Factors affecting the epithelial integrity of human donor corneas

Purpose: To evaluate various factors affecting the integrity of human donor corneal epithelium. Methods: Donor corneal buttons were evaluated for epithelial defect (ED) and exposure. The slit?lamp photographs were taken on day 01, and the data such as age and gender of the donor, cause of death, refrigeration of cadavers, death?to?preservation time (DPT), experience of technician, and distance from site of collection to eye bank were collected. Results: A total of 100 consecutive corneal buttons belonging to 56 donors were evaluated. The median age of donors was 50 years. Males constituted 45 (80.4%). The mean DPT was 9.7 ± 5.3 hours. After death, 34 donors (60.7%) were refrigerated before the collection/retrieval. Most of the corneas (80%) were recovered by technicians having an experience of 0–5 years. Thirty?one donors (55.3%) were located at 1–50 km from the eye bank. The mean area of exposure was 15 ± 4.3 mm2. The mean area of ED was 28.7 ± 5.9 mm2. ED was significantly associated with refrigeration of cadavers and longer DPT. On multivariate analysis, only DPT was found to be significantly associated (P = 0.006; odds ratio [OR] = 1.54 ± 0.24) with the presence of ED. After transplantation, only two corneas had persistent epithelial defects and were treated successfully using various interventions. Conclusion: Integrity of donor corneal epithelium is mainly influenced by the refrigeration of cadavers and DPT.

Intraoperative optical coherence tomography-guided donor corneal tissue assessment and preparation

Purpose: To evaluate the role of intraoperative optical coherence tomography (i?OCT) in donor grading, selection, and preparation during different types of keratoplasty. Methods: Seventy?one consecutive donor corneas collected over 6 months, after clinical grading, were observed by an experienced corneal surgeon under an i?OCT equipped microscope. The donor preparation (manual/automated) for different types of keratoplasty procedures was also undertaken under i?OCT. Results: The mean central corneal thickness of optical and nonoptical grade tissues was 533 ± 19 and 662 ± 52 ?m, respectively. The i?OCT?based grading matched with clinical grading in 98.5% cases. Irregular thickness, anterior stromal hyperreflectivity, and previous scars were appreciated in 1.4, 1.4, and 7.04% donors, respectively. During Descemet stripping automated endothelial keratoplasty, i?OCT facilitated selection of appropriate microkeratome head for automated donor preparation in all cases, besides allowing manual dissection of partially dissected lenticule, identification of site of inadvertent perforation, and eccentric trephination in one case each. During Descemet membrane endothelial keratoplasty, i?OCT?based assessment of preexisting scar (five cases) guided careful tissue selection (2/5) and preparation. During predescemetic endothelial keratoplasty, precise needle advancement allowed successful type?1 bubble formation in all cases. All manually punched donors demonstrated an extra endothelial ledge, while those with automated preparation showed tapering donor margins. Conclusion: i?OCT might serve as a useful imaging tool for objective assessment of donor characteristics. The modality may complement clinical evaluation for donor grading, selection, and preparation.

Reverse graft suturing to avoid Descemet’s membrane detachment of glycerol-preserved donor cornea used for therapeutic penetrating keratoplasty during COVID-19 to overcome the tissue shortage – A novel surgical technique

To overcome tissue shortage during pandemic, we switched to 100% glycerol preservation of the donor cornea, which is economical and provides longer duration of storage than the short and intermediate storage mediums we normally use like McCAREY Kaufman (MK) or cornisol. During our initial few cases of therapeutic penetrating keratoplasty using glycerol preserved donor cornea, we faced spontaneous Descemet’s detachments resistant to air tamponade. We tried reverse graft suturing and successfully reinforced Descemet’s attachment along with air tamponade, in one of the cases after multiple failed air injections. In the subsequent two cases of infective keratitis needing therapeutic penetrating Keratoplasty, we took eight reverse sutures in between the eight cardinals, to anchor the Descemet’s membrane of the graft. Both the grafts showed attached Descemet’s and maintained good graft clarity. The reverse corneal suturing technique has not been described to the best of our knowledge and hope this helps our corneal fraternity.

Utilization rate of corneal tissue obtained from donors over 75 years of age in Western India for keratoplasty

Purpose: To examine the utilization patterns of cornea procured from diseased individuals ?75 years of age at an eye bank in western India. Methods: In this retrospective study, data from 1,217 eyes of 653 donors with age ?75 years were reviewed from October 2008 to December 2019. Donor age, lens status, endothelial cell count (ECD), utilization of the tissue for transplantation or non?clinical purposes (e.g., research, training/discarded), and causes of non?utilization were noted. Results: The mean age of the donors was 80.9 ± 4.6 years and the tissue utilization rate was 36.5% (445 out of 1,217 eyes). The eyes used for keratoplasty procedures had a lower donor age (79.6 ± 5.7 vs. 81.5 ± 5.1; P < 0.001), a higher endothelial cell count (2493 ± 531 vs. 2034 ± 581; P < 0.001), and were more often phakic (61% vs. 36.6%) compared to the unused group. A multivariable logistic regression analysis showed that the likelihood of tissue utilization for keratoplasty was 13% higher with every 100?cell increment in donor ECD (odds ratio [OR] = 1.13, 95% CI = 1.10–1.16, P < 0.001) and 33% lower with having a pseudophakic status in the donor eye (OR = 0.67, 95% CI = 0.52–0.87, P = 0.03). Age was not a significant determinant of tissue utilization when used in the same multivariable model. Conclusion: More than one?third of the eyes (36.5%) can be utilized even when the donors are above 75 years of age. Eyes that were more likely to be utilized for keratoplasty were phakic and had a significantly higher ECD; age was not a determinant in tissue utilization

Características de la córnea donante mediante microscopia endotelial / Donor cornea characterization by endothelial microscopy

RESUMEN Objetivo: Determinar las características del endotelio corneal mediante microscopia endotelial. Métodos: Se realizó un estudio descriptivo y retrospectivo en córneas donantes del banco de ojos del Instituto Cubano de Oftalmología "Ramón Pando Ferrer" en el período de enero a junio del año 2019. La muestra estuvo conformada por 224 córneas donantes. Las variables del estudio fueron: edad, cirugías previas, gerontoxón, pterigion, defectos epiteliales, infiltrado corneal, opacidad corneal, edema, pigmentos endoteliales, guttas, desprendimiento de la Descemet, densidad celular, hexagonalidad y polimegatismo. Resultados: El gerontoxon fue el hallazgo más frecuente (56,69 por ciento); la densidad celular media fue de 2 501 cel/mm2; el coeficiente de variación medio fue 43,32 y la hexagonalidad media 50,02. La densidad celular endotelial entre 2 000 y 2 500 cel/mm2 fue más frecuente entre 60 y 79 años de edad (76,72 por ciento), mientras que entre 20 y 29 años todas las córneas donantes presentaron una densidad endotelial mayor de 2 500 cel/mm2. Conclusiones: En el examen biomicroscópico de la córnea donante fue más frecuente el gerontoxon. Por microscopia endotelial la mayoría de las córneas fueron aptas para trasplante corneal. Un endotelio corneal con densidad celular mayor de 2 500 cel/mm2 no es exclusivo de córneas con menos de 60 años de edad(AU)

ABSTRACT Objective: Determine the characteristics of the corneal endothelium by endothelial microscopy. Methods: A retrospective descriptive study was conducted of donor corneas from the eye bank of Ramón Pando Ferrer Cuban Institute of Ophthalmology from January to June 2019. The sample was 224 donor corneas. The variables analyzed were age, previous surgery, gerontoxon, pterygium, epithelial defects, corneal infiltrate, corneal opacity, edema, endothelial pigments, guttae, Descemet's membrane detachment, cell density, hexagonality and polymegethism. Results: Gerontoxon was the most common finding (56.69 percent), mean cell density was 2 501 cell/mm2, mean variation coefficient was 43.32 and mean hexagonality was 50.02. Endothelial cell density from 2 000 to 2 500 cell/mm2 was more common in the 60-79 years age group (76.72 percent), whereas in the 20-29 years age group all the donor corneas had an endothelial density above 2 500 cell/mm2. Conclusions: Gerontoxon was the most common finding in the biomicroscopic examination of the cornea. Endothelial microscopy found that most corneas were suitable for corneal transplantation. A corneal endothelium with a cell density above 2 500 cell/mm2 is not exclusive of corneas under 60 years of age(AU)

Bio-engineering cornea versus human donor cornea in the treatment of fungal corneal ulcer / 中国组织工程研究

BACKGROUND: Searching for a substitute donor corneal is a hotspot for treating fungal corneal ulcer. OBJECTIVE: To Investigate the clinical effect of bio-engineering cornea and donor cornea on treating fungal corneal ulcer. METHODS: Forty-four cases (44 eyes) of fungal corneal in General Hospital of Northern Theater Command were enrolled, and were randomized into two groups, followed by underwent lamellar keratoplasty using acellular porcine corneal matrix (bio-engineering group, n=22) and human donor cornea (donor group, n=22). The patients were followed up for 12 months. The control rate of infection, visual acuity, graft transparency, epithelizatlon time and complications were observed In both groups. The study was approved by the Ethical Committee of General Hospital of Northern Theater Command, approval No. K(2018)05. RESULTS AND CONCLUSION: (1) The control rate of Infection showed no significant difference between two groups (91%, 91%, P > 0.05). (2) The visual acuity in both groups was improved with time. The visual acuity in the donor group was significantly better than that in the bio-engineering group at 12 months after surgery (P 0.05). (4) The epithelization time showed no significant difference [(6.6±2.0) days, (6.7±1.9) days, P > 0.05]. (5) There was no significant difference In the Incidence of delayed healing of corneal epithelium, rejection reaction of graft, neovascularization, or recurrence between two group (P > 0.05). The rate of graft dissolved In the bio-engineering group was significantly higher than that In the donor group (32%, 8%, P < 0.05). (6) In summary, bio-engineering cornea used for lamellar keratoplasty holds significant efficacy, high safety and good prognosis in the treatment of fungal cornea ulcer, which may as substitute when donor cornea is deficient.

Postoperative detection of unusual pathology in donor corneal tissue

We present a series of three patients with previously undetected corneal pathology in grafted corneal tissue following keratoplasty for keratoconus. Postoperatively, a faint layer of anterior stromal haze involving the graft was observed in each patient upon slit lamp examination. Anterior segment optical coherence tomography (AS-OCT) confirmed the presence of anterior stromal scarring across the transplanted cornea. However, the ocular and systemic medical histories of the donors were unremarkable. As the suboptimal donor corneal tissue may escape the standard screening protocols, eye banks should consider adding AS-OCT imaging for screening donor corneal tissue before transplantation.

Various Treatments Using Invaluable Donor Cornea

PURPOSE: To report cases of transplanting a donor's 2 corneas to 5 patients suffering from several corneal diseases. CASE SUMMARY: Two corneas were donated from a 66-year-old donor, who suffered from brain damage due to asphyxia, one hour after being pronounced dead by doctors. Two penetrating keratoplasties and 3 partial lamellar keratoplasties were performed for patients with corneal opacity, corneal ulcer and corneal perforation. After the procedure all grafts were stable. CONCLUSIONS: Under the present circumstances of decreasing donations of corneas after death and the increasing demand for keratoplasty in Korea, the mutual cooperation among hospitals to treat more than one patient using one donated cornea is a method the authors believe can alleviate this situation.

Penetrating Keratoplasty before and after Establishment of Korean Network for Organ Sharing

PURPOSE: This study was performed to evaluate the status of corneal transplantation in Korea over the last 6 years. METHODS: We evaluated the current status of domestic corneal transplantation using the data obtained from Korean Network for Organ Sharing (KONOS). We evaluated imported corneal transplantation by the number of corneal transplantations, the country of origin of imported cornea, the preserved state of corneas, the time from the death to transplantation and the result of corneal transplantation. The imported corneal transplantation data was obtained from the institution registered in KONOS and the institution recognized by the authers. RESULTS: The number of domestic cornea donations has not increased since 2000, but the number of transplantations using imported corneas has increased year by year. The quality of imported corneas was good. There was no difference in operation results when domestic corneas were used compared to the use of imported corneas from the USA, Australia or Sri Lanka. CONCLUSIONS: The increased use of imported corneas results of a deficiency in the number of domestic cornea donations. Social motivation should be used to increase domestic donations of corneas.

Epidemiologic Studies of Keratoplasty in Korea

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.

Penetrating Keratoplasty before and after Establishment of Korean Network for Organ Sharing

PURPOSE: This study was performed to evaluate the status of corneal transplantation in Korea over the last 6 years. METHODS: We evaluated the current status of domestic corneal transplantation using the data obtained from Korean Network for Organ Sharing (KONOS). We evaluated imported corneal transplantation by the number of corneal transplantations, the country of origin of imported cornea, the preserved state of corneas, the time from the death to transplantation and the result of corneal transplantation. The imported corneal transplantation data was obtained from the institution registered in KONOS and the institution recognized by the authers. RESULTS: The number of domestic cornea donations has not increased since 2000, but the number of transplantations using imported corneas has increased year by year. The quality of imported corneas was good. There was no difference in operation results when domestic corneas were used compared to the use of imported corneas from the USA, Australia or Sri Lanka. CONCLUSIONS: The increased use of imported corneas results of a deficiency in the number of domestic cornea donations. Social motivation should be used to increase domestic donations of corneas.

Epidemiologic Studies of Keratoplasty in Korea

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.

The Clinical Evaluations of the Penetrating Keratoplasty with Imported Donor Corneas

PURPOSE: To evaluate the preoperative donor conditions and surgical outcomes of the penetrating keratoplasty with imported donor corneas. METHODS: We reviewed the medical records of 34 eyes of 34 patients who had undergone penetrating keratoplasty with imported donor cornea between February 2002 and June 2003 in Kangnam St. Mary's Hospital, Seoul. RESULTS: Mean donor age was 49.68 years and preoperative mean endothelial cell density of imported donor corneas was 2, 830 cells/mm2, and was above 2, 500 cells/mm2 in 30 eyes (88.24%). Average death to preservation time was 8.8 hours and death to surgery time was 5.2 days. All cases were compatible with surgical success without complications related to donor cornea at 2 months after keratoplasty. Five eyes showed irreVersible corneal opacity. 4 of which resulted from graft rejection. Postoperative best corrected visual acuity, endothelial cell loss rate, survival rate were satisfactory. CONCLUSIONS: Penetrating keratoplasty with imported donor corneas can be a safe and effective treatment for Koreans who have been waiting for penetrating keratoplasty for a long time.

Screening for Prior Refractive Surgery for Corneal Donation

PURPOSE: To provide fundamental data for screening for prior refractive surgery in donor cornea. METHODS: The corneal curvature map and pachymetric measurements were analyzed in 68 eyes that had undergone corneal refractive surgery. Differences in the corneal curvature of the center and periphery, differences in the corneal thickness of the center and periphery, and the shape factor on the curvature map in postoperative eyes were compared with preoperative measurements. RESULTS: Measurement of the central corneal curvature subtracted from the peripheral corneal curvature was -1.64 +/- 0.71D in the preoperative eyes and 3.10 +/- 1.68D in the postoperative eyes. With a criterion of -0.23D, the sensitivity and specificity were 100% and 98.5%, respectively. The shape factor was 0.24 +/- 0.09 in the preoperative eyes and -0.82 +/- 0.45 in the postoperative eyes. With a criterion of 0.058, the sensitivity and specificity were both 100%. Measurement of the central corneal thickness subtracted from the peripheral corneal thickness was 97.60 +/- 25.42 micrometer in the preoperative eyes and 163.47 +/- 38.5 micrometer in the postoperative eyes. With a criterion of 123.0 micrometer, the sensitivity and specificity were 89.7% and 88.4%, respectively. CONCLUSIONS: Regional differences in corneal curvature and shape factor may be very useful parameters in screening for prior refractive surgery in donor cornea. The difference in corneal thickness may also be a useful parameter.