Amniotic membrane transplantation: indications and results

Adjunctive Green Thermal Laser Photocoagulation for Treatment of Resistant Infectious Keratitis

Purpose

To investigate the safety and efficacy of green thermal laser as an adjunctive therapy for the treatment of resistant infectious keratitis (IK) in the Delta region of Egypt.

Methods

A retrospective case series of 150 patients, within a 4 year duration, with resistant IK, who failed to respond to specific medical treatment alone for 7 days, were included. They all received green thermal laser photocoagulation treatment to the cornea as an adjunctive to medical treatment.

Results

Forty-eight women and 102 men were included in this study with a mean age of 46.2 ± 7.7 years. Common risk factors associated with IK included trauma by material of plant origin and contact lens wear. The mean duration of healing was 2.87 ± 0.7 weeks. A single session of green thermal laser application was adequate in 138 IK cases (92%), while 12 cases (8%) required an additional session a week later. Supplementary amniotic membrane transplantation (AMT) was required in 26 cases (17.3%). Two patients (1.3%) required tectonic keratoplasty for corneal perforation. The final corrected distance visual acuity (CDVA) was counting fingers (CF) or better in 78 patients (52%). No decrease of CDVA was reported throughout the study.

Conclusion

Green thermal laser is a safe and effective adjunctive therapy for the treatment of resistant infectious keratitis.

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.

Bacterial nanocellulose as a corneal bandage material: a comparison with amniotic membrane

Corneal trauma and ulcerations are leading causes of corneal blindness around the world. These lesions require attentive medical monitoring since improper healing or infection has serious consequences in vision and quality of life. Amniotic membrane grafts represent the common solution to treat severe corneal wounds. However, amniotic membrane's availability remains limited by the dependency on donor tissues, its high price and short shelf life. Consequently, there is an active quest for biomaterials to treat injured corneal tissues. Nanocellulose synthetized by bacteria (BNC) is an emergent biopolymer with vast clinical potential for skin tissue regeneration. BNC also exhibits appealing characteristics to act as an alternative corneal bandage such as; high liquid holding capacity, biocompatibility, flexibility, natural - but animal free-origin and a myriad of functionalization opportunities. Here, we present an initial study aiming at testing the suitability of BNC as corneal bandage regarding preclinical requirements and using amniotic membrane as a benchmark. Bacterial nanocellulose exhibits higher mechanical resistance to sutures and slightly longer stability under in vitro and ex vivo simulated physiological conditions than amniotic membrane. Additionally, bacterial nanocellulose offers good conformability to the shape of the eye globe and easy manipulation in medical settings. These excellent attributes accompanied by the facts that bacterial nanocellulose is stable at room temperature for long periods, can be heat-sterilized and is easy to produce, reinforce the potential of bacterial nanocellulose as a more accessible ocular surface bandage.

Progressive large pediatric corneal limbal dermoid management with tissue glue-assisted monolayer amniotic membrane transplantation: A case report

RATIONALE

Limbal dermoids are choristomas known as congenital benign tumors found in abnormal locations. Despite the benign nature, enlarging limbal dermoids may cause visual abnormalities by cornea infiltration with fat component, visual axis invasion, gradually induced corneal astigmatism, and finally result in anisometropic amblyopia. Here we report a rare case of progressive, large pediatric corneal limbal dermoid in a newborn, managed with tissue glue-assisted monolayer amniotic membrane transplantation.

PATIENT CONCERNS

A 1-day-old male baby (gestational age, 36 ± 6 weeks; birth body weight, 2785 gram) presented to our clinic with a whitish mass on his right eye since birth.

DIAGNOSIS

Ocular examination revealed a solid, whitish-yellow, and ovoid mass with central keratinized epithelium over the superior limbus; the lesion covered two-thirds of the cornea with rapid progression in size. The final pathological examination revealed that the lesion is composed of keratotic lining squamous epithelium resembling epidermis, underling dermal fibrotic connective tissue, and mature fat.

INTERVENTIONS

The patient underwent deep lamellar excision followed by mitomycin C (MMC) soaking (0.2 mg/mL, 3 minutes) and tissue glue-assisted monolayer amniotic membrane transplantation with the ring conformer at 2 months of age.

OUTCOMES

The ring conformer was smoothly removed 2 weeks after the operation. The patient showed a smooth healing process with less pain and rapid corneal re-epithelization. The ocular surface was stable during the follow-up visits, and no complications were detected. Only mild post-operative scarring over the incision wound was observed.

LESSONS

Although a combination of excision, lamellar keratoplasty, and multilayer amniotic membrane and limbal stem cell transplantation is advocated for the treatment of grade II and III pediatric corneal limbal dermoids, the procedure used in this study offers an alternative surgical approach. However, because of the large size of the lesion and the young age of the patient, the management of amblyopia with visual rehabilitation and corneal transplantation is still needed in the future.

Growth Factor and Interleukin Concentrations in Amniotic Membrane-Conditioned Medium

PURPOSE

Application of amniotic membrane-conditioned medium (AMM) eye drops is a potential treatment alternative for therapy-resistant corneal epithelial defects. Our purpose was to determine the concentration of growth factors epidermal growth factor (EGF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGFβ1), fibroblast growth factor basic (FGFb), and interleukins, IL-1β, IL-6, IL-8, in AMM following different preparation methods.

METHODS

Amniotic membranes of 10 placentas were prepared and thereafter stored at -80°C using the standard method of our LIONS Cornea Bank. Following defreezing, amniotic membrane pieces with a standard size were inserted in a 12-well plate either complete or cut in small pieces, and 2000 µl DMEM culture medium was added. EGF, NGF, VEGF, TGFβ1, FGFb, IL-1β, IL-6, and IL-8 concentrations in the culture medium were determined following 8, 48, and 96 hours, and 1, 2, 3, and 4 weeks of incubation using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Concentrations of NGF, VEGF, TGFβ1, and IL-1ß were beyond the detection limit at all time points. EGF concentrations were between 0.14 and 0.80 ng/g tissue, FGFb between 0.48 and 2.89 ng/g tissue, IL-6 between 0.11 and 1.41 ng/g tissue, and IL-8 between 0.32 and 6.18 ng/g tissue. A significant difference between both preparation methods was shown for the IL-6 concentration after 8 and 48 hours (p < 0.001; p = 0.01) and in IL-8 concentration after 8 and 96 hours and after 3 weeks (p = 0.02; p = 0.002; p = 0.027).

CONCLUSION

AMM containing EGF and FGFb, and IL-6 and IL-8 AMM is a potential nonsurgical treatment alternative of therapy-resistant corneal epithelial defects. However, the most effective preparation method and the optimal harvesting time point are yet to be determined.

Amniotic Membrane Graft with Argon Laser Photocoagulation Versus Amniotic Membrane Graft with Tissue Debridement for Treatment of Mycotic Keratitis

AIM

To compare augmented therapy with argon laser and amniotic membrane graft (AMG) versus AMG and tissue debridement for resistant mycotic corneal ulcers.

METHODS

This study included 40 cases of resistant fungal corneal ulcers in two groups. In one group, argon laser photocoagulation and AMG were done while AMG with tissue debridement was done as adjunctive therapy for the specific antifungal agents.

RESULTS

Complete healing with no adverse effects was achieved in argon laser group in duration ranging from 2-3 weeks in all cases. In the AMG group, duration of healing ranged from 3-5 weeks. Visual acuity was improved with one or more line gain in eight cases (40%) in the laser group, while in six cases (30%) only in the AMG group.

CONCLUSIONS

Augmented therapy with argon laser and AMG is superior to AMG with tissue debridement for treatment of resistant fungal corneal ulcers.

Argon laser photocoagulation versus intrastromal voriconazole injection in treatment of mycotic keratitis

AIM

To compare argon laser photocoagulation and intrastromal injection of voriconazole as adjunctive treatment modalities in cases of resistant mycotic corneal ulcers.

METHODS

Two groups each of them included 20 cases of resistant mycotic corneal ulcers. Both groups treated with local and systemic specific antimicrobial drugs guided with culture and sensitivity results. In one group argon laser photocoagulation was used as an adjunctive therapy to the specific antifungal drugs and in the other group, intrastromal injection of voriconazole was done besides the specific antifungal drugs. The 40 cases included in the study were proven according to culture and sensitivity to be 28 cases with pure fungal results and 12 cases with mixed (fungal and bacterial). In argon laser group, argon laser irradiation of the corneal ulcer was performed using argon laser 532 nm wavelength (Carl Zeiss LSL 532s AG; Meditec, Inc.) after fluorescein staining. In the other group, voriconazole solution (500 µg/mL) was prepared and injected in the corneal stroma. All cases were followed up for 3mo after healing was achieved.

RESULTS

Complete healing of the epithelial defect and resolution of stromal infiltration with no adverse effects were achieved in argon laser group in duration ranged from 2-4wk in 90% of cases. In voriconazole group 4 cases needed amniotic membrane graft due to thinning and 16 cases healed in duration ranged from 2-6wk (80% of cases).

CONCLUSION

Argon laser photocoagulation is superior to intrastromal voriconazole injection in treatment of resistant fungal corneal ulcers.

Role of argon laser as an adjunctive therapy for treatment of resistant infected corneal ulcers

Purpose

To evaluate the role of argon laser as an adjunctive therapy in ten patients with resistant infected corneal ulcers with or without hypopyon.

Methods

The study included 20 patients, split into two groups of ten, with resistant infected corneal ulcers with or without hypopyon. One group was considered as the control group and treated with local and systemic specific antimicrobial drugs guided with culture and sensitivity tests. The other group started with the same specific therapy as the control group for 1 week with no obvious improvement and then was further treated with argon laser. The ten patients in the control group included five cases of fungal ulcers, three mixed (fungal and bacterial) ulcers, and two viral ulcers. The ten patients in the other group included three cases of fungal ulcers, three mixed (fungal and viral) ulcers, three viral ulcers, and one bacterial ulcer as proven with microbial culture and sensitivity tests. Eight cases of the control group and seven cases of the other group were associated with hypopyon. Before laser treatment, a drop of benoxinate hydrochloride 0.4% and a single drop of fluorescein sodium 0.25% were instilled. Argon laser irradiation of the affected cornea was performed using an argon 532 nm wavelength (Carl Zeiss LSL 532s AG; Carl Zeiss Meditec AG, Jena, Germany). A spot size of 500 μm, pulse duration of 0.2 seconds, and power of 900 mW were used. All cases were followed up for 3 months after healing was achieved.

Results

During the first 4 weeks after laser treatment, all patients showed complete healing of the epithelial defect and resolution of stromal infiltration with no adverse effects. In the control group, four cases needed an amniotic membrane graft due to thinning and the other six cases were healed in a duration that ranged from 3 to 7 weeks.

Conclusion

Argon laser phototherapy is useful as an adjunctive treatment for resistant infected corneal ulcers. More cases are needed to get more reliable results and to confirm our findings.

Therapeutic penetrating keratoplasty for infectious and non-infectious corneal ulcers

This study reports the outcomes of therapeutic penetrating keratoplasties, defined as keratoplasties performed to eradicate active infectious corneal diseases or to repair a structural defect of the cornea. The records of 24 eyes of 24 patients (17 female and 7 male) treated with therapeutic penetrating keratoplasty between 2002 and 2010 were evaluated retrospectively. Patients were divided into infectious keratitis group and non-infectious keratitis group. The mean age was 52.12 ± 17.91 years. The median follow-up time was 22 months (min-max: 6-96). Therapeutic success was achieved and eyes were preserved in 23 patients and one patient required evisceration for recurrent fungal infection. At the end of the follow-up period, 92.9 % (n = 13) and 77.8 % (n = 7) of grafts remained clear in the infectious and non-infectious groups, respectively (p = 0.538). Visual acuity (VA) improved at least one Snellen line in 23 patients. The mean postoperative decimal VA was 0.2 ± 0.3 and 0.1 ± 0.3 in the infectious and non-infectious groups, respectively (p = 0.12). Amniotic membrane transplantation was performed in two eyes preoperatively and in four eyes postoperatively. Therapeutic penetrating keratoplasty continues to be an effective method in the treatment process of serious perforated and non-perforated corneal infectious and non-infectious diseases resistant to medical and other surgical interventions.

Role of multilayered amniotic membrane transplantation for the treatment of resistant corneal ulcers in North India

To study the role of multilayer amniotic membrane transplantation (AMT) in the treatment of non-healing corneal ulcers. This study included 28 patients with non-healing bacterial corneal ulcers. AMT was performed using the 'overlay on-inlay' technique'. The outcome was assessed in terms of best corrected visual acuity (BCVA), corneal re-epithelization, graft/tissue edema and vascularity, graft melting, graft retraction, infection of graft and surface necrosis. The success rate of ulcer healing was 82.1 % (23 patients) 1 month after surgery, 78.5 % (22 patients) after 3 months and 75 % (21 patients) after 6 months. In the early post-operative period, BCVA deteriorated in all patients (perception of light to hand movement) but improved later. In 26 of the 28 patients (92.8 %) graft retraction occurred after 1 month and neovascularization was seen in 17 of the 28 patients (60.7 %). Multilayer AMT using an overlay on-inlay graft in non-healing bacterial corneal ulcers is a good option in terms of ulcer healing and symptomatic improvement.

Management of pediatric corneal limbal dermoids

This paper reviews the data in the published literature (PubMed from 1937 to 2011) concerning the medical and surgical management of pediatric limbal dermoids. Current standard medical treatment for grade I pediatric limbal dermoids (ie, with superficial corneal involvment) is initially conservative. In stages II (ie, affecting the full thickness of the cornea with/without endothelial involvement) and III (ie, involvement of entire cornea and anterior chamber), a combination of excision, lamellar keratoplasty, and amniotic membrane and limbal stem cell tranplantation are advocated. Combinations of these approaches seem to yield better and more stable long-term ocular surface cosmesis and fewer complications in comparison with traditional methods of excision and lamellar keratoplasty. Management of amblyopia (i.e. occlusion treatment, chemical penalization with/without spectacle wear, etc) must continue after surgical excision to yield optimal results when or if the surgery is done at a younger age.

Surgical management of pediatric limbal dermoids with sutureless amniotic membrane transplantation and augmentation

PURPOSE

To further evaluate the efficacy of a new surgical technique for removal of pediatric corneal-limbal dermoids and ocular surface reconstruction using multilayered amniotic membrane.

METHODS

Three pediatric patients with corneal-limbal dermoid (grade I) in one practice were identified in a retrospective fashion. All patients underwent deep lamellar excision followed by sutureless multilayered amniotic membrane transplantation by a single surgeon (AP). Preoperative and postoperative visual acuity, anterior segment examination, anterior segment B-scan, and cycloplegic refraction were performed.

RESULTS

Three patients with ages ranging from 6 months to 18 years had a postoperative follow-up of 9 to 12 months from the time of surgery. This surgical technique achieved rapid postoperative corneal re-epithelialization, reduced postoperative pain, and diminished postoperative scarring in all three patients. Existing preoperative astigmatism remained unchanged throughout the follow-up period. No intraoperative or postoperative complications were noted.

CONCLUSION

This surgical approach offers an alternative surgical technique to a simple excision with or without deep lamellar keratoplasty for removal of pediatric corneal-limbal dermoids (grade I). In the management of pediatric limbal dermoids (grade I), surgical excision combined with sutureless multilayered amniotic membrane transplantation eliminates painful postoperative recovery and corneal neovascularization, and can achieve an improved long-term ocular surface cosmesis.

Outcome of penetrating keratoplasty in corneal ulcer: a single-center experience

Background

Corneal ulcers often lead to scarring and astigmatism, and significant loss of vision is a common consequence.

Objective

To determine the rate of graft rejection, one of the most serious concerns with this procedure, and to evaluate the recovery of visual function in those patients for whom the operation was successful.

Methods

We describe a retrospective study of 33 corneal ulcer patients undergoing penetrating keratoplasty (PK) at the Tabriz Nikookari Eye Hospital.

Results

Mean age of the patients was 44 ± 14 years. Most common risk factors for active keratitis were trauma, dry eye, and malnutrition. Culture-positive results included bacterial keratitis (n = 15) and fungal keratitis (n = 5). Perforation was a significant risk factor for therapeutic failure (P < 0.05). Age or gender had no statistically significant effects on the PK outcome (P > 0.05). Postoperative visual acuity had a significant association with preoperative visual acuity (P < 0.01). Graft rejection rate (27.2%) was similar to that reported in the literature.

Conclusion

Although lamellar keratoplasty has recently been established, there are practical reasons for continuing the use of PK in centers such as ours, with due attention to the requirement for topical immunosuppression to diminish the rate of graft rejection and antimicrobial treatment to prevent postoperative infection.

Fibrin-glue assisted multilayered amniotic membrane transplantation in surgical management of pediatric corneal limbal dermoid: a novel approach

Purpose

To report a new surgical technique for excising pediatric corneal limbal dermoid and the post-resection ocular surface reconstruction.

Methods

We describe a method of deep lamellar excision followed by sutureless multilayered amniotic membrane transplantation in surgical management of corneal limbal dermoid.

Result

This technique achieves a rapid corneal re-epithelization, reduces post-operative pain, and will diminish post-operative scarring. Preoperative corneal astigmatism will persist.

Conclusion

This method offers an alternative surgical approach in comparison to simple excision in removal of simple pediatric corneal limbal dermoids.