Amniotic membrane transplantation in infectious corneal ulcer

Clinical Outcomes and Indications of In-Office Sutureless Dried Gamma Ray-Sterilized Human Amniotic Membrane Transplantation With Bandage Contact Lenses in Various Ocular Surface Disorders

PURPOSE

The purpose of this study was to investigate the efficacy and indications of using dried gamma ray-sterilized amniotic membrane (AM) transplantation with bandage contact lenses for the in-office sutureless treatment of various ocular surface diseases.

METHODS

This study retrospectively included 56 eyes of 52 patients with various ocular surface diseases treated with sutureless dehydrated AM-assisted therapeutic contact lenses. The patients were followed up and assessed 1, 2, and 4 weeks after the treatment, and the therapeutic contact lenses were removed after 1 or 2 weeks. The size of the corneal lesion and the degree of pain experienced by each patient before and after the procedure were measured. Corneal re-epithelization rate and clinical aspects related to re-epithelialization were evaluated.

RESULTS

Complete corneal re-epithelialization of the epithelial defect was observed in 40 eyes. The complete re-epithelialization rates of persistent epithelial defect caused by infectious ulcers, neurotrophic ulcers, ulcers due to burn, toxic keratopathy, previous penetrating keratoplasty or other corneal surgeries, and severe dry eye disease were 69.2%, 80.0%, 77.8%, 100%, 75.0%, and 100%, respectively. Five patients with uncontrolled infectious ulcers, neurotrophic ulcer, bullous keratopathy, and ulcers associated with rheumatic disease did not show significant improvement. Patient pain scores significantly decreased after the procedure.

CONCLUSIONS

Dehydrated AM transplantation with a bandage contact lens is minimally invasive and easily applicable through in-office procedures. This approach is expected to be more actively applied in various ocular surface disorders, not only in severe corneal diseases but also in relatively mild corneal surface diseases.

Treatment Strategies for Filamentous Fungi Keratitis

INTRODUCTION

This research aims to describe clinical findings, epidemiology and treatment outcomes in patients with filamentous fungi keratitis of a tertiary centre in Germany over a 7-year period and to compare the efficacy of different antifungal treatments and the effect of additive topical steroids.

METHODS

This retrospective study included 25 eyes of 23 patients from October 2013 to December 2020 with cultural isolates of filamentous fungi and corresponding keratitis. Best-corrected visual acuity (BCVA), clinical signs, symptoms, risk factors and outcome were extracted from medical records.

RESULTS

Improvement of BVCA was noted in 68% of eyes. Mean BCVA of the study population increased from 0.75 logMAR [median 0.40, standard deviation (SD) 0.82, range 0-2.3] to 0.48 logMAR (median 0.10, SD 0.88, range - 0.1 to 3). The most commonly used antifungal topical treatment was a combination of natamycin 5% and voriconazole 2% (44% of eyes), followed by voriconazole 2% in 36% of cases. An antiinflammatory topical steroid was applied in 52%. In 16% of the eyes, penetrating keratoplasty (pKP) was performed.

CONCLUSION

Diagnosis of filamentous fungi keratitis is often difficult or delayed. Outcomes can be poor even with intensive treatment because of high resistance to common antifungals. Access to natamycin 5% seems to lead to favourable outcomes in filamentous fungi keratitis.

Application of a practical amniotic membrane ring made on-site for restoration of ocular surface health in dry eye disease

PURPOSE

Dry eye disease (DED) is one of the most common ocular surface disorders worldwide. Despite different underlying pathogenic processes, DED is characterized by ocular surface inflammation, which in turn induces further damage to the corneal epithelium and its underlying structures. Amniotic membrane transplants are known to have potent anti-inflammatory effects and also have the ability to enhance epithelial healing. In this study, we aimed to evaluate the clinical efficacy of amniotic membrane ring (AMR) application in treating refractory dry eye disease.

METHODS

A retrospective analysis of 22 patients treated with contact lens-like amniotic membrane rings was performed. This amniotic membrane ring was formed using an aspiration catheter covered by a large piece of amniotic membrane graft. The amniotic membrane was sutured to the catheter using eight sutures. In this way, a customized amniotic membrane ring was prepared for each patient. Patients' demographics, symptoms, use of medications, conjunctival inflammation, corneal staining, and visual acuity were compared before and after treatment. In addition, the amniotic membrane retention duration, the amniotic membrane's effect on ocular surface healing, follow-up time, and complications were evaluated.

RESULTS

Twenty-eight eyes of 22 patients (18 females and 4 males) aged 53.32±13.36 (6-73) years were included. The AMR retention duration ranged from 5 to 16 days, with a mean of 11±3.09 days, at which time the amniotic membrane had dissolved or been removed inadvertently by the patient. Discomfort with the ring was seen in 1 of 28 eyes (3.6%). The patients reported symptomatic relief for a period of 3.64±1.25 months. Symptomatic relief was accompanied by a reduction of OSDI scores (from 63.39±17.24 to 33.19±12.45) (P<0.001), use of topical medications (from 4.21±1.03 to 2.42±0.50) (P<0.001), conjunctival hyperemia (from 1.57±1.19 to 0.35±0.48) (P<0.001), corneal staining (from 2.89±1.16 to 0.57±0.74) (P<0.001), and improvement in visual acuity (from 0.23±0.16 to 0.16±0.25 logMAR) (P=0.001).

CONCLUSIONS

Amniotic membrane ring treatment might be used to treat refractory dry eye disease. This technique has an economic advantage over other commercially available amniotic bandage tissues and can be easily removed and replaced during a follow-up examination.

A Rare Case of Enterococcus faecalis Keratitis in a Neurotrophic Cornea Successfully Treated With Topical Antibiotics and Amniotic Membrane

A patient in his 60s presented with severe keratitis in his right eye. He had a background of diabetes, high body mass index, arthritis and limited mobility, and high alcohol intake. Examination showed lower lid tarsal ectropion, floppy eyelid syndrome, advanced meibomian gland dysfunction, moderate neurotrophia, and large inferior keratitis with hypopyon. Corneal scrapes revealed Enterococcus faecalis, sensitive to vancomycin and ciprofloxacin only. Due to poor compliance with vancomycin, he was started on topical ciprofloxacin resulting in partial improvement but a persistent epithelial defect. Inserting a dry patch of amniotic membrane on the cornea accelerated epithelialization, and 11 weeks from presentation, complete corneal healing was noted. In the presence of multiple systemic and ocular risk factors like diabetes, high body mass index, high alcohol intake, tarsal ectropion, floppy eyelid syndrome, neurotrophic cornea, blepharitis, and ocular surface inflammation, atypical keratitis, like this rare infection, should be suspected. The use of dry amniotic membrane has a role in epithelial healing in patients with neurotrophia.

Debulking corneal biopsy with tectonic amniotic membrane transplantation in refractory clinically presumed fungal keratitis

The treatment of fungal keratitis (FK) is challenging due to the subacute indolent course, and initial misdiagnosis. In this retrospective case series, we highlight both the diagnostic and therapeutic roles of corneal biopsy together with amniotic membrane transplantation (AMT) in patients with refractory clinically presumed FK. Debulking biopsy and tectonic AMT were performed during the initial presentation. Biopsy specimens were sent for KOH smears and cultures. After KOH smears confirmed the presence of fungal elements, topical voriconazole 1% was prescribed for the first 72 h then tailored according to the clinical response and the culture results. The outcome measures were complete resolution of infection and restoration of corneal integrity. Cases associated with culture proven bacterial keratitis were excluded. Twelve cases were included in the study. KOH smears confirmed the presence of fungal growth in all specimens. Cultures grew Aspergillus in 6/12 cases, sensitive to voriconazole (5/6) and amphotericin (3/6); Fusarium (4/12), sensitive to both voriconazole and amphotericin; and no growth in 2/12 cases. Amphotericin 0.15% eye drops were added to the 7 cases with proven sensitivity and to the remaining 2 culture negative cases. Gradual resolution of infection was seen in all cases after 35.6 ± 7.8 days. In FK, a debulking biopsy simultaneously with AMT help decrease the microbial load, suppress the inflammatory process, support the corneal integrity, confirm the presence of fungal pathogen.

Phase I/II randomized, double-masked, placebo-controlled study of processed amniotic fluid drops after PRK

PURPOSE

To evaluate the safety and efficacy of processed amniotic fluid (pAF) used postoperatively after photorefractive keratectomy (PRK).

SETTING

University of Utah, Moran Eye Center, Salt Lake City, Utah.

DESIGN

Randomized, double-masked, placebo-controlled prospective study.

METHODS

61 participants were randomized to receive either placebo or pAF drops, which were instilled 4 times per day for 1 week after PRK along with routine postoperative medications. The primary outcome measure was time to full re-epithelialization in days. Secondary measures included visual acuity at 30 days and postoperative pain scores during the first week.

RESULTS

There was no significant difference in time to re-epithelialization, with a median of 5 days for both groups. There were no difference in pain indicator scores during the first week and no difference in corneal staining scores at day 30 between the 2 groups. There were no adverse events.

CONCLUSIONS

This pilot study evaluating the safety and efficacy of pAF as an additional postoperative topical medication for PRK demonstrated that pAF did not improve the rate of epithelial healing after PRK. pAF may be safely studied in other ocular conditions to determine its effect on epithelial healing.

Challenges and concepts in the diagnosis and management of ocular graft-versus-host disease

Graft-versus-host disease (GVHD) is characterized by tissue inflammation in the host following an allogeneic hematopoietic cell transplantation (HCT). The pathophysiology is complex and only incompletely understood yet. Donor lymphocyte interaction with the histocompatibility antigens of the host plays a crucial role in the pathogenesis of the disease. Inflammation may affect multiple organs and tissues, e.g., the gastrointestinal tract, liver, lung, fasciae, vaginal mucosa, and the eye. Subsequently, alloreactive donor-derived T and B lymphocytes may lead to severe inflammation of the ocular surface (i.e., cornea and conjunctiva) and the eyelids. Furthermore, fibrosis of the lacrimal gland may lead to severe dry eye. This review focuses on ocular GVHD (oGVHD) and provides an overview of current challenges and concepts in the diagnosis and management of oGVHD. Ophthalmic manifestations, diagnostic procedures, grading of severity and recommendations for ophthalmic examination intervals are provided. Management of ocular surface disease with lubricants, autologous serum eye drops, topical anti-inflammatory agents and systemic treatment options are described based on the current evidence. Ocular surface scarring and corneal perforation are severe complications of oGVHD. Therefore, ophthalmic screening and interdisciplinary treatment approaches are highly relevant to improve the quality of life of patients and to prevent potentially irreversible visual loss.

Impact of adjuvant amniotic membrane transplantation in infectious ulcerative keratitis

PURPOSE

To evaluate the effectiveness of cryopreserved human amniotic membrane transplantation (hAMT) in patients with infectious ulcerative keratitis.

METHODS

A retrospective cohort study based on medical records of patients who underwent hAMT procedure over a 2-year period (2020-2021) was conducted at Ege University Hospital, Turkey. Cryopreserved hAM was used. Best corrected visual acuity (BCVA) was measured with the Snellen chart. Detailed ophthalmological examination was performed at all visits. Treatment success was defined as complete healing including disappearance of corneal infiltrates, epithelial defect closure, reduction in anterior segment reaction.

RESULTS

A total of 13 eyes of 12 patients were diagnosed with ulcerative keratitis between 2020 and 2021. hAMT was performed in severe keratitis patients in which corneal infiltrates extending to middle to deep stromal and patients with neurotrophic component, in other words, having trouble for wound healing. The mean age was 60.9 ± 18.7 years, and 66.6% of the patients were male. Average ulcer horizontal diameter was 9.7 ± 2.8 mm. A single-layer human amniotic membrane (hAM) was transplanted 92.3% of eyes. Overlay technique was used in all patients for hAMT. The mean residence time of the amniotic membrane on the ocular surface was 14.1 ± 10.2 days. The mean time from the first presentation to the hAM transplantation was 9.7 ± 6.8 days. The average hospitalization time of all patients was 15 ± 12.1 days, pre-hAMT was 10.2 ± 7.3 days and post-hAMT was 4.8 ± 9.1 days. The mean follow-up time was 3 months. Recovery response was positive in 76.9%. Average healing time was 32.1 ± 14.04 days.

CONCLUSIONS

hAMT was effective in the treatment of infectious ulcerative keratitis by accelerating and supporting wound healing. Performing hAM transplantation at the early stages of the disease and prolonged residence of membrane on the ocular surface increase the success of the treatment and moreover shortens hospitalization time.

A minimally manipulated preservation and virus inactivation method for amnion/chorion

Allogeneic amnion tissues have been widely used in tissue repair and regeneration, especially a remarkable trend of clinical uses in chronic wound repair. The virus inactivation procedures are necessary and required to be verified for the clinical use and approval of biological products. Cobalt-60 (Co-60) or electron-beam (e-beam) is the common procedure for virus and bacterial reduction, but the excessive dose of irradiation was reported to be harmful to biological products. Herein, we present a riboflavin (RB)-ultraviolet light (UV) method for virus inactivation of amnion and chorion tissues. We used the standard in vitro limiting dilution assay to test the viral reduction capacity of the RB-UV method on amnion or chorion tissues loaded with four types of model viruses. We found RB-UV was a very effective procedure for inactivating viruses of amnion and chorion tissues, which could be used as a complementary method to Co-60 irradiation. In addition, we also screened the washing solutions and drying methods for the retention of growth factors.

Comparison of the efficacy of topical insulin with autologous serum eye drops in persistent epithelial defects of the cornea

PURPOSE

To investigate the effect of topical insulin on epithelization in persistent epithelial defects (PED) refractory to usual treatment compared to autologous serum.

DESIGN

Retrospective, consecutive case-control series.

METHODS

The charts of 61 consecutive patients with PED treated with topical insulin (case group) and 23 treated with autologous serum (control group) were reviewed. Primary efficacy end points were the percentage of patients in which epithelization was achieved, as well as the rate and time until epithelization. Secondary efficacy point was need for amniotic membrane transplantation (AMT) or other surgeries.

RESULTS

Mean time between PED diagnosis and start of topical insulin was 22.7 ± 18.5 days (range 13-115) and the mean area was 14.8 ± 16.2 mm² (range 1.1-70.6). In the control group, mean time was 27.9 ± 16.8 days, mean epithelial defect area being 18.6 ± 15.0 mm² (range 1.7-52.9). No differences in baseline characteristics were found between groups (p > 0.05). Epithelization was achieved in 51 patients (84%) on insulin and 11 patients (48%) on autologous serum (p = 0.002). In those patients, mean time until reepithelization was 32.6 ± 28.3 days (range 4-124) in the insulin group and 82.6 ± 82.4 days (range 13-231) in the autologous serum group (p = 0.011). The need for AMT was significantly lower in the insulin group (p = 0.005). PED recurrence was higher in patients treated on autologous serum (43%) compared with insulin (11%) (p = 0.002).

CONCLUSIONS

Topical insulin is an effective treatment and safely promotes healing of PED. In our series, topical insulin presented better epithelization outcomes than autologous serum and could thus be considered as a first-line treatment.

Amniotic membrane transplantation in a patient with impending perforated corneal ulcer caused by Streptococcus mitis: A case report and review of literature

BACKGROUND

Streptococcus mitis (S. mitis) is an opportunistic pathogen that can lead to severe ocular infections. In previous reports, penetrating keratoplasty (PK) was usually adopted for the treatment of persistent corneal ulcers. This report describes an unusual case of nonhealing descemetocele caused by S. mitis treated by antibiotics plus amniotic membrane transplantation (AMT).

CASE SUMMARY

A 63-year-old woman presented with a right persistent corneal ulcer that she had suffered from for the past 9 mo. The culture of a corneal scraping yielded S. mitis. The right eye descemetocele decreased in diameter from 3 to 0.8 mm after the continuous administration of topical vancomycin and ceftriaxone for 2 wk. Due to the slow healing, AMT was performed. Her corneal erosion healed and gradually became clear. Her visual acuity recovered from initially counting fingers to 100/200 at the last follow-up, 67 mo after AMT.

CONCLUSION

Antibiotics plus AMT may be an effective alternative treatment other than PK to promote epithelialization and to reduce inflammation in the corneas complicated by S. mitis keratitis.

Expression of Antimicrobial Peptide Genes in the Canine Amniotic Membrane

The human amniotic membrane has been successfully used in human ocular reconstruction. Several studies have demonstrated its properties, including antimicrobial features. As a result of the restricted availability of human amniotic membrane for veterinary use, canine amniotic membrane has become an attractive alternative. Clinical studies of the application of canine amniotic membrane in animals and the understanding of its biological properties are limited. This study aimed to determine the expression of peptide genes of natural antimicrobials in canine amniotic membrane. Expressions of canine β-defensin 1, 102, and 103, and canine Elafin were determined in healthy puppies by real-time quantitative polymerase chain reaction. Canine β-defensin 1, 103, and Elafin were expressed in all samples, possibly suggesting a role in the innate immune system of normal canine amniotic membrane. Further investigations of protein expression and localization are recommended.

Clinical Outcomes of In-office Sutureless Amniotic Membrane Transplantation in Persistent Epithelial Defect

Purpose

To investigate the efficacy of outpatient clinic-based sutureless amniotic membrane transplantation (AMT) along with therapeutic contact lens (T-lens) application in eyes with persistent epithelial defects (PED).

Methods

Nine eyes of nine patients (mean age: 71.7 ± 5.2 years) diagnosed with PED and treated with in-office sutureless AMT combined with T-lens application were retrospectively reviewed. Demographics, systemic diseases, PED etiology, corneal epithelial defect (ED) size, visual acuity, corneal scraping culture results, and clinical course were evaluated.

Results

Among nine eyes with PED, three had neurotrophic keratopathy, four had infectious keratitis (three with fungal keratitis, one with bacterial keratitis), one had limbal deficiency, and one had marginal keratitis. The mean ED size (calculated as an average of the horizontal and vertical diameters) was 3.13 ± 1.42 mm, and the mean duration from AMT to epithelial healing was 30.1 ± 10.5 days (range: 14-51 days) in successful trials. The success rates were 77.8% (7/9) per patient and 66.7% (8/12) per trial. The causes of failure in two patients were AMT displacement and uncontrolled infection.

Conclusions

Our results demonstrate that in-office sutureless AMT combined with T-lens application can be used in patients with PED who are refractory to medications. It will be especially helpful for elderly patients because of its easy-to-use method. To achieve successful outcomes with AMT, an appropriate periocular environment as well as infection control need to be considered.

Treatment of Chronic Spinal Cord Injury in Dogs Using Amniotic Membrane-Derived Stem Cells: Preliminary Results

Introduction

Intervertebral disc diseases (IVDD) represent the majority of neurological attendance and responsible for the most cases of paralysis in dogs. Treatments currently used do not show satisfactory results in patients with more severe and chronic neurological manifestations.

Methods

To promote nerve and muscular recovery, as well as improve quality of life, we aimed to create a double-blind test method, associating spinal decompression surgery and allogeneic transplantation of amniotic membrane-derived stem cells (AMSCs) in dogs with chronic IVDD. Cells were characterized as fetal mesenchymal cells and safe for application. Eight animals completed the experiment: stem cell applications were made in four animals that had previously undergone an unsuccessful surgical procedure (“SC group”, n = 4); two animals were submitted to surgery, followed by applications of stem cells (“Surgery + SC”, n = 2); two other animals were submitted to surgery, followed by the application of saline solution (“Surgery + placebo”, n = 2). During the surgical procedure, a topical application was performed on the lesion and after fifteen and forty-five days another two applications were made via epidural. Animals were monitored biweekly and reassessed three months after surgery, by functional tests and magnetic resonance exams.

Results

Some animals presented significant neurological improvement, such as the recovery of nociception and ability to remain on station. Despite the need further studies, until the present moment, cell therapy has been feasible and has no harmful effects on animals.

Conclusion

The protocol of preclinical trial showed the association with decompressive surgery and cell transplantation in dogs with thoracolumbar IVDD proved feasible, and it was possible to observe neurological improvement after treatment. No tissue improvement through MRI was found. The double-blind test guaranteed reliability of the evaluations and results obtained that, even with a small sample size, generated satisfactory results for the animals and owners.

Assessment of Antimicrobial Activity of Dehydrated Amniotic Membrane in Infectious Keratitis: A Small Retrospective Case Series and In Vitro Study

PURPOSE

To describe a small case series of infectious keratitis with poor visual outcomes after amniotic membrane (AM) placement and to prospectively evaluate whether AM demonstrates antibacterial activity in vitro against pathogens commonly isolated from infectious corneal ulcers.

METHODS

A retrospective case series and in vitro study of antibacterial activity of dehydrated AM using disk diffusion and measurement of inhibitory zones for bacterial assessment and inverted microscopy analysis for Acanthamoeba sp. growth.

RESULTS

Three cases of known etiology infectious keratitis are described where the clinical presentation worsened after treatment with AM. In vitro analysis of dehydrated AM, with and without a soft contact lens, demonstrated no inhibition of growth against Pseudomonas aeruginosa or Streptococcus pneumoniae. There was minimal growth inhibition of Staphylococcus aureus, although these zones of inhibition were much smaller than that surrounding the positive control. For Acanthamoeba sp., solubilized, dehydrated AM did not alter cyst density.

CONCLUSIONS

In an in vitro analysis, dehydrated AM did not provide evidence for a potentially clinically meaningful antibacterial effect against organisms commonly isolated from corneal ulcers.

Foundational concepts in the biology of bacterial keratitis

Bacterial infections of the cornea, or bacterial keratitis (BK), are notorious for causing rapidly fulminant disease and permanent vision loss, even among treated patients. In the last sixty years, dramatic upward trajectories in the frequency of BK have been observed internationally, driven in large part by the commercialization of hydrogel contact lenses in the late 1960s. Despite this worsening burden of disease, current evidence-based therapies for BK - including broad-spectrum topical antibiotics and, if indicated, topical corticosteroids - fail to salvage vision in a substantial proportion of affected patients. Amid growing concerns of rapidly diminishing antibiotic utility, there has been renewed interest in urgently needed novel treatments that may improve clinical outcomes on an individual and public health level. Bridging the translational gap in the care of BK requires the identification of new therapeutic targets and rational treatment design, but neither of these aims can be achieved without understanding the complex biological processes that determine how bacterial corneal infections arise, progress, and resolve. In this chapter, we synthesize the current wealth of human and animal experimental data that now inform our understanding of basic BK pathophysiology, in context with modern concepts in ocular immunology and microbiology. By identifying the key molecular determinants of clinical disease, we explore how novel treatments can be developed and translated into routine patient care.

Freeze-Dried Versus Cryopreserved Amniotic Membranes in Corneal Ulcers Treated by Overlay Transplantation: A Case-Control Study

PURPOSE

The purpose of this study was to assess cryopreserved amniotic membrane (C-AM) versus chorion-free freeze-dried amniotic membrane (FD-AM) overlay transplantation for corneal ulcers in a French tertiary ophthalmology hospital.

METHODS

Between March and July 2020, when C-AMs were not available because of the COVID-19 pandemic, 28 corneal ulcers underwent FD-AM overlay transplantation and were retrospectively compared with 22 corneal ulcers treated with C-AM during the same period in 2018. All patients had at least 3 months of follow-up, and those who underwent combined surgeries were excluded. Ulcers were assessed at baseline and then at 72 hours, 1 month, and 3 months. Population demographics, follow-up time, ulcer etiologies, epithelial defect size, ulcer depth, and complications were also recorded.

RESULTS

Baseline characteristics and clinical features of both groups were comparable. There was no statistically significant difference in the number of overlay AM transplantations (P = 0.52) or early detachments (P = 0.57). At 3 months, the corneal healing rate was almost the same in both groups (89% and 91% for FD-AM and C-AM, respectively; P = 0.87). Complications were equally uncommon (11% and 9%, respectively; P = 0.92). In logistic regression, the type of the membrane did not influence corneal healing at 1 month (P = 0.42) or 3 months (P = 0.99), regardless of the depth of the ulcer. However, whatever the type of AM used, the deeper the ulcer was, the less likely it was to heal at 3 months (P = 0.02).

CONCLUSIONS

This is the first study that provides positive insight into the effectiveness of FD-AM compared with C-AM when used as overlay transplantation for treating corneal ulcers.

Amniotic membrane transplantation for infectious keratitis: a systematic review and meta-analysis

Infectious keratitis (IK) is the 5th leading cause of blindness globally. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK, though adjuvant treatment or surgeries are often required in refractory cases of IK. This systematic review aimed to examine the effectiveness and safety of adjuvant amniotic membrane transplantation (AMT) for treating IK. Electronic databases, including MEDLINE, EMBASE and Cochrane Central, were searched for relevant articles. All clinical studies, including randomized controlled trials (RCTs), non-randomized controlled studies and case series (n > 5), were included. Primary outcome measure was time to complete corneal healing and secondary outcome measures included corrected-distance-visual-acuity (CDVA), uncorrected-distance-visual-acuity (UDVA), corneal vascularization and adverse events. A total of twenty-eight studies (including four RCTs) with 861 eyes were included. When compared to standard antimicrobial treatment alone, adjuvant AMT resulted in shorter mean time to complete corneal healing (− 4.08 days; 95% CI − 6.27 to − 1.88; p < 0.001) and better UDVA (− 0.26 logMAR; − 0.50 to − 0.02; p = 0.04) at 1 month follow-up in moderate-to-severe bacterial and fungal keratitis, with no significant difference in the risk of adverse events (risk ratio 0.80; 0.46–1.38; p = 0.42). One RCT demonstrated that adjuvant AMT resulted in better CDVA and less corneal vascularization at 6 months follow-up (both p < 0.001). None of the RCTs examined the use of adjuvant AMT in herpetic or Acanthamoeba keratitis, though the benefit was supported by a number of case series. In conclusion, AMT serves as a useful adjuvant therapy in improving corneal healing and visual outcome in bacterial and fungal keratitis (low-quality evidence). Further adequately powered, high-quality RCTs are required to ascertain its therapeutic potential, particularly for herpetic and Acanthamoeba keratitis. Future standardization of the core outcome set in IK-related trials would be invaluable.

Antimicrobial Activity of Human Fetal Membranes: From Biological Function to Clinical Use

The fetal membranes provide a supportive environment for the growing embryo and later fetus. Due to their versatile properties, the use of fetal membranes in tissue engineering and regenerative medicine is increasing in recent years. Moreover, as microbial infections present a crucial complication in various treatments, their antimicrobial properties are gaining more attention. The antimicrobial peptides (AMPs) are secreted by cells from various perinatal derivatives, including human amnio-chorionic membrane (hACM), human amniotic membrane (hAM), and human chorionic membrane (hCM). By exhibiting antibacterial, antifungal, antiviral, and antiprotozoal activities and immunomodulatory activities, they contribute to ensuring a healthy pregnancy and preventing complications. Several research groups investigated the antimicrobial properties of hACM, hAM, and hCM and their derivatives. These studies advanced basic knowledge of antimicrobial properties of perinatal derivatives and also provided an important insight into the potential of utilizing their antimicrobial properties in a clinical setting. After surveying the studies presenting assays on antimicrobial activity of hACM, hAM, and hCM, we identified several considerations to be taken into account when planning future studies and eventual translation of fetal membranes and their derivatives as antimicrobial agents from bench to bedside. Namely, (1) the standardization of hACM, hAM, and hCM preparation to guarantee rigorous antimicrobial activity, (2) standardization of the antimicrobial susceptibility testing methods to enable comparison of results between various studies, (3) investigation of the antimicrobial properties of fetal membranes and their derivatives in the in vivo setting, and (4) designation of donor criteria that enable the optimal donor selection. By taking these considerations into account, future studies will provide crucial information that will enable reaching the optimal treatment outcomes using the fetal membranes and their derivatives as antimicrobial agents.

Human amniotic membrane as a delivery vehicle for stem cell-based therapies

Stem cell-based therapy is known as a regenerative approach for a variety of diseases and tissue injuries. These cells exert their therapeutic effects through paracrine secretions namely extracellular vesicles. To achieve higher therapeutic potential, a variety of delivery routes have been tested in clinical and preclinical studies. Direct cell injection, intra-venous administration, and intra-arterial infusion are widely used methods of stem cells delivery but these methods are associated with several complications. As one of the most popular biological delivery systems, amniotic membrane has been widely utilized to support cell proliferation and differentiation therefore facilitating tissue regeneration without endangering the stem cells' viability. It is composed of several extracellular matrix components and growth factors. Due to these characteristics, amniotic membrane can mimic the stem cell's niche and can be an ideal carrier for stem cell transplantation. Here, we provide an overview of the recent progress, challenges, and future perspectives in the use of amniotic membrane as a delivery platform for stem cells.

Efficacy of Amniotic Membrane Transplantation for the Treatment of Corneal Ulcers

PURPOSE

To evaluate the outcome of amniotic membrane transplantation (AMTX) as a treatment for corneal ulcers.

METHODS

Patients treated with AMTX for refractory corneal ulcers between 2012 and 2017 were evaluated in a retrospective analysis. Primary outcome measure was complete reepithelialization.

RESULTS

A total of 149 patients were included (mean age 68 ± 18 years). The mean duration between ulcer onset and AMTX was 42 ± 46 days. The longest time between ulcer diagnosis and AMTX was found in bacterial ulcers and the shortest time to AMTX in eyes with trauma/chemical burns (mean 65 ± 15 days and 14 ± 4 days, respectively). In 70% of the patients, a single AMTX procedure was sufficient to achieve epithelial closure (21% <1 month, 40% within 1 -3 months, and 9% within 3-6 months). Treatment failure was observed in 30% of all patients, and most of them underwent further interventions. Highest closure rates were found in bacterial ulcers, herpetic ulcers, and neurotrophic ulcers (80%, 85%, and 93%, respectively), whereas the lowest reepithelialization rates were found in ulcers after corneal surgery and ulcers associated with rheumatic disease (52% and 57%, respectively).

CONCLUSIONS

AMTX is a valuable treatment option to achieve corneal epithelial wound healing in cases refractory to conventional treatment. Success rates differ depending on the etiology of ulcer.

Biocompatibility improvement of artificial cornea using chitosan-dextran nanoparticles containing bioactive macromolecules obtained from human amniotic membrane

Corneal transplantation, by which the damaged cornea is replaced by a new one, suffers from limited access to HLA-compatible-donors and high maintenance and surgical costs. Therefore, artificial corneas are considered as alternative tools with promising prospects. In our previous study, a two-part-polymeric artificial cornea was composed of enhanced hydrophilic surface electrospun poly(ε-caprolactone) nanofibrous scaffold that is thermally connected to a polyvinyl alcohol-based hydrogel disk was prepared. Characterization tests revealed the prepared artificial cornea had similar biocompatible and structural characteristics regarding the natural cornea. In current study, human amniotic membrane extract containing growth factors, cytokines, anti-inflammatory factors, and anti-angiogenic factors was prepared, nano-encapsulated in chitosan-dextran nanoparticles, and physically decorated on the poly(ε-caprolactone)-polyvinyl-alcohol artificial cornea. Physicochemical and biological characterizations revealed the nano-decorated artificial cornea has more biocompatibility than the unmodified one. Our study demonstrated the bioactive macromolecules loaded on chitosan-dextran nanoparticles enhanced the anti-angiogenic property of artificial cornea through the sustained release of anti-angiogenic factors such as thrombospondin-1, endostatin, and heparin sulfate proteoglycan. Real-time-PCR and flow-cytometry assessments elucidated the vascularization was inhibited through a decrease in the expression of cluster of differentiation 31 and von-Willebrand-Factor. Our study proposed the use of biocompatible artificial cornea could be a promising strategy in corneal transplantation.

Insights on the Human Amniotic Membrane in Clinical Practice with a Focus on the New Applications in Retinal Surgery

Recently, the use of the human amniotic membrane (hAM) has been extended to treat retinal disorders such as refractory macular holes, retinal breaks and dry and wet age-related macular degeneration. Not only the hAM has proved to be an excellent tool for repairing retinal tissue, but it has also shown a promising regeneration potential. This review aims to highlight the novel use of the hAM in treating retinal diseases. Although the hAM has been used in the ocular anterior segment reconstruction for more than 60 years, in the last 2 years, we have found in literature articles showing the use of the hAM in the retinal surgery field with interesting results in terms of tissue healing and photoreceptor regeneration.

Novel Method of Plugging the Hole: Anatomical and Functional Outcomes of Human Amniotic Membrane-Assisted Macular Hole Surgery

Purpose:

To describe the surgical outcomes of macular holes (MHs) by inserting a human amniotic membrane (hAM) plug.

Methods:

In this retrospective, interventional, comparative case series, 10 patients who had undergone hAM plugging for a MH were included in the study. Seven patients had idiopathic full-thickness MHs, 1 patient had traumatic MH, and 1 patient each had a MH-induced retinal detachment and combined retinal detachment. The control group included 10 cases with similar configuration and duration of MHs treated with the inverted peeling of the internal limiting membrane technique. All patients underwent a standard 3-port, 25-gauge transconjunctival pars plana vitrectomy and hAM plug transplantation in the subretinal space under the MH. The anatomic and functional outcomes were assessed at 4 weeks postsurgery.

Results:

At the 4-week follow-up visit, all the MHs in the hAM plug group achieved hole closure, whereas 80% of the eyes in the control group were able to achieve hole closure. Improvement of 0.1 logMAR vision was noted in 8 of the 10 patients. At the 4-week follow-up visit, the external limiting membrane and ellipsoid zone layer continuity over the hAM was defined only in one case. No significant difference was found between the hAM plug group and controls in visual and anatomical responses. No complications following hAM transplantation such as rejection, endophthalmitis, or hypotony were noted following surgery.

Conclusion:

Subretinal hAM graft transplantation can be a useful option in the repair of primary or refractory MHs not only for achieving anatomic closure but also for the accompanying visual improvement.

Self-retained cryopreserved amniotic membrane for treating severe corneal ulcers: a comparative, retrospective control study

To compare the effectiveness of self- retained cryopreserved AM as an adjuvant therapy for infectious corneal ulcers. Retrospective, case–control study of 24 eyes of 24 consecutive patients with central and paracentral corneal infectious ulcers and initial visual acuity worse than 20/200. Among them, 11 eyes of 11 patients received additional placement of self-retained cryopreserved AM. Epithelialization and Best Corrected Snellen Visual Acuity (BCSVA) were compared between the two groups. At baseline, both groups had comparable age, gender, visual acuity (VA), size and location of corneal ulcer. Patients receiving additional placement of cryopreserved AM had significantly faster epithelialization within 3.56 ± 1.78 weeks vs 5.87 ± 2.20 weeks (p = 0.01) and achieved complete epithelialization in significantly more patients (72.7% vs 23.1% p = 0.04) despite overall larger baseline defect size (32.7 ± 19.5 mm² vs 21.5 ± 10.7 mm², p = 0.11). Consequently, the AM group had clinically significant BCSVA (> 3 lines) (81.8% vs 38.4%, p = 0.047) and total VA improvement (log MAR 0.7 ± 0.6 vs 1.6 ± 0.9, p = 0.016) compared to the control group at the time of complete epithelialization. In-office sutureless AM may be an effective adjuvant therapy in treating sight-threatening infectious corneal ulcers by promoting faster corneal epithelialization and overall better recovery of the VA.

Surgical alternatives to keratoplasty in microbial keratitis

Penetrating keratoplasty is often required in microbial keratitis not responding to the standard treatments available or the development of complications like corneal perforation. Performing keratoplasty in microbial keratitis has several challenges, the major ones being the availability of donor corneal tissue and the poor success of the corneal graft performed in such a setting. For overcoming these challenges, several alternatives to keratoplasty have been described. Broadly, these options could be categorized into autologous tissues such as conjunctival and tenon tissue, synthetic products like tissue adhesives and therapeutic contact lenses, or biological tissues like amniotic membrane graft. These alternative modalities are not universal. They have their specific indications in microbial keratitis. Most of these alternatives are useful only for small corneal perforations. While autologous tissues are cost-effective and readily available, lack of tectonic support is a significant limitation. Tissue adhesives are excellent alternatives in terms of tectonic support, but surface irregularity and tissue reaction are their potential limitations. The amniotic membrane is useful for small corneal perforations, but availability, cost, and poor tectonic support restrict its use. Herein, we discuss these various alternatives to keratoplasty in microbial keratitis, their indications, advantages, disadvantages, and the various techniques of performing these procedures.

Validation and assessment of an antibiotic-based, aseptic decontamination manufacturing protocol for therapeutic, vacuum-dried human amniotic membrane

Amniotic membrane (AM) is used to treat a range of ophthalmic indications but must be presented in a non-contaminated state. AM from elective caesarean sections contains natural microbial contamination, requiring removal during processing protocols. The aim of this study was to assess the ability of antibiotic decontamination of AM, during processing by innovative low-temperature vacuum-drying. Bioburden of caesarean section AM was assessed, and found to be present in low levels. Subsequently, the process for producing vacuum-dried AM (VDAM) was assessed for decontamination ability, by artificially loading with Staphylococcus epidermidis at different stages of processing. The protocol was highly efficient at removing bioburden introduced at any stage of processing, with antibiotic treatment and drying the most efficacious steps. The antibacterial activity of non-antibiotic treated AM compared to VDAM was evaluated using minimum inhibitory/biocidal concentrations (MIC/MBC), and disc diffusion assays against Meticillin-resistant Staphylococcus aureus, Meticillin-resistant S. epidermidis, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis. Antibacterial activity without antibiotic was low, confirmed by high MIC/MBC, and a no inhibition on agar lawns. However, VDAM with antibiotic demonstrated effective antibacterial capacity against all bacteria. Therefore, antibiotic decontamination is a reliable method for sterilisation of AM and the resultant antibiotic reservoir is effective against gram-positive and –negative bacteria.

Effectiveness of Cryopreserved Amniotic Membrane Transplantation in Corneal Ulceration: A Meta-Analysis

PURPOSE

To evaluate the effectiveness of cryopreserved amniotic membrane transplantation (AMT) in corneal ulceration.

METHODS

The following electronic databases were searched: PubMed, EMBASE, and Cochrane Library. We evaluated the corneal epithelium healing rate (CEHR) and vision improvement rate (VIR) after AMT in the treatment of corneal ulceration. We analyzed the differences in the CEHR and VIR between the 2 groups of infective and noninfective corneal ulcerations. Subgroup analysis for the CEHR and VIR was performed based on the surgical methods. There were 3 subgroups: single-layered inlay, multilayered inlay, and sandwich (SAN). The differences were tested by referring to the Cochrane Handbook. Pooled estimates were determined with STATA software, version 15.

RESULTS

Eighteen eligible studies reporting the outcomes in 390 eyes of 385 patients were included. The results of the meta-analysis showed that the pooled CEHR was 97% (I = 37.9%, 95% confidence interval: 0.94-0.99, P = 0.089). The pooled VIR was 53% (I = 68.1%, 95% confidence interval: 0.42-0.65, P < 0.001). There were no significant differences in either the CEHR or the VIR between the 2 groups of infective and noninfective corneal ulcerations. Among the 3 subgroups of single-layered inlay, multilayered inlay, and SAN, the differences in both CEHR and VIR were statistically significant.

CONCLUSIONS

Consistent with many published reports, this meta-analysis also concluded that AMT was effective in the treatment of corneal ulceration. The curative effect of AMT was not different between the infective and noninfective corneal ulcerations. The differences in both CEHR and VIR were statistically significant among the subgroups.

<em>Acanthamoeba</em> keratitis: a challenge in diagnosis and the role of amniotic membrane transplant as an alternative therapy

Acanthamoeba keratitis (AK) is a very rare, sight-threatening corneal disease caused by the infection of a free-living amoeba. The aim of this report was to demonstrate the challenges in the diagnosis of AK with an atypical presentation. Amniotic membrane transplantation (AMT) was done in this case to accelerate wound healing. A woman who frequently used contact lens came with redness and a whitish spot in her left eye 2 weeks before admission. There was a history of rinsing contact lens in tap water. The patient had already been on a topical steroid for 2 weeks. Visual acuity of the left eye was light perception with wrong projection. Examination of the left cornea showed a semi-circular central ulcer with a 5.8-mm area and 1/3 stromal depth. It is surrounded by a feathery-edge infiltrate with positive satellite lesions but without hypopyon. It was diagnosed as corneal ulcers due to mixed infection (bacteria and fungi). After 2 weeks of bacterial and fungal therapy, the size of the ulcer decreased, but the corneal infiltrate remained; therefore, an Acanthamoeba culture was done to determine the possibility of Acanthamoeba infection. Two weeks after the Acanthamoeba topical therapy, the visual acuity improved. AMT was performed to accelerate wound healing. Two months post-AMT, visual acuity improved to 1/60 with no conjunctival or ciliary vasodilation, and the ulcer was resolved. The patient was planned to undergo keratoplasty. The diagnosis of AK with an atypical presentation is challenging. AMT can be used as an alternative therapy to accelerate wound healing.

Corneal Cross-Linking Window Absorption (CXL-WA) as an Adjuvant Therapy in the Management of Aspergillus niger Keratitis

PURPOSE

To evaluate the effectiveness of corneal cross-linking window absorption (CXL-WA) as an adjuvant therapy for Aspergillus keratitis.

METHODS

A 90-year-old male came to our clinic complaining of hyperemic conjunctivitis and progressive visual loss in the right eye. Slit-lamp examination showed keratic precipitates, severe corneal opacity, and stromal edema. Corneal scraping culture was positive for Aspergillus niger. Because the clinical condition did not sufficiently improve with antifungal therapy, the patient underwent CXL-WA as an adjuvant therapy.

RESULTS

During the first week after treatment, the Tyndall effect, corneal edema, and signs of ocular inflammation progressively lessened. At the third postoperative month, the cornea was stable without signs of fungal keratitis. However, after this period, a descemetocele appeared in the cornea (2 × 2 mm in diameter), so the patient underwent a corneal penetrating keratoplasty. Histological evaluation of the removed corneal tissue revealed the presence of hyphae and fungal infection.

CONCLUSIONS

We reported a case of in vivo CXL-WA used as an adjuvant therapy for deep stromal Aspergillus keratitis. CXL did not completely eradicate the fungal infection which caused perforation 4 months after treatment and it still cannot be considered a definitive solution to mycotic keratitis, which maintains a poor long-term prognosis.

Amniotic Membrane Transplantation in Reconstructive and Regenerative Ophthalmology

Background

The goal of this study was to investigate numbers, indications, surgical techniques, and experiences of amniotic membrane transplantation at the University Eye Hospital Tübingen over the last 16 years.

Material/Methods

Data from all amniotic membrane transplantations from January 2001 to December 2016 were retrospectively analyzed. Data was accessed from the electronic database and the annual reports of the Eye Bank at the University Eye Hospital Tübingen.

Results

A total of 771 amniotic membrane transplantations were performed between 2001 and 2016 at the University Eye Hospital Tübingen. The mean number of amniotic membrane transplantations was 48 per year (range: 7–81). Overall, the mean number of amniotic membrane transplantations more than doubled, from 31 amniotic membrane transplantations per year during the first 8-year period to 66 amniotic membrane transplantations per year during the second 8-year period (p<0.0001). The most common surgical indications for amniotic membrane transplantation were corneal ulcers and persistent corneal epithelial defects. The inlay, overlay, and sandwich technique became the favored surgical methods for various disorders of the ocular surface.

Conclusions

Our study showed a significant increase of amniotic membrane transplantations from 2001 to 2016. This increase is likely influenced by the introduction of different surgical amniotic membrane transplantation techniques, the rising knowledge about containing growth factors, neurotrophins and cytokines, and the demographic change with aging of the population.

Self-Retained Amniotic Membrane Combined With Antiviral Therapy for Herpetic Epithelial Keratitis

PURPOSE

To evaluate the therapeutic benefit of self-retained cryopreserved amniotic membrane in conjunction with oral antiviral therapy in herpetic epithelial keratitis.

METHODS

Retrospective review of 4 patients with primary (1 eye) and recurrent (3 eyes) unilateral herpetic epithelial keratitis treated with cryopreserved amniotic membrane through the placement of the PROKERA Slim (PKS) (Bio-Tissue, Inc) in conjunction with oral acyclovir. Their symptoms, conjunctival inflammation, corneal staining, and visual acuity were compared before and after treatment.

RESULTS

Herpetic epithelial keratitis presented as dendritic (3 eyes) and geographic (1 eye) epithelial lesions. After epithelial debridement and placement of the PKS for 5 ± 3.7 days, all patients reported significant relief of symptoms, rapid corneal epithelialization, and reduction of ocular surface inflammation. The visual acuity was also improved in all eyes from 0.7 ± 0.7 to 0.4 ± 0.7 logarithm of the minimum angle of resolution (P = 0.2). They remained symptom-free during a follow-up period of 2.7 to 50.8 (20.3 ± 21.7) months.

CONCLUSIONS

The PKS in conjunction with oral acyclovir facilitates the ease of early intervention to accelerate restoration of a normal corneal epithelium in herpetic epithelial keratitis.

A self-assembled clavanin A-coated amniotic membrane scaffold for the prevention of biofilm formation by ocular surface fungal pathogens

Amniotic membrane (AM) is frequently used in ophthalmologic surgery for rapid ocular surface reconstruction. Sometimes it may create a major problem with associated infections after biofilm formation over the membrane. To overcome this problem, AM was coated with the antimicrobial peptide clavanin A. The antifungal activity of clavanin A in the native and self-assembled form was determined against the common ocular surface pathogens Candida albicans, Aspergillus fumigatus, Alternaria sp. and Fusarium sp. Biofilm formation over the coated surface was significantly reduced in comparison with the uncoated membrane. The coated membrane revealed effectiveness in terms of biocompatibility, cell attachment colonization when tested in non-cancerous 3T3 and human embryonic kidney (HEK)-293 cell lines. Clavanin A-coated AM also exhibited excellent physical, morphological and antifungal characteristics, indicating potential applicability for ocular surface infection control.

A stepping stone in treating dendritic keratitis

PURPOSE

To report the outcome of self-retained amniotic membrane after debridement in recurrent dendritic keratitis.

OBSERVATIONS

A 70-year-old female with a recurrent dendritic corneal ulcer received debridement followed by placement of self-retained amniotic membrane. Five days after treatment, the patient experienced a complete resolution of symptoms, marked reduction of inflammation, complete re-epithelialization of the cornea and improvement of visual acuity. The corneal surface remained stable for 18 months despite noncompliance in using antiviral therapy.

CONCLUSIONS AND IMPORTANCE

Self-retained amniotic membrane after debridement appears effective in treating dendritic keratitis. While early debridement is crucial to remove the infected corneal epithelium, amniotic membrane was shown to enhance the healing without scarring or recurrence. Besides the known anti-inflammatory and anti-scarring effects of the amniotic membrane, it may have a potential topical antiviral effect that warrants further investigation.

Human amniotic membrane as newly identified source of amniotic fluid pulmonary surfactant

Pulmonary surfactant (PS) reduces surface tension at the air-liquid interface in the alveolar epithelium of the lung, which is required for breathing and for the pulmonary maturity of the developing foetus. However, the origin of PS had never been thoroughly investigated, although it was assumed to be secreted from the foetal developing lung. Human amniotic membrane (hAM), particularly its epithelial cell layer, composes the amniotic sac enclosing the amniotic fluid. In this study, we therefore aimed to investigate a potential contribution of the cellular components of the hAM to pulmonary surfactant found in amniotic fluid. We identified that cells within the native membrane contain lamellar bodies and express all four surfactant proteins as well as ABCA3. Lipidomic profiling by nanoESI – MS/MS revealed the presence of the essential lipid species as found in PS. Also, the biophysical activity of conditioned cell culture supernatant obtained from hAM was tested with captive bubble surfactometry. hAM supernatant showed the ability to reduce surface tension, similar to human PS obtained from bronchoalveolar lavage. This means that hAM produces the essential PS-associated components and can therefore contribute as second potential source of PS in amniotic fluid aside from the foetal lung.

Amniotic membrane in ophthalmology: properties, preparation, storage and indications for grafting-a review

The use of amniotic membrane in ophthalmic surgery and other surgical procedures in the fields of dermatology, plastic surgery, genitourinary medicine and otolaryngology is on the increase. Furthermore, amniotic membrane and its epithelial and mesenchymal cells have broad use in regenerative medicine and hold great promise in anticancer treatment. Amniotic membrane is a rich source of biologically active factors and as such, promotes healing and acts as an effective material for wound dressing. Amniotic membrane supports epithelialization and exhibits anti-fibrotic, anti-inflammatory, anti-angiogenic and anti-microbial features. Placentas utilised in the preparation of amniotic membrane are retrieved from donors undergoing elective caesarean section. Maternal blood must undergo serological screening at the time of donation and, in the absence of advanced diagnostic testing techniques, 6 months postpartum in order to cover the time window for the potential transmission of communicable diseases. Amniotic membrane is prepared by blunt dissection under strict aseptic conditions, then is typically transferred onto a nitrocellulose paper carrier, usually with the epithelial side up, and cut into multiple pieces of different dimensions. Amniotic membrane can be stored under various conditions, most often cryopreserved in glycerol or dimethyl sulfoxide or their mixture with culture medium or buffers. Other preservation methods include lyophilisation and air-drying. In ophthalmology, amniotic membrane is increasingly used for ocular surface reconstruction, including the treatment of persistent epithelial defects and non-healing corneal ulcers, corneal perforations and descemetoceles, bullous keratopathy, as well as corneal disorders with associated limbal stem cell deficiency, pterygium, conjunctival reconstruction, corneoscleral melts and perforations, and glaucoma surgeries.

Excisional keratectomy combined with focal cryotherapy and amniotic membrane inlay for recalcitrant filamentary fungal keratitis: A retrospective comparative clinical data analysis

The aim of the present study was to investigate the efficacy of a novel surgical intervention, excisional keratectomy combined with focal cryotherapy and amniotic membrane inlay (EKCAI), for the treatment of recalcitrant filamentary fungal keratitis. A retrospective analysis was performed of patients who underwent excisional keratectomy combined with conjunctival flap inlay (EKCFI), EKCAI or therapeutic penetrating keratoplasty (TPK) from January 2006 to January 2011. Recalcitrance was determined as being unresponsive to standard medical antifungal therapy for at ≥1 week. Outcome measures among the three intervention modalities were compared. A total of 128 patients had a follow-up of ≥1 year after the primary intervention. The success rates of interventions at 1-year follow-up were 58.33% in the EKCFI group, 88.37% in the EKCAI group and 93.44% in the TPK group (P<0.0002). The preoperative visual acuity of the three groups were similar (P=0.6458), while the postoperative best-corrected visual acuity (BCVA) of patients without recurrence was significantly different among the three groups 3 months after surgery. The best postoperative BCVA was found in the TPK group, while the worst was in the EKCFI group. In conclusion, EKCAI does not require donor cornea, is straightforward surgically, and has a favorable success rate compared with EKCFI.

Long-term Outcomes of Amniotic Membrane Transplantation in Contact Lens-Induced Pseudomonas Keratitis with Impending Corneal Perforation

Purpose:

To report the anatomical and visual outcomes of double layered amniotic membrane transplantation (AMT) in eyes with advanced Pseudomonas keratitis leading to Descemetocele formation.

Methods:

This prospective interventional case series included 6 eyes of 6 female patients with pseudomonas keratitis caused by contact lens-induced infection who underwent double layered AMT. Surgery was performed after the ulcers were found to be poorly responsive to antibiotics, and severe thinning or Descemetocele had developed. All patients underwent a complete examination pre- and postoperatively, as well as anterior segment optical coherence tomography (OCT) and pachymetry or Orbscan after the procedure.

Results:

Mean follow-up period was 24 months. There was neither frank corneal perforation nor a need for emergent corneal transplantation in any of the eyes. All patients had visual acuity of hand motions before the procedure which improved to 20/50 to 20/30 three months after surgery. No surgical or postoperative complication occurred in this series.

Conclusion:

Double layered AMT may result in acceptable anatomical outcomes in patients with advanced Pseudomonas keratitis with Descemetocele formation and can eliminate the need for emergent corneal transplantation.

Established and emerging ancillary techniques in management of microbial keratitis: a review

Microbial keratitis is a sight-threatening condition and an ocular emergency, because of the potential for rapid progression. Intensive topical antimicrobials are the mainstay and the gold standard of treatment for microbial keratitis. However, despite appropriate diagnosis and therapy, treatment failure is still common, and can result in significant morbidity due to corneal perforation and/or scarring. For this reason, clinicians continue to seek novel treatment techniques in order to expand the armamentarium of tools available to manage microbial keratitis, and in doing so improve clinical outcomes. In this review, we examine the evidence for some established, as well as a few emerging ancillary techniques used to manage microbial keratitis. These include topical corticosteroids, corneal collagen cross-linking, intrastromal antimicrobials, amniotic membrane transplantation and miscellaneous other techniques. Of these, collagen cross-linking shows some promise for selected cases of infectious keratitis, although more research in the area is required before it is accepted as mainstream treatment for this potentially blinding condition.

Amniotic Membrane Transplantation for the Treatment of Infectious Ulcerative Keratitis Before Elective Penetrating Keratoplasty

PURPOSE

Emergency keratoplasties for inflamed eyes are considered to have a worse prognosis because of immunologic graft rejection. Amniotic membranes have antiinflammatory and antiangiogenic abilities. Therefore, amniotic membrane transplantation (AMT) was performed to stabilize the situation of eyes with severe infectious keratitis before elective penetrating keratoplasty (PK).

METHODS

Retrospective, nonrandomized observational case series. Seven to 41 days (median, 20 days) after the onset of intensive antiinfectious medication, an AMT (6 multigrafts and 6 sandwich) was performed in 12 patients [8 men and 4 women; age 46-80 years (median, 66 years)] with herpetic (n = 5), bacterial keratitis (n = 3), or combinations (n = 4). Three to 12 months (median, 5 months) after cessation of the inflammatory status of the eye, a central elective PK (diameter, 7-8 mm) became feasible in 10 eyes. Follow-up ranged from 4 to 38 months (median, 20 months) after PK.

RESULTS

The primary success rate of AMT was 11/12 (92%). Five recurrences (41%) were treated successfully 4 times by repeat AMT (sandwich) and 1 time by emergency PK. In 2 of the 12 eyes, an irreversible endothelial immunologic graft reaction appeared 18 and 21 months after PK. One eye suffered from reversible recurrence of herpetic keratitis on the corneal graft. At the end of the follow-up, 10 of 12 grafts (83%) were clear.

CONCLUSIONS

A rapid decrease in the inflammatory reaction and a fast reepithelialization because of AMT after intensive antiinfectious medication in case of severe ulcerative keratitis may help to avoid an emergency keratoplasty and improves the prognosis of the elective keratoplasty.

Regulatory Impact of Amniotic Membrane Transplantation on Presence of Adhesion/Growth-Regulatory Galectins-1 and -7 in Corneal Explants from Acanthamoeba Keratitis Patients: Clinical Note

PURPOSE

To assess the impact of Acanthamoeba keratitis (AK) and amniotic membrane transplantation (AMT) in corneal explants on presence of two multifunctional endogenous lectins, i.e. galectins-1 and -7.

METHODS

Ten corneal explants from AK patients (five with previous AMT and five controls without this treatment) and seven specimens of disease-free control cornea were processed by indirect fluorescent immunohistochemistry.

RESULTS

Immunostaining for both galectins was obtained in the epithelium, stroma and the endothelial layer of all controls, with the strongest positivity in the epithelium. Significantly decreased intensity for galectin-1 was recorded in the epithelium of corneal explants from patients with AK and AMT. The signal for galectin-7 was significantly decreased in the epithelium of AK patients and normalized after AMT.

CONCLUSIONS

AMT has a marked impact on presence of the two galectins in opposite directions, encouraging complete profiling for this family of endogenous effectors.

Long-term efficacy of glycerine-processed amniotic membrane transplantation in patients with corneal ulcer

PURPOSE

The aim of this study was to determine the long-term treatment efficacy of glycerine-preserved human amniotic membrane transplantation in patients suffering from corneal ulcers.

METHODS

This was a retrospective, non-controlled, monocentric analysis. Included were patients with corneal ulcers that were non-responsive to ointment or contact lenses and had been treated by amniotic membrane transplantation with either the overlay or sandwich procedure. Analysis parameters were visual acuity before and following treatment, recurrence rate and subjective comfort at the last follow-up.

RESULTS

Of the 371 amniotic membrane transplantations that were conducted, 135 surgical treatments in 108 patients (51.9% male, 48.1% female; mean age 63.7 years) met the inclusion criteria. In total, 99 overlay and 36 multilayer amniotic membrane transplantations were performed. The follow-up period was 47.5 ± 66.7 weeks (mean ± SD). The recurrence rate at the last follow-up was 47.8% with overlay membranes and 51.8% with the sandwich technique. There was no significant change in best-corrected visual acuity following treatment with overlays (p = 0.219) or sandwich procedure (p = 0.703). At the last follow-up, 72.1% (overlay) and 78.3% (sandwich) of the patients reported either no pain or increased comfort.

CONCLUSION

The recurrence rates and changes in visual acuity following overlay or sandwich amniotic membrane transplantation in patients suffering from corneal ulcer were lower than reported elsewhere in the literature. More than half of the patients profited from each of the amniotic membrane transplantation techniques with respect to recurrence and postoperative comfort.

Amniotic membrane covering promotes healing of cornea epithelium and improves visual acuity after debridement for fungal keratitis

AIM

To investigate the effect of amniotic membrane covering (AMC) on the healing of cornea epithelium and visual acuity for fungal keratitis after debridement.

METHODS

Twenty fungal keratitis patients were divided into two groups randomly, the AMC group and the control group, ten patients each group. Both debridement of the infected cornea tissue and standard anti-fungus drugs treatments were given to every patients, monolayer amniotic membrane were sutured to the surface of the entire cornea and bulbar conjunctiva with 10-0 nylon suture for patients in the AMC group. The diameter of the ulcer was determined with slit lamp microscope and the depth of the infiltration was determined with anterior segment optical coherence tomography. Uncorrected visual acuity (UCVA) was tested before surgery and three month after healing of the epithelial layer. The healing time of the cornea epithelium, visual acuity (VA) was compared between the two groups using t-test.

RESULTS

There was no statistical difference of the diameter of the ulcer, depth of the infiltration, height of the hypopyon and VA between the two groups before surgery (P>0.05). The average healing time of the AMC group was 6.89±2.98d, which was statistically shorter than that of the control group (10.23±2.78d) (P<0.05). The average UCVA of the AMC group was 0.138±0.083, which was statistically better than that of the control group (0.053±0.068) (P<0.05).

CONCLUSION

AMC surgery could promote healing of cornea epithelium after debridement for fungal keratitis and lead to better VA outcome.

Amniotic membrane graft to conjunctival flap in treatment of non-viral resistant infectious keratitis: a randomised clinical study

PURPOSE

To evaluate and compare the results of bipedicle conjunctival flap (CF) and cryopreserved amniotic membrane graft (AMG) in the treatment of non-viral infectious keratitis resistant to medical treatment.

METHODS

This prospective randomised interventional study included 40 eyes of 40 patients with resistant non-viral infectious keratitis. Twenty eyes received CF and 20 eyes received AMG. In the CF group, there were 12 eyes with fungal keratitis, 7 eyes with bacterial keratitis and 1 eye with Acanthamoeba keratitis. In the AMG group there were 13 eyes with fungal keratitis, 5 eyes with bacterial keratitis and 2 eyes with Acanthamoeba keratitis. In the CF group, three ulcers had descemetocele and four ulcers were perforated. In the AMG group, four ulcers had descemetocele and two ulcers were perforated. In CF, 360° peritomy was done and a bipedicle CF from the upper conjunctiva was dissected from Tenon's capsule, mobilised to cover the cornea and sutured to episclera. In AMG, one or two layers of AM were trimmed to fit the ulcer and sutured to the cornea. The follow-up period was 6 months.

RESULTS

Successful results were observed in 18/20 eyes (90%) in each group. Postoperatively, no significant differences between the two groups were found regarding success rate (p=1.0), epithelialisation time (p=0.75) or visual acuity improvement (p=0.84).

CONCLUSIONS

CF and AMG are effective in treatment-resistant infectious keratitis. They could restore ocular surface integrity and provide metabolic and mechanical support for corneal healing. For large corneal perforation, it may be better to use another procedure such as penetrating keratoplasty to restore ocular integrity.

Treatment of an 8-mm myxoma using acellular corneal tissue

A myxoma is a benign tumor found in the heart and in various soft tissues; however, a corneal myxoma is rare. A mucinous mass of unknown etiology was observed on the left cornea of a 32-year-old male patient. We performed deep anterior lamellar keratoplasty using acellular corneal tissue and concurrent amniotic membrane transplantation. Hematoxylin and eosin staining revealed vacuolation of the parenchyma and myxoid change in the corneal tissue that occurred in the anterior half of the corneal parenchyma. We identified a myxoid stroma by Alcian blue staining and observed collagen fibers with denatured stroma by Masson trichrome staining. The patient's visual acuity improved from light perception to 20 / 200, and the intraocular pressure remained within the normal range for one year after surgery. The transplanted cornea survived successfully with well-maintained transparency, and recurrence was not observed one year after surgery.