Microbiological profile of donor corneas: a retrospective study from an eye bank in north India

PURPOSE: To study the microbiological profile and the antibiotic sensitivity of the microorganisms cultured from donor corneas and evaluate with respect to the decontamination protocols during the study period. METHODS: Retrospective review of microbiological culture reports of 2,291 donor eyes sent from January 2000 to December 2003. Donor corneas were treated with 0.4% gentamicin (phase I), 1% povidone-iodine and 0.4% gentamicin (phase II), and 5% povidone-iodine with 0.4% amikacin (phase III). Limbal swabs taken by the eye bank technician after antimicrobial decontamination of donor eyes and sent to the microbiology laboratory for culture were tracked. The positive culture reports with antibiotic sensitivity pattern were studied and results correlated with decontamination protocols. RESULTS: Staphylococcus epidermidis, Pseudomonas aeruginosa, and Alkaligenes faecalis were the 3 most common isolates overall. The percentage of positive bacterial cultures reduced when we used 5% povidone-iodine and 0.4% amikacin (31.3%) as compared to 1% povidone-iodine and 0.4% gentamicin (61.8%) (P < 0.001). Addition of povidone-iodine decreased positive fungal cultures from 6% in phase I to 2.2% in phase II (P < 0.01) and 1.9% in phase III (P < 0.01). Amongst the total bacterial cultures sent after antimicrobial treatment, Gram-positive bacteria decreased from 38.6% (64/166) in phase I to 27.6% (402/1457) and 10.8% (72/668) in phases II and III, respectively (P < 0.001), and Gram-negative bacteria increased from 10.2% (17/166) to 18.8% (274/1457) and 19.8% (132/668), respectively (P = 0.02). Amongst the positive bacterial cultures, the proportion of Gram-positive bacteria decreased from 79.0% (64/81) in phase I to 59.5% (402/676) and 35.3% (72/204) in phases II and III, respectively (P < 0.001), and that of Gram-negative bacteria increased from 21.0% (17/81) to 40.5% (274/676) and 64.7% (132/204), respectively (P < 0.001). CONCLUSIONS: Different combinations of antimicrobials failed to eliminate all organisms, especially Gram-negative bacteria from the donor corneal surface. The increase in proportion of Gram-negative bacteria despite the use of amikacin combined with povidone-iodine suggests a need to find a better combination for decontamination of donor corneal tissue.     

Evaluation and transplantation of corneas from pseudophakic donor eyes

PURPOSE: To evaluate the quality of corneal donor tissue from pseudophakic eyes for transplantation. METHODS: Only capsular-supported posterior chamber pseudophakia was studied. Forty-five pairs of donor eyes were assessed and evaluated by standard Minnesota Lions Eye Bank (MLEB) protocol. Thirty-three pairs were unilaterally pseudophakic with the unoperated phakic eye used as a control eye. Twelve donors were bilaterally pseudophakic. All corneas were rated for corneal clarity, epithelial defects, stromal edema, Descemet's membrane folding, endothelial cell density (ECD), and cell damage by slit-lamp examination and specular microscopy. If the corneas were not transplanted, the endothelium was vital stained with trypan blue and counterstained with alizarin red S for quantitation, localization, and visualization of cell morphology and damage. RESULTS: Sixty-eight of the 90 corneas in this study did not meet transplantation criteria. A significant difference in ECD (>22%) and in overall corneal rating was found in seven (21%) of 33 pairs of unilateral pseudophakic donors. Fourteen corneal transplants were performed using corneas from the donors in this study. Nine corneas from pseudophakic donor eyes were transplanted, resulting in one primary graft failure reported. CONCLUSION: Corneas from pseudophakic donor eyes may need more extensive evaluation for endothelial viability than is currently required by eye bank standards.     

The efficacy of postenucleation saline wash and the effect of different antimicrobial agents on microbial contamination of donor eyes

OBJECTIVES: To evaluate the efficacy of postenucleation saline wash and the effect of different antimicrobial agents on the microbial contamination of donor eyes. METHODS: Two hundred donor eyes were given saline wash and treated with any one of the following 5 randomly selected antimicrobial solutions: 1% povidone-iodine for 3 min, 0.3% gentamycin for 10 min, 0.3% ciprofloxacin for 10 min, a combination of neomycin 1,700 IU, gramicidin 0.025% and polymyxin B 5,000 IU (Neosporin(R)) for 10 min and a combination of 0.3% amikacin for 10 min, followed by 2.5% cefazolin for 10 min. Limbal swabs were sent for culture before and after saline wash and after treatment with antimicrobial agents. RESULTS: On culture of the pretreatment swabs, 77.5% were positive for growth with 75.5% bacterial and 11.5% fungal. Coagulase-negative Staphylococcus (29.1%) was the most common bacterial contamination followed by Pseudomonas aeruginosa (18.5%), Acinetobacter sp. (18.5%) and Alcaligenes faecalis (13.2%). A 20-ml sterile saline wash resulted in a 20% decrease (p < 0.01) in the amount of contamination. The maximum antimicrobial effect with regard to bacterial decontamination was achieved with povidone-iodine (64% decrease in the amount of contamination, p < 0.01) followed by ciprofloxacin (47.6% decrease, p < 0.05), the combination of cefazolin and amikacin (42.5%, p < 0.05), Neosporin (38.5%, p < 0.05) and then gentamycin (21.7%, p = NS). CONCLUSIONS: A thorough saline wash and treatment with 1% povidone-iodine for 3 min is a more effective method for the decontamination of donor eyes as compared to most currently available and frequently used antibiotics.     

Effect of gatifloxacin 0.3% and moxifloxacin 0.5% ophthalmic solutions on human corneal epithelium following 2 dosing regimens

PURPOSE: To determine whether gatifloxacin 0.3% ophthalmic solution or moxifloxacin 0.5% ophthalmic solutions are toxic to the corneal epithelium when used with 1 of 2 dosing regimens in healthy human eyes. SETTING: Price Vision Group, Indianapolis, Indiana, USA. METHODS: In this double-masked randomized fellow-eye comparison study, gatifloxacin 0.3% was instilled in 1 eye and moxifloxacin 0.5% in the other eye either 4 times a day for 7 days or hourly for 10 hours. Before and after dosing, all eyes were examined with a slitlamp and the cell layers in the central cornea were evaluated by confocal microscopy. Subject discomfort with study drop instillation was also assessed. RESULTS: There was no statistically significant increase in the incidence or severity of superficial punctuate keratitis following use of gatifloxacin 0.3% or moxifloxacin 0.5% when instilled 4 times a day for 7 days or hourly for 10 hours. Hourly use of gatifloxacin 0.3% for 10 hours resulted in a mild but statistically significant increase in conjunctival hyperemia (P = .029). Use of moxifloxacin 0.5% resulted in a small but statistically significant deterioration of the corneal epithelial surface as assessed by confocal microscopy (P = .045). The incidence of subject discomfort with study drop instillation was comparable for the 2 antibiotics (P = .67). CONCLUSION: Use of ophthalmic solutions of gatifloxacin 0.3% or moxifloxacin 0.5% did not result in clinically significant epithelial toxicity in healthy human corneas after dosing regimens of 4 times a day for 7 days or hourly for 10 hours dosing regimens.     

不同种族角膜植片对穿透性角膜移植术效果的影响

目的 通过观察不同种族间穿透性角膜移植手术的效果,总结不同种族之间穿透性角膜移植的可行性。设计 回顾性病例系列。研究对象 北京同仁眼科中心2002年10月至2003年3月因角膜白斑、角膜内皮失代偿、角膜移植术后植片失败等接受穿透性角膜移植术患者10例（10眼）。方法 采用国际组织库提供的中期保存角膜植片进行穿透性角膜移植术,其中高加索人种角膜8片,西班牙人种1片,非洲人种1片。术前收集患者资料,术后进行随访和临床观察,评价角膜植片的存活情况以及疗效。主要指标 视力,角膜植片透明度,角膜新生血管分级。结果 10例患者平均随访（12.6±3.86）个月,4例患者角膜植片基本保持透明,视力平均提高1~2行。6例（60%）患者出现植片混浊、植片水肿、新生血管长入等排斥反应,视力不提高。结论 本文小样本观察显示不同种族角膜供体可以用于穿透性角膜移植治疗。（眼科, 2013, 22:98-100）     

Evaluation of donor tissue with a new videokeratoscope: the Keratron Scout.

PURPOSE: To evaluate the percentage of corneas with an epithelial surface quality sufficient for a reliable screening of donor eyes with keratoconus and after photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) treatment for refractive errors. The usefulness of the computer-assisted, video-keratography system Keratron Scout in making this determination was evaluated. METHODS: Forty eyes from 20 donors were screened within 30 minutes after enucleation and within 24 hours postmortem. At first a meticulous slit-lamp evaluation of the corneal surface and stroma was performed; thereafter eight pictures per eye were taken with the Keratron Scout, and an ultrasound pachymetry reading of the corneal center was taken. "True curvature," algorithm-based color maps were used for analysis. Epithelium was not removed, because all corneas were suitable for transplantation. Balanced salt solution was used to keep the corneas moist. The low intraocular pressure regularly found in postmortem eyes was raised to within normal ranges by intravitreal injection. Corneas were classified according to the integrity of their epithelial surface, which influences the regularity of the topography maps. RESULTS: The quality of the images acquired varied, depending mostly on the quality of the epithelium. Regular topography patterns were found in 15 eyes (37.5%); in 14 eyes (35%), minimal epithelial roughness or sloughing in just one quadrant of the cornea was detected. Moderate to severe epithelial irregularities or defects were found in nine eyes (22.5%). Screening for abnormal shape was possible in 90% of the tested eyes, where no changes caused by prior refractive surgery or keratoconus were apparent. CONCLUSION: The postmortem quality of the epithelial surface allows screening for keratoconus or refractive procedures in the majority of donor eyes. Video-keratography with the Keratron Scout seems to offer a sensitive and quick method for this purpose, thereby adding an additional safety feature to eye banking in view of the rapid development of corneal refractive surgery.     

Comparison of ophthalmic gatifloxacin 0.3% and ciprofloxacin 0.3% in healing of corneal ulcers associated with Pseudomonas aeruginosa-induced ulcerative keratitis in rabbits.

OBJECTIVE: Evaluation of gatifloxacin 0.3% ophthalmic solution efficacy in a corneal ulcer model of Pseudomonas keratitis. METHODS: Heptanol-induced corneal ulcers in New Zealand White rabbits (n = 41; 8 females/group) were inoculated with 10(6) CFU of Pseudomonas aeruginosa. Gatifloxacin 0.3% dosing varied among 4 groups with frequencies of 16-48 doses/day (days 1-2), 3-16 doses/day (days 3-7), and maintenance dosing of 3-4 doses/day (days 8-22). Ciprofloxacin 0.3% was administered as labeled for corneal ulcers, with 44 doses on day 1, 16 doses on day 2, and 4 doses/day on days 3-21. RESULTS: All eyes showed evidence of infection by 48 hours postinoculation with 36 of 41 eyes (87.8%) exhibiting moderate-to-severe keratitis. All eyes exhibited corneal healing by day 15, with no significant differences among groups. Three of 4 groups receiving gatifloxacin tended to have smaller fluorescein retention area scores than did the ciprofloxacin group. No eyes tested positive for Pseudomonas at the end of the study. No corneal precipitates were found following as many as 48 doses/day of gatifloxacin. CONCLUSION: Ophthalmic gatifloxacin 0.3% is at least as effective as ciprofloxacin at healing corneal ulcers infected with Pseudomonas aeruginosa when gatifloxacin is administered less frequently than ciprofloxacin. Trends favored gatifloxacin in fluorescein retention scores.     

French Directory of Eye Banks. Report on activities during 1993-1997]

PURPOSE: To describe the activity of the eye banks participating in the French Eye Bank Directory over the period 1993-1997. METHODS: Since 1993, the eye banks have answered annually a questionnaire concerning technical aspects (procurement procedures, microbiological testing, tissue evaluation and preservation procedures) and activity (number of corneas processed, preserved and issued). Data from these banks were collected and presented in the Directory each year. RESULTS: In 1997, a total of 2,432 eyes were processed. Most of the eye banks (84%) used organ culture as the storage method. Thirty percent of the processed corneas were not used for transplantation. The main reasons for discarding corneas were inadequate endothelium before preservation (15.5%) and positive serology (27%), contamination during preservation (4.6-7.2%), and inadequate endothelium after preservation. CONCLUSION: Quality assurance, microbiological safety and tractability requirements are currently an integral part of the cornea transplantation circuit in France. Publication of eye bank activity has enabled and evaluation of the different procedures.     

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.     

Corneal buttons obtained from patients with HSK harbor high copy numbers of the HSV genome

PURPOSE: To detect herpes simplex virus (HSV) genome in the cornea, we sampled the limbal corneas and scleras of the imported eye bank eyes and recipient's corneal buttons and quantitated HSV genome in them by real-time polymerase chain reaction (PCR). METHODS: Forty-four recipient corneas including 7 corneas with and 37 corneas without a history of herpetic keratitis, 70 eye bank donor limbal corneas, and 35 eye bank donor scleras were obtained. Primers for real-time PCR were synthesized using the HSV-1 and -2 common regions of the viral DNA polymerase. Primers for conventional PCR were designed to detect HSV-1 and -2 and varicella zoster virus (VZV). RESULTS: Significantly higher copy number of HSV DNA was detected in corneas with a history of herpetic keratitis 85.7% (6/7), with an average of 1.6 x 10(4) copies/mg tissue weight than in corneas without a history of herpetic keratitis 10.8% (4/37), with an average of 8.7 copies/mg tissue weight (P < 0.05, Mann-Whitney U test). HSV DNA was detected in 5.7% (4/70) of the eye bank donor corneas, with an average of 4.9 x 10(2) copies/mg tissue weight, and in 8.6% (3/35) of the donor scleras, with an average of 10.6 copies/mg tissue weight. HSV-2 and VZV-DNA were not detected in these samples. CONCLUSIONS: Real-time PCR quantitated HSV genome in the cornea even at a quiescent phase of infection. HSV genome was detected in the corneas and scleras without a past history of herpetic keratitis by this method.     

The New Zealand National Eye Bank study 1991-2003: a review of the source and management of corneal tissue

PURPOSE: To evaluate donor demographics and source, donor tissue processing and storage, biologic contamination, and the utilization and distribution of corneal tissue procured by the New Zealand National Eye Bank. METHODS: As part of a prospective longitudinal study, the electronic records of the NZNEB for the 13-year period 1991-2003 were analyzed for each year with respect to donor demographics, donor source and cause of death, death-to-preservation interval, storage methods, endothelial assessment, biologic contamination, corneal tissue utilization, and distribution. RESULTS: During the study period, 3221 corneas were retrieved from 1628 donors (69.8% male, 30.2% female), with the mean age of donors 59.4 years (SD 18.3 years) and range 4 to 95 years. No significant correlation was identified between donor age group (using 10-year intervals) and the proportion of corneas suitable for transplantation. Donors were procured from the Coroner's service (67.6%), public hospitals, (23.5%) and multiorgan donors (7.1%). The most common causes of donor death were cardiovascular disease, trauma, and cerebrovascular disease. Average storage duration increased from 3.5 to 11.8 days when organ culture replaced hypothermic storage in 1992. Biologic contamination occurred in 5% of all donor corneas. The most common bacterial and fungal isolates were coagulase-negative staphylococci and Candida spp, respectively. A significant decrease in contamination rate over the years of the study was identified. Overall, 79.4% of corneal tissue procured was used for corneal transplantation (75.8% for penetrating keratoplasty, 2.1% for lamellar keratoplasty, and 1.5% for unspecified transplants), and 21.6% was discarded. Most common reasons for discarding tissue were biologic contamination, abnormal serology, and failed endothelial assessment. CONCLUSION: Analysis of the NZNEB database provides valuable information in relation to eye banking and corneal transplantation in New Zealand. Significant trends were identified in donor demographics, donor procurement source, improved donor tissue processing and storage, decreased biologic contamination, and increased utilization of corneal tissue.     

Therapeutic keratoplasty using preserved corneas from keratoconus eyes

PURPOSE: To report and discuss cases of lamellar keratoplasty using corneas obtained during previous penetrating keratoplasty in keratoconus eyes. METHODS: Corneal buttons were obtained from 7 keratoconus patients and stored in a preserving solution for 7-60 days (average, 32.4 days) before use. The recipient eyes comprised recurrent pterygium 3 eyes, primary pterygium 1 eye, pseudopterygium 1 eye, corneal perforation with iris prolapse due to fungal corneal ulcer 1 eye, and limbal dermoid 1 eye. RESULTS: The recipient eyes ran favorable courses in general. Graft rejection developed in 2 eyes and was successfully treated with topical and systemic corticosteroid. CONCLUSIONS: Preserved corneas from keratoconus eyes were found useful in therapeutic lamellar keratoplasty. By this procedure, the current inadequate supply of donor corneas in eye banks in Japan can be augmented.     

Zymar (Gatifloxacin 0.3%) shows excellent Gram-negative activity against Serratia marcescens and Pseudomonas aeruginosa in a New Zealand White rabbit keratitis model

PURPOSE: Whereas gatifloxacin, a newer fluoroquinolone, was engineered to increase its Gram-positive potency, we assessed whether it still retained significant Gram-negative activity in vivo. Specifically, we compared the efficacy of Zymar (gatifloxacin 0.3%), Ciloxan (ciprofloxacin 0.3%), and fortified tobramycin (14 mg/mL) in the treatment of experimental Gram-negative bacterial infections of Serratia marcescens (SM) and Pseudomonas aeruginosa (PA) in the New Zealand White (NZW) rabbit keratitis model. METHODS: A total of 30 NZW rabbits each were intrastromally inoculated in both eyes with approximately 1000 CFU of SM and PA. By E-test, the minimum inhibitory concentrations (MICs; microg/mL) for SM were gatifloxacin (0.125), ciprofloxacin (0.047), and tobramycin (1.5), and for PA were gatifloxacin (0.125), ciprofloxacin (0.19), and tobramycin (0.5). After 16 hours, the rabbits were divided into 4 treatment groups: (1) Zymar, (2) Ciloxan, (3) fortified tobramycin, and (4) saline control. One drop was instilled in both eyes every 15 minutes for 5 doses and then every 30 minutes for 14 doses. One hour after the final treatment, the animals were euthanized, and bacterial colony counts from the corneas were determined. RESULTS: For SM, Zymar and Ciloxan significantly reduced (P < 0.001, ANOVA) the colony counts compared with tobramycin and saline control. Zymar was more effective than Ciloxan (P < 0.001, ANOVA). For PA, all antibiotics reduced equivalently the colony counts compared with the saline control (P = 0.005, ANOVA). CONCLUSIONS: The enhanced Gram-positive activity of gatifloxacin is not associated with any decreased Gram-negative activity in vivo. Zymar may prove useful for SM and PA keratitis.     

Optical coherence tomography for the detection of laser in situ keratomileusis in donor corneas

PURPOSE: In 2001, more than one million laser in situ keratomileusis (LASIK) procedures were performed worldwide. Considering the increasing number of refractive procedures, eye banks will be increasingly confronted with the problem of how to identify those donors with prior refractive surgery. To date, efficient screening methods to identify LASIK surgery in donor eyes have not been established. Therefore, the purpose of the current study was to determine whether optical coherence tomography (OCT) can be used to detect the presence of LASIK-induced changes in human corneas. METHODS: Laser in situ keratomileusis was performed on 20 organ-cultured human cornea disks. The excimer laser ablation performed ranged from 0 to 12 diopters. The corneas were maintained in culture, and the visibility of flap-stromal interface by OCT was assessed up to 6 months after the LASIK procedure. Additionally, two donor corneas with the history of LASIK treatment before death were screened for structural changes. RESULTS: Optical coherence tomography scans were able to detect the interface between the corneal flap and the residual stromal tissue in all corneas and at all examined time intervals. There were no differences in signal intensity among the different depths of ablation. The relative signal intensity of the interface compared with the averaged stromal intensity ranged from 2.1 to 6.0. In both donor corneas with suspected prior LASIK surgery, OCT scanning showed the characteristic stromal interface as found in the in vitro model. CONCLUSIONS: Corneal examination by OCT could be an appropriate technique for eye banks to screen donor corneas for prior LASIK surgery.     

Use of cryopreserved donor corneal tissues first time in India for therapeutic penetrating keratoplasty during COVID-19 pandemic – A case series

Coronavirus disease (COVID-19) pandemic caused restricted eye retrieval leading to acute scarcity of donor corneas. Nine patients with perforated corneas needed urgent donor tissues where we used 10 cryopreserved corneal tissues for therapeutic penetrating keratoplasty (TPK). Repeat TPK was done in one eye for recurrence of infection. The anatomical integrity of the eyeball was maintained in seven eyes, while two eyes were lost to phthisis. Thus, cryopreserved corneas can be taken into consideration for TPK when other donor tissues are not available.     

Role of Staphylococcus epidermidis in outer eye infections

Coagulase-negative staphylococci (CNS) from 57 patients with outer eye infections and healthy control eyes were isolated according to the Schleifer and Cloos classification and the sensitivity to antibiotics of the isolated CNS was examined. The pathogenicity of CNS in rabbit cornea was studied by direct inoculation of CNS. The results showed that of 57 strains of CNS, 25 strains (43.9%) belonged to S. epidermidis, 22 (38.6%) belonged to non-detectable strains, 4 (7%) belonged to S. capitis, 3 (5.3%) belonged to S. hominis and 2 (3.5%) belonged to S. saprophyticus. Furthermore these CNS were resistant to aminoglycoside and machloride antibiotics which are commonly used as eye drops for ocular infectious diseases. Control rabbit corneas inoculated with CNS almost became clear within 24 hours. Therefore, it was suggested that ocular CNS infections can occur in immunologically compromised host patients.     

Reducing contamination when removing and storing corneas: a multidisciplinary, transversal, and environmental approach

PURPOSE: The combination of a shortage of cornea grafts in France and a national average contamination rate of 9% to 10%, has led us to search for the origins of this contamination. The objective of our study was to reduce the number of unusable grafts resulting from contamination of corneas in organ culture. METHODS: An external audit was carried out by an independent pharmacist on the removal conditions and treatment procedures for corneas. An environmental study was carried out, consisting of microbiological sampling of the corneas of donors who just died (<24 hours) as well as water and air samples in the premises used for removal. The Cornea Bank's procedures were submitted to a microbiological risk analysis using the "failure mode effects and criticity analysis" (FMECA) method. RESULTS: The critical contamination periods were found to be before removal, during mortuary washing and during decontamination of the conjunctival cul-de-sac at the removal stage. The corrective measures taken have reduced contamination rates by half in 1 year. CONCLUSION: Highlighting the sources of contamination has led to the implementation of effective targeted and low-cost measures that have allowed us to reduce significantly the number of cornea graft losses as a result of bacterial and fungal contamination.     

Comparison of corneal surface effects of gatifloxacin and moxifloxacin using intensive and prolonged dosing protocols

PURPOSE: To compare the effects of the commercial formulations of moxifloxacin and gatifloxacin on rabbit corneal epithelium using two dosing protocols: high-frequency dosing for bacterial keratitis and cataract surgery prophylaxis. METHODS: Forty eyes of 20 New Zealand white rabbits were randomized to receive topical gatifloxacin, topical moxifloxacin, or no drops as controls. Eighteen eyes received 1 drop of antibiotic every 5 minutes for 15 minutes followed by 1 drop every 15 minutes for 4 hours. Twelve eyes received topical gatifloxacin or topical moxifloxacin 4 times a day for 10 days. Rabbits were euthanized, eyes enucleated, and the corneas separated, washed, and fixed; scanning electron microscopy was performed. Photomicrographs of three separate areas from the corneal apex were taken at x1200 and x3000 for each cornea. Two masked, experienced examiners then graded the corneal epithelial damage. RESULTS: In the high-frequency dosing group, mean corneal damage score for eyes treated with gatifloxacin was 1.593, that for moxifloxacin was 1.407, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.41), gatifloxacin and control (P = 0.14), or moxifloxacin and control (P = 0.23). In the cataract surgery prophylaxis group, mean corneal damage scores for eyes treated with gatifloxacin was 1.167, that for moxifloxacin was 1.368, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.23), gatifloxacin and control (P = 0.08), or moxifloxacin and control (P = 0.23). CONCLUSION: Despite differences in formulations, with short-term dosing neither gatifloxacin nor moxifloxacin appears to be toxic to the corneal epithelium in this rabbit model.     

The grave necessity to make eye bank specular microscopy mandatory in all eye banks in the subcontinent to improve utilization of scarce donor corneas

Context:

Donor tissue scarcity, Eye Bank Specular Microscopy as yet not made mandatory and tissue utilization often based on clinical judgment only.

Aims:

Prospectively analyze alteration in clinical grading of donor corneas and hence utilization, based on Eye Bank Specular Microscopy (EBSM) and to infer if EBSM should be mandatory in all eye banks.

Materials and Methods:

200 consecutive otherwise ‘suitable for surgery’ donor eyes were graded clinically. On quantitative and qualitative analysis of endothelial cells by EBSM, final grading was adjusted. Impact on subsequent utilization for various surgeries was analyzed with regard to Age of Donor, Death to Enucleation Time, Death to Preservation Time and Lens Status of Donor Eye.

Results:

76 eyes (38%) (P < 0.05) had significant change in grading. 12/59 (20.30%) tissues from donors <=40 years showed Cell Density (CD) between 1801-2500. 19/76 (25%) tissues from donor >60 years showed CD >= 2500. From donor >=81 years, 2/13 (15.3%) eyes showed CD between 2501-3000 and 1 (7.6%) eye showed CD > 3000. Owing to better grading after EBSM, 13/14 (92.85%) tissues with DTET >6 hours and 5/5 (100%) tissues with DTPT > 16 hours were transplanted. Out of 45 (22.5%) pseudo-phakic tissues, 21 (46.67%) tissues were used for Therapeutic/Tectonic Penetrating Keratoplasty (PKP) while 24 (53.33%) tissues were used for Optical PKP.

Conclusions:

EBSM significantly alters final grading of tissues and its subsequent utilization. Acquiring huge importance in areas where adequate supply of corneas is lacking, EBSM becomes an indispensable tool for optimizing availability of qualified tissues for surgery. EBSM should be made a mandatory analysis.