Amniotic Membrane Transplantation in Severe Bacterial Keratitis

Restoring the Ocular Integrity of Perforated Corneal Ulcer Using Living Surgical Donor Tissues Derived From Keratoplasty in the COVID-19 Pandemic

The coronavirus disease 2019 (COVID-19) caused an unprecedented crisis for corneal surgeons who were forced to strategize for an acute shortage of tissues. Here, we report the initial clinical outcomes of utilizing host corneal buttons derived from optical penetrating keratoplasties of pseudophakic bullous keratoplasty (PBK) patients. Two patients presented to our department with a perforated fungal corneal ulcer in one eye during the COVID-19 pandemic. One eye of each of the patients was operated on with non-vascularized host cut tissues preserved in glycerin. The tissues were secured using 10-0 nylon sutures. Good anatomical integrity was achieved in both eyes. An optical penetrating keratoplasty (PK) was done in both eyes after one year for visual rehabilitation, with a final visual acuity of 20/120 and 20/80, respectively, at six months. In conclusion, therapeutic PK using host tissues obtained from the recipients of optical PK is a safe and effective option to restore ocular integrity during a shortage of fresh or glycerol-preserved corneas. However, optical PK is required for the final visual rehabilitation.

Surgical management of infectious keratitis

The successful management of infectious keratitis is usually achieved with a combination of tools for accurate diagnosis and targeted timely antimicrobial therapy. An armamentarium of surgical interventions is available in the acute stage which can be resorted to in a step wise manner or in combination guided by the response to treatment. Simple surgical modalities can facilitate accurate diagnosis e.g. corneal biopsy and alcohol delamination. Surgery to promote epithelial healing can vary from tarsorrhaphy, amniotic membrane transplantation or conjunctival flaps depending on the extent of infection, visual prognosis, availability of tissue and surgeon's experience. Collagen crosslinking has been increasingly utilized with successful results to strengthen the cornea and reduce the infective load consequently the need for further elaborate surgical interventions. It has shown encouraging results specially in superficial bacterial and fungal keratitis but for deeper infections, viral and acanthamoeba keratitis, its use remains questionable. When globe integrity is compromised, corneal gluing is the most commonly used procedure to seal small perforations. In larger perforations/fulminant infections a tectonic/therapeutic graft is advisable. Partial thickness grafts are increasingly popular to treat superficial infection or internally tamponade perforations. Peripheral therapeutic grafts face challenges with potential requirement for a manually fashioned graft, and increased risk of rejection due to proximity to the limbal vessels. Late stage visual rehabilitation is likely to require further surgical interventions after complete resolution of infection and inflammation. A preliminary assessment of corneal sensation and integrity of the ocular surface are key for any successful surgical intervention to restore vision.

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.

Bacterial keratitis: identifying the areas of clinical uncertainty

Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.

Amniotic Membrane Transplantation for Persistent Epithelial Defects and Ulceration due to Pseudomonas Keratitis in a Rabbit Model

Purpose

The use of amniotic membrane has been suggested in the treatment of infectious keratitis for its intrinsic anti-infective properties probably mediated by its anti-inflammatory effects. The aim of this study was to investigate the effect of amniotic membrane transplantation (AMT) along with ciprofloxacin to cure the primary stages of Pseudomonas keratitis.

Methods

In total, 28 rabbits were selected and divided in four groups as follows: group 1 as control, group 2 with amniotic membrane, group 3 with ciprofloxacin, and group 4 with amniotic membrane combined with ciprofloxacin. About 0.05 cc suspension of Pseudomonasaeruginosa, 27853 ATCC was injected into corneal stroma.

Results

The results showed groups of AMT, AMT + ciprofloxacin, and ciprofloxacin had 0% perforation while the control group had 85.6%. Average infiltration of 5.5 mm was observed in ciprofloxacin group, 5 mm in AMT + ciprofloxacin group, 24 mm in AMT group, and finally 23.75 mm for control. Amniotic membrane showed to be effective in prevention of cornea perforation as well as remission of Pseudomonas keratitis. There was no significant difference between ciprofloxacin groups in comparison with ciprofloxacin + AMT group. However, regarding the anti-inflammatory effect, the process of improvement of inflammation in ciprofloxacin + AMT group was faster.

Conclusion

Transplantation of amniotic membrane in the primary stages of Pseudomonas keratitis treatment remarkably prevents the disease and it can be used to control its process.

Sutureless fixation of amniotic membrane using a soft ring for ocular surface diseases

PURPOSE

To evaluate the efficacy of sutureless amniotic membrane transplantation using a soft bioavailable ring in the management of ocular surface disorders.

METHODS

We present a modified technique using a soft, special designed bioavailable ring set (Amnioring) for sutureless amniotic membrane fixation to the ocular surface. A fresh amniotic membrane with a diameter greater than the outside diameter of the ring was folded inwardly over the ring such that the inner side of the ring was covered with the amniotic membrane. The ring was inserted onto the ocular surface.

RESULTS

The ring was inserted in 4 eyes of 4 consecutive patients with ocular surface disorders. The mean total operating time was 3 min. The ring fixated the amniotic membrane to the bulbar conjunctiva and provided a quick and easy sutureless placement of amniotic membrane. In all cases, pain was significantly relieved. The corneal epithelial defect and inflammation were markedly reduced.

CONCLUSIONS

This novel ring designed for sutureless placement of amniotic membrane provided very good anatomic and functional outcomes in patients with ocular surface disorders. It is less invasive, less time consuming and allows placement in the office conditions with low cost.

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.

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.

12-year analysis of incidence, microbiological profiles and in vitro antimicrobial susceptibility of infectious keratitis: the Nottingham Infectious Keratitis Study

BACKGROUND/AIMS

To examine the incidence, causative microorganisms and in vitro antimicrobial susceptibility and resistance profiles of infectious keratitis (IK) in Nottingham, UK.

METHODS

A retrospective study of all patients who were diagnosed with IK and underwent corneal scraping between July 2007 and October 2019 (a 12-year period) at a UK tertiary referral centre. Relevant data, including demographic factors, microbiological profiles and in vitro antibiotic susceptibility of IK, were analysed.

RESULTS

The estimated incidence of IK was 34.7 per 100 000 people/year. Of the 1333 corneal scrapes, 502 (37.7%) were culture-positive and 572 causative microorganisms were identified. Sixty (4.5%) cases were of polymicrobial origin (caused by ≥2 different microorganisms). Gram-positive bacteria (308, 53.8%) were most commonly isolated, followed by Gram-negative bacteria (223, 39.0%), acanthamoeba (24, 4.2%) and fungi (17, 3.0%). Pseudomonas aeruginosa (135, 23.6%) was the single most common organism isolated. There was a significant increase in Moraxella spp (p<0.001) and significant decrease in Klebsiella spp (p=0.004) over time. The in vitro susceptibilities of Gram-positive and Gram-negative bacteria to cephalosporin, fluoroquinolone and aminoglycoside were 100.0% and 81.3%, 91.9% and 98.1%, and 95.2% and 98.3%, respectively. An increase in resistance against penicillin was observed in Gram-positive (from 3.5% to 12.7%; p=0.005) and Gram-negative bacteria (from 52.6% to 65.4%; p=0.22).

CONCLUSION

IK represents a relatively common and persistent burden in the UK and the reported incidence is likely underestimated. Current broad-spectrum antimicrobial treatment provides a good coverage for IK, although challenged by some level of antimicrobial resistance and polymicrobial infection.

Amniotic membrane transplantation for infectious corneal ulcer treatment: a cohort retrospective study

BACKGROUND Corneal ulcer is one of the most common causes of corneal blindness. This study aimed to describe the outcomes of amniotic membrane transplantation (AMT) in patients with infectious corneal ulcer. METHODS A retrospective cohort study based on medical records of patients who underwent an adjuvant AMT procedure over a 2-year period (2015–2017) was conducted at Cipto Mangunkusumo Hospital Jakarta. Uncorrected visual acuity (UCVA) was measured with the Snellen chart. Treatment success was marked by complete healing (disappearance of corneal infiltrates, epithelial defect closure, and corneal scar formation). Healing time was the duration from AMT surgery to complete healing. RESULTS 50 cases of infectious corneal ulcer, 12 of which had perforation were included. Gram-positive cocci (18%), gram-negative rods (14%), fungi (4%), and Acanthamoeba (2%) were isolated from culture specimens. Successful results were observed in 90% of cases (20/21 moderate cases and 25/29 severe cases). Healing time was 21 (14–63) days in moderate cases and 28 (14–90) days in severe cases. Baseline UCVA improved from 2.48 (0.22–2.80) logMAR to 1.30 (0–2.80) logMAR within 3–4 weeks postoperatively and to 0.94 (0–2.80) logMAR at the last follow-up. Post-AMT complications included recurrent perforation in 4 eyes, persistent epithelial defects in 2 eyes, amniotic membrane infection in 1 eye, and membrane retraction in 1 eye. CONCLUSIONS AMT was successfully used to treat moderate and severe infectious corneal ulcer, particularly in nonresponsive and some perforated cases. AMT provides biochemical and mechanical support for corneal wound healing with good visual outcomes.

Amniotic Membrane Transplantation in Ophthalmology: An Updated Perspective

Aim

The aim of this paper is to provide a succinct literature review of the different clinical applications for AMT usage in an ophthalmic setting, ranging from commonly used applications to less mainstream approaches. The hope is that this review enables the reader to have a better understanding of the biological properties of amnion as well as the indications and scenarios in which AMT can be used, whilst presenting relevant evidence from within the literature which may be of interest. We also provide an update on the methods of preservation of amniotic membrane and the application methodologies.

Methods

Literature search. A PubMed search was performed using the search terms “amniotic membrane transplant”, “amnion AND cornea”, amnion AND ophthalmology”, “amnion AND ocular surface” and “Amnion AND eye”. A full review of the literature using the PubMed database was conducted up until 01/05/20. The articles used were written in English, with all articles accessed in full. Both review articles and original articles were used for this review. All full publications related to ophthalmology were considered.

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.

Wound healing in the eye: Therapeutic prospects

In order to maintain a smooth optical surface the corneal epithelium has to continuously renew itself so as to maintain its function as a barrier to fluctuating external surroundings and various environmental insults. After trauma, the cornea typically re-epithelializes promptly thereby minimizing the risk of infection, opacification or perforation. A persistent epithelial defect (PED) is usually referred to as a non-healing epithelial lesion after approximately two weeks of treatment with standard therapies to no avail. They occur following exposure to toxic agents, mechanical injury, and ocular surface infections and are associated with significant clinical morbidity in patients, resulting in discomfort or visual loss. In the case of deeper corneal injury and corneal pathology the wound healing cascade can also extend to the corneal stroma, the layer below the epithelium. Although significant progress has been made in recent years, pharmaco-therapeutic agents that promote corneal healing remain limited. This article serves as a review of current standard therapies, recently introduced alternative therapies gaining in popularity, and a look into the newest developments into ocular wound healing.

Umbilical Cord Patch Transplantation for Corneal Perforations and Descemetoceles

PURPOSE

To evaluate the clinical outcome of umbilical cord patch (UCP) transplantation for deep corneal ulcers with perforations and descemetoceles.

METHODS

In this retrospective, noncomparative, interventional case series, 11 eyes of 11 patients with corneal perforation or descemetocele were included. The thickness and microstructure of UCP were measured. All eyes were treated with UCP and amniotic membrane transplantation for corneal reconstruction. Corneal ulcer healing, corneal thickness, anterior chamber formation, and best-corrected visual acuity (BCVA) were recorded and analyzed.

RESULTS

The thickness of human UCP is 398.6 ± 102.8 μm (n = 5) with compact aligned fibers. The average age was 56.2 ± 15.8 (ranging from 22 to 75) years. The mean follow-up period was 7.1 ± 1.7 (ranging from 5 to 10) months. Four patients had descemetocele and 7 had perforation. The anterior chambers in all the 7 perforated corneas were formed at postoperative day 1. All patients regained a normal corneal thickness and smooth corneal surface within the first postoperative month. The vision improved in 10 eyes and remained unchanged in 1 eye. No recurrence nor side effects occurred during the follow-up.

CONCLUSIONS

UCP can serve as an alternative material in the treatment of corneal perforations and descemetoceles. This treatment option is also beneficial in those countries with limited cornea donors and eye bank services.

Adjunctive Therapies for Bacterial Keratitis

Bacterial keratitis is the most common type among all types of infectious keratitis. Currently, antibiotics are the main-stay of treatment. The objective of this systematic review is to review published clinical studies which discuss the adjunctive treatment of bacterial keratitis to guide clinical decision-making. We reviewed the role of a variety of medications and surgeries which can help in managing bacterial keratitis complications, which include as thinning, perforation, and impaired wound healing. We have included appropriate animal and laboratory studies, case reports and case series, and randomized clinical trials regarding each therapy.

Surgical outcomes of perforated and unperforated corneal descemetocele

OBJECTIVE

To compare the surgical outcomes of amniotic membrane transplantation (AMT) and penetrating keratoplasty (PK) in perforated and non-perforated corneal descemetocele.

METHOD

In this study, we retrospectively examined 48 eyes of 48 patients operated with AMT, and 32 eyes of 32 patients operated with PK for perforated and non-perforated descemetocele.

RESULTS

There were no significant differences between the two groups with regard to age, sex, laterality, follow-up duration, cause of descemetocele, and localization (p > 0.05). Thirty-six (75%) eyes in the AMT group and 17 (53.1%) eyes in the PK group were perforated prior to operation (p = 0.043). Surgical success was achieved in 35 (73%) of 48 eyes underwent AMT and 28 (87.5%) of 32 eyes underwent PK (p = 0.118). Perforation size was the only parameter significantly affecting surgical success (AMT p = 0.001, PK p = 0.003). The visual acuity was significantly better at the postsurgical period compared to the presurgical period in both groups (p = 0.003, p < 0.001). It was observed that the postsurgical change in the visual acuity score was significantly greater in the PK group (p = 0.001).

CONCLUSION

Penetrating keratoplasty is superior to AMT for achieving ocular surface integrity and enhancing visual acuity. Amniotic membrane transplantation saves time for patients and surgeons when donor cornea supply is limited and it allows PK to be performed at a quiet period when inflammation is suppressed.

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.

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.

Update on amniotic membrane transplantation

Cryopreserved amniotic membrane modulates adult wound healing by promoting epithelialization while suppressing stromal inflammation, angiogenesis and scarring. Such clinical efficacies of amniotic membrane transplantation have been reported in several hundred publications for a wide spectrum of ophthalmic indications. The success of the aforementioned therapeutic actions prompts investigators to use amniotic membrane as a surrogate niche to achieve ex vivo expansion of ocular surface epithelial progenitor cells. Further investigation into the molecular mechanism whereby amniotic membrane exerts its actions will undoubtedly reveal additional applications in the burgeoning field of regenerative medicine. This article will focus on recent advances in amniotic membrane transplantation and expand to cover its clinical uses beyond the ocular surface.

[Severe bacterial keratitis referred to ophthalmology emergency departments: a retrospective study of 268 cases]

PURPOSE

To investigate epidemiological, microbiological and clinical aspects of severe bacterial keratitis, in order to update current understanding of risk factors (RF) and prognosis.

PATIENTS AND METHODS

We conducted a monocentric retrospective study from January 2005 to January 2011, identifying and collecting data from inpatients admitted for severe documented bacterial keratitis.

RESULTS

We found 268 unilateral corneal ulcers. At least one local or systemic risk factor was identified in 255/268 patients (95%). The leading risk factor was contact lens wear (129/268), followed by underlying corneal disease (50/268) and prior corneal surgery (47/268). Initial and final visual acuities were 0.06 and 0.2 (1.20 and 0.72 LogMAR) respectively. Contact lens wear was associated with better prognosis and shorter hospitalization (P<0.05). Corneal healing was obtained in 255/268 patients (95%), with adjuvant surgery for 33 patients. The most frequently isolated pathogens were Gram+ cocci, more commonly associated with degenerative keratopathy or prior corneal surgery, and Gram- bacilli, more commonly associated with contact lenses (P<0.05). Both demonstrated a similar prognosis.

CONCLUSION

Specific risk factors should be investigated in cases of severe bacterial keratitis. Contact lens wear is the most frequent risk factor, but with a better prognosis than underlying corneal disease, prior corneal surgery or systemic risk factors. The specific bacterial pathogen no longer appears to dramatically influence the outcome of severe corneal ulcers.

A controlled study of amniotic membrane transplantation for acute Pseudomonas keratitis

OBJECTIVE

To evaluate the efficacy of amniotic membrane transplantation (AMT) to improve the outcomes of acute Pseudomonas keratitis as compared with a control group.

DESIGN

Prospective interventional case series with retrospective controls.

PARTICIPANTS

We studied 14 eyes with Pseudomonas keratitis as the AMT group and 11 eyes with Pseudomonas keratitis as the control group.

METHODS

Eyes in the AMT group were treated with antibiotic therapy followed by single-layer AMT at 2 to 3 days. Eyes in the control group received only antibiotic therapy. Patients were followed for 11.1 ± 2.4 months.

RESULTS

In the AMT group, pain significantly decreased from a mean score of 2.4 ± 0.5 preoperatively to 1.1 ± 0.9 at day 2 postoperatively (p < 0.001). Corneal epithelial defects healed completely within 13.2 ± 2.6 days in the AMT group compared with 15.5 ± 3.4 days in the control group (p = 0.07). At final follow-up visits, the sizes of corneal opacity and deep neovascularization were not different between the 2 groups. However, the mean score for density of the corneal opacity was significantly less in the AMT group compared with the control group (2.1 ± 0.4 vs 2.5 ± 0.7, respectively, p = 0.04). Although the best corrected visual acuity using hard contact lenses was not different between the 2 groups, uncorrected visual acuity was better in the AMT group (0.45 ± 0.22 logMAR) than in the control group (0.71 ± 0.32 logMAR, p = 0.03). No patient in either group developed significant corneal thinning or perforation.

CONCLUSIONS

AMT in acute Pseudomonas keratitis was associated with immediate pain relief, less density of the final corneal opacity, and better uncorrected visual acuity at the final follow-up visit.

Facial nerve damage following surgery for cerebellopontine angle tumours. Prevention and comprehensive treatment

Facial nerve (CN VII) palsy or even its transient paresis causes physical disability but is also a psychosocial problem. Immediately after vestibular schwannoma removal, different degrees of CN VII paresis occur in 20-70% of patients. Facial nerve paresis is observed in 10-40% after surgery of cerebellopontine angle meningiomas. Postoperative facial nerve weakness significantly reduces or completely withdraws with time in the majority of cases. However, even if prognosis for CN VII regeneration is good, proper management is needed because of the potential for serious ophthalmic complications. In this paper, the authors raise the issue of perioperative prophylaxis and comprehensive treatment of postoperative paresis of CN VII. Prophylaxis and treatment of ophthalmic complications are discussed. Current trends in the treatment of intraoperative loss of facial nerve continuity, management of facial paresis with good prognosis and dealing with facial palsy with no spontaneous recovery are also described in the paper.

Sutureless amniotic membrane transplantation for severe bacterial keratitis

PURPOSE

To evaluate the efficacy of early sutureless amniotic membrane transplantation in the management of severe bacterial keratitis to reduce pain, inflammation, and haze, and to promote healing.

METHOD

A noncomparative case series including 3 eyes of 3 consecutive patients with severe bacterial keratitis exhibiting persistent epithelial defect/ulcer, more than 5 mm in diameter, located within 3mm from the visual axis with infiltration occupying more than 50% of the corneal thickness. They were retrospectively reviewed following early (ie, within 96 hours) sutureless amniotic membrane transplantation via ProKera together with selective topical antibiotics and preservative-free steroid. Pain relief, inflammation, haze, and corneal epithelial healing were monitored.

RESULTS

ProKera was inserted once in 1 eye and twice in the other 2 eyes. Pain was significantly relieved and inflammation was markedly reduced in all cases. The corneal epithelial defect and stromal ulceration rapidly healed while visual acuity improved in 2 of the 3 eyes.

CONCLUSION

Temporary sutureless amniotic membrane transplantation via ProKera allows easy insertion and replacement of the membrane in the office, as well as early intervention to promote epithelialization, reduce pain, haze and inflammation in cases with severe bacterial keratitis. This result justifies large series controlled studies in the future.

Amniotic membrane transplantation: indications and results

PURPOSE

To describe amniotic membrane transplantation indications and results at the authors' institution.

METHODS

In this study, chart review of 108 patients who underwent amniotic membrane transplantation between January 2002 and April 2006 was performed. The survival rate of corneal integrity was compared, using Kaplan-Meier survival analysis, as a measure of success rate.

RESULTS

The mean age of the patients was 55.2+/-20.1 (6-87 years, 75 female, 51 male). The patients underwent amniotic membrane transplantation for six different diagnoses: nontraumatic corneal perforation (32 eyes, Group 1), persistent epithelial defect (29 eyes, Group 2), aphakic/pseudophakic bullous keratopathy (18 eyes, Group 3), infectious ulcer resistant to treatment (14 eyes, Group 4), necrotizing keratitis secondary to endophthalmitis (10 eyes, Group 5), and caustic injury (5 eyes, Group 6). The mean survival of corneal integrity was similar in all groups (p=0.156).

CONCLUSIONS

Amniotic membrane transplantation is a successful adjunctive method in achieving corneal epithelization in the study indications.

Primary diseases of corneal perforation in Shandong Province, China: a 10-year retrospective study

PURPOSE

To analyze primary diseases of corneal perforation in Shandong Province, China.

DESIGN

Retrospective, noncomparative study.

METHODS

Medical records of 1,056 patients (1,080 eyes) with corneal perforation treated from January 1, 1997 through December 31, 2006 at Shandong Eye Institute were reviewed retrospectively, and primary diseases were evaluated.

RESULTS

Corneal perforations mainly were caused by ocular trauma 715 eyes (66.8%) and infectious keratopathy 294 eyes (27.5%). In the traumatic eyes, corneal penetrating wound accounted for 608 eyes (85.0%), followed by explosion injury 42 eyes (5.9%), thermal burn 34 eyes (4.8%), and chemical injury 29 eyes (4.1%). In the infectious eyes, the most common pathogens were herpes simplex virus 124 eyes (42.2%), fungus 74 eyes (25.2%), and bacterium 20 eyes (6.8%). Repeated corneal perforation occurred in nine eyes, with primary diseases of herpes simplex keratitis (HSK; four eyes), Mooren ulcer (two eyes), necrotizing keratitis and scleratitis (one eye), bacterial keratitis (one eye), and alkali burn (one eye). Corneal grafts perforated in 31 eyes, resulting from recurrent HSK (eight eyes), implant autoproteolysis (seven eyes), bacterial infections (six eyes), recurrent Mooren ulcer (four eyes), immunologic rejection (three eyes), trauma (two eyes), and fungal recurrence (one eye).

CONCLUSIONS

Ocular trauma and infectious keratopathy dominated among the primary diseases of corneal perforation in Shandong Province, China, during the past 10 years. HSK seems to be the most common cause of repeated corneal perforation. Recurrent primary diseases and implant autoproteolysis and infection more often result in graft perforation.

Multilayer amniotic membrane transplantation for bacterial keratitis with corneal perforation after hyperopic photorefractive keratectomy

We report a case of corneal infection caused by Streptococcus pneumoniae after hyperopic photorefractive keratectomy (PRK) that produced severe corneal melting, ulceration, and multiple perforations. Treatment included antibiogram-based antibiotic topical therapy and multilayer amniotic membrane transplantation (AMT) performed to seal the perforations and restore the globe integrity. Clinical and anterior segment optical coherence tomography (Visante OCT, Carl Zeiss Meditec) examinations documented progressive integration of the amniotic membrane tissues within the cornea, stromal and epithelial healing, and recovery of a stable and regular anterior chamber. The cornea healed with an avascular leucoma; the best corrected visual acuity was reduced to 20/200. Severe pneumococcal ulcerative perforation is a potential complication of PRK. Penetrating keratoplasty, at high risk for failure in the acute settings of an infected and inflamed eye, can be delayed until the cornea is healed. Amniotic membrane transplantation may be an alternative surgical option to achieve this goal.