Donor Corneas Research Articles

ECM-based bioadhesive hydrogel for sutureless repair of deep anterior corneal defects.

Corneal transplantation is the gold standard treatment for corneal-related blindness; however, this strategy faces challenges such as limited donor cornea, graft rejection, suture-related complications, and the need for specialized equipment and advanced surgical skills. Development of tissue adhesives for corneal regeneration is of great clinical value. However, currently available corneal tissue sealants pose challenges, such as lack of safety, biocompatibility, and desired mechanical properties. To meet these requirements simultaneously, a bovine stromal corneal extracellular matrix (dCor) was used to design a bioadhesive photocurable hydrogel based on gelatin methacrylate (GelMA) and polyethylene glycol diacrylate (PEGDA) hydrogels (dCor/Gel-PEG). Integration of dCor into the dual networks of GelMA and PEGDA (Gel-PEG) led to a bioadhesive hydrogel for curing corneal defects, which could be crosslinked by Irgacure 2959 within 5 min ultraviolet irradiation. The viability of corneal stromal stem cells (CSSCs) was improved on the dCor/Gel-PEG hydrogel in comparison to the Gel-PEG hydrogel. The gene expression profile supported the keratocyte differentiation of CSSCs seeded on dCor/Gel-PEG via increased KERA and ALDH, with inhibited myofibroblast transdifferentiation via decreased α-SMA due to the presence of dCor. Interestingly, the dCor/Gel-PEG hydrogel exhibited favorable mechanical performance in terms of elasticity and bioadherence to the host corneal stroma. Ex vivo and in vivo examinations proved the feasibility of this hydrogel for the sutureless reconstruction of deep anterior corneal defects with promising histopathological results.

Artificial corneas ‐ Recent developments

Many regenerative medicine technologies have now entered the clinical realm with the help of biomaterials. Biomaterials, in conjunction with therapeutic stem or immune cells or cell products, are used to engineer tissues for in vivo testing platforms (organs‐on‐chips) or clinical use. However, biomaterials can also be used to stimulate in situ tissue regeneration to avoid adverse immune reactions. In ophthalmology, human donor corneas have served well for corneal transplant surgery. However, the massive shortage of suitable donor tissue combined with the expense and technical challenges of eye banking leaves a substantial proportion of the world's population without access to treatment. Here, we discuss the development of novel biomaterials for corneal implants that stimulate in situ tissue regeneration and the pathway to getting these into clinical trials. The results of clinical and pre‐clinical trials will be discussed.

Gene expression in calcium triggered healthy primary limabal epithelial cells, in vitro

Aims/Purpose: Calcium supplementation can induce differentiation of several cell types. The tear film has an important role in maintenance of the ocular surface homeostasis with an ionic calcium concentration of 0.4 mM‐1.0 mM. The effect of calcium concentration on healthy primary limbal epithelial cells (LECs) has not been analysed, yet. Our purpose was to investigate the effect of calcium supplementation on gene expression of primary limbal epithelial cells (LECs) of healthy donor corneas, in vitro.Methods: Primary LECs were isolated from corneoscleral rims of healthy donors (n = 6) and were cultured in serum free low calcium (0.06 mM Ca+2) Keratocyte growth medium 3 (KGM3). The primary LECs were then supplemented by 0.3 mM‐2.0 mM Ca+2 concentrations for 72 h. Control LEC cultures were supplemented by low calcium (0.06 mM Ca+2) KGM3 medium. After cell harvesting, RNA and protein were extracted from treated and control LECs to perform qPCR and western blot analysis.Results: The calcium supplementation had no significant effect on PAX6 mRNA expression after 72 h. The differentiation marker and adhesion protein DSG1 and the cornea specific keratin K3 expression did not change significantly through Ca+2 supplementation (p ≥ 0.5). The retinoic acid signalling component fatty acid binding protein FABP5 expression (p ≥ 0.5) the wound healing and vascularization marker CAV1 gene expression (p ≥ 0.5) did not change significantly through Ca+2 supplementation, after 72 h.Conclusions: Calcium supplementation for 72 h did not change PAX6 expression and did not trigger differentiation of healthy primary limbal epithelial cells. We plan to analyse the effect of longer incubation time in the future in order to trigger a full differentiated status of limbal epithelial cells, using calcium supplementation.

Outcomes of hemi-Descemet membrane endothelial keratoplasty and phacoemulsification for the treatment of primary Fuchs' endothelial corneal dystrophy combined with cataract

This study evaluates the long-term results of surgical treatment of patients with Fuchs' endothelial corneal dystrophy and cataract. The study included 24 patients (24 eyes) with primary Fuchs' endothelial corneal dystrophy and cataract, who underwent cataract phacoemulsification with IOL implantation and of Descemet's membrane endothelial keratoplasty with a semicircular graft (hemi-DMEK). The effect of treatment was assessed by best corrected visual acuity (BCVA), central corneal thickness (CCT) and endothelial cell density (ECD). In total, surgical treatment involved 14 donor corneas that were divided in half during the preparation and isolation of the Descemet's membrane (DM). By month 12 after the surgery an increase in visual functions and graft transparency were observed in 23 patients (23 eyes) out of 24. Repeated keratoplasty was required in one case due to fibrosis of the posterior layers of recipient's corneal stroma. At 12 months postoperatively, the study group showed an increase in BCVA from 0.16±0.1 to 0.75±20, a decrease in CCT from 650.9±4.5 μm to 519.6±43.9, and a decreased in ECD from 2850.5±84.7 cells/mm2 up to 1285.5±277.2 cells/mm2. Thus, the loss of endothelial cells at one year after surgery amounted to 54.9%. The developed method for transplantation of a semicircular DM fragment provides a tissue-saving approach to endothelial keratoplasty, and considering the high percentage of transparent engraftment of grafts and complete visual rehabilitation, it can be recommended in the treatment of patients with cataract and Fuchs' endothelial corneal dystrophy.

Performance outcomes from a DMEK peeling and preparation wet lab

ObjectiveTo evaluate the Descemet membrane endothelial keratoplasty (DMEK) preparation performance of trainee surgeons in an ex vivo human donor cornea DMEK wet lab simulation setting.MethodsHuman donor corneoscleral rims unsuitable for...

Surgery after corneal grafts

There is one available donor per 70 patients so we need to identify those whose vision would benefit from corneal transplantation and minimize risks that could jeopardize corneal graft survival possibility1.The two leading causes of graft failure post Penetrating Keratoplasty (PKP) are graft rejection and secondary glaucoma development. The existence of preoperative glaucoma increases two to three times the chances of graft rejections in any corneal transplantation2,3. The 10‐year Cornea Donor Study also confirmed that pre‐existing glaucoma is a risk factor for graft failure4. The 3‐year graft survival rate has been shown to be 71% in patients with preop glaucoma and 89% in patients without preop glaucoma5.In cases following Descemet Striping Endothelial Keratoplasty (DSAEK), Ocular Hypertension (OHT) ranges in otherwise healthy eyes from 29 to 47% and increases to 43 to 54% in cases with pre‐existing glaucoma or high‐risk eyes. Glaucoma can be presented in up to 15% in post‐DSAEK cases which increases twice the relative risk of rejection. Concurrent gonio‐synechiolysis is considered an additional risk factor whereas 18.6% of high IOP cases considered as secondary to steroid administration. Acute raise in IOP can be attributed in pupillary block at an estimated rate of 13%6,7.In cases of Descemet Membrane Endothelial Keratoplasty (DMEK) OHT or intraocular pressure (IOP) elevation is presented to 6.5 up to 11.1% and de novo glaucoma can be found from 2.8 to 6.5%, whereas progression of pre‐existing glaucoma is less than 2.5%8. In cases with simultaneous DMEK and cataract surgery there is greater likelihood of post‐op OHT or glaucoma. In DMEK cases the early postoperative increase in pressure is usually due to a combination of anterior (inferior) and posterior (superior) pupillary blocks when patient is sitting upright9.The late post‐DMEK IOP increase is attributed to Blockage of TM by inflammatory cells, PAS formation or steroid use. However, steroid‐induced glaucoma post‐DMEK is not as common as that in post‐PKP or post‐DSAEK due to the shortest steroid regime post‐DMEK cases. Treatment methods include medical treatment, trabeculectomy or tubes. Some cases with Xen®10 and Micropulse cyclodidode11 laser have been reported in endothelial cases, however with little degree of evidence.Controversy still exists to which surgical procedure is the best for graft survival and IOP control, as well as when is the best time of the surgery in patients with pre‐existing glaucoma, before, simultaneously or after, and if needed, graft surgery. Certainly a “try not to create glaucoma” strategy needs always to be followed by not producing additional iatrogenic risk factors with improved technique(s) and by respecting the tissue(s).

Deep Anterior Lamellar Keratoplasty Using Dehydrated versus Standard Organ Culture-Stored Donor Corneas: Prospective Randomized Trial

PurposeTo compare the outcomes of deep anterior lamellar keratoplasty (DALK) using dehydrated versus standard organ culture stored donor corneas for eyes with keratoconus. DesignProspective, randomized, single-center trial conducted in Italy ParticipantsAdult patients with keratoconus (≥ 18 years old) with keratoconus scheduled for an elective DALK MethodsCases with successful type 1 bubble pneumatic dissection using standard DALK technique were intraoperatively randomized to receive either dehydrated (n=30) or standard organ culture stored donor corneas (n=30). Main Outcome MeasuresThe primary study outcome was best spectacle-corrected visual acuity (BSCVA) 12 months after surgery. Secondary outcomes were refractive astigmatism (RA), endothelial cell density (ECD) and complication rates. ResultsPostoperative logMAR BSCVA did not significantly differ between groups at both time points (mean difference at 6 months = 0.030 [95%CI: -0.53-0.10] p = 0.471) and at 12 months = -0.013 [95%CI: -0.10-0.08] p = 0.764). No significant differences between groups were observed in terms of postoperative RA and ECD at all time points. In the first 3 days after DALK, an epithelial defect was present in 10 cases (33%) of the organ culture cornea group and in 29 cases (97%) of the dehydrated cornea group. Complete re-epithelialization was achieved by day 7 in all cases (100%) of both groups. ConclusionsThe study provides evidence that the use of dehydrated corneas is non-inferior to the use of standard organ culture donor corneas for DALK. Corneal tissue dehydration represents a viable solution that can allow long-term cornea preservation and avoid wastage of unused corneas.

Characterization of cornea donors at a tissue center in the city of Medellin, Colombia

The cornea transplant is considered the most frequently performed type of transplant in the world, with a demand that has been increasing in recent years. An observational descriptive study was conducted, focusing on the ocular tissue extracted from cadaveric donors from January 2019 to December 2021 at the Red Cross Eye Bank in Medellin, Colombia. This is the first epidemiological characterization of corneal donor tissues within the eye banks of our city, where high rates of violence-related deaths explain that tissue donors are mostly young individuals. This, in turn, results in excellent counts of endothelial cells and tissue viability in their microscopic studies. Additionally, there are lower rates of discarded tissues compared to similar studies.

Impact of cleanroom status on the reasons for discarding organ-cultured corneal transplants in a modern eye bank - More donor corneas thanks to astronaut suit?

This study investigated the influence of cleanroom conditions on the discard rates of donor corneas in a German university eye bank. Discard rates were analysed from 2017 to 2020 at the LIONS Cornea Bank at Saarland University Medical Center. 1941 corneas from 971 donors were included. 1262 corneas (65.1%) were stored in a class D cleanroom from 2017 to 2019 and processed in a cleanroom class A sterile bank (group 1). 679 corneas (34.9%) were continuously stored in a class B cleanroom and processed in a class A cleanroom safety cabinet in the same room from 2019 to 2020 (group 2). The target parameter of this work was the number of contamination-related discards. Although they cannot be influenced by the spatial conditions, the discards due to insufficient endothelial quality, serology, contraindications, scars and technical causes were also recorded. Statistical analysis was performed using SPSS and various testing procedures. In group 1, significantly more corneas were discarded due to positive serology (6.9%|3.8%, p = 0.020). There was no significant change between both groups for either contamination or the other reasons for discard. Optimization of hygiene standards from cleanroom class D to B did not reduce contamination. Serology, endothelial quality, medical contraindications and the presence of scars cannot be influenced by cleanroom conditions.

Novel strategy for multi-material 3D bioprinting of human stem cell based corneal stroma with heterogenous design

Three-dimensional (3D) bioprinting offers an automated, customizable solution to manufacture highly detailed 3D tissue constructs and holds great promise for regenerative medicine to solve the severe global shortage of donor tissues and organs. However, uni-material 3D bioprinting is not sufficient for manufacturing heterogenous 3D constructs with native-like microstructures and thus, innovative multi-material solutions are required. Here, we developed a novel multi-material 3D bioprinting strategy for bioprinting human corneal stroma. The human cornea is the transparent outer layer of your eye, and vision loss due to corneal blindness has serious effects on the quality of life of individuals. One of the main reasons for corneal blindness is the damage in the detailed organization of the corneal stroma where collagen fibrils are arranged in layers perpendicular to each other and the corneal stromal cells grow along the fibrils. Donor corneas for treating corneal blindness are scarce, and the current tissue engineering (TE) technologies cannot produce artificial corneas with the complex microstructure of native corneal stroma. To address this, we developed a novel multi-material 3D bioprinting strategy to mimic detailed organization of corneal stroma. These multi-material 3D structures with heterogenous design were bioprinted by using human adipose tissue -derived stem cells (hASCs) and hyaluronic acid (HA) -based bioinks with varying stiffnesses. In our novel design of 3D models, acellular stiffer HA-bioink and cell-laden softer HA-bioink were printed in alternating filaments, and the filaments were printed perpendicularly in alternating layers. The multi-material bioprinting strategy was applied for the first time in corneal stroma 3D bioprinting to mimic the native microstructure. As a result, the soft bioink promoted cellular growth and tissue formation of hASCs in the multi-material 3D bioprinted composites, whereas the stiff bioink provided mechanical support as well as guidance of cellular organization upon culture. Interestingly, cellular growth and tissue formation altered the mechanical properties of the bioprinted composite constructs significantly. Importantly, the bioprinted composite structures showed good integration to the host tissue in ex vivo cornea organ culture model. As a conclusion, the developed multi-material bioprinting strategy provides great potential as a biofabrication solution for manufacturing organized, heterogenous microstructures of native tissues. To the best of our knowledge, this multi-material bioprinting strategy has never been applied in corneal bioprinting. Therefore, our work advances the technological achievements in additive manufacturing and brings the field of corneal TE to a new level.

Eye Donation Counsellor Skill Evaluation Tool (EDC-SET): A step toward improved eye donation counseling.

The expansion of the Hospital Corneal Retrieval Programme (HCRP) and the role of Eye Donation Counsellors (EDCs) have shown promising results in increasing donor cornea availability. To further enhance EDC competency and improve cornea availability for transplantation, the study proposes the Eye Donation Counsellor Skill Evaluation Tool (EDC-SET). Key words: Competency assessment, corneal blindness, Eye Donation Counsellors (EDCs), eye health, Hospital Corneal Retrieval Programme (HCRP), skill evaluation. A competency framework for EDCs and a tool for evaluation of the competency level (EDC-SET) was designed, along with scripts for emulating realistic counselling scenarios. Independent assessors were trained on using EDC-SET and evaluated EDCs participating in role-plays based on the pre-designed scripts. EDCs were briefed a priori on the EDC-SET but not on the role play scripts which were used during evaluation. We piloted the tool at a tertiary eye hospital, and it was found to capture EDC competency reliably. The study evaluated seven EDCs each assessed by two independent assessors. Conformity, kappa, and intraclass correlation coefficient (ICC) values were calculated to estimate the parameter-wise reliability of the EDC-SET. The results suggest that the scores from both assessors closely matched for most of the parameters, and overall, their ratings showed moderate agreement. The difficulty level of each parameter as assessed by the two assessors was also calculated. It was observed that most participants found "Initiation of the Case" and "Empathy and Emotional Support" challenging. However, "Body Language," "Cultural Awareness," and "Attentiveness to Family Dynamics" were perceived as relatively easy or not difficult by participants. Evaluation of EDCs using EDC-SET revealed the varying competency levels of EDCs and showed agreement on the evaluation between the assessors. Implementing the EDC-SET could help standardise the mapping and measurement of the skill set of EDCs, thereby enhancing their performance and reducing corneal blindness in India.

Effect of Anterior Chamber Air on Central Corneal Thickness in Human Donor Eyes.

The purpose of this study was to describe the effects of intracameral air on corneal edema. A laboratory investigation was performed on human donor corneas. Baseline pachymetry measurements through anterior segment optical coherence tomography and endothelial cell density were obtained for all corneas. Each pair of corneas was separated and randomly assigned to undergo air injection or Optisol-GS into a BIONIKO artificial anterior chamber for 5 minutes at physiologic intraocular pressure confirmed by digital palpation. Photographs were obtained immediately on connection of the cornea to the artificial anterior chamber and on completion of the 5 minutes of treatment, with anterior chamber air being exchanged for Optisol-GS. Pretreatment and posttreatment photographs were obtained. Immediately after treatment, pachymetry was again obtained on all corneas. Pachymetry data underwent statistical analysis. Corneal pachymetry improved from 690.5 ± 126.6 to 576.1 ± 87.2 μm, yielding a 114.4 ± 50.4 μm improvement of pachymetry in the group with air injected into the anterior chamber. This was a significant improvement of pachymetry when compared with the group with Optisol-GS injected into the anterior chamber, which showed an improvement from 662.3 ± 126.5 to 613.5 ± 108.0 μm, yielding an improvement of 48.8 ± 34.3 μm. Injection of air into the anterior chamber leads to a significant decrease in corneal pachymetry. We thereby propose that injecting air intracamerally is an effective intraoperative intervention when visualization is negatively affected by corneal edema.

Descemet Membrane Endothelial Keratoplasty: 10-Year Cell Loss and Failure Rate Compared With Descemet Stripping Endothelial Keratoplasty and Penetrating Keratoplasty.

The aim of this study was to assess long-term endothelial cell loss (ECL) and graft failure with Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping endothelial keratoplasty (DSEK) versus penetrating keratoplasty (PK) performed for the same indications (primarily Fuchs dystrophy and pseudophakic corneal edema) in the Cornea Donor Study. This retrospective study included consecutive primary DMEK (529 recipients, 739 eyes) and DSEK cases (585 recipients, 748 eyes) with 1 or more endothelial cell density (ECD) measurements at 6 months to 16 years. Main outcomes were ECD, longitudinal ECL, and graft failure. Between 6 months and 8 years the ECD declined linearly by approximately 118 cells/mm2/yr after DMEK and 112 cells/mm2/yr after DSEK. Beyond 8 years postoperatively the rate of decline slowed substantially. Selective dropout from graft failure did not significantly affect the ECD trend. At 10 years, median ECL (interquartile range) was 63% (45, 73) with DMEK, 68% (48, 78) with DSEK, and 76% (70, 82) with PK (P = 0.01 DMEK vs. DSEK, P <0.001 DMEK vs. PK, and P < 0.001 DSEK vs. PK). The proportion of surviving grafts with 10-year ECD <500 cells/mm2 was 1.4% with DMEK, 7.3% with DSEK, and 23.9% with PK. The cumulative risk of graft failure between 6 months and 10 years was 5% with DMEK, 11% with DSEK, and 19% with PK (P < 0.001). Compared with PK and DSEK, DMEK had significantly lower ECL and significantly lower risk of secondary graft failure through 10 years.

Incisional surface quality of electron-beam irradiated cornea-extracted lenticule for stromal keratophakia: high nJ-energy vs. low nJ-energy femtosecond laser.

Corneal lenticules can be utilized as an additive material for stromal keratophakia. However, following extraction, they must be reimplanted almost immediately or cryopreserved in lenticule banks. Electron-beam (E-beam) irradiated corneas permit room-temperature storage for up to 2 years, enabling keratophakia to be performed on demand. This study aims to compare the performance of high nano Joule (nJ)-energy (VisuMax) and low nJ-energy (FEMTO LDV) femtosecond laser systems on the thickness consistency and surface quality and collagen morphology of lenticules produced from fresh and E-beamed corneas. A total of 24 lenticules with -6.00 dioptre power were cut in fresh human donor corneas and E-beamed corneas with VisuMax and FEMTO LDV. Before extraction, the thickness of the lenticules was measured with anterior segment-optical coherence tomography (AS-OCT). The incisional surface roughness of extracted lenticules was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Multiphoton microscopy was then used to assess the surface collagen morphometry. The E-beamed lenticules that were cut using FEMTO LDV were significantly thicker than the fresh specimens as opposed to those created with VisuMax, which had a similar thickness as the fresh lenticules. On the vertex, they were ∼11% thicker than the fresh lenticules. The surface roughness (Rq) of E-beamed lenticules incised with FEMTO LDV did not differ significantly from the fresh lenticules. This contrasted with the VisuMax-fashioned lenticules, which showed notably smoother surfaces (∼36 and ∼20% lower Rq on anterior and posterior surfaces, respectively) on the E-beamed than the fresh lenticules. The FEMTO LDV induced less cumulative changes to the collagen morphology on the surfaces of both fresh and E-beamed lenticules than the VisuMax. It has been previously demonstrated that the low nJ-energy FEMTO LDV produced a smoother cutting surface compared to high nJ-energy VisuMax in fresh lenticules. Here, we showed that this effect was also seen in the E-beamed lenticules. In addition, lower laser energy conferred fewer changes to the lenticular surface collagen morphology. The smaller disparity in surface cutting quality and collagen disturbances on the E-beamed lenticules could be beneficial for the early visual recovery of patients who undergo stromal keratophakia.

Gamma-irradiated corneas for therapeutic penetrating keratoplasty, anterior lamellar keratoplasty, and sclera for glaucoma valve surgery

Objectives: To report clinical outcomes of gamma-irradiated donor cornea (GIDC) for therapeutic penetrating keratoplasty (TPK), deep anterior lamellar keratoplasty (DALK) and gamma-irradiated donor sclera (GIDS) for glaucoma patch graft (GPG) in glaucoma filtering surgery (GFS) with Ahmed glaucoma valve (AGV). Materials and Methods: A prospective non-randomized, non-comparative, interventional case series of GIDC and GIDS involving 26 patients, of which 20 received GIDC (11 TPK, 9 DALK) and 6 GIDS (6 GPG). Main outcome measures were post-operative tissue characteristics as epithelialization and tissue clarity; and complications including rejection, infection, corneal melt, and other adverse effects. Results: Study included 26 patients, of these 20 received GIDC (11 TPK, 9 DALK) and 6 GIDS (6 GPG). Mean follow up was 8.32 ± 2.31 months. Corneal epithelium healed in 6.2 ± 2.58 days. Graft clarity was achieved in 9 (100%) DALK patients. Only 1 eye (3.8%) had a corneal melt. There were no incidences of rejection or infection in the follow up time. Conclusion: Gamma-irradiated sterilization of donor cornea and sclera is a new innovation to enhance utilization of donor tissue. GIDC is a promising treatment option for TPK and DALK; GIDS for GPG with good epithelialization time and tissue clarity. Gamma irradiation of both donor cornea and sclera achieved adequate sterilization and provided a long shelf life.

The Effect of SkQ1 on the Oxidative Stress and Inflammatory Responses in Corneal Endothelial Cells During Ex Vivo Expansion

Purpose: The purpose of this study was to characterize the oxidative stress and inflammatory responses in ex vivo corneal endothelial cells (evCEnC) during expansion and assess the impact of SkQ1, an antioxidant and anti-inflammatory compound, on measures of oxidative stress and inflammation. Methods: A CEnC line (HCEnC-21T) was cultured in media supplemented with varying SkQ1 concentrations to determine the optimal SkQ1 dose range of toxicity and protective effect on CEnC exposed to acute oxidative stress. The impact of SkQ1 treatment on intracellular free radical (IFR) levels, NRF2-mediated oxidative stress response, and NFkB-mediated inflammatory response was determined at each passage of evCEnC isolated from donor corneas and cultured in SkQ1-supplemented and untreated media. Results: HCEnC-21T cultured in media supplemented with ≤250 nM SkQ1 retained over 95% cell viability compared with untreated cells. SkQ1 provided oxidative stress protection to HCEnC-21T in a dose-dependent manner up to 500 nM. In evCEnC, 50 nM and 250 nM SkQ1 supplementation significantly reduced IFR levels across passages 0 to 3 (P-values of 0.015 and 0.023, respectively) and 50 nM SkQ1 supplementation led to decreased levels of active NRF2 in evCEnC at passage 2. However, media supplementation with SkQ1 (50 nM and 250 nM) did not alter NFkB activation at any passage. Conclusions: SkQ1 media supplementation provides oxidative stress protection to HCEnC-21T in a dose-dependent manner and decreases IFR levels and NRF2 activation in evCEnC during expansion at concentrations that do not negatively affect CEnC viability. These findings indicate that SkQ1 supplementation may increase the expansion potential of evCEnC.

Comparison of corneal endothelial cell density and morphology with Optisol GS and Life4C storage media in the eye bank: a 5-year retrospective analysis.

Optisol GS and Life4C are corneal storage media used by eye banks worldwide. We sought to determine if either solution was associated with superior corneal endothelial cell density (ECD) or morphology in a large cohort of donor corneas. From January 2016 through December 2020, 10,316 corneas from 5,624 unique donors were acquired and analyzed at Rocky Mountain Lions Eye Bank. In April 2019, Life4C replaced Optisol GS as the sole storage medium. We compared ECD and morphology before and after April 2019, and excluded corneas processed within the transition period. Univariable and multivariable regression analyses accounted for age, sex, tobacco use, heavy alcohol use, and diabetes. Only right corneas were analyzed to account for the correlation between eyes. Of 5042 right corneas analyzed, 3486 were stored in Optisol GS and 1556 in Life4C. There was no significant difference in ECD across groups (2794 vs. 2793 cells/mm2 in Optisol GS and Life4C, p=0.88). In multivariate analyses, there was no significant difference in corneal ECD (0.6 cells/mm2 higher with Life4C, p=0.96) or hexagonality (0.22% higher with Life4C, p=0.31). However, the coefficient of variation was significantly lower in the Life4C group (-0.0039, p=0.03). After adjustment for above factors, corneas in Life4C demonstrated a 3.1% decreased likelihood of exhibiting CV values greater than 0.40 (p=0.009). This study demonstrates comparable and favorable outcomes using both storage media and confirms their overall efficacy. The decreased CV in Life4C is not of clinically significant magnitude, but merits further research in clinical and long-term settings.

Analysis of cardiovascular risk factors for the viability of cornea donors: a case–control study

ObjectiveThe main objective of the study was to evaluate the influence of arterial hypertension, diabetes, dyslipidaemia, smoking, alcoholism and COPD (chronic obstructive pulmonary disease) on the viability of the extracted...

Thickness Profile of Donated Corneas Preserved in Optisol-GS versus Sinasol: An Ex-vivo Study.

This study aimed to compare the thickness profile and the endothelial cell density (ECD) of donated corneas maintained in Optisol-GS with those preserved in Sinasol over seven days. Twenty paired donor corneas were received from the Central Eye Bank of Iran. After recording the osmolarity of each medium, one of each of the cornea pairs was preserved in either Optisol-GS or Sinasol media. Then, slit-lamp biomicroscopy and specular microscopic examinations were performed at the baseline and on day seven. Visante optical coherence tomography (V-OCT) was also performed at 1 hour (h), 24h, 72h, and one week post-preservation. The specular microscopic and V-OCT values were then compared between the two groups. The mean osmolarity of the Sinasol group was significantly less than the Optisol-GS group (296 vs. 366 mOsm/L, = 0.0008). The mean central corneal thickness at the measurement points was comparable between the two groups. However, the increase of thickness one week post-preservation in the Sinasol group was remarkably lower than those in the Optisol-GS group ( = 0.027). The mean ECD was comparable between the groups at the baseline and on day seven. However, the mean change of ECD from baseline to day seven was considerably higher in the Optisol-GS group than in the Sinasol group ( = 0.019). Corneal storage in Sinasol over seven days provides better and superior maintenance and preservation of corneal tissue deturgescence and a lower rate of ECD loss over Optisol-GS.

Bowman Layer Marking for Correct Placement of Corneal Allogeneic Intrastromal Ring Segments.

Corneal allogeneic intrastromal ring segments (CAIRS) refer to the placement of allogeneic rings and segments in intrastromal channels within the cornea. Currently, a deepithelialized donor cornea is used as the allogeneic source for CAIRS and the cut ring is turned sideways and implanted so that the thickness can be varied by varying the distance between the concentric trephine blades. In addition, to obtain a greater effect, CAIRSs are preferred to be implanted with the Bowman layer (BL) facing the corneal apex and posterior stroma facing limbally. Being flexible tissue, it is, however, important to prevent twisting and to maintain correct orientation. We describe a simple technique of marking the BL with a gentian violet surgical marker to simplify CAIRS insertion. BL marking allows easy visibility of twists and helps identify improper orientation, thus allowing correct insertion of CAIRS.