[Analysis of factors affecting the quality of donor corneal endothelial cells].

Objective: To explore the factors influencing the quality of donor corneal endothelium. Methods: A retrospective case series study was conducted. Data from 568 donor corneas obtained from the Shandong Eye Bank between July 1, 2020, and June 30, 2021, were collected for analysis. The corneal endothelium of the donor corneas was observed using corneal endothelial microscopy to assess corneal endothelial cell density (ECD), coefficient of variation, and hexagonal cell ratio (HEX). Relevant factors of corneal donors were collected, including gender, age, cause of death, season of death, time from death to corneal retrieval, and methods of corpse preservation, to investigate their impact on the quality of donor corneal endothelium. The age factor was divided into five age groups: 0-20 years, 21-40 years, 41-60 years, 61-80 years, and >80 years. The time of corneal retrieval was divided into three periods based on the time elapsed since the donor's death: <6 hours, 6-12 hours, and >12 hours. The relationship between these factors and corneal endothelial conditions was analyzed. Results: The 568 donor corneas were obtained from 288 donors, including 225 males (78.13%) and 63 females (21.87%). The mean age was 51.77±18.48 years. The causes of death among donors were as follows: cardiovascular diseases 54.58% (275 individuals), cancer 17.96% (74 individuals), organ failure 14.26% (49 individuals), and accidents 13.20% (64 individuals). The mean time of corneal retrieval after donor death was 140 (76, 400) minutes (ranging from 30 minutes to 45 hours). Among the 145 corneas (25.53%) that had their initial corneal endothelial microscopy examination, the images were not clear, and after thorough rewarming, 106 corneas (18.7%) still had unclear images and could not be analyzed. Among the 462 corneas (81.3%) with clear images, the ECD was (2 602.23±318.40) cells/mm², the coefficient of variation was 36.61%±4.81%, and the HEX was 52.73%±7.15%. The ECD of corneas from older donors was lower compared to younger donors, and the differences between age groups were statistically significant (P<0.001). Corneas from donors who died due to accidents had a higher ECD [(2 829.88±313.90) cells/mm²] compared to those who died from cancer, cardiovascular diseases, and organ failure, and the differences were statistically significant (P<0.001). The ECD was highest when corneas were retrieved within 6 hours after death, and the difference was statistically significant (P<0.001). Older donors had higher coefficients of variation but lower HEX values (both P<0.05). Corneas retrieved after a longer time from death had higher coefficients of variation, and the difference was statistically significant (P<0.05), but there was no statistically significant difference in HEX (P>0.05). Organ failure, cryopreservation, and corneal retrieval time >12 hours were risk factors for unclear corneal endothelial imaging (all P<0.001). Among the 136 corneal endothelial images (23.94%), circular, oval, or band-shaped dark areas were observed, and corneas with dark areas had lower ECD (P<0.05). The longer the time elapsed from death to corneal retrieval, the more dark areas were observed (P<0.001). The presence of dark areas did not affect the coefficient of variation and HEX (P>0.05). Conclusion: Advanced donor age, death due to chronic diseases, longer time elapsed from death to corneal retrieval, and cryopreservation of the body lead to a decrease in the quality of donor corneal endothelium.

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.

Endothelial Cell Viability after DMEK Graft Preparation.

Aim: To evaluate the effect of graft preparation and organ-culture storage on endothelial cell density (ECD) and viability of Descemet membrane endothelial keratoplasty (DMEK) grafts.Materials and methods: DMEK grafts (n = 27) were prepared at Amnitrans EyeBank Rotterdam from 27 corneas (15 donors) that were eligible for transplantation but could not be allocated due to the Covid-19-related cancellation of elective surgeries. Cell viability (by Calcein-AM staining) and ECD of five grafts originally scheduled for transplantation were evaluated on the originally planned surgery day, whereas 22 grafts from paired donor corneas were evaluated either directly post-preparation or after 3-7 days of storage. ECD was analyzed by light microscopy (LM ECD) and Calcein-AM staining (Calcein-ECD).Results: Light microscopy (LM) evaluation of all grafts showed an unremarkable endothelial cell monolayer directly after preparation. However, median Calcein-ECD for the five grafts initially allocated for transplantation was 18% (range 92-73%) lower than median LM ECD. For the paired DMEK grafts, Calcein-ECD determined by Calcein-AM staining on the day of graft preparation and after 3-7 days of graft storage showed a median decrease of 1% and 2%, respectively. Median percentage of central graft area populated by viable cells after preparation and after 3-7 days of graft storage was 88% and 92%, respectively.Conclusion: Cell viability of most of the grafts will not be affected by preparation and storage. Endothelial cell damage may be observed for some grafts within hours after preparation, with insignificant additional ECD changes during 3-7 days of graft storage. Implementing an additional post-preparation step in the eye bank to evaluate cell density before graft release for transplantation may help to reduce postoperative DMEK complications.

Techniques, Outcomes, and Complications of Preloaded, Trifolded Descemet Membrane Endothelial Keratoplasty Using the DMEK EndoGlide.

PURPOSE: To describe 2 insertion techniques, outcomes, and complications of preloaded, trifolded Descemet membrane endothelial keratoplasty (DMEK) cases using the DMEK EndoGlide inserter. METHODS: This retrospective, consecutive case series analyzed the first 35 cases using the DMEK EndoGlide performed between October 2018 and October 2019 at a single center. Preloaded, trifolded DMEK tissues were delivered through a fluid-injected or pull-through technique. To inject the tissue, a burst of fluid was delivered into the lumen of the injector with a second instrument. Postoperatively, best-spectacle corrected visual acuity (BSCVA), pachymetry, graft survival, and complications were assessed. RESULTS: Thirty-five eyes of 29 patients underwent DMEK alone (n = 11), with cataract surgery (n = 21), or with additional surgeries (n = 3). Of these, 19 (54.3%) grafts were injected. Video analysis revealed a median time of 3.5 minutes from graft insertion to opening for gas insertion. Median preoperative BSCVA of 0.398 logMAR improved to 0.097 logMAR (P = 0.02) at 9 months. Median pachymetry decreased from 619 µm to 551 µm (P = 0.03) at 9 months. Median donor endothelial cell count of 2890.5 cells/mm2 reduced to 2123 cells/mm2 (26.6% endothelial cell loss; P = 0.008) 6 months postoperatively. One (2.9%) graft failed due to inverted marking at the eye bank and subsequent reverse implantation. CONCLUSIONS: Pre-loaded, tri-folded tissues can be implanted with acceptable levels of endothelial cell loss. We describe a no-touch method of injecting pre-loaded, tri-folded tissue and highlight incorrect marking as a potential complication. This may not be identifiable intraoperatively due to lack of scroll formation.

Vertical Scrolling Axis of Corneal Endothelial Grafts for Descemet Membrane Endothelial Keratoplasty.

PURPOSE: Heterogeneity in scrolling behavior of Descemet membrane endothelial keratoplasty (DMEK) grafts complicates DMEK surgery. This prospective observational study assessed scrolling axes of DMEK grafts relative to the donor's eye. METHODS: The eye bank randomly marked the rim of corneoscleral donor buttons during trephination and recorded the position relative to the donor's axis. Surgeons were masked to the absolute position of the eye bank marking and recorded the scrolling axis relative to the eye bank marking and DMEK upside-down orientation. The scrolling axis was categorized as vertical (0 to 30 degrees and 150 to 180 degrees), oblique (>30 to 60 degrees and 120 to <150 degrees), and horizontal (>60 to <120 degrees). Scrolling patterns of corneas from the same donor were assessed. RESULTS: Scrolling patterns of 202 donor corneas from 149 donors were determined. The donor graft scrolled predominantly vertically to the donor's cornea [75%; 95% confidence interval (CI), 68%-80%]. Horizontal axes (11%) and oblique axes (14%) were less common. The median deviation in scrolling axes after unfolding the grafts was 0 degrees from the original scrolling axis (interquartile range, 0-15), indicating that scrolling axes were stable. Fellow eyes of 46 donors had 3.55 times higher odds of a nonvertical scrolling pattern if the first eye had a nonvertical scrolling pattern (95% CI, 1.37-9.20), suggesting that donor factors influencing both eyes could contribute to scrolling patterns. CONCLUSIONS: DMEK grafts have a natural and stable scrolling tendency at vertical axis of donor's cornea. Anticipating scrolling axes might help improve preparation techniques for DMEK grafts and outcomes.

Eye Bank Management of Irregular Descemet Stripping Automated Endothelial Keratoplasty Lenticules.

PURPOSE: To report the management of precut Descemet stripping automated endothelial keratoplasty (DSAEK) lenticules unsuitable for transplantation because of irregular anterior profile after microkeratome cutting. METHODS: After preparation for DSAEK, 20 tissues were considered unsuitable for transplantation because of nonhomogeneous posterior stromal thickness. To convert them into suitable tissues for surgery, manual stromal delamination was performed by removing the excess stromal layers after the indications obtained through optical coherence tomography. These tissues were further transplanted as ultrathin DSAEK. RESULTS: Nineteen tissues were delaminated successfully. The average reduction in thickness in the center (63 ± 69 µm; P = 0.0101) and periphery (129 ± 39 µm; P < 0.0001) before and after delamination was significantly different. One tissue showed signs of perforation during manual dissection and therefore considered unsuitable for transplantation. Primary graft failure was reported in one case, but it was not correlated with the tissue preparation. No other clinical complications were observed after surgery. CONCLUSIONS: Manual delamination of the stroma because of irregular microkeratome cutting is a viable option to obtain a uniform graft thickness required for DSAEK surgeries. This technique can further reduce tissue wastage that is observed after microkeratome cutting errors.

One-Year Clinical Outcomes of Preloaded Descemet Membrane Endothelial Keratoplasty Versus Non-Preloaded Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To compare the one-year outcomes of preloaded Descemet membrane endothelial keratoplasty (pDMEK) and non-preloaded DMEK (n-pDMEK) in patients with Fuchs endothelial corneal dystrophy (FECD). METHODS: This retrospective comparative cohort study consecutively included 68 eyes with Fuchs endothelial corneal dystrophy who underwent either pDMEK (n = 38) or n-pDMEK (n = 30) performed by cornea fellows with an experienced surgeon between 2016 and 2018 at the Massachusetts Eye and Ear Infirmary. Exclusion criteria were previous surgery (other than uncomplicated cataract surgery) and any documented evidence of macular or other corneal diseases. Corrected distance visual acuity (CDVA), central corneal thickness, intraocular pressure, patient characteristics, postprocessing endothelial cell count, donor graft data, and complications were compared. RESULTS: CDVA showed similar results for pDMEK (0.12 ± 0.11 logarithm of the minimal angle of resolution [LogMAR]) and n-pDMEK (0.13 ± 0.13 LogMAR) (P = 0.827). Sixty-six percent of the pDMEK eyes and 57% of the n-pDMEK eyes achieved a VA of ≥0.1 LogMAR, and 95% and 97%, respectively, achieved a CDVA ≥0.3 LogMAR. The preoperative central corneal thickness of pDMEK and n-pDMEK (644 ± 62.2 µm, 660.5 ± 56.2 µm) decreased significantly after surgery (525.1 ± 43.6 µm, 526.5 ± 45.2 µm, P < 0.001), with no difference between groups (P = 0.840). The postprocessing endothelial cell count did not differ between pDMEK (2959.2 ± 182.9 cells/mm2) and n-pDMEK (2939.3 ± 278.7 cells/mm2) (P = 0.484). Complication rates were comparable with just the rebubbling performed in a minor procedure room showing a lower rate for pDMEK (13.16%) compared with n-pDMEK (33.33%) (P < 0.045). CONCLUSIONS: One-year clinical outcomes were similar between pDMEK and n-pDMEK procedures, rendering eye bank-prepared pDMEK tissues a useful tool in the treatment of endothelial dysfunction.

Eye Banking: One Cornea for Multiple Recipients.

PURPOSE: Corneal transplantation is the most frequently performed transplant procedure. In much of the world, the demand for donor tissue heavily outstrips supply. With developments within lamellar corneal graft surgery, the use of split corneal donor tissue to increase donor tissue supply seems a pragmatic solution to reduce the supply and demand mismatch. This is especially important with tissue supply expected to be affected by the COVID-19 pandemic. METHODS: A literature review of techniques was performed, enabling multiple transplants to be derived from a single donor and simulation of a model to quantify the number of corneas potentially saved. RESULTS: Studies on splitting corneal donor tissue have demonstrated that up to 5 recipients may benefit from 1 donor scleral button. The impact of splitting donor tissue may provide a saving of up to 25.3% of donor graft tissue. CONCLUSIONS: Splitting and preparing the donor tissue within an eye bank will improve tissue validation and donor tissue availability and may increase surgeon efficiency.

The Last 200 Surgeon-Loaded Descemet Membrane Endothelial Keratoplasty Tissue Versus the First 200 Preloaded Descemet Membrane Endothelial Keratoplasty Tissue.

PURPOSE: The purpose of this study was to compare the clinical outcomes from using eye bank-prepared, endothelium-out preloaded Descemet membrane endothelial keratoplasty (DMEK) tissue with those obtained with endothelium-out surgeon-loaded DMEK tissue using the same surgical technique at 1 site. METHODS: This study retrospectively reviewed 400 consecutive cases of DMEK from March 2016 to April 2018. The last 200 cases using surgeon-loaded tissue were compared with the first 200 cases using preloaded tissue. Statistical analysis was performed using the Wilcoxon signed-rank test, binomial logistic regression, Kruskal-Wallis 1-way analysis of variance, Student t test, or Pearson χ tests. RESULTS: Comparing surgeon-loaded versus preloaded DMEK tissue, respectively, no statistical difference was found in the mean 6-month postoperative values for endothelial cell loss (32.9% ± 18.5% vs. 29.9% ± 16.4%, P = 0.31), best corrected visual acuity (20/26 vs. 20/25, P = 0.54), or change in central corneal thickness (-14.4% ± 8.9% vs. -15.6% ± 11.7%, P = 0.43). The mean 1-year endothelial cell loss was also not significantly different (37.6% ± 17.2% vs. 33.2% ± 14.8%, P = 0.07). Overall, the rebubble rate for surgeon-loaded tissue was 17.5% and 12.5% for preloaded tissue, a statistically nonsignificant difference. Operative outcomes for mean tissue scroll tightness (1-4) and tissue unscroll time (minutes) for surgeon-loaded and preloaded tissue were similar between groups (2.4 vs. 2.2, P = 0.12 and 3.5 vs. 3.3 minutes, P = 0.50). CONCLUSIONS: Tissue that is trephinated, stained, and loaded into an injector by the eye bank and then shipped to the surgeon had no difference in clinical outcomes compared with tissue where the surgeon performs these steps. The safety and speed of using preloaded tissue should be considered by DMEK surgeons.

Optimizing pre-Descemet endothelial keratoplasty technique.

Pre-Descemet endothelial keratoplasty (PDEK) is an alternative technique to Descemet membrane endothelial keratoplasty (DMEK). The preparation of PDEK tissue by pneumatic dissection is simple and reproducible. The PDEK clamp helps to consistently obtain a type 1 big bubble. The mean size of type 1 big bubble is 7.255 ± 0.535 × 6.745 ± 0.668 mm. The volume of air required to obtain type 1 big bubble is 0.14 to 0.37 mL. Dissection of PDEK tissue can be achieved by trephination or manual excision. Insertion of tissue into the recipient eye can be by injection or pulling. Unfolding techniques used for PDEK are similar to those used in DMEK. Unlike DMEK, PDEK tissue is easier to handle and unscroll and allows use of younger donors. It could help surgeons converting to endothelial keratoplasty, with significant advantages in preparation, handling, and unscrolling in the eye.

Trephine- and dye-free technique for eye bank preparation of pre-stripped Descemet membrane endothelial keratoplasty tissue.

We describe a rapid and easy technique for the preparation of pre-stripped Descemet membrane (DM) endothelial keratoplasty (DMEK) tissue in the eye bank, without the use of dye or trephining by the eye bank technician. After drawing 2 radial marks 90° apart on the scleral rim of the cornea, a circumferential incision was made internal to the trabecular meshwork and the edge of the DM opposite to the marked area was scored and gently peeled towards the marked area. Finally, the peeled DM was gently unrolled and attached to the posterior stromal bed via absorbing excess liquid from the periphery. The prepared DMEK tissue while reattached on the posterior aspect of the cornea was subjected to slit-lamp biomicroscopic and specular microscopic examinations. In case of proper preparation of DMEK tissue and suitability of endothelial cells for DMEK surgery, the tissue was distributed for transplantation. At the time of surgery, trypan blue staining was performed by the cornea surgeon before DM trephination. Duration of DMEK tissue preparation, uneventful preparation, post-preparation endothelial cell loss, surgeon's satisfaction, and intra- and post-operative attachment of the tissue were investigated variables in this study. Over a 2-year period, 28 DMEK tissues were successfully prepared from 30 corneas using our new technique. The median duration of DMEK preparation was 100 s. The area of endothelial cell loss was 1.8% ± 1.2% centrally and 6.2% ± 1.8% in areas close to the forceps contacts. Seven out of the 28 (25%) DMEK tissues were ruined by surgeons during surgery and the overall rate of re-bubbling in 19 transplanted DMEK tissues was 16%. The presented method, which uses no trephining or vital dye, has simplified and expedited the preparation process of pre-stripped DMEK tissue in the eye banks.

Standardizing Descemet Membrane Endothelial Keratoplasty Graft Preparation Method in the Eye Bank-Experience of 527 Descemet Membrane Endothelial Keratoplasty Tissues.

PURPOSE: To share the experience and provide a standardized protocol for Descemet membrane endothelial keratoplasty (DMEK) graft preparation. METHODS: A retrospective study based on 527 prestripped DMEK tissues that were prepared between 2014 and 2017. The experience of using different instruments and techniques has been described, and a standardized technique for preparing DMEK grafts has been identified. The tissues in general were prepared by superficially tapping the endothelial side with a Moria trephine (9.5 mm diameter). The plane of cleavage was identified using a cleavage hook, and the DMEK graft was deadhered from the trephined site throughout the circumference for ease of excising the graft. The DMEK graft was peeled using either one or multiple quadrant methods depending on the challenges faced during excision. The graft was finally marked with the letter "F" to identify the orientation during surgery. Data on endothelial cell loss (ECL) and challenging cases were observed, monitored, and recorded during this period. RESULTS: Less than 1 percent trypan blue-positive cells with tissue wastage of <6% was observed during the study period. Our standardized stripping technique has resulted in an overall ECL of 4.6%. Marking Descemet membrane showed 0.5% cell mortality. CONCLUSIONS: Standardizing DMEK technique using specific tools and simple techniques would help new surgeons to decide the instruments and improve their tissue preparation skills also in challenging cases such as previous cataract incisions or horseshoe-shaped tears, further reducing ECL or tissue wastage.

Peripheral Blunt Dissection: Using a Microhoe-Facilitated Method for Descemet Membrane Endothelial Keratoplasty Donor Tissue Preparation.

PURPOSE: To describe a modified technique for Descemet membrane donor tissue preparation that facilitates the original Melles stripping technique. METHODS: Descemet membrane is prepared using a Rootman/Goldich modified Sloane microhoe, using a blunt instrument as opposed to a sharp blade or needle and begins dissection within the trabecular meshwork. The trabecular tissue is dissected for 360 degrees, and then Descemet membrane is stripped to approximately 50%. A skin biopsy punch is then used to create fenestration in the cornea, which is used to mark an "F." on the stromal side of Descemet membrane to aid in orientation of the graft. Trephination of the membrane is then performed and stripping is completed. The tissue is stained with 0.06% trypan blue and aspirated into an injector for insertion into the anterior chamber. RESULTS: Before converting to the technique described, 5 of 75 (6.7%) tissues were wasted and 7 of 75 (9.3%) tissues with radial tears were salvaged for use. Since converting to the new technique, only 1 of 171 (0.6%) (P = 0.01) tissues was wasted and 7 of 171 (4.1%) (P = 0.2) tissues with radial tears were salvaged. CONCLUSIONS: The peripheral blunt dissection technique offers an improvement over the technique originally described by Melles et al, as the incidence of tissue wastage and tears is lower, it is easy to learn, has low stress, and is reproducible. Combining this with a stromal surface letter mark ensures correct orientation of the tissue against the corneal stroma of the recipient.

Outcomes of Descemet Stripping Endothelial Keratoplasty Using Eye Bank-Prepared Preloaded Grafts.

PURPOSE: To evaluate the feasibility of Descemet stripping endothelial keratoplasty using grafts preloaded by an eye bank in a commercially available insertion device. METHODS: In this retrospective case series, a series of 35 eyes in 34 consecutive patients who underwent Descemet stripping endothelial keratoplasty for Fuchs endothelial dystrophy or previously failed full-thickness grafts at a single tertiary care center from March 2013 to March 2014 was included. The donor tissue had undergone pre-lamellar dissection, trephination, and loading into EndoGlide Ultrathin inserters at the Lions Eye Institute for Transplant and Research (Tampa, FL) and was shipped overnight in Optisol GS to the surgeon (K.C.). Surgery was performed within 24 hours from tissue preparation and loading by the eye bank. Donor and recipient characteristics, endothelial cell density (ECD), best-corrected visual acuity, and central corneal thickness were recorded. The main outcome measures were intraoperative and postoperative complications and ECD loss at 3, 6, and 12 months. RESULTS: One primary graft failure (2.8%), 2 rebubblings (5.7%), and 1 graft rejection (2.8%) occurred. Mean preoperative donor ECD was 2821 ± 199 cells/mm. Six months postoperatively, the mean endothelial cell loss was 25.3% ± 17.2% (n = 32), which remained stable at 1 year (31.5% ± 17.9%, n = 32). Mean best-corrected visual acuity improved from 20/100 preoperatively to 20/25 at a mean follow-up of 1 year (n = 32). Mean central corneal thickness was reduced from 711 ± 110 µm to 638 ± 66 µm at the last follow-up visit. CONCLUSIONS: Donor graft tissue preloaded by an eye bank can be used successfully for endothelial keratoplasty. Preloading reduces intraoperative tissue manipulation.

Factors that influence the suitability of human organ-cultured corneas.

PURPOSE: The purpose was to assess the influence of donor and storage factors on the suitability of organ-cultured corneas for transplantation. METHODS: Data from 1340 donor corneas stored between 2009 and 2015 were analyzed retrospectively. Logistic regression analysis was used to assess the influence of different factors on the suitability of grafts for transplantation. RESULTS: Forty-one percent (553/1340) of corneas were discarded. The leading causes were medical contraindication (20.2 %) and poor endothelial quality (19.3 %). Donor age influenced suitability for transplantation significantly. Corneas from donors aged 80 years and older were more likely to be discarded because of endothelial insufficiency (P < 0.0001). The cause of donor death including infection and multiple organ dsyfunction syndrom (MODS) increased the risk of bacterial or fungal contamination during organ culture (P = 0.007 and P = 0.014, respectively). Prolonged time between death and enucleation was associated with an increased risk of unsuitability for transplantation (P < 0.0001). The amount of time between death and corneoscleral disc excision and duration of storage influenced the suitability for transplantation (P = 0.0007 and P < 0.0001, respectively). CONCLUSION: Donor age, cause of death, storage time, death to enucleation and death to disc excision times influenced transplantation suitability. The percentage of discarded corneas may be reduced by shortening storage time, death to enucleation, and death to corneoscleral disc excision times. Setting a maximum donor age could reduce the percentage of discarded corneas. However, as long as there is a lack of donor corneas, we do not recommend any donor age limit.

Comparison of two in situ corneal donation technique: morgue trephination or scleracorneal removal technique.

PURPOSE: To compare the two different 'in situ' methods of corneal trephination technique under morgue condition (morgue trephination technique, MTT) and classic scleracorneal removal technique (SRT). METHODS: A total of 1179 cases were evaluated for cornea donation at Gazi University Faculty of Medicine mortuary between the years 2008 and 2013 and were included to the study. Suitable donor corneas were retrieved with in situ trephination technique under morgue condition (group 1, MTT) or with in situ classic SRT (group 2, SRT). The two different 'in situ' methods were compared in terms of donor corneal biological quality (endothelial cell count, ECC) and functional outcome (presence of infection and primary graft failure). RESULTS: One hundred and fifty-two of 1179 cases were suitable for corneal donation. Two hundred and twenty-nine corneas of 152 cases were transplanted, 108 corneas were obtained with MTT and 121 corneas were obtained with SRT. Pretransplant and post-transplant ECCs were 2402.5 ± 115.6 and 2108.3 ± 108.23 (p = 0.065) in MTT, respectively, and 2512.7 ± 130.4 and 2235.4 ± 201.8 (p = 0.059) in SRT, respectively. The incidence of primary graft failure and infection was not statistically significantly different between two method [2.7% and 1.6% (p = 0.223), 0.9% and 0.8% (p = 0.115)]. CONCLUSION: The two different 'in situ' methods, MTT and SRT, were similar in terms of donor ECC, presence of infection and primary graft failure. Cornea excision performed through the technique described herein may increase the corneal donation rates as result of reduced disfigurement to donor body and offer important contributions during surgery with good anatomic adaptation of tissues.

Anterior corneal buttons from DSAEK donor tissue can be stored in optisol GS for later use in tectonic lamellar patch grafting.

PURPOSE: The aim of this study was to evaluate the feasibility of storing anterior corneal buttons split from donor Descemet stripping automated endothelial keratoplasty (DSAEK) tissue for later use in tectonic lamellar patch grafting. METHODS: Donor corneas for DSAEK were split into anterior and posterior lamellae using a 350-µm depth microkeratome, and the remaining anterior corneal buttons were stored for up to 4 weeks at 4°C in Optisol GS before use in patch grafting of the cornea and sclera. RESULTS: Optisol GS-preserved anterior lamellar patch grafts successfully restored and maintained corneoscleral integrity after the removal of limbal dermoids (5 cases), after the coverage of the exposed polypropylene suture ends of scleral fixated posterior chamber intraocular lenses (2 cases), corneoscleral melting after pterygium excision (3 cases), sterile corneal ulceration with or without perforation (5 cases), Mooren ulceration (3 cases), and pseudomonas corneal ulceration with impending perforation (1 case). It was also used as a temporary substitute while waiting for a full-thickness corneal graft in a fulminant candida infection after DSAEK (1 case). All grafts remained structurally intact at the last postoperative examination of 19.2 ± 7.6 months after the tectonic surgery. CONCLUSIONS: Anterior corneal buttons from DSAEK donor tissue may be stored in Optisol GS for later use in tectonic patch grafting. This method obviates the longer operating time required for the surgeon to manually dissect the donor cornea in the operating room and reduces the wastage of precious donor corneas in countries where there are chronic shortages of eye bank donor tissue.

Tissue quality of eye-bank-prepared precut corneas for Descemet's stripping automated endothelial keratoplasty.

OBJECTIVE: To evaluate endothelial cell density (ECD) of eye-bank-prepared tissue for use in Descemet's stripping automated endothelial keratoplasty (DSAEK). DESIGN: Prospective case series of consecutive corneal tissue prepared for DSAEK surgery. PARTICIPANTS: Sixty-seven sequential corneal-scleral tissue specimens representing 48 human donors processed for use in DSAEK surgery by the Regional Tissue Bank (Halifax, Nova Scotia). METHODS: Corneal-scleral donor tissue was obtained by in situ recovery. ECD was recorded using the EB-3000 XYZ (HAI Laboratories Inc, Lexington, MA) specular microscope within 24 hours of preservation. Before the tissue was dissected, the corneal thickness was measured using the DGH-550 PACHETTE 2 (DGH Technology, Exton, PA) ultrasound pachymeter. The dissection was performed using a 300-µm Moria ALTK model microkeratome (Moria Inc). The posterior bed thickness was measured, and the anterior flap was replaced. Endothelial cell count density was obtained after re-preservation. RESULTS: Complete measurements were obtained for 42 of 67 corneas. In 25 corneas it was not possible to obtain a postdissection ECD measurement. The mean ECD before dissection was 2806 ± 317 cells/mm(2). The mean ECD after dissection was 2772 ± 318 cells/mm(2). There was an average loss of 34 cells/mm(2) (95% CI -110 to 40 cells/mm(2), p = 0.3). CONCLUSIONS: This case series confirms that ECD is preserved when DSAEK tissue is prepared in advance of surgery by trained eye-bank technicians in a low-volume Canadian eye bank. It was difficult to obtain clear images of the endothelial cell layer postdissection, possibly because of tissue swelling or distortion. Sixty-six of 67 corneas included in the study were used for surgery.

Comparison of organ cultured precut corneas versus surgeon-cut corneas for Descemet's stripping automated endothelial keratoplasty.

To compare precut and surgeon-cut organ cultured donor corneas for DSAEK. A total of 119 consecutive eyes treated with DSAEK were retrospectically identified. 65 grafts were cut by the surgeon (Moria, ALTK System) prior to DSAEK and 54 grafts were precut by laboratory technicians from the Danish Eye Bank (Horizon single-use system). 1 year after surgery, tomographic images were obtained with the Pentacam HR. Endothelial cell density (ECD) and best-corrected visual acuity (BCVA) was determined. Graft thickness and graft asymmetry was evaluated in the centre and 1 mm from the edge of the graft in 6 semi-meridians. 1 year after surgery, the ECD loss was similar in the two groups, averaging 25.9 ± 14 % in surgeon-cut, and 22.9 ± 17 % in precut group (p = 0.33). Mean central graft thickness was 172 ± 6 µm in surgeon-cut grafts and 182 ± 6 µm in precut grafts (p = 0.30). BCVA was similar in surgeon-cut and precut corneas; being 0.25 ± 0.02 logMAR and 0.24 ± 0.02 logMAR, respectively (p = 0.59). The graft asymmetry index was 1.48 ± 0.02 for surgeon-cut and 1.44 ± 0.02 for precut grafts. There were no significant differences in complications rate in both groups. No correlations between BCVA and central graft thickness or graft asymmetry index in both groups were observed. Organ cultured precut donor corneas are comparable with surgeon-cut grafts with respect to ECD, graft thickness and asymmetry, and postoperative complication rate.

Thin lenticule Descemet's stripping automated endothelial keratoplasty: single, slow pass technique.

BACKGROUND: To evaluate the outcomes of single pass thin lenticule sutureless Descemet's stripping automated endothelial keratoplasty with donor lenticules prepared using a 400 µm microkeratome head. DESIGN: Interventional case series. PARTICIPANTS: Cases with corneal endothelial dysfunction. METHODS: Fifteen cases with corneal endothelial dysfunction (eight pseudophakic bullous keratopathy, three Fuchs' endothelial dystrophy, three congenital hereditary endothelial dystrophy and one failed graft) underwent thin lenticule Descemet's stripping automated endothelial keratoplasty at a tertiary care hospital. Donor lenticule was prepared with a single pass 400 µm Carriazo Barraquer microkeratome (Moria, Antony, France) head. Sutureless Descemet's stripping automated endothelial keratoplasty was performed in all the cases through a 3.5 mm corneoscleral tunnel using a Busin glide for graft insertion. MAIN OUTCOME MEASURES: Main parameters evaluated were postoperative donor lenticule thickness and best-corrected visual acuity. RESULTS: Donor lenticules were harvested successfully for all 15 cases without any complications. At 6-months follow up, the mean logMAR best-corrected visual acuity improved from 1.87 ± 0.52 to 0.109 ± 0.11 (P = < 0.0001). The mean donor lenticule thickness was 111 ± 17.62 µm (range 70-134 µm) at the last follow up. The mean endothelial cell loss was 26.33 ± 1.34%. CONCLUSIONS AND RELEVANCE: Thin donor lenticules for Descemet's stripping automated endothelial keratoplasty can be safely harvested using a single pass technique with 400 µm microkeratome head and can be used for a successful Descemet's stripping automated endothelial keratoplasty surgery.