Comparing quantitative and qualitative indices of the donated corneas maintained in Optisol-GS with those kept in Eusol-C

A Comprehensive Review of Donor Corneal Preservation Strategies

ABSTRACT

Successful corneal transplantation relies on the viability of the corneal endothelium. Although various preservation systems have been developed in the field of eye banking, long-term storage of the corneal endothelium poses challenges and is costly. Optisol-GS in the past has been the most commonly used solution for intermediate-term corneal storage in the United States. However, disruptions in the availability of Optisol-GS, caused by rising costs and supply shortages, have necessitated alternative methods of corneal preservation. Previously described preservation methods include hypothermia (2-8°C) for short-term storage (7-14 days), organ culture (28-37°C) for intermediate storage (4-7 weeks), and cryopreservation for longer-term storage. In this review, we examine standard practice and alternative methods for corneal storage.

Comparative Analysis of Endothelial Cell Density and Central Thickness of Corneas Used for Endothelial Keratoplasty Procedures Using Various Storage Solutions

PURPOSE

The goal of this study was to evaluate the effect of various Food and Drug Administration-approved storage solutions on endothelial cell density (ECD) and central corneal thickness (CCT).

METHOD

We analyzed 6220 tissues used for endothelial keratoplasty procedures between January 2022 and June 2023 that were stored in either Life4°C, Optisol-GS, Kerasave, or Eusol-C under hypothermic conditions. We analyzed preprocessing CCT, success rate of meeting surgeon's Descemet stripping automated endothelial keratoplasty (DSAEK) thickness preferences, and preprocessing and postprocessing ECD. Results were analyzed using one-way analysis of variance, followed by multiple pairwise comparisons using the Tukey test.

RESULTS

Mean preprocessing CCT was significantly lower in the Life4°C group (532 μm) than in Optisol-GS (549 μm), Kerasave (582 μm), and Eusol-C (589 μm) groups (all P < 0.0001). Preprocessing CCT in the Optisol-GS group was significantly lower than in Kerasave and Eusol-C groups (F (3, 3273) = 153.1, all P < 0.0001). Success rate of meeting surgeon DSAEK preferences was statistically similar among all 4 groups. Preprocessing ECD of the Kerasave group (2821 cells/mm2) was numerically higher than of the Eusol-C (2791 cells/mm2), Life4°C (2759 cells/mm2), and Optisol-GS (2768 cells/mm2) groups (P = 0.3232, 0.0004, and 0.0015, respectively).

CONCLUSIONS

Corneal tissues stored in Kerasave and Eusol-C are significantly thicker than those in Life4°C and Optisol-GS. However, the success rate of meeting surgeon DSAEK preferences is similar among all 4 storage solutions.

Assessment of performance and safety of Corneal Chamber hypothermic storage medium and PSS-L corneal rinsing solution in human and porcine corneas

PURPOSE

To prove the safety and performance of the hypothermic corneal storage medium "Corneal Chamber" and the rinsing solution "PSS-L" in support of the new Conformité Européenne (CE) certification process in accordance with the Medical Device Regulation.

METHODS

Fifteen (n=15) human donor corneas and 11 (n=11) porcine corneas were evaluated for the following parameters: endothelial cell density (ECD) and mortality, percentage of hexagonal cells (HEX%), coefficient of cellular area variation (CV%) and corneal transparency at Day 0 and after 14±1 days of storage in Corneal Chamber medium at 2-8°C. Then, the same parameters were assessed after rinsing of corneas in PSS-L for 1 min at room temperature. Evaluation of gentamicin sulfate carryover after corneal storage and PSS-L rinsing was performed by ultra-high performance liquid chromatography analysis on human corneas homogenates.

RESULTS

Human and porcine corneas stored in Corneal Chamber medium showed a good overall quality of the tissue according to the quality parameters evaluated. In particular, mean ECD, HEX% and CV% did not show statistically significant changes at the end of storage and endothelial mortality increased to 3.1±3.3 and 7.8±3.5% in human and porcine corneas, respectively. Tissue rinsing with PSS-L did not affect the quality parameters evaluated before and gentamicin sulfate residues were absent in human corneas.

CONCLUSIONS

Corneal preservation in Corneal Chamber medium at 2-8°C for 14 days and the corneal rinse with PSS-L are safe and effective procedures allowing the preservation of the corneal quality parameters as well as the complete elimination of gentamicin sulfate from the tissues before transplantation.Cite Now.

Biaxial hyperelastic and anisotropic behaviors of the corneal anterior central stroma along the preferential fibril orientations. Part I: Measurement and calibration of personalized stress-strain curves

Lacking specimens is the biggest limitation of studying the mechanical behaviors of human corneal. Extracting stress-strain curves is the crucial step in investigating hyperelastic and anisotropic properties of human cornea. 15 human corneal specimens extracted from the small incision lenticule extraction (SMILE) surgery were applied in this study. To accurately measure the personalized true stress-strain curve using corneal lenticules, the digital image correlation (DIC) method and finite element method were used to calibrate the stress and the strain of the biaxial extension test. The hyperelastic load-displacement curves obtained from the biaxial extension test were performed in preferential fibril orientations, which are arranged along the nasal-temporal (NT) and the superior-inferior (SI) directions within the anterior central stroma. The displacement and strain fields were accurately calibrated and calculated using the digital image correlation (DIC) method. A conversion equation was given to convert the effective engineering strain to the true strain. The stress field distribution, which was simulated using the finite element method, was verified. Based on this, the effective nominal stress with personalized characteristics was calibrated. The personalized stress-strain curves containing individual characteristic, like diopter and anterior surface curvature, was accurately measured in this study. These results provide an experimental method using biaxial tensile test with corneal lenticules. It is the foundation for investigating the hyperelasticity and anisotropy of the central anterior stroma of human cornea.

Swept-source OCT for corneal graft quantitative evaluation in the eye bank and the correlation of the measurements to pre-excision values

Quantitative evaluation of the human corneal grafts stored in the tissue banks is usually limited to endothelial cell density and central thickness. Swept-source OCT (SS-OCT) is capable of measuring the central curvatures of the corneal tissue prepared for transplantation without loss of sterileness, providing insights on its refractive state. The aim of the paper is to compare in vitro SS-OCT measurements with pre-excision values. Hand-held keratometry and ultrasound pachymetry was performed on 22 corneas before excision of corneoscleral button and insertion in the vial with Eusol-C solution (AlchimiaS.r.l, Nicolò, Italy). After 12 to 36 h of hypothermic storage the corneas were examined within the vials with custom built SS-OCT system maintaining a sterile environment. The anterior and posterior central curvatures, and central corneal thickness (CCT) were measured. Rotation of the corneoscleral button was controlled by making a 6-o'clock mark during excision. Mean pre-excision CCT was 626.45 ± 28.71 µm and 468.05 ± 52.96 µm when measured with SS OCT (r = 0.55; p < 0.001). Respective values for average keratometry were 7.74 ± 0.39 mm and 7.92 ± 0.57 mm (r = 0.6; p = 0.22). Although high differences were observed in corneal thickness, keratometric radius of curvature at the flat (r = 0.42; p < 0.001) and steep (r = 0.62; p = 0.014) meridian of the anterior corneal surface, as well as corneal anterior astigmatism (r = 0.3; p < 0.001), showed good correlation with pre-excision values. SS-OCT is capable of providing quantitative evaluation of the human corneal grafts in hypothermic storage. Good correlation between curvature measurements before excision and during banking in the vial indicates its clinical utility.

Comparison of Graft Outcomes Reusing Original Intermediate-Term Cold Storage Solution for Entire Corneal Donor Storage Period With Exchanged Fresh Storage Solution After Donor Preparation in the Cornea Preservation Time Study

PURPOSE

The purpose of this study was to evaluate outcomes of Descemet stripping automated endothelial keratoplasty comparing exchange with fresh intermediate-term cold storage solution after lenticule preparation versus reuse of the original solution in the Cornea Preservation Time Study.

METHODS

In the Cornea Preservation Time Study, 508 donor corneas had lenticules prepared by the eye bank with fresh solution exchange (Fresh group) and 283 with reuse of the original solution (Original group). Storage time for all donors was ≤11 days. Graft success rates, central endothelial cell loss at 3 years, and frequency of positive donor rim cultures were compared between the 2 groups.

RESULTS

The 3-year graft success rate (95% confidence interval) was 93.4% (90.7%-95.3%) in the Fresh group and 95.2% (91.8%-97.2%) in the Original group (adjusted hazard ratio for graft failure = 0.64, 95% confidence interval, 0.33-1.24, P = 0.19). The mean percentage endothelial cell loss was significantly greater in the Fresh group versus Original group (45% ± 22% vs. 38% ± 20%, respectively, P = 0.004). Cultures were positive in 4 (1.5%) of 267 donor rims (3 fungal and 1 bacterial) in the Fresh group and in 4 (2.5%) of 158 in the Original group (P = 0.57). There were 2 postoperative infections in the Original group and none in the Fresh group.

CONCLUSIONS

The use of the original intermediate-term cold storage solution did not reduce the 3-year graft success rate compared with exchanging with fresh solution after lenticule preparation for Descemet stripping automated endothelial keratoplasty, while the frequency of positive donor rim cultures did not significantly differ between groups.

Cold Storage Media versus Optisol-GS in the Preservation of Corneal Quality for Keratoplasty: A Systematic Review

Optisol-GS is the most widely used pharmaceutical composition to preserve corneas for transplantation. This systematic review investigated the effects of different cold corneal storage media (CCSM) compared with Optisol-GS on the quality of stored corneas. The literature was searched throughout May 2022 on six databases and grey literature. Studies including corneas (population) exposed to distinct cold storage media (exposure) and Optisol-GS (comparison) that reported qualitative and/or quantitative parameters of cornea quality (outcome) were included. Methodological quality was assessed using ToxRTool. From 4520 identified studies, fourteen were included according to the eligibility criteria, comprising 769 evaluated cornea samples comparing Optisol-GS with commercial and noncommercial media. All studies showed good methodological quality. Experimental times ranged from 1–28 days, mainly using 4 °C as the preservation temperature. Viable endothelial cell density (ECD) and endothelial cell morphology (EC) were the most assessed parameters. ECD results for Cornisol were higher than Optisol-GS in 10 days (p = 0.049) and favored Cornea ColdTM up to 4 weeks (p < 0.05), which also showed better qualitative results. While the standardization of test protocols could improve comparisons, evidence indicates that most CCSM present similar performances on cornea preservation for transplantation at seven days, while some formulations may increase preservation at extended times.

Characterisation of corneas following different time and storage methods for their use as a source of stem-like limbal epithelial cells

The transplantation of expansions of limbal epithelial stem cells (LESC) remains one of the most efficient therapies for the treatment of limbal stem cell deficiency (LSCD) to date. However, the available donor corneas are scarce, and the corneas conserved for long time, under hypothermic conditions (after 7 days) or in culture (more than 28 days), are usually discarded due to poor viability of the endothelial cells. To establish an objective criterion for the utilisation or discarding of corneas as a source of LESC, we characterized, by immunohistochemistry analysis, donor corneas conserved in different conditions and for different periods of time. We also studied the potency of LESCs isolated from these corneas and maintained in culture up to 3 cell passages. We hoped that the study of markers of LESCs present in both the corneoscleral histological sections and the cell cultures would show the adequacy of the methods used for cell isolation and how fit the LESC enrichment of the obtained cell populations to be expanded was. Thus, the expressions of markers of the cells residing in the human limbal and corneal epithelium (cytokeratin CK15 and CK12, vimentin, Collagen VII, p63α, ABCG2, Ki67, Integrin β4, ZO1, and melan A) were analysed in sections of corneoscleral tissues conserved in hypothermic conditions for 2-9 days with post-mortem time (pmt) < 8 h or for 1 day with pmt > 16 h, and in sclerocorneal rims maintained in an organ culture medium for 29 days. Cell populations isolated from donor corneoscleral tissues were also assessed based on these markers to verify the adequacy of isolation methods and the potential of expanding LESCs from these tissues. Positivity for several putative stem cell markers such as CK15 and p63α was detected in all corneoscleral tissues, although a decrease was recorded in the ones conserved for longer times. The barrier function and the ability to adhere to the extracellular matrix were maintained in all the analysed tissues. In limbal epithelial cell cultures, a simultaneous decrease in the melan A melanocyte marker and the putative stem cell markers was detected, suggesting a close relationship between the melanocytes and the limbal stem cells of the niche. Holoclones stained with putative stem cell markers were obtained from long-term, hypothermic, stored sclerocorneal rims. The results showed that the remaining sclerocorneal rims after corneal transplantation, which were conserved under hypothermic conditions for up to 7 days and would have been discarded at a first glance, still maintained their potential as a source of LESC cultures.

Sinasol versus Optisol-GS for cold preservation of human cornea: a prospective ex vivo and clinical study

To compare ex vivo results of donor corneas maintained in Sinasol with those stored in Optisol-GS and reporting clinical outcomes of grafted Sinasol-versus Optisol-GS-stored corneas. In phase I, paired donor corneas were maintained in Sinasol or Optisol-GS. Afterward, the corneas were subjected to slit-lamp biomicroscopic and specular microscopic examinations on days 1 and 7, and then to trypan blue staining on day 7. The same examinations were performed on the corneas that were kept in Sinasol or Optisol-GS for 14 days. In phase II, the post-operative reports of 72 consecutive corneal transplantations were recorded using Sinasol- or Optisol-GS-preserved corneas. In phase I, 128 corneas from 64 donors and 59 corneas from 33 donors were investigated for 7 and 14 days, respectively. The EC indices were comparable between the groups at the measurement periods. The EC losses over 7 and 14 days were 3.7% and 19.9% in Sinasol against 4.6% and 20.8% in Optisol-GS. Although fair quality corneas were more common in Optisol-GS group after 7 (P = 0.04) and 14 days (P = 0.034), changes of stromal edema, Descemet's fold, and other quality ratings during 14 days were not different between the groups. In phase II, all the transplanted corneas were postoperatively clear with no adverse reactions. The overall results indicate that Sinasol is a safe, effective, and affordable intermediate cold storage medium for preservation of corneas.

Factors influencing endothelial cell density of corneas for transplantation

To evaluate factors affecting corneal endothelial cell density (ECD) under enucleation and preservation time studies at Eye Bank of the Federal District of Brazil. We conducted a case-control study collecting data from 1128 corneas where death-to-enucleation time and enucleation-to-preservation time were within 24 h. Low cell count were those corneas with an ECD less than 2000 cells/mm² and high cell count was defined as those with ECD greater than 2000 cells/mm². We calculated the independent risk factors related to: cause of death, donor age, death-to-enucleation time, enucleation-to-preservation time and primary graft failure. Correlation analysis was used to assess which parameters influence ECD: death-to-enucleation time, enucleation-to-preservation time, average cell area (AVE), coefficient of variation and percentage of hexagonal cells. Of the total number of corneas, 1004 had ECD data and were selected for the study. 87.4% (n = 877) had high cell counts with 2699 ± 412 cells/mm². The mean donor age was 38.8 ± 16 years. The most common causes of death were external causes (48.6%, n = 488). Longer times from death-to-enucleation, up to 24 h were not associated with a decrease in ECD (OR 0.58; P = 0.44) or risk of graft survival (P = 0.74). Enucleation-to-preservation intervals greater than 12 h showed increased risk of graft survival (P = 0.04). AVE was the main parameter for ECD (R² = 0.96, P < 0.001). The overall graft survival rate was 98.2% (n = 761). Donors with 40 years of age and above did not present a higher risk of graft survival (P = 0.09). We suggest that the maximum time from death-to-enucleation should be 24 h, assuming the body has been refrigerated after 6 h; and from enucleation-to-preservation time of 12 h, followed by proper processing and cornea morphology examination.

Endothelial Safety and Efficacy of Ex Vivo Collagen Cross-linking of Human Corneal Transplants

PURPOSE

To assess endothelial safety and efficacy of ex vivo corneal collagen cross-linking (CXL) in human corneal transplants stored in 2 different culture media.

DESIGN

Fellow-eye controlled laboratory study of ex vivo human donor corneas.

METHODS

Three sets of paired human donor corneas, 5 pairs each, were stored in organ culture medium before deswelling either at 31 C or at room temperature. One eye of each pair was cross-linked by 0.1% riboflavin in hydroxylpropyl methylcellulose (HPMC) instillation for 10 minutes followed by 10 minutes of ultraviolet-A (9 mW/cm²) irradiation while contralateral eyes served as controls. In Set 1, endothelial cell densities were determined. In Set 2, paired samples were assigned to the 2 deswelling media and CXL efficacy was assessed comparing to untreated controls using collagenase-A-assisted enzymatic digestion. In Set 3, biomechanical testing was performed in the eye pairs (treated vs control) by stress/strain measurements.

RESULTS

There was no difference in endothelial cell counts between CXL samples and controls (P = .21). No statistically significant difference in digestion dynamics was found between tissues stored in the 2 different culture media. Complete enzymatic digestion was slowed down by 3 hours in the cross-linked samples (P = .036). Stress needed for a 12% strain was increased by 34% in the treatment group compared to control (P = .04).

CONCLUSIONS

Ex vivo CXL of human donor tissue is an effective and safe procedure with no difference regarding efficacy between 2 commercially available deswelling media. Biochemical and biomechanical resistance were significantly increased after CXL. Patients requiring keratoplasty owing to corneal melting might benefit from the strengthening effect of preoperative CXL of donor tissue.

A new storage solution for the hypothermic preservation of corneal grafts: an experimental study

In this experimental study we used for the first time Tiprotec^® as a solution for corneal preservation and cold storage. We compared the resultant endothelial cell morphology and viability with this obtained after preservation of the ex-vivo corneas with both usual standard techniques: conventional cold storage (using Eusol-C) and organ culture. This prospective, in vitro, 3-armed parallel study was performed with the use of 90 porcine corneas (examined for their endothelial quality and transparency) randomly selected for preservation in three storage methods (each 30 corneas): organ culture, standard cold storage (Eusol-C) and experimental cold storage (Tiprotec^®) Endothelium cell quantity and quality as well as corneal opacification were assessed. The degree of endothelial transparency was significantly reduced over time with all preservation media, without any significant difference among the three groups at any point of time. A reduction in endothelial cell density was also observed with all three preservation media after 30 days of storage without statistically significant differences between groups. The number of hexagonal and pentagonal endothelium cells was significantly reduced overtime in all media with significantly more hexagonal and pentagonal in the organ culture group compared to the cold storage groups. We could show that the cryopreservation medium Tiprotec^®, used until now for the preservation of vascular grafts, was of similar quality compared to the medium Eusol-C for the hypothermic storage of corneal tissue for an extended period of time up to 30 days. In comparison to organic culture with culture medium KII, both Tiprotec^® and Eusol-C were found less effective in preserving endothelial cell quality, as assessed by the morphometric analysis, and viability, as assessed by the degree of vacuolization at least up to the 30th day of storage. However, both, Tiprotec^®- and Eusol-C-preserved corneas demonstrated a certain capacity to recover after their submission in organ culture.

Comparison of structural integrity and functional status of corneal endothelium stored in Cornisol and Optisol-GS

Purpose:

To compare the structural integrity and functional status of the donor corneas stored in Cornisol and Optisol-GS.

Methods:

Fifteen optical grade corneal donor buttons (6 pairs; 3 individual) obtained from Rotary Aravind International Eye Bank were used for the study. The left eye of the paired sample was preserved in Cornisol and the right in Optisol-GS. The three individual buttons were used for the baseline data. The corneas were assessed with slit lamp and specular microscope before and after storage time (7, 10, or 14 days). They were then immunostained for markers of structural integrity (ZO-1, Phalloidin) and functionality (Na⁺/K⁺ ATPase). The images were acquired using confocal microscope and analyzed using ImageJ software.

Results:

There was no difference in the clinical evaluation of the corneal layers between the two media. No marked variation was observed in the immunostaining data with reference to the storage period. Intact cellular integrity was identified in 91% (51%, 98%) [Median (min, max)] of cells in Cornisol and 94% (38%, 98%) cells in Optisol based on ZO-1 staining, comparable to the baseline data [87% (76%, 97%)]. Stress fibers were detected in 42.5% (1%, 88%) cells in Cornisol stored corneas and in 55% (11%, 94%) in Optisol when stained for actin cytoskeleton, which correlated with the presence of epithelial defect before storage and vacuolated endothelial cells after storage. No difference was observed between the two media based on the staining pattern for Na⁺/K⁺ ATPase.

Conclusion:

Cornisol and Optisol-GS are equivalent in maintaining the structural integrity and functionality of the donor corneas.

Effect of Cornea Preservation Time on Success of Descemet Stripping Automated Endothelial Keratoplasty: A Randomized Clinical Trial

Importance

Demonstrating that success of Descemet stripping automated endothelial keratoplasty is similar across donor cornea preservation times (PTs) could increase the donor pool.

Objective

To determine whether the 3-year rate of graft success using corneal donor tissue preserved 8 to 14 days is noninferior to that of donor tissue preserved 7 days or less.

Design, Setting, and Participants

A multicenter, double-masked, randomized noninferiority clinical trial was conducted from April 16, 2012, to June 5, 2017, at 40 clinical sites (70 surgeons) in the United States, with donor corneas provided by 23 US eye banks. A total of 1090 individuals (1330 study eyes) underwent Descemet stripping automated endothelial keratoplasty (1255 eyes [94.4%] for Fuchs endothelial corneal dystrophy).

Interventions

Descemet stripping automated endothelial keratoplasty with random assignment of a donor cornea with a PT of 7 days or less (0-7d PT) or 8 to 14 days (8-14d PT).

Main Outcomes and Measures

Graft success at 3 years.

Results

Of the 1090 participants (1330 study eyes; 60.2% women and 39.8% men; median age at enrollment, 70 years [range, 42-90 years]), the 3-year cumulative probability of graft success was 95.3% (95% CI, 93.6%-96.9%) in the 0-7d PT group and 92.1% (95% CI, 89.9%-94.2%) in the 8-14d PT group (difference, 3.2%). The upper limit of the 1-sided 95% CI on the difference was 5.4%, exceeding the prespecified noninferiority limit of 4%. The difference was mostly owing to more primary donor failures in the 8-14d PT group, with the conditional probability of failure after the first month being 2.4% in the 0-7d PT group and 3.1% in the 8-14d PT group. In preplanned secondary analyses, longer PT was associated with a lower rate of graft success (unadjusted hazard ratio for graft failure per additional day of PT, 1.10; 95% CI, 1.03-1.18; P = .008 [PT analyzed as days]), with success rates of 96.5% (95% CI, 92.3%-98.4%) for PT of 4 days or less, 94.9% (95% CI, 92.5%-96.6%) for PT of 5 to 7 days, 93.8% (95% CI, 91.0%-95.8%) for PT of 8 to 11 days, and 89.3% (95% CI, 84.4%-92.7%) for PT of 12 to 14 days (P = .01 [PT analyzed as categorical variable]).

Conclusions and Relevance

The 3-year success rate in eyes undergoing Descemet stripping automated endothelial keratoplasty was high irrespective of PT. However, the study was unable to conclude that the success rate with donor corneas preserved 8 to 14 days was similar to that of corneas preserved 7 days or less with respect to the prespecified noninferiority limit. Although longer PT was associated with a lower success rate, the difference in rates was small when PT was less than 12 days.

Impact of osmoregulatory agents on the recovery of collagen conformation in decellularized corneas

The process of decellularization of the cornea leads to the removal of cells and antigens. However, during decellularization the ultrastructure of the corneal matrix is usually damaged and a secondary conformation of the collagen fibrils is modulated resulting in altered transparency and physical properties. The strategy for recovering modulation in collagen conformation may help to attain the native physical properties and transparency of the cornea. Decellularized corneas were treated with varied concentrations of glycerol and dextran, and the collagen conformation was monitored by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), x-ray diffraction (XRD) and Raman spectroscopic analysis. The peak at ~4 Å in XRD established the presence of transitional conformations that decreased with the application of osmoregulatory agents, but could not be completely eliminated. This was validated by the results of ATR-FTIR and Raman analysis. Importantly, the mechanism of this loss and the regaining of transparency has been proposed on the basis of the detachment of decorin molecules from the collagen triple helices, due to the change in collagen conformation during decellularization, and the subsequent partial reversal due to the desiccation effect of the osmoregulatory agents on collagen molecules. Taken together, collagen conformational transition can be considered as an indexing tool for the development of improved decellularization techniques.

Endothelial Cell Viability of Donor Corneas Preserved in Eusol-C Corneal Storage Medium

OBJECTIVES

To evaluate the efficacy of Eusol-C as a corneal storage medium on the survival of donor endothelium.

MATERIALS AND METHODS

Twenty-seven corneas not suitable for transplant were included in this study. All donor corneas were stored in Eusol-C at 4°C. Daily donor corneal endothelial cell counting was performed with an eye bank specular microscope. All corneas were discarded after the study process.

RESULTS

Mean donor age was 51.3 ± 18.8 years (range, 25-94 y). The mean duration between death and corneal excision was 9.5 ± 6.7 hours (range, 3-23 h). Mean endothelial cell density was 2195 ± 383 cells/mm² at the beginning of the preservation (range, 1361-2899 cells/mm²). Donor endothelial cell density was between 1500 to 2000 cells/mm² in 9 corneas, 2000 to 2500 in 11 corneas, 2500 to 3000 in 5, and higher than 3000 in 2 corneas at baseline. Mean endothelial cell density was found 1658 cells/mm² on the eighth day of storage, with a mean endothelial cell loss rate of 24.5%. Corneas stored 9 to 24 days in Eusol-C had a rate of endothelial cell damage of 3.1% per day.

CONCLUSIONS

Although our results revealed a higher endothelial cell loss than previous reports, overall performance of Eusol-C in preserving the donor endothelium may be satisfactory for clinical use.