluoride (SF6), in Descemet's membrane endothelial keratoplasty (DMEK).

MATERIALS AND METHODS

The medical records of 138 patients who underwent DMEK were reviewed retrospectively, with the primary outcome being the rebubbling rate in the first week following surgery. Other clinical outcomes, such as best-corrected visual acuity (BCVA), central corneal thickness (CCT), incidence of rebubbling after the first week, endothelial cell density (ECD), graft detachment, graft failure, pupillary block, and intraocular pressure (IOP) changes were also analyzed.

RESULTS

Of the 138 patients, 57 were in group 1 (treated with air), 44 in group 2 (treated with 10% C3F8), and 37 in group 3 (treated with 10% SF6). Group 3 showed significantly lower rates of graft detachment and rebubbling compared to groups 1 and 2 (P<0.001). However, there was no significant difference in postoperative BCVA among the groups. At one year, the mean endothelial cell loss was 32% in group 1, 30% in group 2, and 33% in group 3 (P=0.715). One patient in group 1 experienced pupillary block and increased IOP, while there were no such occurrences in the other groups. There was no difference between the groups in terms of graft failure.

CONCLUSION

The use of 10% SF6 in DMEK surgery may be a good option due to its efficacy in preventing graft detachment, low rebubbling rate, and potential for minimizing complications.

New forceps free injection technique for delivering descemet membrane endothelial keratoplasty preloaded endothelium-in grafts

PURPOSE

To describe a new method for delivering DMEK grafts into the recipient's eye with endothelium inward configuration using a no-forceps injection technique.

METHODS

We retrospectively review 11 patients that underwent DMEK surgery at our institution using a no-forceps injection technique. The graft was preloaded into an intraocular lens (IOL) cartridge and connected to an anterior chamber maintainer (ACM). A 5 ml non luer lock syringe was inserted into the other end of the ACM to create a one-flow system. The cartridge was inserted into the posterior end of an injector, and the graft was successfully delivered into the recipient's eye.

RESULT

Twelve eyes of 11 patients were included. Mean follow-up was 9.16 ± 1.3 months. At baseline, mean best corrected visual acuity (BCVA) was 0.76 ± 0.13 logMAr and mean endothelial cell density (ECD) was 2619.00 ± 115.89 cells/mm2. At follow-up, BCVA significantly improved to 0.22 ± 0.05 logMAR (p = 0.003). Although we observed a significant reduction in ECD at follow-up (1688 ± 182.20, p = 0.002), our patients lost only 35.69 ± 6.36% of endothelial cells.

CONCLUSION

Our technique can help surgeons safely deliver an endothelium-in graft into the recipient's eye. The method doesn't require the use of a forceps, minimizing the risk of endothelial cell loss or graft damage.

Size and Shape Matter: Cell Viability of Preloaded Descemet Stripping Automated Endothelial Keratoplasty Grafts in Three Different Carriers

PURPOSE

The aim of this study was to examine endothelial cell loss (ECL) associated with preloaded Descemet stripping automated endothelial keratoplasty (DSAEK) grafts loaded into 3 carriers of different size and shape.

METHODS

Thirty-six donor corneas were prepared for DSAEK and loaded into an EndoGlide Ultrathin (control) (2.0 mm × 3.5 mm lumen, 4.5 mm/4.9 mm incision for scleral tunnel/clear corneal insertion), Descemet membrane endothelial keratoplasty EndoGlide (experimental) (1.1 mm × 1.7 mm lumen, 2.65 mm incision), or round glass Jones tube (experimental) (1.8 mm lumen, 3.0 mm incision). Control grafts were stored for 6 days in Optisol-GS and experimental grafts stored for 24 hours in Life4C before analysis using Calcein AM staining. Grafts were imaged and ECL was analyzed by FIJI segmentation. The statistical significance of ECL was determined using 1-way ANOVA and Tukey post hoc analysis.

RESULTS

There were no significant differences in donor characteristics for grafts in each cohort. ECL for grafts loaded into the EndoGlide Ultrathin was 10.3% ± 2.3% (graft thickness: 60-189 μm, n = 9). ECL for grafts loaded into the Descemet membrane endothelial keratoplasty EndoGlide was 22.2% ± 7.1% (graft thickness: 38-63 μm, n = 9). ECL for thin grafts (34-60 μm, n = 9) loaded into the Jones tube was 24.0% ± 5.0%. ECL for thick grafts (92-119 μm, n = 9) loaded into the Jones tube was 34.2% ± 6.1% ECL ( P < 0.001). Combined regression analysis revealed that graft thickness is directly correlated to ECL ( P < 0.01).

CONCLUSIONS

The size and shape of the carrier can influence the cell viability of preloaded DSAEK grafts. Compared with a larger carrier, smaller lumen carriers are associated with greater ECL. In smaller lumen carriers, ECL increases with increasing DSAEK graft thickness.

Preloaded DMEK With Endothelium Outward: A Multicenter Clinical Study Using DMEK Rapid Device

PURPOSE

The objective of this study is to validate Descemet membrane endothelial keratoplasty (DMEK) Rapid device for preloading DMEK grafts with endothelium outward.

METHODS

In this multicenter retrospective clinical study, DMEK tissues (n = 27) were peeled and preloaded (8.25 mm) in a DMEK Rapid device. The device was loaded in a container prefilled with the storage solution and shipped from a single center in Italy to 4 different centers located in Italy and the United Kingdom. Preloaded tissues were delivered by injecting the graft in the anterior chamber. Patients were monitored at days 1 and 15 and at months 1, 3, and 6, as well as at the last follow-up (9-12 months) postoperatively. Main outcome measures included rebubbling rate and graft failure, corrected distance visual acuity, endothelial cell loss (ECL), and central corneal thickness at all time points. A one-way analysis of variance test comparing day 1 with all later time points was followed with significance at P < 0.05.

RESULTS

The average recorded surgical time was 6 to 25 minutes with no immediate surgical complications. Rebubbling was observed in 7 of 26 cases with one graft failure within 15 days postoperatively. The mean corrected distance visual acuity at day 1 was 0.64 ± 0.49 logMAR, which improved to 0.18 ± 0.43 logMAR at the last follow-up. Endothelial cell density values showed a significant decrease at the last follow-up (1827 ± 565 cells/mm 2 ) ( P < 0.001) compared with the preoperative value (2503 ± 128 cells/mm 2 ), with an average endothelial cell loss of 27%. Central corneal thickness significantly dropped from 694 ± 157 μm at day 1 to 502 ± 42 μm at the last follow-up ( P < 0.001).

CONCLUSIONS

DMEK Rapid device is quick, easy, and efficient for preloading and shipping DMEK grafts internationally in endothelium-outward orientation.

Persistent Localized Descemet Membrane Endothelial Keratoplasty Detachments Secondary to Corneal Ink Stain Marks

PURPOSE

The aim of this study was to describe 2 cases of persistent endothelial graft detachments secondary to corneal gentian violet ink stain marks.

METHODS

This study included a case review of hospital records of 2 eyes with localized Descemet's membrane detachments after Descemet membrane endothelial keratoplasty (DMEK) surgery.

RESULTS

Two patients underwent consecutive uncomplicated DMEK surgery for Fuchs endothelial dystrophy with identical techniques. The grafts were marked with an ink marker through a stromal window to ensure correct orientation during donor graft preparation. Both patients had localized detachments around the ink mark on day 1, week 1, and up to 1 month at postoperative review. The persistent detachment was believed to be due to the gentian violet marker used which had a higher concentration of isopropyl alcohol solvent than the standard marking pen routinely used.

CONCLUSIONS

Ink markers with higher concentrations of isopropyl solvent may result in higher DMEK detachment rates and caution is advised when using these markers.

Clinical Outcomes of Transscleral-Sutured Intraocular Lens Combined With Descemet Membrane Endothelial Keratoplasty

PURPOSE

The aim of the study was to report clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) combined with transscleral-sutured intraocular lens (IOL) compared with DMEK combined with phacoemulsification and posterior chamber IOL (Phaco-DMEK).

METHODS

A retrospective chart review of all patients who underwent DMEK combined with transscleral-sutured intraocular lens fixation or combined with phacoemulsification for Fuchs endothelial corneal dystrophy from 2016 to 2021 at the Toronto Western Hospital or the Kensington Eye Institute (Toronto, ON, Canada) and had at least 18 months of follow-up was performed. Main outcomes were postoperative distance-corrected visual acuity, rebubbling rate, graft survival rate, and complications.

RESULTS

Twenty-one cases of DMEK combined with transscleral-sutured IOL (DMEK-TSS-IOL) and 44 cases of Phaco-DMEK were evaluated. Twelve eyes (57.15%) had a foldable acrylic 3-piece IOL (AR40E) and 9 (42.85%) had a single-piece polymethylmethacrylate (PMMA) IOL (CZ70BD). LogMAR distance-corrected visual acuity improved significantly from 1.48 ± 0.62 (SD) to 0.86 ± 0.82 ( P = 0.01) 12 months after DMEK-TSS-IOL and from 0.41 ± 0.29 logMAR to 0.11 ± 0.11 logMAR ( P < 0.0001) after Phaco-DMEK. No statistically significant differences were observed in donor ( P = 0.97) or 1-year postoperative endothelial cell density ( P = 0.11) between the groups. Rebubbling was necessary in 33.33% of eyes in DMEK-TSS-IOL compared with 25% of Phaco-DMEK eyes ( P = 0.55). Graft survival rate was 76.19% in the DMEK-TSS-IOL group compared with 90.90% in the Phaco-DMEK group ( P = 0.13).

CONCLUSIONS

Transscleral-sutured IOL combined with DMEK is an option for the management of endothelial diseases in aphakic eyes or those which require IOL exchange for the experienced surgeon. However, when compared with routine Phaco-DMEK, there are higher complication and lower survival rates at 18 months.

Corneal densitometry patterns in Descemet membrane endothelial keratoplasty and Descemet stripping automated keratoplasty

PURPOSE

To compare corneal densitometry in a consecutive series of 52 endothelial keratoplasties (DMEK/DSAEK) using a Scheimpflug-based device after six months of follow-up.

METHODS

Corneal densitometry (CD) values of 102 eyes were divided into three main groups: 33 DMEKs, 19 DSAEKs, and 50 healthy eyes without previous ocular surgery. The CD values were then analyzed and compared between the groups. We measured three main layers in depth and four different concentric zones at 1, 3, and 6 months postoperatively.

RESULTS

In the DMEK group, total CD significantly decreased from 38.02 ± 10.21 grayscale units (GSU) to 31.13 ± 9.25 GSU (P < 0.01) between the first and the sixth month postoperative. In the DSAEK group, we found significant changes only between the first and three months after surgery (from 42.62 ± 9.31 GSU to 38.71 ± 10.53 GSU (P < 0.01). Regarding the concentric zones, CD in the DMEK group significantly decreased in the central zone from 33.55 ± 12.07 GSU to 30.63 ± 10.15 GSU (P < 0.01) and significantly increased in the periphery from 30.63 ± 10.15 GSU to 36.72 ± 9.37 GSU, (P < 0.01). The DSAEK group showed no changes in the central zone (from 36.91 ± 13.80 GSU to 36.14 ± 11.47 GSU, P = 0.52) and CD significantly increased in the periphery (41.91 ± 9.28 GSU, P < 0.01).

CONCLUSION

When comparing CD values in DMEK versus DSAEK, we found no differences by layers or at central-paracentral concentric zones, although CD differences in the peripheral zones were statistically significant. This finding may be attributed to the thicker graft at periphery with a delayed clearance and less anatomical interphase in DSAEK.

Cost Drivers of Endothelial Keratoplasty: A Time-Driven Activity-Based Costing Analysis

PURPOSE

To determine cost drivers of endothelial keratoplasty (EK) through evaluation of surgical costs and procedure length based on type of EK, use of preloaded grafts, and performance of simultaneous cataract surgery.

DESIGN

This study was an economic analysis of EKs at a single academic institution using time-driven activity-based costing (TDABC) methodology.

PARTICIPANTS

Endothelial keratoplasty surgical cases, including Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), at the University of Michigan Kellogg Eye Center from 2016 to 2018 were included in the analysis.

METHODS

Data and inputs were obtained via the electronic health record (EHR) and from prior literature. Simultaneous cataract surgeries were included and separately categorized for analysis. Endothelial keratoplasty expenses were determined with TDABC, a method for cost calculation that incorporates the time that key resources are used and each resource's associated cost rate.

MAIN OUTCOME MEASURES

Main outcome measures included surgery length (in minutes) and day-of-surgery costs.

RESULTS

There were 559 EKs included: 355 DMEKs and 204 DSAEKs. Fewer DSAEKs had simultaneous cataract extraction (47; 23%) than DMEK (169; 48%). Of the DMEKs, 196 (55%) used preloaded corneal grafts. Descemet membrane endothelial keratoplasty cost $392.31 less (95% confidence interval, $251.05-$533.57; P < 0.0001) than DSAEK and required 16.94 fewer minutes (14.16-19.73; P < 0.0001). Descemet membrane endothelial keratoplasty cases that used preloaded corneal grafts cost $460.19 less ($316.23-$604.14; P < 0.0001) and were 14.16 minutes shorter (11.39-16.93; P < 0.0001). In multivariate regression, preloaded graft use saved $457.19, DMEK (compared with DSAEK) saved $349.97, and simultaneous cataract surgery added $855.17 in day-of-surgery costs.

CONCLUSIONS

Cost analysis of TDABC identified a day-of-surgery cost and surgical time reduction associated with the use of preloaded grafts for DMEK, DMEK compared with DSAEK, and isolated EK compared with EK combined with cataract surgery. This study provides an improved understanding of surgical cost drivers and margin incentivization, which may explain trends and indirectly influence patient care decisions in cornea surgery practices.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Descemet membrane endothelial keratoplasty graft detachments in superior versus temporal approach

PURPOSE

To evaluate the difference in Descemet Membrane Endothelial Keratoplasty (DMEK) graft detachment rate comparing superior versus temporal main incision approach.

METHODS

Retrospective comparative study on patients who underwent DMEK surgery for Fuchs endothelial dystrophy or bullous keratopathy with main wound incision performed at either 90° in the superior approach, or at 180°/0° in the temporal approach. All main incisions were secured with a single 10-0 nylon suture at the end of surgery. Data collected were donor age and gender, endothelial cell counts, graft diameter, recipient age and gender, indication for transplant, surgeon grade, re-bubbling rate, air fill in the anterior chamber (AC) at day one and intra- and early postoperative complications.

RESULTS

187 eyes were included in the study. 99 eyes had DMEK surgery with superior approach, while 88 eyes had temporal approach. The two groups had no differences in donor age and sex, endothelial cell counts, graft diameter, recipient age and sex, indication for transplant, surgeon grade, and air fill in the anterior chamber at day one. Re-bubbling rate was 38.4% for surgeries performed with superior access and 29.5% for those with temporal access(p = 0.186). After exclusion of patients with intraoperative and/or postoperative complication, the difference in re-bubbling rate was higher, although non-significant (37.5% and 25% for superior and temporal approach respectively, p = 0.098).

CONCLUSION

The temporal approach in DMEK showed a trend towards a clinically significant lower rate of post-operative re-bubbling compared to the superior approach, however, no statistically significant difference was noted comparing the two approaches, which both remain feasible options in DMEK surgery.

A Comparison of the Corneal Thickness Following Descemet's Stripping Automated Endothelial Keratoplasty and Descemet's Membrane Endothelial Keratoplasty

PURPOSE

To compare the central corneal thickness before and after Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK), and to evaluate the recipient corneal thickness following DSAEK.

METHODS

The corneal thickness was compared between two groups of eyes following DMEK and DSAEK, performed by a single surgeon between 2015 and 2017. We evaluated the recipient corneal thickness and central corneal thickness pre- and postoperatively at 1, 3, and 6 months using anterior segment optical coherence tomography. Recipient corneal thickness was defined as the corneal thickness without graft thickness.

RESULTS

We included DMEK and DSAEK eyes (n = 26 each), which were similar in terms of their etiologies. Preoperatively, there was no significant difference in the central corneal thickness between the groups (DSAEK, median [interquartile range]: 721 [606.5 to 847.8] µm; and DMEK: 690 [618 to 722.3] µm; p = 0.30). Despite the tendency of the central corneal thickness to be significantly greater (p < .01) at 6 months following DSAEK (619.5 [607.8 to 661.3] µm) compared with that following DMEK (497.5 [475.8 to 525.3] µm), there was no significant difference at 6 months between the recipient corneal thickness following DSAEK (488.5 [443.8 to 515] µm) and central corneal thickness following DMEK (p = 0.54).

CONCLUSIONS

DSAEK eyes display a similar tendency of stromal thinning as DMEK eyes.

Rebubbling and graft detachment in Descemet membrane endothelial keratoplasty using a standardised protocol

OBJECTIVES

To analyse risk factors and long-term outcomes after rebubbling and graft detachment in Descemet membrane endothelial keratoplasty (DMEK).

METHODS

176 consecutive DMEK grafts of 125 patients performed by 8 surgeons with a standardised technique between January 2015 and July 2022 were analysed. Main outcome measures were graft detachments, rebubbling rate, postoperative outcomes, and risk factors for graft failure and rebubbling.

RESULTS

6 (3.4%) grafts required rebubbling (>1/3 area detached). 40 (22.7%) grafts developed self-resolving partial detachments (<1/3 area detached). The mean time to rebubble was 16 ± 9.4 days. Mean BSCVAs at 5 years postoperative were 0.03 ± 0.16, 0.03 ± 0.14, and 0.15 ± 0.31 logMAR in fully attached, partially detached and rebubbled grafts (P = 0.437). 5-year graft survival were 98%, 90%, and 83% in fully attached, partially detached and rebubbled eyes (P = 0.02). There was significantly greater endothelial cell loss (ECL) in the rebubbled eyes (P = 0.018). Intraoperative trauma was a risk factor for graft failure (HR 1.81; 95% CI: 1.33-2.50; P = 0.023). An indication for surgery other than Fuchs endothelial dystrophy was a risk factor for rebubbling (HR 5.28; 95% CI: 5.11-72.4; P = 0.007).

CONCLUSION

DMEK grafts had better graft survival if there was no partial detachment or rebubbling at 5 years postop. There was significant ECL associated with rebubbling. A standardised technique reduces rebubbling and graft failure risk.

Influence of Descemet Membrane Endothelial Keratoplasty Graft Preparation Patterns on Postoperative Clinical Outcome

PURPOSE

The aim of this study was to quantify preparation difficulties and complications during DMEK graft preparation and their influence on clinical outcome.

METHODS

A retrospective evaluation of 214 consecutive DMEK surgeries from the prospective Cologne DMEK database was performed between July 2018 and December 2019. Preparation conditions (such as central and peripheral adherences, tissue fragility, and Descemet membrane splitting) were quantified and divided into 3 groups: easy, difficult, and very difficult preparation. At follow-up (3, 6, and 12 months after DMEK), best spectacle-corrected visual acuity, endothelial cell count (ECC), and rebubbling rates were evaluated and compared between groups.

RESULTS

An easy preparation was possible in 41.6% of cases (group 1, n = 89), a difficult preparation of the DMEK graft occurred in 30.8% (group 2, n = 66), and a very difficult preparation occurred in 27.6% (group 3, n = 59). There was no difference between groups for best spectacle-corrected visual acuity at 3, 6, and 12 months ( P = 0.179, P = 0.325, and P = 0.682, respectively) or for ECC at 3 and 6 months ( P = 0.537 and P = 0.606, respectively). Only at 12 months, the ECC was slightly significant between groups ( P = 0.045). Regarding the rebubbling rate, there was no difference ( P = 0.585). 17.9% of eyes from group 1, 25.7% of eyes from group 2, and 23.7% of eyes from group 3 received at least 1 rebubbling.

CONCLUSIONS

These data suggest that difficult preparation conditions do not lead to any worsening of visual acuity or rebubbling rate in the 1-year outcome after DMEK. The endothelial cell density at 12 months showed slightly poorer results in the cases of very difficult preparation.

Manufacturing of human corneal endothelial grafts

PURPOSE

Human corneal endothelial cells (HCECs) play a significant role in maintaining visual function. However, these cells are notorious for their limited proliferative capacity in vivo. Current treatment of corneal endothelial dysfunction resorts to corneal transplantation. Herein we describe an ex vivo engineering method to manufacture HCEC grafts suitable for transplantation through reprogramming into neural crest progenitors.

METHODS

HCECs were isolated by collagenase A from stripped Descemet membrane of cadaveric corneoscleral rims, and induced reprogramming via knockdown with p120 and Kaiso siRNAs on collagen IV-coated atelocollagen. Engineered HCEC grafts were released after assessing their identity, potency, viability, purity and sterility. Phase contrast was used for monitoring cell shape, graft size, and cell density. Immunostaining was used to determine the normal HCEC phenotype with expression of N-cadherin, ZO-1, ATPase, acetyl-α-tubulin, γ-tubulin, p75NTR, α-catenin, β-catenin, and F-actin. Stability of manufactured HCEC graft was evaluated after transit and storage for up to 3 weeks. The pump function of HCEC grafts was measured by lactate efflux.

RESULTS

One HCEC graft suitable for corneal transplantation was generated from 1/8th of the donor corneoscleral rim with normal hexagonal cell shape, density, and phenotype. The manufactured grafts were stable for up to 3 weeks at 37 °C or up to 1 week at 22 °C in MESCM medium and after transcontinental shipping at room temperature by retaining normal morphology (hexagonal, >2000 cells/mm2, >8 mm diameter), phenotype, and pump function.

CONCLUSIONS

This regenerative strategy through knockdown with p120 and Kaiso siRNAs can be used to manufacture HCEC grafts with normal phenotype, morphology and pump function following prolonged storage and shipping.

Sutured Descemet Membrane Endothelial Keratoplasty in Patients With Complex Anatomy or Difficulty Positioning

PURPOSE

In Descemet membrane endothelial keratoplasty (DMEK), some patients cannot adhere to postoperative positioning requirements or lack anatomic support for a gas bubble in the anterior chamber. We describe a suturing technique that stabilizes the graft postoperatively without tearing or tenting it.

METHODS

One to two 10-0 nylon sutures with a spatulated needle are used to secure DMEK grafts. Tied with minimal tension, the sutures traverse the corneal stroma at a steep, almost perpendicular angle and approach the graft from the limbus at an angle tangential to the circular graft to prevent vaulting the tissue off the central cornea. We report preoperative and postoperative best spectacle-corrected visual acuity, corneal pachymetry, and anterior segment optical coherence tomography confirming graft attachment in 3 patients.

RESULTS

In case 1 (aphakia, postvitrectomy, and positioning difficulty), pachymetry decreased from 637 μm preoperatively to 495 μm and best spectacle-corrected visual acuity improved from 20/70 to 20/50 at postoperative week 1. In case 2 (aphakia, limited follow-up, and medication adherence), pachymetry decreased from 1106 μm preoperatively to 783 μm at postoperative month 1. In case 3 (tube shunt and loss of gas bubble at 2 hours), slit-lamp examination at postoperative day 1 showed corneal clearing and graft attachment. Pachymetry decreased from over 795 μm preoperatively to 582 μm at postoperative month 1. Anterior segment optical coherence tomography confirmed graft attachment in all patients.

CONCLUSIONS

Single or opposing tangentially oriented sutures can be safely applied to secure DMEK grafts postoperatively in challenging cases.

Thinning rate over 24 months in ultrathin DSAEK

AIM

To describe the changes in corneal graft thickness following ultrathin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK) comparing pre- and postoperative values over a 24-month period.

METHODS

In this retrospective single-center case series, patients who received eye bank-prepared tissues for UT-DSAEK surgery were included. Preoperative and postoperative graft thickness measurements were determined in the eye bank and in clinic using anterior segment optical coherence tomography (AS-OCT) images. Graft thickness measurements and their percentage change between preoperative values and values at 1 day, 1 week and 1, 6, 12, 24 months were calculated.

RESULTS

In total, 47 eyes of 47 patients with a mean age of 69 ± 11 years (29 males) were included. Twnty-three patients had Fuchs' endothelial dystrophy (49%) and the remaining 24 had pseudophakic bullous keratopathy (51%). In total, 29/47 eyes underwent UT-DSAEK alone (62%) and 18/47 received combined cataract surgery as a triple procedure (38%). Preoperative donor graft thickness was 92 ± 28 μm. Compared to preoperative values, where graft thickness increased to 194 ± 101.3 μm at 1 day, 151.1 ± 71.4 μm at 1 week, and 108.4 ± 52.5 μm at 1 month. Graft thickness continued to gradually decrease over time until 6 months (91.7 ± 33.6 μm), and then plateaued at 12 months (83.9 ± 25.0 μm), showing minimal changes at 2 years (101.4 ± 37.5 μm).

CONCLUSION

Preoperative DSAEK graft thickness measurements as reported by the eye bank are a valid approximation of DSAEK graft thickness at 6 months after surgery and these measurements tend to stabilize over time up to 2 years after surgery.

Five-Year Safety and Efficacy of Femtosecond Laser-Assisted Descemet Membrane Endothelial Keratoplasty

PURPOSE

The purpose of this study was to evaluate 5-year safety and efficacy outcomes of femtosecond-enabled Descemet membrane endothelial keratoplasty (F-DMEK) in patients with Fuchs' endothelial dystrophy (FED).

METHODS

This was a retrospective study, including patients with FED and cataract who underwent either F-DMEK (16 eyes of 15 patients) or manual DMEK (M-DMEK) (42 eyes of 37 patients) combined with cataract extraction. Outcome measures included visual acuity, graft detachment, graft survival, and endothelial cell loss.

RESULTS

The average follow-up in F-DMEK and M-DMEK was 57.1 ± 12.4 months and 58.5 ± 17.3 months, respectively ( P = 0.757). The rates of primary failure (0% vs. 9.5%, P = 0.567), secondary failure (0% for both), and graft rejection (0% vs. 7.1%, P = 0.533) did not differ significantly between the groups. Improvement in best spectacle-corrected visual acuity was similar in F-DMEK and M-DMEK (0.32 ± 0.27 logarithm of the minimum angle of resolution and 0.35 ± 0.44 logarithm of the minimum angle of resolution, respectively, P = 0.165) and persisted at 2, 3, 4, and 5 years and at the last follow-up. The rates of graft detachment and rebubbling were significantly lower with 6.25% in F-DMEK and 33.3% in M-DMEK ( P = 0.035). Cell-loss rates were lower in F-DMEK compared with M-DMEK throughout the follow-up, significantly so up to 2 years with a difference of 8.6% at 1 year ( P = 0.023), 11.8% at 2 years ( P = 0.021), 7.6% at 3 years ( P = 0.088), 5.8% at 4 years ( P = 0.256), 13.6% at 5 years ( P = 0.169), and 7.1% at the final follow-up ( P = 0.341).

CONCLUSIONS

F-DMEK had an excellent safety and efficacy profile which was maintained over 5 years of follow-up. Lower endothelial cell-loss rates in F-DMEK compared with M-DMEK may help extend the duration of graft survival.

Yogurt Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation: Early Clinical Outcomes

PURPOSE

The aim of this study was to evaluate the efficacy and safety of the Yogurt technique for Descemet membrane endothelial keratoplasty (DMEK) graft preparation.

METHODS

This study included patients who underwent DMEK combined or not with phacoemulsification surgery using donor tissues prepared by a surgeon with the DMEK Tzamalis disposable punch at 2 referral hospitals between October 2019 and June 2021. Primary outcomes were duration of graft preparation, surgeon grading of graft quality, and endothelial cell density measured at 1 and 6 months after surgery. Secondary outcomes were best-corrected visual acuity (BCVA) measured at 1 and 6 months postoperatively and DMEK intraoperative and postoperative complications.

RESULTS

Forty-nine patients were included in this study. The mean DMEK graft preparation time was 7.2 ± 1.4 minutes. Donor grafts were rated good in 67.3% of cases (33 of 49), sufficient in 24.5% (12 of 49), and poor in 8.2% (4 of 49). Donor mean endothelial cell density was 2580 ± 155 preoperatively, which were reduced to 2269 ± 191 ( P < 0.000) and 1697 ± 142 ( P < 0.0001) at 1 and 6 months, respectively. No significant difference was found in graft preparation outcome ( P = 0.543). The preoperative BCVA was 0.65 ± 0.44 logMAR, which improved to 0.31 ± 0.43 logMAR ( P < 0.0001) and 0.12 ± 0.14 logMAR ( P < 0.0001) at 1 and 6 months after surgery, respectively.

CONCLUSIONS

This study shows that the DMEK Tzamalis punch can be used as an effective and safe method for DMEK graft preparation with a shallow learning curve that allows it to be successfully performed by relatively inexperienced surgeons.

Effects of Systemic Diseases on Graft Preparation in Descemet Membrane Endothelial Keratoplasty

OBJECTIVES

To evaluate the effects of the systemic diseases and drugs of the donor on Descemet membrane (DM) graft preparation.

METHODS

Seventy-eight corneas of 58 donors, of whom the DM grafts were used in Descemet membrane endothelial keratoplasty (DMEK) surgery, between January 2018 and January 2020, were enrolled in this retrospective study. The hospital records of the donors were analyzed. Age, sex, blood type, systemic diseases, and drugs; complete blood count; biochemistry panel for liver and kidney functions in the past 48 hours; and the drugs used in the hospital, if any, in the past 24 hours were recorded. The grafts with tears that occurred while preparation were included in group 1, and the successful grafts with no tears were included in group 2.

RESULTS

There were no statistically significant differences in the characteristics of the donors between groups. However, breast cancer and the use of sevelamer were found to be significantly higher in group 1 ( P =0.010, P =0.033, respectively). No statistically significant difference in the use of other drugs was found between groups.

CONCLUSION

Although diabetic donors have been reported to be inappropriate candidates for the preparation of DM grafts for DMEK, most of the donors with several systemic diseases including diabetes can be used in DMEK surgery, with the right technique in DM graft preparation.

Descemet Membrane Endothelial Keratoplasty and Goniosynechialysis in Iridocorneal Endothelial Syndrome: Surgical Perspective and Long-Term Outcomes

PURPOSE

The purpose of this study was to report the long-term outcomes of Descemet membrane endothelial keratoplasty (DMEK) with goniosynechialysis in eyes with iridocorneal endothelial syndrome with an emphasis on the surgical technique.

METHODS

This was a retrospective series of 5 eyes of 5 patients undergoing a DMEK procedure at a tertiary eye care institute by a single surgeon. Modifications in the standard surgical technique, including the release of peripheral anterior synechiae, peripheral descemetorhexis, the release of adherent membranes, maneuvers in the anterior chamber with or without cataract extraction were logged. Long-term outcomes of the surgery in these patients are reported.

RESULTS

Five DMEK procedures were performed in 5 eyes of 5 patients. The average age of the patients was 48.2 ± 10.8 years, and the donor was 55.2 ± 3.2 years with a mean endothelial cell density (ECD) of 2784.6 ± 231 cells/mm 2 . After a mean follow-up period of 29.6 months (24-41 mo), all the 5 grafts remained clear; the mean BCVA at the last follow-up was 0.18 ± 0.17 logarithm of the minimum angle of resolution with a mean ECD of 1086.2 ± 338 cells/mm 2 with a 61.1% reduction in ECD. intra ocular pressure was normal in all the cases. None of the patients had graft detachments that required rebubbling, and all eyes had a clear graft at the last follow-up.

CONCLUSIONS

DMEK can be performed successfully in a case with iridocorneal endothelial syndrome with good visual outcomes with modifications to the surgical technique, including peripheral anterior synechiae release and minimizing surgical manipulation.

Glasses-Assisted 3D Display System-Guided Descemet Membrane Endothelial Keratoplasty Tissue Preparation

PURPOSE

The aim of this study was to evaluate the feasibility of Descemet membrane endothelial keratoplasty (DMEK) tissue preparation using a glasses-assisted 3-dimensional (3D) display system and to compare it with a conventional surgical microscope.

METHODS

Healthy pairs of human corneas suitable for penetrating keratoplasty surgery were selected for this study. The tissues were randomly divided into 2 groups. Each pair of corneas had 1 cornea (group 1) prepared with NGENUITY (Alcon) with a 5-second staining time with vision blue, and the fellow cornea (group 2) was prepared using a OPMI Lumera 700 surgical microscope (Carl Zeiss Meditec, Jena, Germany) with a 30-second staining time. DMEK graft preparation time, speed of stripping, graft width, and endothelial cell loss were evaluated.

RESULTS

Twenty-eight pairs of corneas were included in this study. The graft preparation time was significantly higher in the 3D group than in the conventional group (498 ± 147 vs. 418 ± 85 seconds, P value = 0.031). The mean speed of stripping was 0.59 ± 0.081 mm/s in group 1 and 0.089 ± 0.005 mm/s in group 2 ( P value = 0.024). The mean endothelial cell density in group 1 and group 2 before tissue preparation was 2162 ± 115.21 and 2153 ± 122.45, respectively ( P value > 0.1). After tissue preparation, the endothelial cell density reduced to 1911 ± 150.72 in group 1 and 1998 ± 90.72 in group 2 ( P value = P value > 0.05). The graft width was 5.05 ± 0.71 mm in group 1 and 4.92 ± 0.23 mm in group 2 ( P value > 0.05).

CONCLUSIONS

DMEK tissue preparation with 3D display system NGENUITY is feasible with a slightly increased preparation time. The improved visualization allows a reduced staining time that could be beneficial for eye banks because it may reduce the toxic effect of staining colorants.

Outcomes of Descemet Membrane Endothelial Keratoplasty Using Cornea From Elderly Donors Aged 80 Years and Older: In the Aftermath of Current Donor Shortage

PURPOSE

The purpose of this study was to report the outcomes of Descemet membrane endothelial keratoplasty (DMEK) using corneas from elderly donors aged 80 years and older.

METHODS

Eighty eyes of 78 patients who underwent DMEK-only or DMEK combined with cataract extraction (triple-DMEK) with surgeon-prepared graft between April 2016 and March 2020 were reviewed. Corrected distance visual acuity, endothelial cell density (ECD), and endothelial cell loss after 6 months, 1 year, and 2 years were analyzed.

RESULTS

The mean donor age was 83.6 ± 3.7 years (range: 80-100 years), and the mean donor ECD was 2889 ± 177 cells/mm 2 (range: 2604-3460 cells/mm 2 ). The mean recipient age was 67.2 ± 6.9 years (range: 60-89 years), and the mean follow-up was 21 ± 11 months (range: 6-52 months). The mean corrected distance visual acuity improved from a preoperative value of 1.36 ± 0.67 logarithm of the minimum angle of resolution to 0.22 ± 0.18 at 6 months (n = 75), 0.21 ± 0.2 at 1 year (n = 64), and 0.23 ± 0.3 logarithm of the minimum angle of resolution at 2 years (n = 41), respectively ( P < 0.001). In 72 eyes (96%), the graft remained transparent until the last follow-up visit. The mean postoperative ECD was 2073 ±336 (n = 75), 1951 ± 379 (n = 65), and 1807 ± 431 cells/mm 2 (n = 41) at 6 months, 1 year, and 2 years, respectively. Five eyes (6.7%) had donor detachments of which 4 required rebubbling. Two grafts failed after 1 year, and 2 eyes (2.6%) had graft rejection, of which 1 eye was reverted successfully by medical management.

CONCLUSIONS

Cornea from elderly donors aged 80 years and older with good selection criteria may be considered for DMEK with successful outcomes. For India and other countries with unmet tissue needs, every best single cornea counts.

Graft Thickness at 6 Months Postoperatively Predicts Long-Term Visual Acuity Outcomes of Descemet Stripping Automated Endothelial Keratoplasty for Fuchs Dystrophy and Moderate Phakic Bullous Keratopathy: A Cohort Study

PURPOSE

It remains unclear whether preoperative central graft thickness (CGT) contributes to visual outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK). This retrospective cohort study examined the ability of preoperative and postoperative CGT to predict 12-month best spectacle-corrected visual acuity (BSCVA) after DSAEK for Fuchs endothelial corneal dystrophy/moderate pseudophakic bullous keratopathy/second graft.

METHODS

All consecutive patients who underwent DSAEK in 2015 to 2018 were included. The primary end point was 12-month BSCVA. DSAEK-CGT was measured preoperatively and 6 times between postoperative day 8 and month 12. Eyes were divided according to preoperative CGT 130 μm (ultrathin-DSAEK threshold) or 6-month postoperative CGT 100 μm (mean 6-month postoperative DSAEK-CGT). The t test assessed CGT evolution of the 4 groups over time. Multivariate analyses examined whether preoperative CGT or 6-month CGT categories predicted 12-month BSCVA. Multivariate analysis assessed the preoperative/perioperative factors that predicted 6-month CGT.

RESULTS

A total of 108 eyes (68 patients) underwent DSAEK. Preoperative CGT was >130 and ≤130 μm in 87 and 21 eyes, respectively. Postoperative CGT was >100 and ≤100 μm in 50 and 58 eyes, respectively. Thin 6-month postoperative grafts thinned significantly more relative to preoperative thickness than thick grafts ( P < 0.001). Preoperative CGT subgroups did not show this difference. Six-month postoperative CGT ( P = 0.01), but not preoperative CGT, predicted 12-month BSCVA. Preoperative CGT strongly predicted 6-month CGT ( P = 0.0003).

CONCLUSIONS

Postoperative, but not preoperative, DSAEK-CGT predicted 6-month BSCVA. The correlation between preoperative and postoperative CGT and interstudy variation in preoperative CGT measurement accuracy may explain literature disparities regarding the importance of preoperative CGT in DSAEK outcomes.

Considerations for Corneal Surgery With Patients in the 10th Decade of Life

PURPOSE

The purpose of this study was to report the indications, ocular and systemic comorbidities, and surgical outcomes of corneal transplantation in patients older than 90 years.

METHODS

A retrospective review was conducted to identify individuals 90 years and older who underwent corneal transplantation surgery at the Bascom Palmer Eye Institute between January 2013 and October 2020. Outcomes included best-corrected visual acuity and graft survival over time. Paired t tests were used to compare visual acuity preoperatively versus postoperatively. Graft survival was evaluated with Kaplan-Meier curves.

RESULTS

Fifty-eight eyes of 52 consecutive individuals were included. The mean age of individuals was 92 ± 2 years; 26.9% were male; and 48.1% self-identified as non-Hispanic White and 38.5% as Hispanic. Postoperative follow-up was 14.7 ± 12.1 months. Of the 58 eyes, 44.8% (26/58) underwent penetrating keratoplasty, 46.6% (27/58) Descemet stripping automated endothelial keratoplasty, and 6.9% (4/58) keratoprosthesis. All surgeries were performed under monitored local anesthesia, without major complications. Surgical indications included pseudophakic bullous keratopathy (36.2%), glaucoma-associated corneal decompensation (27.6%), Fuchs endothelial dystrophy (25.9%), and perforated corneal ulceration (19.0%). The best-corrected visual acuity improved by 0.32 (95% confidence interval 0.14-0.50; P < 0.01) as early as 1 month postoperatively, and vision gains were sustained for at least 12 months. Graft survival probability at 12 months was 88%.

CONCLUSIONS

Corneal transplantation is a safe and successful procedure in restoring the visual acuity for patients older than 90 years after careful preoperative evaluation. Further research is needed to evaluate the impact of corneal transplantation on quality of life in patients in the 10th decade of life.

DescePrep Significantly Increases Descemet Membrane Endothelial Keratoplasty Processing Efficiency and Success Rate in Diabetic Human Donor Corneas in Comparison With Manual Dissection

PURPOSE

The purpose of this study was to compare the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft processing device, DescePrep, with a manual dissection technique through the measurement of tissue yield, processing time, and graft viability in nondiabetic and diabetic donor corneas.

METHODS

Nondiabetic (n = 20) and diabetic (n = 20) donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Nondiabetic (n = 20) and diabetic (n = 24) donor corneas were also processed through manual dissection. Corneas were stained, processed, and then evaluated for processing success rate and time. Randomly selected corneas (n = 5, each) were evaluated for cell viability using live/dead staining.

RESULTS

One hundred percent of nondiabetic and 95% of diabetic corneas were processed successfully with DescePrep in an average of 3.37 minutes. Ninety percent of nondiabetic and 50% of diabetic corneas were processed successfully with manual dissection in an average of 9.87 minutes. DescePrep had a significantly lower processing time ( P < 0.0001) and significantly higher success rate in comparison with manual dissection. DescePrep grafts had an average cell viability of 91.1% ± 3.3% in nondiabetic and 91.5% ± 2.4% in diabetic corneas. Grafts prepared with manual dissection had an average cell viability of 89.5% ± 5.8% in nondiabetic and 88.1% ± 4.3% in diabetic corneas.

CONCLUSIONS

DescePrep provides a more effective and efficient method of cornea preparation in comparison with the current standard, particularly in diabetic corneas, while providing comparable cell viability. Thus, DescePrep offers standardized DMEK processing that produces high-quality grafts at high yields, with the potential to expand access and improve the quality of DMEK graft preparation in a larger pool of donors.

Examination of a Modified Graft Preparation Technique to Induce Double-Scroll Formation and Promote the Use of Younger Descemet Membrane Endothelial Keratoplasty Donor Tissue

PURPOSE

The purpose of this study was to determine whether controlled balanced salt solution (BSS) bursts during graft preparation can safely promote formation of a double-scrolled Descemet membrane endothelial keratoplasty (DMEK) graft in younger donor tissue.

METHODS

DMEK grafts prepared from young donor tissue (average age, 55 years; range, 39-66 years) were floated in BSS to spontaneously form scrolls (N = 10 pairs). Controlled BSS bursts were used to promote double-scroll (DS) formation in 1 member of each pair. Grafts were stained, preloaded, and shipped before cell viability analysis. After appropriate training, a less experienced technician performed this technique on 10 additional corneas. Outcomes measured for both technicians include the success rate for obtaining a DS, scroll conformation after shipping, and endothelial cell loss (ECL).

RESULTS

There was no difference in ECL between grafts subjected to additional manipulation compared with unmanipulated mate grafts (observer 1: 15.2% ± 3.3% vs. 15.2% ± 4.4%, P = 0.99; observer 2: 16.3% ± 2.9% vs. 15.9% ± 4.5%, P = 0.8). A technician experienced with this technique had a 90% success rate, whereas a less experienced technician had a 70% success rate. The mean ECL of the 10 grafts manipulated by the less experienced technician was not significantly different from results obtained from the experienced technician (observer 1: 18.5% ± 6.0% vs. 15.2% ± 3.3%, P = 0.15; observer 2: 18.1% ± 5.6% vs. 16.3% ± 2.9%, P = 0.34). Scrolls maintained their conformation during shipping events.

CONCLUSIONS

Double-scroll graft formation using controlled BSS bursts is a reliable technique that can be performed without causing additional damage to DMEK grafts. This technique may make graft unscrolling easier and can promote the use of younger donor tissue for DMEK.

Descemet Membrane Endothelial Transfer (DMET) in Pseudophakic Bullous Keratopathy After DSEK-A Case Report and Review of Literature

PURPOSE

The purpose of this study was to report a Descemet membrane endothelial transfer (DMET) in a patient with pseudophakic bullous keratopathy (PBK) who developed graft dislocation after manual Descemet stripping endothelial keratoplasty.

METHODS

A 60-year-old man presented with defective vision in the left eye; after Descemet stripping endothelial keratoplasty, graft dislocation was noted 1 month after surgery.

RESULTS

Corneal clarity was improving slowly over 3 months without any secondary surgical intervention. The mechanism of DMET and the review of literature were enunciated.

CONCLUSIONS

DMET occurs commonly in eyes with Fuch endothelial dystrophy and rarely in patients with PBK. The mechanism of DMET in PBK probably occurs because of migration of the donor endothelial cells from partially attached Descemet stripping endothelial keratoplasty grafts to the host stroma, in contrast to Fuch endothelial dystrophy, where the endothelial cells from the periphery migrate to the center. Hence, waiting for spontaneous corneal clarity is pivotal because of DMET even in patients with PBK for at least 3 months.

Clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) with imported donor corneas in eyes of Asian patients; endothelium-in versus endothelium-out method

Objective

We investigated whether (1) imported pre-cut tissue is feasible for Descemet membrane endothelial keratoplasty (DMEK) in eyes of Asian patients, (2) the clinical outcome is comparable between the endothelium‐in and endothelium‐out methods, and (3) the corneal edema-induced anterior curvature changes may have an effect on the refractive error.

Methods

The medical records of 32 DMEK patients who underwent either the endothelium-out or endothelium-in method using imported pre-cut grafts with a 3-day pre-cut-to-use time were retrospectively analyzed. Fuchs’ endothelial dystrophy (37.5%) and bullous keratopathy (62.5%) cases were included. The main clinical outcome measures were graft survival, best corrected visual acuity (BCVA), endothelial cell density (ECD), corneal thickness (CT), and complications. Correlation of the anterior curvature changes with refractive error was analyzed in the DMEK with cataract surgery group.

Results

The overall survival rate was 71.9%. Final graft failures were caused by rejection, glaucoma, and infection. Visual acuities improved by 89.3%. BCVA better than 20/40 and 20/20 was found in 75% and 28.6% of patients, respectively. The ECDs at 3 months and 1 year were 1400 and 1083 cells/mm², respectively. The mean survival time, ECD, BCVA, CT, and complication rates were not different between the endothelium-in and endothelium-out methods. A hyperopic shift by +0.42 D was not related to the anterior curvature changes.

Conclusion

Imported pre-cut tissues with a ≤ 3-day pre-cut-to-use time are feasible for DMEK in the treatment of corneal endothelial edema in eyes of Asian patients, and both endothelium-in and endothelium-out methods appear to be comparatively effective. Edema-induced anterior curvature change may not affect the refractive shift.

"Air-Assisted" Donor Lenticule Insertion in Descemet Stripping Endothelial Keratoplasty in Aphakia With Large Iris Defect and Without Posterior Capsular Support

PURPOSE

The purpose of this study was to report a novel technique of donor lenticule insertion in Descemet stripping endothelial keratoplasty (DSEK) in aphakic corneal edema with large iris defect and without any posterior capsular support.

METHODS

This was a retrospective consecutive interventional case series. Clinical records of ten 1-eyed aphakic patients with corneal edema with large iris defect and no capsular support who underwent air-assisted donor lenticule insertion in DSEK were evaluated. After making 6.0- to 6.5-mm sclerocorneal tunnel and 2 side ports, limited anterior vitrectomy was performed if required. Then, Descemetorhexis was performed under air through side ports. Manually dissected donor lenticule was inserted into the anterior chamber under full-chamber air by a 30-G needle push-in technique. Further air tamponade was given if necessary. No fluid-air exchange was performed. The patient was kept on the same operating table for at least 1 hour and then shifted. Graft attachments in early postoperative period, corrected distant visual acuity, and endothelial cell density after 3, 6, and 12 months were analyzed.

RESULTS

The mean postoperative follow-up period was 19.2 ± 6.7 months. There was no donor dislocation in this small group. All patients achieved a corrected distant visual acuity of 0.70 (20/100) after 3 months and maintained until 12 months. The endothelial cell density at 3 months (n = 8) was 2028 ± 151/mm 2 , at 6 months (n = 7) 1776 ± 198/mm 2 , and at 12 months (n = 7) 1721 ± 172/mm 2 . The corresponding endothelial cell loss was 25.8% ± 5.6%, 34.4% ± 5.1%, and 37.8% ± 7.1%, respectively. One graft failed after 15 months.

CONCLUSIONS

"Air-assisted" donor lenticule insertion in DSEK is a safe surgical technique in aphakic patients with corneal edema with large iris defect and no capsular support.

Descemet membrane endothelial keratoplasty in complex eyes

PURPOSE OF REVIEW

To review the current literature on Descemet membrane endothelial keratoplasty (DMEK) in complex eyes.

RECENT FINDINGS

DMEK surgery has become a standardized procedure in Fuchs endothelial dystrophy and simple bullous keratopathy. But eyes with more complex disease present unique intraoperative and postoperative challenges to the DMEK surgeon. Poor visualization during surgery, complex anterior segment anatomy, altered anterior chamber dynamics, glaucoma shunts, and congenital or iatrogenic missing or altered iris and lens make DMEK surgery extremely difficult to accomplish.

SUMMARY

DMEK is feasible in complex eyes, including advanced bullous keratopathy, eyes with history of glaucoma or vitreoretinal surgery, previous penetrating keratoplasty, uveitis, pediatric, and congenital anterior segment disorders. The tools and methods reported in the literature to accomplish DMEK in complex eyes vary widely with no particular consensus or standardization of techniques. The outcomes noted for some of these conditions demonstrate the difficulty of the surgery and the uncertainty of long-term graft survival in complex eyes. Both surgical standardization and randomized prospective data will better help elucidate DMEK's role in the corneal rehabilitation of complex eyes.

Severe Corneal Edema Increases ECL From Grafts After DSAEK-Corneal Edema and ECL After DSAEK

OBJECTIVES

To determine the relationship between the preoperative degree of corneal edema in the recipient and the endothelial cell density in grafts after Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

This retrospective case series enrolled 111 eyes of 107 patients who underwent DSAEK. The preoperative and postoperative central corneal thickness (CCT) was measured by anterior-segment optical coherence tomography. Eyes were divided into three groups according to the preoperative recipient CCT: group A (mild edema): 550 μm

RESULTS

The recipient CCT (all groups combined) was 805.99±132.70 μm preoperatively and decreased to 656.31±105.02 μm at 1 month, decreased to 626.08±81.40 μm at 6 months, and remained stable between 12 (P=0.144) and 24 months (P=0.485) postoperatively. The mean ECL was 27.34±15.43%, 33.56±17.13%, 39.18±16.71%, and 45.87±14.27% at 1, 6, 12, and 24 months, respectively. The percentage of ECL in group C was higher than that in the other 2 groups through the 24-month follow-up. The difference in ECL between groups A and C was significant at 24 months (group A: 42.45±14.47%; group C: 52.49±10.65%; P=0.019).

CONCLUSIONS

The degree of corneal edema in the recipient was associated with implant ECL. Compared with mild and moderate corneal edema, the severe corneal edema may cause greater ECL after DSAEK.

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Key Words

• dsaek
• endothelial cell loss
• degree of corneal edema

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MESH Headings

• Corneal Diseases/etiology
• Corneal Diseases/surgery
• Corneal Edema/etiology
• Corneal Edema/surgery
• Descemet Stripping Endothelial Keratoplasty/adverse effects
• Descemet Stripping Endothelial Keratoplasty/methods
• Endothelial Cells
• Endothelium, Corneal/transplantation
• Humans
• Retrospective Studies

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Affiliation(s)

Shaofeng Gu Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Rongmei Peng Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Gege Xiao Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Jing Hong Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.

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Eye bank versus surgeon prepared Descemet stripping automated endothelial keratoplasty tissues: Influence on adhesion force in a pilot study

PURPOSE

To evaluate and compare the biomechanical properties of the eye bank-prepared and surgeon prepared Descemet stripping automated endothelial keratoplasty (DSAEK) tissues.

METHODS

In this laboratory study, corneal tissues for research were randomly allocated in the following groups: a) surgeon-cut DSAEK and b) eye bank-prepared (pre-cut and pre-loaded) DSAEK. Endothelial cell loss (ECL), immunostaining for tight junction protein ZO-1, elastic modulus, and adhesion force were investigated.

RESULTS

ECL was not found to be significantly different between surgeon-cut DSAEK (7.8% ±6.5%), pre-cut DSAEK (8.6% ±2.3%), and pre-loaded DSAEK (11.1% ±4.8%) (P = 0.5910). ZO-1 was expressed equally across all groups. Surgeon-cut DSAEK grafts showed a significantly higher elastic modulus compared to pre-cut and pre-loaded DSAEK groups (P = 0.0047 and P < 0.0001, respectively). Adhesion force was significantly greater in the surgeon-cut DSAEK compared to pre-cut (P < 0.0001) or pre-loaded DSAEK groups (P = 0.0101).

CONCLUSION

The laboratory data on the biomechanics of DSAEK grafts suggests that surgeon-cut DSAEK grafts present higher elastic modulus and adhesion force compared to eye bank-prepared DSAEK grafts.

Long-term Outcomes of Descemet Stripping Endothelial Keratoplasty: Ten-Year Graft Survival and Endothelial Cell Loss

PURPOSE

To determine 10-year outcomes for graft and endothelial cell survival after Descemet stripping endothelial keratoplasty (DSEK), including risk factors for graft failure.

DESIGN

Retrospective clinical cohort study.

METHODS

Three hundred fifty-six consecutive DSEK grafts performed by 10 surgeons using a standardized protocol were analyzed. Primary outcomes were cumulative graft survival and percentage endothelial cell loss (ECL) from 6 months to 10 years; secondary outcomes included risk factors for graft failure, postoperative complications, visual outcomes, and central corneal thickness.

RESULTS

Indications include Fuchs endothelial dystrophy (n = 209), bullous keratopathy (n = 88), and previous graft failure (n = 39). One hundred and four eyes (29%) had preoperative glaucoma. Cumulative graft survival rates of all eyes at 1, 3, 5, and 10 years were 97%, 90%, 85%, and 79%, respectively. Ten-year graft survival for Fuchs endothelial dystrophy was 92%. Mean ± SD percentage ECL of all grafts was 46.6% ± 17.3% at year 1, 54.9% ± 18.7% at year 3, 59.6% ± 17.4% at year 5, and 73.1% ± 9.7% at year 10. Cox regression identified preoperative glaucoma (hazard ratio [HR]: 8.41; 95% CI, 1.30-54.5; P = .026), including previous glaucoma surgery (HR: 3.63; 95% CI: 1.03-12.74; P = .04) and regrafts (HR: 5.29; 95% CI: 2.02-13.89; P = .001) as significant risk factors for graft failure.

CONCLUSIONS

At 10 years, DSEK survival rate was 79% for all eyes, including complex grafts, and ECL was 73%. For Fuchs endothelial dystrophy, 10-year graft survival rate was 92%. Despite a mean 10-year endothelial cell count of only 692 cells/mm², graft survival remained high with good vision. DSEK continues to be a viable treatment option, especially in complex eyes with comorbidity.

[On the issue of allocating the pre-Descemet's layer in the corneal structure]

Selective keratoplasty is known to be based on surgical manipulations aimed at dosed isolation of layered grafts in the corneas of the donor and the recipient. Some technological features of obtaining transplants have served as the basis for expanding the understanding of the corneal structure. Thus, analysis of the process of corneal stroma pneumodissection for isolation of the Descemet's membrane led to a suggestion that there was another layer in the cornea, it was designated as the pre-Descemet's layer. This article discusses the practicability of separating the pre-Descemet's layer from the perspective of structural, functional and surgical anatomy.

Effect of Body Refrigeration Time on Cornea Donor Tissue

PURPOSE

To determine how early body refrigeration affects corneal donor transplant suitability and endothelial cell density.

METHODS

Donor information was obtained from the CorneaGen Eye Bank including demographics, time of death to preservation, and body refrigeration status, for donors between 2012 and 2016. The death to preservation interval was classified into 3 categories: 0 to 10, 10 to 20, and 20+ hours. Two primary logistic method models were fit using a main effects model and an interaction model to determine the association of body refrigeration on unsuitability of transplantation and endothelial cell density.

RESULTS

Analysis was from 42,929 donor eyes, with a mean (standard deviation) endothelial cell count of 2743 (415) cells/mm2. Fifty-nine percent of donor eyes were from male donors in the eye bank data set, and the mean death to preservation interval was 11.0 (5.6) hours for all eyes. Unsuitability for transplantation demonstrated a reduced adjusted odds ratio by 22% (OR = 0.78, P = 0.009) when the body was refrigerated during the death to preservation interval versus when the body was not refrigerated. Eyes that were refrigerated, however, exhibited no statistically significant difference in endothelial cell count from eyes that were not refrigerated (P = 0.12).

CONCLUSIONS

We demonstrate an appreciable effect of early body refrigeration on transplant suitability in this large cohort of eye bank eyes. There was no beneficial effect of body refrigeration on endothelial cell count.

Implantation of an Artificial Endothelial Layer for Treatment of Chronic Corneal Edema

PURPOSE

The purpose of this study was to describe a novel device that may serve as an alternative to Descemet membrane endothelial keratoplasty (DMEK) for the treatment of chronic corneal edema.

METHODS

The EndoArt (EyeYon Medical, Israel) is a flexible, 50-μm thin artificial endothelial layer that matches the cornea's posterior curvature and functions as a fluid barrier at the posterior stroma, replacing the diseased endothelium. Similar to a DMEK approach, it is implanted into the anterior chamber, carefully positioned on the posterior stroma, and secured using an air-gas mixture. Two patients with chronic corneal edema resulting from endothelial decompensation underwent implantation of the new artificial lamella.

RESULTS

In patient 1, the central corneal thickness (CCT) decreased from 730 μm preoperatively to 593 μm at 1 day postoperatively. In patient 2, the CCT decreased from 761 μm preoperatively to 487 μm at 1 day postoperatively. Both patients reported high satisfaction and an overall brighter visual quality. Although dislocation of the lamella occurred in both cases, the CCT was promptly restored after a repositioning procedure and remained stable at the 17-month follow-up (CCT of 526 and 457 μm for patients 1 and 2, respectively). In contrast to DMEK donor tissue, the artificial lamella is sufficiently robust to allow easy intraocular manipulation without the risk of damaging the implant. It is easily removable and does not require any immunosuppressive treatment because of its nonbiological nature.

CONCLUSIONS

Implantation of the EndoArt led to rapid corneal deturgescence and CCT restoration, presenting a possible option for patients with chronic corneal edema.

Early Complications With Preloaded Descemet Membrane Endothelial Keratoplasty Are Not Dependent on Optisol-GS Washout or Trypan Blue Restaining

PURPOSE

To describe the intraoperative and early postoperative complications using preloaded Descemet membrane endothelial keratoplasty (DMEK) grafts with intraocular injection of the graft in Optisol-GS and omission of trypan blue restaining.

METHODS

This is a retrospective case series of 132 consecutive eyes with Fuchs endothelial dystrophy or endothelial failure who underwent DMEK using preloaded donor tissue prepared as previously described. The graft was not restained with trypan blue by the surgeon, and Optisol-GS was injected with the graft into the eye instead of being rinsed from the injector. Early postoperative complications (0-8 wk) including intraoperative fibrin formation, intraocular inflammation, elevated intraocular pressure, partial graft detachment requiring rebubble, and early graft failure were recorded.

RESULTS

No eyes developed intraoperative fibrin formation or postoperative inflammation (such as toxic anterior segment syndrome) or elevated intraocular pressure. For eyes with Fuchs corneal dystrophy, our rebubble rate was 21% (22/106 eyes). Early graft failure was noted in 2% (3/132 eyes), which is similar to previous reports.

CONCLUSIONS

Our results suggest that injection of Optisol-GS into the anterior chamber during DMEK graft injection does not lead to increases in intraoperative or early postoperative complications. Trypan blue restaining is not necessary for intraoperative visualization. This simplification can reduce graft manipulation and save time and resources for this procedure.

Mechanotransductive Differentiation of Hair Follicle Stem Cells Derived from Aged Eyelid Skin into Corneal Endothelial-Like Cells

Corneal endothelial insufficiency is one of the leading causes of blindness. The main contemporary treatment for corneal blindness is endothelial keratoplasty, which, however, is unsatisfactory as a medical therapy due to the lack of donor corneas and graft rejection. Therefore, autologous stem cell-based corneal endothelial tissue substitutes may be a promising alternative to conventional grafts in the future. To address the age of most patients suffering from corneal endothelial deficiencies, we investigated the presence and potential of hair-derived stem cells from older tissue donors. Our studies revealed the presence of pluripotency- and neural crest-associated markers in tissue sections from blepharoplasty patients aged 50 to 80 years. In vitro outgrowths from eyelid hair follicles on collagen-coated tissue culture plates revealed a weak decrease in stem-cell potency. In contrast, cells within the spheres that spontaneously formed from the adherent cell layer retained full stem-cell potency and could be differentiated into cells of the ecto- meso and endodermal lineages. Although these highly potent hair follicle derived stem cells (HFSC) were only very slightly expandable, they were able to recognize the biomimicry of the Descemet’s-like topography and differentiate into corneal endothelial-like cells. In conclusion, HFSCs derived from epidermal skin of eyelid biopsies are a promising cell source to provide autologous corneal endothelial replacement for any age group of patients.

Younger Donor Tissue in Descemet Membrane Endothelial Keratoplasty Surgery: Clinical Outcomes

PURPOSE

To determine whether using younger donor tissue for Descemet membrane endothelial keratoplasty (DMEK) surgery influences clinical outcomes.

METHODS

Scroll tightness, unscrolling time, rebubble rate, and preoperative and 3- and 6-month postoperative endothelial cell density (ECD) and endothelial cell loss (ECL) were compared for 661 DMEK grafts prepared from younger (aged younger than 50 yrs, n = 81) and older donors (aged 50 yrs or older, n = 580) with Student t test, χ2 test, or Mann-Whitney U test.

RESULTS

There was no difference in overall unscrolling time (younger donors: 3.1 ± 3.1 min, older donor: 2.9 ± 2.7 min, P = 0.503). Experienced faculty surgeons, compared with fellows, had a significantly lower unscrolling times for both younger donors (2.4 ± 2.3 vs. 4.6 ± 3.9 min, P = 0.002) and older donors (2.5 ± 2.1 vs. 3.7 ± 3.3 min, P <0.001). Rebubble rates were not statistically different between younger (12.3%) and older donors (15.0%, P = 0.527). Three-month ECD was higher in grafts from younger compared with that in those from older donors (2138 ± 442 vs. 1974 ± 470 cells/mm2, P = 0.024). Six-month ECD was similar for younger (1972 ± 509 cells/mm2) and older donors (1947 ± 460 cells/mm2, P = 0.585). There was no difference in 3- or 6-month ECL comparing younger (3-mo: 24.3% ± 13.4%; 6-mo: 31.1% ± 15.2%) with older donors (3-mo: 25.9% ± 15.5%, P = 0.489; 6-mo: 27.8% ± 15.1%, P = 0.231).

CONCLUSIONS

DMEK grafts prepared from younger donors exhibited similar unscrolling times, rebubble rates, and 3- and 6-month ECL compared with older donors. Experienced surgeons might begin to accept DMEK grafts from younger donors with confidence.

Comparison of the rabbit and human corneal endothelial proteomes regarding proliferative capacity

The shortage of human donor corneas has raised important concerns about engineering of corneal endothelial cells (CECs) for clinical use. However, due to the limited proliferative capacity of human CECs, driving them into proliferation and regeneration may be difficult. Unlike human CECs, rabbit CECs have a marked proliferative capacity. To clarify the potential reason for this difference, we analysed the proteomes of four human corneal endothelium samples and four rabbit corneal endothelium samples with quantitative label-free proteomics and downstream analysis. We discovered that vitamin and selenocompound metabolism and some signaling pathways such as NF-kappa B signaling pathway differed between the samples. Moreover, TGFβ, PITX2 and keratocan were distinctively expressed in rabbit samples, which might be associated with active proliferation in rabbit CECs. This study illustrates the proteomic differences between human and rabbit CECs and might promote CEC engineering strategies.

Endothelial Keratoplasty Update 2020

ABSTRACT

Endothelial keratoplasty has revolutionized the treatment of corneal endothelial dysfunction and lowered the threshold for treatment by providing rapid visual rehabilitation and setting a high standard for safety and efficacy. Over time, endothelial keratoplasty techniques have evolved toward the use of thinner tissue to optimize visual outcomes; refinements have facilitated donor tissue preparation, handling, and attachment; and adaptations have expanded utilization in eyes with challenging ocular anatomy. Despite early concerns about graft longevity, emerging 10-year endothelial cell loss and graft survival data have been encouraging. A shortage of human donor corneas restricts utilization in many areas of the world and is driving a search for keratoplasty alternatives. Further work is needed to expand the donor supply, minimize impediments to adoption, optimize graft survival, and improve refractive predictability.

A Novel Approach of Harvesting Viable Single Cells from Donor Corneal Endothelium for Cell-Injection Therapy

Donor corneas with low endothelial cell densities (ECD) are deemed unsuitable for corneal endothelial transplantation. This study evaluated a two-step incubation and dissociation harvesting approach to isolate single corneal endothelial cells (CECs) from donor corneas for corneal endothelial cell-injection (CE-CI) therapy. To isolate CECs directly from donor corneas, optimization studies were performed where donor Descemet’s membrane/corneal endothelium (DM/CE) were peeled and incubated in either M4-F99 or M5-Endo media before enzymatic digestion. Morphometric analyses were performed on the isolated single cells. The functional capacities of these cells, isolated using the optimized simple non-cultured endothelial cells (SNEC) harvesting technique, for CE-CI therapy were investigated using a rabbit bullous keratopathy model. The two control groups were the positive controls, where rabbits received cultured CECs, and the negative controls, where rabbits received no CECs. Whilst it took longer for CECs to dislodge as single cells following donor DM/CE incubation in M5-Endo medium, CECs harvested were morphologically more homogenous and smaller compared to CECs obtained from DM/CE incubated in M4-F99 medium (p < 0.05). M5-Endo medium was hence selected as the DM/CE incubation medium prior to enzymatic digestion to harvest CECs for the in vivo cell-injection studies. Following SNEC injection, mean central corneal thickness (CCT) of rabbits increased to 802.9 ± 147.8 μm on day 1, gradually thinned, and remained clear with a CCT of 385.5 ± 38.6 μm at week 3. Recovery of corneas was comparable to rabbits receiving cultured CE-CI (p = 0.40, p = 0.17, and p = 0.08 at weeks 1, 2, and 3, respectively). Corneas that did not receive any cells remained significantly thicker compared to both SNEC injection and cultured CE-CI groups (p < 0.05). This study concluded that direct harvesting of single CECs from donor corneas for SNEC injection allows the utilization of donor corneas unsuitable for conventional endothelial transplantation.

Treatment of corneal endothelial damage in a rabbit model with a bioengineered graft using human decellularized corneal lamina and cultured human corneal endothelium

Objective

We aimed to investigate the functionality of human decellularized stromal laminas seeded with cultured human corneal endothelial cells as a tissue engineered endothelial graft (TEEK) construct to perform endothelial keratoplasty in an animal model of corneal endothelial damage.

Methods

Engineered corneal endothelial grafts were constructed by seeding cultured human corneal endothelial cell (hCEC) suspensions onto decellularized human corneal stromal laminas with various coatings. The functionality and survival of these grafts with cultured hCECs was examined in a rabbit model of corneal endothelial damage after central descemetorhexis. Rabbits received laminas with and without hCECs (TEEK and control group, respectively).

Results

hCEC seeding over fibronectin-coated laminas provided an optimal and consistent endothelial cell count density and polygonal shape on the decellularized laminas, showing active pump fuction. Surgery was performed uneventfully as standard Descemet stripping automated endothelial keratoplasty (DSAEK). Corneal transparency gradually recovered in the TEEK group, whereas haze and edema persisted for up to 4 weeks in the controls. Histologic examination showed endothelial cells of human origin covering the posterior surface of the graft in the TEEK group.

Conclusions

Grafting of decellularized stroma carriers re-surfaced with human corneal endothelial cells ex vivo can be a readily translatable method to improve visual quality in corneal endothelial diseases.

Poly-ε-lysine based hydrogels as synthetic substrates for the expansion of corneal endothelial cells for transplantation

Dysfunction of the corneal endothelium (CE) resulting from progressive cell loss leads to corneal oedema and significant visual impairment. Current treatments rely upon donor allogeneic tissue to replace the damaged CE. A donor cornea shortage necessitates the development of biomaterials, enabling in vitro expansion of corneal endothelial cells (CECs). This study investigated the use of a synthetic peptide hydrogel using poly-ε-lysine (pεK), cross-linked with octanedioic-acid as a potential substrate for CECs expansion and CE grafts. PεK hydrogel properties were optimised to produce a substrate which was thin, transparent, porous and robust. A human corneal endothelial cell line (HCEC-12) attached and grew on pεK hydrogels as confluent monolayers after 7 days, whereas primary porcine CECs (pCECs) detached from the pεK hydrogel. Pre-adsorption of collagen I, collagen IV and fibronectin to the pεK hydrogel increased pCEC adhesion at 24 h and confluent monolayers formed at 7 days. Minimal cell adhesion was observed with pre-adsorbed laminin, chondroitin sulphate or commercial FNC coating mix (fibronectin, collagen and albumin). Functionalisation of the pεK hydrogel with synthetic cell binding peptide H-Gly-Gly-Arg-Gly-Asp-Gly-Gly-OH (RGD) or α2β1 integrin recognition sequence H-Asp-Gly-Glu-Ala-OH (DGEA) resulted in enhanced pCEC adhesion with the RGD peptide only. pCECs grown in culture at 5 weeks on RGD pεK hydrogels showed zonula occludins 1 staining for tight junctions and expression of sodium-potassium adenosine triphosphase, suggesting a functional CE. These results demonstrate the pεK hydrogel can be tailored through covalent binding of RGD to provide a surface for CEC attachment and growth. Thus, providing a synthetic substrate with a therapeutic application for the expansion of allogenic CECs and replacement of damaged CE.