Comparison of Corneal Tissue Profile of Pseudophakic and Phakic Donors.

PURPOSE: To compare the endothelial quality of corneas obtained from pseudophakic donors with age-matched phakic controls. METHODS: Retrospective analysis of 100 corneas each from pseudophakic and phakic eyes with donor age ≥60 years in both the groups was performed. The endothelial cell density, coefficient of variation, and percentage of hexagonal cells obtained by specular microscopy were compared between the two groups. The cut-off level of endothelial cell density (ECD) taken for optical keratoplasty was 2,000 cells/mm2. RESULTS: The male and female donors constituted 60% (n=120) and 40% (n=80), respectively. The mean age of the donors was 66.9±7.3 years in the phakic group and 69.9±7.7 years in pseudophakic group. The mean ECD in the phakic group was 2757.6±328.5 cells/mm2 and that in the pseudophakic group was 2225.5±471.9 cells/mm2 (P<0.0001). The mean coefficient of variation in the phakic group was 37.1±5.0 and that in the pseudophakic group was 38.6±11.1 (P=0.234). The mean percentage of hexagonality in the phakic group and the pseudophakic group was 52.0±6.4% and 51.2±7.2%, respectively (P=0.414). Both in univariate and multivariate linear regression analysis, age of the donor was found to be negatively associated in predicting ECD (P=0.002 and P=0.003, respectively). Sixty-nine and thirty-three corneas from the phakic and pseudophakic donor pool were used respectively. CONCLUSION: Difference in ECD between the phakic and the pseudophakic donor group was found to be statistically significant. The ECD in the pseudophakic group was found to be above the cut-off limit required for keratoplasty. Hence, pseudophakic corneas may also be used for transplantation.

The role of corneal biopsy in the management of microbial keratitis.

PURPOSE: Corneal biopsy helps in diagnosing deep-seated or recalcitrant lesions of microbial keratitis (MK). We aim to analyze its role in managing these challenging cases. METHODS: This is a retrospective review of 22 cases of corneal biopsy at our institute from January 2010 to December 2021. Data were retrospectively collected using the electronic medical record (EMR) system. Those cases of indolent, progressive MK or deep-seated lesions where cornea scraping was not possible were considered for corneal biopsy to establish the microbiological diagnosis. The primary aims of our study were to analyze the indications, success rates, and outcomes for biopsy patients in our series. Additional outcomes that were analyzed included the average time from presentation to biopsy, the type of causative organism isolated from the biopsy by either histopathological or microbiological method, and the frequency and outcome of surgical interventions performed. Descriptive statistics using mean (±standard deviation) and median (±range) were used to interpret the demographic data. RESULTS: Overall, 15 of 22 patients (68%) had a positive corneal biopsy after microbiological or histopathological examinations. The most identified organism was microsporidia (n = 4,30.7%), followed by mycobacteria (n = 2,15.4%), gram-negative bacilli (n = 2,15.4%), acid-fast bacilli (n = 1,7.6%), fungus (n = 2,15.4%), gram-positive cocci (n = 1,7.6%), and mixed bacterial infection (n = 1,7.6%). CONCLUSION: Corneal biopsy should be considered a diagnostic modality for patients with deep-seated or unresponsive MK. It can improve the treatment for MK, ensuring targeted therapy.

Microkeratome versus manually dissected donor tissue for Descemet stripping endothelial keratoplasty: A randomized prospective study.

PURPOSE: To compare the visual outcomes, postoperative complications, and graft asymmetry between precut and manually dissected donor tissues for Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet stripping endothelial keratoplasty (DSEK) procedures, respectively. METHODS: Seventy eyes of 70 patients undergoing DSEK/DSAEK at a tertiary eyecare center in eastern India were included in this prospective randomized control study. The 70 eyes were divided equally into two groups. Group A (n = 35) and Group B (n = 35) underwent DSEK and DSAEK procedures, respectively. the operating surgeons prepared the manually dissected corneal grafts using lamellar dissectors. the eye bank technicians prepared the precut corneal grafts using a microkeratome. The patients were investigated postoperatively after 1 day, 1 week, 1 month, 3 months, and 6 months. The data were compared for visual outcomes [uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical and cylindrical refraction, and spherical equivalent], incidence of postoperative complications, and pachymetry. RESULTS: The mean age was 56.5 (±17.8) years, and the male-to-female ratio was 1.3:1. The most common indications were pseudophakic bullous keratopathy (45.71%, 32/70), failed graft (32.86%, 23/70), and Fuchs' endothelial corneal dystrophy (10%, 7/70). The indications for surgery (P = 0.732) and donor (P = 0.258) and host pachymetry (P = 0.986) were comparable between both groups. There was no significant difference in change of UCVA, BCVA, and postoperative refraction (mean spherical refraction, P = 0.849; mean cylindrical refraction, P = 0.516; spherical equivalent, P = 0.518) between the two groups. Postoperative complications like graft detachment (P = 0.179), graft failure (P = 0.513), graft infiltrate (P = 0.428), and endophthalmitis (P = 0.493) were higher in the DSAEK group; however, the difference between the groups was insignificant. The graft asymmetry index was higher in DSAEK than in DSEK; the difference was significant till the 1-month follow-up (P = 0.005). CONCLUSION: The outcome was similar in both groups. Therefore, manual donor dissection can be an alternative for microkeratome-assisted dissection in low-resource centers and countries to achieve good results.

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.

Sequelae of carbide-related thermo-chemical injury: A retrospective analysis.

Purpose: To describe the outcomes of eyes with calcium carbide (CaC2)-related thermo-chemical injury. Methods: This study included 28 eyes of 23 patients who presented with calcium carbide-related ocular burns. Only patients with more than three months of follow-up were included. Group A included 16 eyes with Dua's Grade I-III burns, while Group B included 12 eyes with Grade IV-VI burns. Electronic medical records were reviewed to provide data on the etiology of burn, presenting clinical signs and visual acuity, sequelae, and surgical interventions performed, both in the acute and chronic phases. Results: The overall mean age was 28.48 ± 11.8 years. Fifteen patients were injured while using carbide to create an explosion to scare away animals on farms. The median presenting BCVA (best-corrected visual acuity) in Group A (20/160) was significantly better than in Group B [(20/2000) (P = 0.002)]. Five eyes in Group A and one eye in Group B underwent medical management. There was no difference in the duration of follow-up for both groups (P = 0.24). The median final BCVA in Group A (20/32) was significantly better than in Group B [(20/200) (P = 0.02)]. Two eyes in Group A and nine eyes in Group B developed LSCD. Two eyes in Group B were phthisical at the last visit. Conclusion: Calcium carbide-related ocular injuries can result in significant visual morbidity in young adults. Early presentation and management may improve outcomes. Prevention of these injuries by increasing awareness and increasing advocacy efforts is necessary.

Preservation of donor corneal epithelium in McCarey-Kaufman medium.

Purpose: To evaluate the role of McCarey-Kaufman (MK) medium in maintaining the integrity of donor corneal epithelium. Methods: Nineteen corneal buttons were harvested and stored in MK media at 2°C-8°C for four days. Serial photographs were done every day till the 3rd day, and images were then analyzed with ImageJ software (LOCI, University of Wisconsin, USA). The area of exposure and epithelial defect (ED) was calculated every day for each corneal button. Results: The average age of the donors was 56.5 ± 22.7 years and mean time from death to preservation of the corneal buttons was 7.7 ± 3.1 hours. The average corneal area was 145.6 ± 18.8 mm2. The total mean area of exposure was 3.6 ± 4.8, 7.2 ± 9.2, and 9.0 ± 11.9 mm2, and ED was 1.7 ± 4.6, 2.8 ± 5.3, and 3.3 ± 5.9 mm2 on days 1, 2, and 3, respectively. The percentage of increase in the area of exposure and ED in MK media was 3.71% and 1.1% from day 1 to day 3, respectively. Six out of 19 corneal buttons (31.57%) were utilized for keratoplasties, of which two were utilized in house and four were distributed outside. Of the two utilized corneas, none had epithelial defect on postoperative day 1. Rest 13 corneas were either used for training and research purposes, stored in glycerol media, or discarded. Conclusion: Since the percentage change in area of exposure/ED is not much at the end of day 3, corneas stored in MK media can be safely used even after three days of storage. Hence, MK medium serves as an excellent medium in maintaining the integrity of donor corneal epithelium.

Efficacy of voriconazole and amphotericin B in corneal preservative media.

PURPOSE: To evaluate the efficacy of voriconazole and amphotericin B in McCarey-Kaufman (MK) media. METHODS: MK media vials were supplemented with either voriconazole at 1, 2, 20, 50, 100 µg/mL or amphotericin B at 0.5, 1, 2, 10, 20 µg/mL. The standard inoculum of the American Type Culture Collection (ATCC) strain of Candida albicans, Aspergillus flavus, and Fusarium keratinoplasticum was added to the set of vials. The efficacy outcomes were calculated as 'viable fungal colony counts' determined from the samples taken on Days 0 and 4. MK media containing fungal inoculum but without antifungal supplements were used as control. RESULTS: In the voriconazole arm, on Day 4, a reduction in the colony count was observed for Candida albicans (1 µg/mL, 36%; 100 µg/mL, 100%), Aspergillus flavus (1 µg/mL, 53.8%; 100 µg/mL, 80.4%), and Fusarium keratinoplasticum (1 µg/mL, 39.0%; 100 µg/mL, 72.2%). Similarly, in the amphotericin B arm, on Day 4, a reduction in the colony count was observed for Candida albicans (0.5 µg/mL; 99.9%; 20 µg/mL, 100%), Aspergillus flavus (0.5 µg/mL, 65.2%; 20 µg/mL, 84.8%), and Fusarium keratinoplasticum (0.5 µg/mL, 90.1%; 20 µg/mL, 100%). CONCLUSION: Compared to voriconazole, the addition of amphotericin B significantly reduces fungal contamination in MK media.

Early changes in host and donor lenticule thickness after Descemet stripping endothelial keratoplasty.

PURPOSE: To analyze the early changes in host and donor lenticule thickness after Descemet Stripping Endothelial Keratoplasty (DSEK). METHODS: DSEK was performed on 32 eyes of 31 patients. Pre- and post- operative slit lamp examination and anterior segment Optical Coherence Tomography (OCT) was done on day-1, day-7, 1 month, and 3 months. RESULTS: There were significant changes in host, lenticule, and total corneal thicknesses between day-1 and day-7, and day-7 and 1 month. There were significant changes in host thickness and total corneal thickness between 1 month and 3 months. Thickness changes were significant between day-1 and day-7, and 1 month and 3 months for thick and thin host, respectively, whereas these changes were observed both for thick and thin host between day-7 and 1 month. Similarly, significant changes were observed between day-7 and 1 month, and day-7 and 1 month in thin lenticule whereas in case of thick lenticule, it was observed till the 3 months follow-up period. There was a significant improvement in visual acuity till the 3 months follow-up period. No significant correlation was observed between visual acuity and host and lenticule thickness. CONCLUSION: The thicknesses of host and lenticule decrease continuously. Lenticule thickness stabilizes before host. Thinner cornea stabilizes earlier compared to thicker cornea.

Neurotization of the human cornea - A comprehensive review and an interim report.

We present a comprehensive review of existing literature on surgical corneal neurotization (SCN) as a treatment modality for neurotrophic keratopathy (NK) with an interim report of seven cases where SCN was performed using the indirect approach and followed up till 18 months postoperatively to look for improvement in ocular surface, corneal sensations, and nerve regeneration by using in vivo confocal microscopy (IVCM). A literature search was performed for publications with keywords "corneal nerves," "neurotization," "esthesiometry," "corneal anesthesia," and "neurotrophic keratopathy." All literature available till December 31, 2020 was reviewed and included to describe NK and its management options, particularly SCN. NK is associated with absent or reduced corneal sensations and is managed using a step-ladder algorithm ranging from medical management for symptomatic relief to surgical corneal neurotization. Both direct and indirect approaches of SCN have a favorable outcome with reduced surgical morbidity in the indirect approach using sural nerve graft. Post neurotization, corneal sensation recovery may take up to 3-6 months, while nerve regeneration on confocal microscopy can take as long as 6 months-1 year.

Safety and efficacy of corneal tissue harvested from organophosphorous deceased patients.

PURPOSE: To analyze the quality of tissues and outcome of corneal transplants from tissues harvested from the donors of organophosphorus poisoning victims. METHODS: A retrospective study was carried out on corneas harvested from organophosphorus poisoning victims between January 2016 and December 2018. Details of quality of tissues and outcome following keratoplasty were collected from the eye bank and outpatient records, respectively. RESULTS: Four hundred and seventy-eight donor corneas were collected from the victims of organophosphorus poisoning during the study period. The mean age of the donor was 38.8 ± 16.5 years. The mean donor-to-preservation time was 6.2 ± 3.2 hours. The mean endothelial cell density on specular microscopy was 2986.5 ± 369.0 cells/mm2. Four hundred and twenty-two (88.2%) donor corneas were utilized. Of the 121 corneas utilized at our institute for transplantation, 73 and 48 corneas were for optical and therapeutic/tectonic indications, respectively. Of the 73 optical grafts, 25 patients were lost-to-follow-up and 58.3% (28/48) who came for one-year follow-up were found to be clear. CONCLUSION: Donor corneas retrieved from organophosphorus poisoning are safe for transplantation. The postoperative outcome of the tissue utilized from these donors is satisfactory.