Amniotic membrane transplantation for persistent epithelial defects with ulceration

The use of autologous serum tears in persistent corneal epithelial defects

PURPOSE

Persistent corneal epithelial defects (PED) present a very challenging problem to anterior segment surgeons. Autologous serum tears had been demonstrated to be beneficial in the treatment of PED. The current study was conducted to review the local spectrum of indications and to examine the outcome of autologous serum tear usage.

METHODS

All cases of PED treated with autologous serum tears at a tertiary referral centre for the period August 1999 - July 2001 were identified and reviewed.

RESULTS

A total of 10 eyes from 10 patients were identified (5OD : 5OS). The gender ratio was 7M : 3F and the mean age was 36.8 (range 17-73) years old. The mean duration of PED before the usage of autologous serum tears was 22.4+/-69.6 days. Six eyes healed within 2 weeks, but two eyes failed to heal after 1 month of treatment and two patients defaulted follow-up. No adverse effects were observed with the addition of autoserum tears.

CONCLUSIONS

The results of the current study correlated well with previous reported studies. Autologous serum tears may be considered as a valuable adjunct in the management of recalcitrant cases of PED.

Effect of amniotic membrane after laser-assisted subepithelial keratectomy on epithelial healing: clinical and refractive outcomes

PURPOSE

To evaluate the effect of an amniotic membrane (AM) on reepithelialization time, corneal haze, and postoperative visual and refractive outcomes after laser-assisted subepithelial keratectomy (LASEK) for myopia and myopic astigmatism.

SETTING

Department of Ophthalmology, Yonsei University College of Medicine, and Balgeunsesang Ophthalmology Clinic, Seoul, Korea.

METHODS

One hundred fifty-two eyes of 84 patients with myopia or myopic astigmatism were prospectively evaluated for 6 months after LASEK. An AM was placed as a strip on the inferior limbus in 94 eyes of 54 patients after LASEK; 58 eyes of 30 patients served as the control group. Postoperative epithelial healing time, uncorrected visual acuity (UCVA), best corrected visual acuity, remaining refractive error, and corneal haze were examined.

RESULTS

The reepithelialization time was shorter in the AM group (2.40 days +/- 0.94 [SD]) than in the control group (3.90 +/- 0.97 days) (P<.001). At 6 months, 86 eyes (91.5%) in the AM group had a UCVA of 20/25 or better and 90 eyes (95.7%) had a UCVA of 20/40 or better; 48 eyes (82.8%) and 53 eyes (91.4%) in the control group had a UCVA of 20/25 or better and 20/40 or better, respectively. The mean spherical equivalent in the AM group was -0.48 +/- 0.54 diopter (D) and in the control group, -0.94 +/- 0.60 D (P<.001). The corneal haze was significantly less in the AM group than in the control group (P<.001).

CONCLUSION

Amniotic membrane use after LASEK induced rapid epithelial healing with more favorable visual and refractive outcomes and lower corneal haze scores than conventional LASEK.

Incidence of microbial infection after amniotic membrane transplantation

OBJECTIVE

To report the incidence and characteristics of microbial infection following amniotic membrane transplantation (AMT).

METHODS

We retrieved the clinical and microbiological records of a total of 326 patients undergoing AMT from January 1994 to February 2001 at Bascom Palmer Eye Institute to determine the incidence and characteristics of post-AMT infections with respect to the interval between AMT and the time of microbial culturing, types of organisms, and clinical outcomes and to correlate these infections with the microbiologic results of AM storage media submitted immediately after AMT and the underlying ocular diagnosis.

RESULTS

We subdivided these 326 patients into two groups: 76 patients (from January 1994 to June 1998) used AM prepared from a research laboratory and did not submit AM storage media for culture under an Institutional Review Board-approved protocol, and 250 patients thereafter used AM obtained from a commercial source and routinely submitted AM storage media for culture. A total of 11 culture-positive infections (3.4%) were identified, and among them 7 infections (9.2%) were from the first group, and 4 (1.6%) were from the second group (P = 0.004). All 4 infections (5.2%) occurring within 1 month after AMT were exclusively from the first group (P = 0.003). All AM storage media from the second group were culture negative. Gram-positive organisms were the most frequent isolate (64%). Infections were not correlated with the underlying ocular diagnosis.

CONCLUSIONS

AMT is a safe method for ocular surface reconstruction with a very low rate of microbial infections, especially if AM is prepared according to Good Tissue Banking Practice set forth by FDA. Gram-positive isolates seem to be the most frequent isolates in infections after AMT.

[Amniotic membrane transplantation improves experimental herpetic keratitis. Modulation of matrix metalloproteinase-9]

PURPOSE

Transplantation of human amniotic membrane (AMT) accelerates the healing of experimental ulcerative herpetic keratitis. Here the expression and activity of matrix metalloproteinase (MMP)-9 was studied.

METHODS

BALB/c mice were corneally infected with HSV-1. Whereas the infected corneas of mice in group 1 were covered with AM, tarsorrhaphies were performed in others (group 2). After 2 days, the appearance of corneal ulcers and stromal inflammation was judged clinically, and the corneal PMN infiltration was studied histologically. The expression of MMP-9 in the corneas was localized by immunohistochemistry and analyzed by Western-blot technique. The MMP-9 activity in the corneas was determined by zymography.

RESULTS

On day 14, the ulcerating corneas had a dense PMN infiltration, the ulcers and the majority of PMNs were highly positive for MMP-9, and the active forms of MMP-9 were detected. Gelatinolytic activity was found in these corneas by zymography. Compared with the mice of group 2, ulceration, stromal inflammation and neovascularization markedly improved clinically and histologically within 2 days in mice of group 1. This was associated with a reduced expression of MMP-9 in corneal tissue and in PMNs. The gelatinolytic activity of MMP-9 was reduced after AMT.

CONCLUSIONS

These observations suggest that improvement of herpetic corneal ulcers and reduced corneal neovascularization after AMT may result from a reduced expression and activity of MMP-9.

Correlation of long term phenotypic and clinical outcomes following limbal epithelial transplantation cultivated on amniotic membrane in rabbits

AIM

To determine the epithelial phenotype in rabbits with total limbal stem cell deficiency (LSCD) after reconstruction with autologous limbal epithelial stem cells ex vivo expanded on rabbit amniotic membrane (AM).

METHODS

Left eyes of 52 rabbits were rendered total LSCD, verified by impression cytology. The fibrovascular pannus of each cornea was removed. Group I (n = 10) received rabbit AM transplantation alone, while groups II-IV (n = 42) underwent transplantation of LSC cultured on rabbit AM (LSC-AM) from a small limbal biopsy taken from the right eye. Clinical outcome was graded as "success," "partial success," or "failure" depending on the corneal smoothness and avascularity. Epithelial phenotype was determined by immunostaining and graded as "corneal (K)," "conjunctival (J)," or "mixed (M)" depending on expression of K3 and Muc5AC.

RESULTS

After 1 year follow up, group I showed 100% failure and groups II-IV showed 26% success (p<0.001). Clinical failure correlated with J phenotype p = 0.001), while clinical success correlated with K phenotype p = 0.01). When the phenotypic outcome was used for comparison, J phenotype was significantly high in group I (p = 0.003), while K phenotype was significantly high in groups II-IV (p<0.05).

CONCLUSION

There is a strong correlation between clinical success and resultant corneal epithelial phenotype. Ex vivo expanded LSC can successfully reconstruct corneal surfaces with unilateral total LSCD.

Transplantable cultivated mucosal epithelial sheet for ocular surface reconstruction

Ocular surface reconstruction by tissue engineering using somatic stem cells is a second-generation therapeutic modality. In view of future treatment of bilaterally affected, severe ocular surface disorders, two types of transplantable cultivated mucosal epithelial sheets can be used for reconstruction. One is an allogeneic corneal epithelial stem cell sheet, and the other is an autologous oral mucosal epithelial cell sheet. We first investigated the feasibility of amniotic membrane as an epithelial carrier, and found that denuded amniotic membrane was the most appropriate substrate for this purpose. Thus, cultivated corneal epithelial stem cell sheets were created by co-culturing with 3T3 fibroblast and air-lifting on amniotic membrane. These epithelial sheets demonstrated positive keratin 3 and 12 specific to in vivo corneal epithelium, light junction related proteins and proliferative activity. The transplanted allogeneic human corneal epithelial sheets existed successfully on the corneal surface, and were quite effective in achieving ocular surface stability in severe ocular surface disorders. A few cases, however, developed immunological reactions or opportunistic infections, etc. Secondly, we established transplantable autologous cultivated oral mucosal epithelial sheets in rabbits. The in vitro oral mucosal epithelial sheets showed histological characteristics similar to those of in vivo corneal epithelial sheets; for example, positive keratin 3 expression. Based on the fact that, the transplanted autologous oral mucosal epithelial sheets resembled corneal epithelium and that we achieved the recovery of corneal transparency in rabbits, we propose that cultivated oral mucosal epithelium may become the substitute for corneal epithelium in ocular surface reconstruction.

The amniotic membrane in ophthalmology

The amniotic membrane is the innermost of the three layers forming the fetal membranes. It was first used in 1910 in skin transplantation. Thereafter it has been used in surgical procedures related to the genito-urinary tract, skin, brain, and head and neck, among others. The first documented ophthalmological application was in the 1940s when it was used in the treatment of ocular burns. Following initial reports, its use in ocular surgery abated until recently when it was re-discovered in the Soviet Union and South America. Its introduction to North America in the early 1990s heralded a massive surge in the ophthalmic applications of this membrane. The reintroduction of amniotic membrane in ophthalmic surgery holds great promise; however, although it has been shown to be a useful and viable alternative for some conditions, it is currently being used far in excess of its true useful potential. In many clinical situations it offers an alternative to existing management options without any distinct advantage over the others. Further studies will undoubtedly reveal the true potential of the membrane, its mechanism(s) of action, and the effective use of this tissue in ophthalmology.

Neurotrophic keratitis

Neurotrophic keratopathy is a degenerative corneal disease induced by an impairment of trigeminal nerve. Impairment of loss of corneal sensory innervation is responsible for corneal epithelial defects, ulcer, and perforation. In the present report, we reviewed the pathogenesis, diagnosis, and therapeutic aspects of this disease. An accurate history and clinical examination, including the function of cranial nerves, together with the clinical features of the ocular surface are essential for a prompt diagnosis. The evaluation of the corneal sensitivity and tear film function are important diagnostic steps as well. Specific medical and surgical treatments, based on the clinical staging of the disease, are often able to halt its progression. Future developments in the medical treatment including the administration of neuropeptide and growth factors are presented.

Evaluation of umbilical cord serum therapy for persistent corneal epithelial defects

AIMS

To evaluate umbilical cord serum therapy as a means of promoting the healing of persistent corneal epithelial defects.

METHODS

Umbilical cord serum or autologous serum drops were used to promote the healing of persistent epithelial defects. The study design was a prospective randomised controlled clinical trial. 60 eyes of 59 patients were divided into two groups, 31 in the cord serum group and 29 in the autologous serum control group. Epithelial defects measuring at least 2 mm in linear dimension resistant to conventional medical management were included. Serial measurements of the size of the epithelial defects-namely, two maximum linear dimensions perpendicular to each other, and the area and perimeter was done at start of therapy and follow up days 3, 7, 14, 21. Rate of healing of the epithelial defects were measured as percentage decrease from the baseline parameter at each subsequent follow up. The data were analysed by the non-parametric Wilcoxon rank sum test using STATA 7.0.

RESULTS

The median percentage decrease in the size of the epithelial defect was significantly greater in the cord serum group at days 7, 14 and 21 (p<0.05) when measured in terms of the area and perimeter. A greater number of patients showed complete re-epithelialisation with umbilical cord serum (n = 18) than with autologous serum (n = 11) (Pearson chi = 0.19). None of the patients reported any side effects or discomfort with either treatment.

CONCLUSIONS

Umbilical cord serum leads to faster healing of the persistent corneal epithelial defects refractory to all medical management compared to autologous serum.

Bilateral Keratoconjunctivitis Associated with Lichen Planus

PURPOSE

To describe a case of bilateral keratoconjunctivitis in a patient with lichen planus.

METHODS

Case report and review of the English literature.

RESULTS

To our knowledge, this is the fourth reported case of keratoconjunctivitis associated with lichen planus. A 33-year-old Navajo man with lichen planus had recurrent and progressive keratoconjunctivitis that failed to improve on multiple topical medications. Tapered oral prednisone, 2% topical cyclosporin, and amniotic membrane transplantation pacified the acute exacerbation.

CONCLUSIONS

Our patient with lichen planus developed an ocular surface disease with cicatricial conjunctivitis, keratouveitis, keratoconjunctivitis sicca, punctate epithelial erosions, and persistent epithelial defects leading to noninfectious or infectious corneal ulceration. Amniotic membrane transplantation may play an adjunctive role in refractory cases of lichen planus-related keratoconjunctivitis. Topical cyclosporin may stabilize the ocular surface when combined with systemic immunosuppression in severe cases.

Donor source affects the outcome of ocular surface reconstruction in chemical or thermal burns of the cornea11The authors do not have any proprietary interest in the products mentioned used in this study

PURPOSE

To study the association between surgical approach and postoperative results in chemical and thermal burns of the cornea.

DESIGN

Retrospective, interventional, noncomparable case series.

PARTICIPANTS

Thirty-two eyes of 32 patients with chemical (n = 27) or thermal (n = 5) burns of the cornea that were associated with total limbal dysfunction. Eight eyes had a history of previous keratoplasty.

INTERVENTION

Patients were treated by amniotic membrane transplantation combined with either conjunctivolimbal autograft transplantation (autograft group, n = 11) or keratolimbal allograft transplantation (allograft group, n = 21). Fifteen eyes had simultaneous penetrating keratoplasty (simultaneous group), and 6 had keratoplasty several months after ocular surface reconstruction (2-step group).

MAIN OUTCOME MEASURES

Reconstruction of the corneal surface by corneal epithelium, clarity of the cornea, and incidence of postoperative complications. The outcome was compared between the autograft and allograft groups and also between the simultaneous and 2-step groups.

RESULTS

At final examination, 17 eyes (53.1%) showed stable corneal epithelialization. Preoperative conditions were similar in the autograft and allograft groups and also in the simultaneous and 2-step groups. The autograft group showed significantly better results than the allograft group in both corneal epithelialization (Kaplan-Meier analysis, P = 0.003) and clear cornea (P = 0.010). Although the incidences of corneal epithelialization and clear corneas did not significantly differ between the simultaneous and 2-step groups, the former had a higher rate of endothelial rejection in the central graft (P = 0.019).

CONCLUSIONS

In chemical or thermal burns of the cornea with monocular involvement, autografting should be considered as a first choice of surgery. Even in eyes with opaque corneal stroma, it may be safer to perform ocular surface reconstruction first, followed by keratoplasty as a secondary procedure.

Amniotic membrane graft: Histopathological findings in five cases

Amniotic membrane transplantation (AMT) is an effective treatment for ocular surface reconstruction; however, the mechanisms through which amniotic membrane (AM) exerts its effects as well as its fate after transplantation have not been entirely elucidated and have been investigated only in part. We evaluate the integration of AM in the host cornea in five patients who underwent AMT as the result of Bowen's disease, band keratopathy, radio- or cryotherapy-induced keratopathy, chemical burn or post-herpetic deep corneal ulcer with descemetocele. Due to persistent opacification in four cases and a progressing tumor in one case, penetrating keratoplasty (PK) and enucleation were performed as early as 2 months and up to 20 months after AMT. The corneas were analyzed histopathologically. To evaluate AM remnants, corneas were stained with periodic acid Schiff's reaction (PAS), Alcian blue, and Gomory and Masson trichrome; immunostaining including collagens III and IV antibodies was also performed. None of the corneas showed remnants of AM. In all cases, we observed discontinuity of Bowman's membrane. In three cases, the corneal epithelium was completely restored, ranging from three to six cell layers. In the other two cases, we detected an intense inflammatory reaction with rich neovascularization; the epithelial surface of the central cornea was completely restored, while at the periphery of the cornea goblet mucus-producing cells were present. Although clinically useful in all cases, restoration of a stable corneal epithelium through AMT is limited by the extent and severity of limbal stem cell deficiency (LSCD). The lack of histologically documented AM remnants in our cases seems to explain the efficacy of AMT more through its biological properties than through its mechanical properties.

Amniotic membrane transplantation in ocular surface disorders

Chronic ocular surface disorders, which can result in severe functional impairment, have been viewed for decades as untreatable diseases. In 1995, the reintroduction of amniotic membrane transplantation (AMT), either alone or associated with limbal stem cell transplantation, has offered new hope of using tissue and cell therapy strategies to repair ocular surface disorders. Amniotic membrane (AM) has been found to exert its effects by acting as a substrate for the growth of ocular surface epithelia, by suppressing inflammation and scarring and by serving as an anti-microbial barrier. Moreover, AM has recently been used as a substrate for ex vivo expansion of corneal epithelial cells for ocular surface reconstruction. Notwithstanding the substantial agreement among Authors regarding its clinical efficacy, there are still many uncertainties regarding the fate of grafted AM and consequently the mechanisms through which it exerts its long-term effects. Further studies including controlled clinical trials with numerous cases are required to understand which ocular surface conditions are certain to benefit from AM transplantation and how its mechanical properties interact with the mediators produced to favor ocular surface reconstruction.

Concept and Clinical Application of Cultivated Epithelial Transplantation for Ocular Surface Disorders

Corneal epithelial replacement using a tissue engineering technique holds much promise for ocular surface reconstruction in cases of corneal epithelial stem cell deficiency. However, even though an autologous cultivated corneal epithelial stem cell sheet is the safest and most reliable form of sheet, bilaterally affected ocular surface disorders cannot be treated by this method. To treat bilateral cases, we must choose either an allogeneic cultivated corneal epithelial sheet or an autologous cultivated oral mucosal epithelial sheet. In the case of the former, immunological reaction is a threat. Thus, understanding of the immunological background of ocular surface reconstruction using allogeneic tissues is essential. In the case of the latter, the transplanted sheet is not exactly the same as corneal epithelium, and understanding ocular surface epithelial biology is important. In this review, we summarize and explain the concept and clinical application of cultivated mucosal epithelial transplantation for ocular surface disorders.

Management of acute ulcerative and necrotising herpes simplex and zoster keratitis with amniotic membrane transplantation

AIM

To report promoted healing of acute ulcerative and necrotising herpetic keratitis after amniotic membrane transplantation (AMT).

METHODS

Retrospective, non-comparative case series of seven patients with acute ulcerative and necrotising herpetic stromal keratitis. Single or multilayer AMT with epithelial side facing up was performed. The main outcome measures were wound healing of the corneal ulcers and decrease of stromal inflammation.

RESULTS

The mean follow up was 10.7 (SEM 1.4) months (range 5-15 months). AMT was performed once in five cases, and twice in further two. Improvement of stromal inflammation was noted within 16.4 (2.5) days (range 7-28 days). Epithelial defects healed within a mean of 17 (2.7) days (range 7-28 days). Vision improved in all but two patients. No serious side effects occurred during the follow up.

CONCLUSIONS

Although performed in an uncontrolled and non-randomised series of patients, these findings indicate that the AMT shows promise in selected cases for the restoration of ocular surface integrity, reduction of stromal inflammation, and improvement of vision in acute ulcerative and necrotising herpetic keratitis.

Conjunctival Healing after Amniotic Membrane Graft over Ischemic Sclera

PURPOSE

To present a case of chemical injury associated with calcification and severe conjunctival and scleral ischemia, in which tissue regeneration was achieved using an amniotic membrane graft.

METHODS

A 65-year-old man presented to our department 8 weeks after suffering a chemical injury of his left eye with sulfuric acid. There was extensive calcification of the cornea and conjunctiva, associated with severe ischemia of the adjacent sclera. After resection of the calcified tissue and nonviable tissue, amniotic membrane was grafted to cover the extensive zone of scleral ischemia.

RESULTS

In the weeks following grafting, slow epithelialization and revascularization was observed over the amniotic membrane, stemming from the surrounding healthy conjunctiva.

CONCLUSION

Although the presence of ischemia at the base of the graft has been considered a contraindication for amniotic membrane transplantation, this case demonstrates that, provided that the surrounding tissue is not affected, a graft may be useful. In such cases an amniotic membrane graft could be attempted before other alternatives, such as conjuntival or oral mucosal autografts.

Management of the Late Ocular Sequelae of Stevens-Johnson Syndrome

The acute conjunctivitis seen initially in Stevens-Johnson syndrome is followed by a cicatricial phase, which often leads to severe ocular surface disease and visual morbidity. Manifestations include keratinization of the conjunctiva, lid margins, and lacrimal and meibomian ducts, resulting in an unstable tear film and mechanical trauma to the conjunctiva and cornea with blinking. Limbal stem cell deficiency is the most vision-threatening sequela of Stevens-Johnson syndrome, as it causes corneal neovascularization, chronic corneal inflammation, and an irregular corneal epithelium. Management of late sequelae often requires a multipronged approach, including strategies for ocular surface protection, ocular surface support, and ocular surface reconstruction. In this review, established therapies, as well as new experimental therapies, are discussed.

Amniotic Membrane for Repair of Exposed Hydroxyapatite Orbital Implant

Exposure of a hydroxyapatite orbital implant measuring 10 x 3 mm developed in a 25-year-old man. The exposure was repaired with an amniotic membrane graft. Follow-up examinations at 5 days, 2 weeks, 2.5 months, and 5 months after surgery demonstrated closure of the conjunctival defect. The author concludes that amniotic membrane may be useful for the treatment of hydroxyapatite orbital implant exposures.

Amniotic membrane transplantation for ocular surface pathology: long-term results

Amniotic membrane transplantation has been used for >90 years for cutaneous and mucous lesions for regeneration of tissues. In recent years its effectiveness has been demonstrated in the treatment of diseases of the ocular surface. We present our experience with 53 amniotic membrane transplantations for different ocular pathologies with two different forms of implantation. The 53 cases were divided into three groups according to pathology and type of implant. Group 1 included 24 eyes with amniotic membrane grafts after resection of extensive conjunctival lesions. Group 2 included 19 eyes with amniotic membrane grafts for corneal pathology, and group 3 consisted of 10 eyes with amniotic membrane patches for corneal epithelial defects without ulceration. No intra- or postoperative complications were observed during an average follow-up period of 32 months (24-48 months). Group 1 demonstrated rapid healing of the lesions with minimal scarring in all cases. In group 2 a favorable response was observed in 16 of 19 cases. In group 3 complete healing was achieved in only 3 of 10 cases, and the time for which the graft remained was related to the success of the treatment. The primary intention was to achieve prolonged fixation of the implant. Finally, amniotic membrane transplantation is a safe and effective technique for the treatment of different pathologies of the ocular surface. After the resection of extensive conjunctival lesions it is currently the preferred treatment. In corneal pathology, it represents an additional therapeutic alternative when conservative medical treatments fail.

Ex vivo expansion of corneal limbal epithelial/stem cells for corneal surface reconstruction

PURPOSE

The management of severe ocular surface disease due to limbal stem cell deficiency has changed dramatically. The concept of limbal stem cells, as the source of corneal epithelium revolutionised the therapeutic approach of ocular surface reconstruction. Deficiency of limbal stem cells results in blinding ocular surface diseases. Grafting viable limbal tissue, from either fellow healthy eye or a donor eye, with the resident stem cell population may replenish limbal stem cells and can restore the corneal surface to normality. Transplanting the limbal tissue can be achieved through a variety of procedures that include cadaveric keratolimbal allograft (KLAL), live or living related conjunctival limbal allograft (Ir-CLAL) and limbal autograft. Advances in tissue engineering techniques have offered a viable alternative to overcome the limitation of limbal tissue available for transplantation. Epithelial stem cells harvested from a small limbal biopsy can be expanded in vitro on a suitable carrier and then transplanted to the diseased cornea to successfully restore the corneal surface. This article is a chronological review of the important steps that brought ex vivo expanded stem cell transplantation in ocular, particularly corneal surface reconstruction.

METHODS

The MEDLINE data base was searched for the years 1966-2002, using key words cornea, cell culture, ex-vivo expansion, limbus, stem cell, ocular surface and transplantation. Several articles that were not found by MEDLINE search were taken from references from other articles. Inclusion or exclusion of article was based on the relevance to the subject.

CONCLUSIONS

Corneal epithelial reconstruction with ex vivo expanded limbal cells is a potential tool in ocular surface reconstruction, although the technique is currently investigational. Strategies to achieve conjunctival epithelial restoration and tear film replenishment will allow ophthalmic surgeons to truly reconstruct the ocular surface.

Phototherapeutic keratectomy with amniotic membrane for severe subepithelial fibrosis following excimer laser refractive surgery

We report 2 patients who developed subepithelial opacities and myopic regression after photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy. Both cases were treated successfully with manual debridement of the epithelium, phototherapeutic keratectomy, and PRK with amniotic membrane application.

Staphylococcus epidermidis adherence to human amniotic membrane and to human, rabbit, and cat conjunctiva

PURPOSE

To evaluate Staphylococcus epidermidis adherence to human amniotic membrane (HAM) and compare it with S epidermidis adherence to human, rabbit, and cat conjunctiva in vitro.

SETTING

Research laboratory, Loyola University Medical Center, Maywood, Illinois, USA.

METHODS

Commercially available HAM (N = 3) was used. Conjunctival specimens from humans, rabbits, and cats (n = 3 each) were processed similarly to HAM. The tissues were exposed to S epidermidis (3 x 10(8) colony-forming units per milliliter) for 0, 5, 30, and 90 minutes, rinsed in sterile saline, and processed for light, scanning (SEM), and transmission (TEM) electron microscopy. Scanning electron microscopy (x2000) was used to quantify adherent bacteria/mm(2) of tissue (SEM photographs = 144).

RESULTS

The following mean levels (+/- SD) of adherent S epidermidis/mm(2) were found at 0, 5, 30, and 90 minutes: HAM, 3833 +/- 1570, 9060 +/- 2512, 15,431 +/- 10,752, and 30,315 +/- 14,803, respectively; human conjunctiva, 1493 +/- 672, 7218 +/- 3179, 17,273 +/- 7168, and 19,861 +/- 9624, respectively; rabbit conjunctiva, 3385 +/- 5074, 14,386 +/- 14,569, 15,283 +/- 13,679, and 20,113 +/- 24,016, respectively; and cat conjunctiva, 4032 +/- 2240, 12,345 +/- 3413, 8512 +/- 4032, and 19,214 +/- 5584, respectively. No statistically significant differences were found at any time point (P>.16).

CONCLUSION

There was no statistically significant difference in the adherence of S epidermidis to HAM and to human, rabbit, and cat conjunctiva. Bacterial adherence to HAM may be clinically significant.

Corneal calcification after amniotic membrane transplantation

BACKGROUND

/aims: Amniotic membrane transplantation (AMT) has become well established as a treatment for chronic epithelial defects, conjunctival reconstruction, and partial limbal cell deficiency. The aim of this study was to describe cases of corneal calcification following AMT and to search for risk factors that might predispose to this unusual finding.

METHODS

Details of 117 AMTs on 93 corneas of 91 patients with a follow up period of at least 1 month performed since 1999 were collected prospectively. In those with calcification clinical photographs were studied and the medical records retrospectively examined.

RESULTS

15 calcifications in 117 AMTs (12.8%) were identified, occurring 3-17 (median 6.1) weeks after AMT, during a follow up period of 4-151 (median 25) weeks. Overall epithelial healing rate was 83%. Calcification covered a surface area between 0.7-40.5 mm(2) maximum size with varied morphology. The primary diagnosis was diverse. Risk factors included the use of phosphate eye drops and pre-existing calcification in the operative or other eye. No patient with a "patch" AMT developed calcification.

CONCLUSIONS

Corneal calcification occurs after some cases of AMT. A common risk factor was the postoperative use of phosphate containing eye drops.

Scleral contact lenses may help where other modalities fail

PURPOSE

To describe the vision-correcting and therapeutic benefits of gas-permeable scleral contact lenses (GP-ScCL) in the management of irregular corneal surface disorders and ocular surface diseases.

METHODS

The charts of 48 consecutive patients (66 eyes) whose management included the use of GP-ScCL were reviewed.

RESULTS

The most common indication for fitting the lenses was keratoconus in patients who had to stop wearing other types of corneal lenses (44 eyes, 74.6%). Other indications included extreme corneal irregularity after penetrating keratoplasty, nonhealing corneal ulcer, postoperative dry eye syndrome following laser in situ keratomileusis (LASIK), severe exposure keratitis and acid burn. Mean follow-up was 17 months (range, 2-96). Mean wearing time of the GP-ScCL was 16.2 hours per day (range, 3-18). Visual acuity of 20/40 or better was achieved in 90.9% of keratoconus patients and in 81.8% of postkeratoplasty patients. A gain of two or more Snellen lines was observed in 94.5% of eyes treated for improving vision. Marked subjective improvement in quality of life was reported by 86% of the patients, mainly as a result of improvement in their visual function and reduction in discomfort. Five patients (seven eyes) failed to wear GP-ScCL.

CONCLUSION

GP-ScCL can provide successful and safe visual and therapeutic solutions for ocular conditions when conventional contact lenses and medical treatment have failed and where surgery is undesirable or contraindicated.

Repair of scleromalacia using preserved scleral graft with amniotic membrane transplantation

PURPOSE

To evaluate the use of preserved scleral graft with amniotic membrane transplantation (AMT) for the surgical repair of scleromalacia.

METHODS

A prospective study of eight eyes (eight patients) was performed. We grafted glycerin-preserved sclera onto the areas of scleral thinning with impending perforation and then covered them with an amniotic membrane with a thick basement membrane instead of a conjunctival flap.

RESULTS

All patients experienced loss of ocular pain and inflammation, rapid reepithelialization of the ocular surface, and marked improvement in visual acuity. All of the scleral grafts remained intact, and no recurrence of scleromalacia was observed.

CONCLUSION

Preserved scleral graft with AMT was simple, fast, and effective. It was particularly advantageous when large scleral defects or conjunctival scarring was present. With these therapeutic results, preserved scleral graft with AMT qualifies as a new treatment alternative for scleromalacia.

Experimental anterior lens capsule transplantation for chronic corneal ulcers-Bowman's layer replacement?

PURPOSE

This study was designed to measure the value of allografted anterior lens capsule in the reepithelialization of recurrent corneal ulcers.

METHODS

Mechanical ulcers of uniform size were created with a 6-mm corneal trephine in both eyes of four Chinchilla male rabbits at one-third corneal depth. Following initial epithelial regrowth, an identical injury was created in the same area of each cornea a second time. In four eyes (treated group), an anterior lens capsule from a healthy donor rabbit was sutured into the ulcer bed followed by antibiotic/steroid drops three times daily for 1 week. The remaining four control eyes were allowed to heal without surgical intervention using the same antibiotic/steroid drops only. Slit-lamp examination and histopathology findings were recorded over a 6-month follow-up period.

RESULTS

The four treated eyes reepithelialized after the second injury at a faster rate than the control group eyes and had a lower percentage of corneal opacification at all follow-up exam dates. Histopathology revealed normal epithelium overlying the transplanted anterior lens capsule and no infiltration of inflammatory cells in the subepithelial stroma.

CONCLUSIONS

In experimental conditions, allotransplantation of anterior lens capsule speeds up reepithelialization after repeated mechanical trauma to the cornea. To our knowledge, this is the first experimental transplantation of an anterior lens capsule to create an artificial Bowman's layer in recurrent corneal ulcerations to aid reepithelialization and minimize corneal scarring.

Temporary amniotic membrane patching for acute chemical burns

PURPOSE

To describe the surgical technique, and its usefulness, of temporary amniotic membrane patching (AMP) in the acute phase of ocular chemical injury.

METHODS

Temporary AMP with modification in suture placement was performed on five eyes of five consecutive patients inflicted with acute chemical injury having a greater than grade II injury by the Roper-Hall classification.

RESULTS

All patients reported herein presented with a large epithelial defect on the cornea and conjunctiva. Case 3 was classified as grade III while the other four cases were classified as grade II. The causative chemical agents were anhydrous acetic acid in Case 1, calcium oxide in Case 2, sodium hydroxide in Case 3, sodium silicate in Case 4, and sulphuric acid in Case 5. All cases experienced rapid relief of pain after AMP. Epithelialization of the cornea with improvement of visual acuity was observed in all cases when the amniotic membrane was removed within 2 weeks after surgery. During the mean follow-up of 19.6 months, the ocular surface remained stable and no cicatricial complications were noted.

CONCLUSIONS

These results suggest that immediate AMP is quite useful for managing moderately severe acute ocular chemical injury by facilitating rapid epithelialization and pain relief, and securing ocular surface integrity.

Amniotic membrane transplantation for partial and total limbal stem cell deficiency secondary to chemical burn

PURPOSE

To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular surface reconstruction in chemical burn with limbal stem cell deficiency.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty eyes of 20 consecutive patients with limbal stem cell deficiency secondary to ocular chemical injury.

INTERVENTION

AMT with or without adjunctive limbal transplantation using limbal tissue from either the healthy contralateral eye (CLAU) or a living related donor (lr-CLAL).

MAIN OUTCOME MEASURES

Reconstruction of corneal epithelium (clear appearance without epithelial defect, normal fluorescein permeability and the absence of conjunctiva-derived goblet cells on impression cytology), decrease in corneal vascularization and improvement in visual acuity.

RESULTS

With a mean follow-up time of 19 months (range, 8-27 months), satisfactory ocular surface reconstruction was obtained in 15 eyes (75%), with reduced inflammation and vascularization of the ocular surface and a mean epithelialization time of 3.3 weeks. Success was observed in all cases of partial limbal stem cell deficiency (PLD) and in 68.75% (11 eyes) of cases of total limbal stem cell deficiency (TLD). Surgical failure was observed in five severe cases (31.25%). A significant visual improvement was observed in all cases after surgery, except for 2 eyes that maintained preoperative visual acuity.

CONCLUSIONS

AMT seems to be an efficient adjunct for ocular surface reconstruction in chemical burns with PLD. When performed in conjunction with limbal stem cell transplantation, it is also effective in most cases of TLD.

Amniotic membrane transplantation for reconstruction of the conjunctival fornices

PURPOSE

To describe the clinical outcome of amniotic membrane transplantation (AMT) for fornix reconstruction in a variety of ocular surface disorders.

DESIGN

Noncomparative interventional case series.

PARTICIPANTS

Seventeen eyes in 15 patients with symblepharon. Four eyes had ocular-cicatricial pemphigoid, two eyes had symblepharon after pterygium excision, four eyes had chemical or mechanical trauma, two eyes had strabismus surgery, two eyes (one patient) had Stevens-Johnson syndrome, one eye had toxic epidermal necrolysis, and two eyes (one patient) had chronic allergic conjunctivitis.

INTERVENTION

The subconjunctival scar tissue was dissected from the episclera, and the freed conjunctival flap was recessed to the fornix. A layer of amniotic membrane (AM) was applied to cover the exposed episclera. The fornical edge of the membrane was anchored with sutures passing through the full thickness of the lid.

MAIN OUTCOME MEASURES

A deep conjunctival fornix, lack of motility restriction.

RESULTS

The mean follow-up period was 37 +/- 24 months (range, 9-84 months). Complete fornix reconstruction was demonstrated in 12 of 17 eyes (70.6%), whereas 2 eyes had a partial success, and 3 eyes (3 patients) had recurrence of symblepharon with restricted motility. In eyes that demonstrated partial success or failure, the underlying etiology was either an autoimmune disorder or a recurrent pterygium. The most successful outcome was observed in eyes with symblepharon associated with trauma.

CONCLUSIONS

AMT is an effective method of fornix reconstruction for the repair of symblepharon in a variety of ocular surface disorders. Future modifications, including an epithelial cellular component on the AM (conjunctival autograft or ex vivo expanded epithelial stem cells) may improve the outcome of this surgical procedure.

Staining characteristics of preserved human amniotic membrane

PURPOSE

Amniotic membrane is an ultra-thin cellophane-like membrane that is used in ocular surface reconstruction. We evaluated the staining characteristics of commonly available dyes on preserved human amniotic membrane to aid in handling of amniotic membrane during transplantation.

METHODS

Five dyes, indocyanine green (2.5%, 1.0%, and 0.5%), fluorescein (0.25%), rose bengal (1%), lissamine green B (1%), and trypan blue (0.5%), were used to stain amniotic membrane. After staining, the specimens were observed under a dissecting microscope to evaluate for the uptake of the stains. Positively stained membranes were evaluated for the persistence of staining by placing them in 2 to 3 mL of balanced saline solution that was changed every 30 minutes over 6 hours.

RESULTS

Preserved human amniotic membrane is stained by indocyanine green, rose bengal, lissamine green B, and trypan blue. Of these four dyes, only the membrane stained with 1% lissamine green B was free of stain after 120 minutes. Indocyanine green, rose bengal, and trypan blue continued to strongly stain the membrane after 24 hours.

CONCLUSIONS

Indocyanine green, rose bengal, trypan blue, and lissamine green B all stain amniotic membrane. Lissamine green B appears to have advantages over the other dyes in that it will stain the membrane well, and in our model, dissipate in 120 minutes. Intraoperative staining with lissamine green B may be a simple and effective way to assist surgeons in the proper handling of amniotic membrane.

Proliferation and stratification of keratinocyte on cultured amniotic epithelial cells for tissue engineering

Human amniotic epithelial cells (HAECs) are formed from amnioblasts, separated from the epiblast at about the 8th day after fertilization. Recent studies suggest that HAECs can produce various biologically active substances. In this study, the effects of cultured HAECs on keratinocytes were investigated. First of all, the effect of the medium conditioned by cultured HAECs on the proliferation of keratinocytes was examined. The conditioned medium significantly enhanced the proliferation (P<0.05). Next, the effect of co-culture with HAECs was also examined. The keratinocytes formed a stratified epithelium on day 7 after the start of co-culture. The cultured epithelium formed by the co-culture was five to six layers thick, could be detached by dispase treatment, and had sufficient strength as a sheet. These results suggest that HAECs will be a novel supplemental material for the tissue engineering of skin.

Amniotic membrane transplantation with conjunctival autograft for recurrent pterygium

OBJECTIVE

To study the effect of amniotic membrane transplantation (AMT) combined with either limbal autograft transplantation (LAT) or conjunctival autograft transplantation (CAT) in recurrent pterygium.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-seven eyes of 27 patients with recurrent pterygium. The mean number of prior surgeries was 3.1 (range, 1-10). Fifteen eyes each had restriction of ocular movement and symblepharon before surgery.

INTERVENTION

Patients were treated by AMT with either LAT (n = 15) or CAT (n = 12).

MAIN OUTCOME MEASURES

Recurrence of pterygium, improvement in ocular movement, and symblepharon formation.

RESULTS

Twenty-three (85.2%) of 27 eyes showed no recurrence with a mean observation period of 67.0 weeks. Fourteen eyes (93.3%) each showed improvement in ocular movement restriction and symblepharon after AMT. In four eyes that developed recurrence, three had LAT and one had CAT combined with AMT, suggesting that there was no difference in surgical outcome between LAT and CAT.

CONCLUSIONS

AMT with CAT is a safe and effective method for recurrent pterygium, especially that associated with ocular movement restriction and symblepharon. Considering the potential adverse effects associated with limbal excision, AMT plus CAT may be preferred over AMT plus LAT.

Sterile corneal melting and necrotizing scleritis after cataract surgery in patients with rheumatoid arthritis and collagen vascular disease

The onset of post-operative corneal melting and necrotizing scleritis in patients with rheumatoid arthritis and collagen vascular disease who undergo cataract surgery can have devastating ocular and systemic consequences. Even though ocular surface factors such as sicca and surgical trauma are among the important variables that contribute to this entities, signs and symptoms of systemic disease need to be thoroughly investigated in order to prevent life-threatening complications associated with these ocular manifestations. The management of surgical induced corneal melting and necrotizing scleritis in these patients, include local therapy and in most instances, systemic immuno-modulation. Moreover, the development of corneal melting and necrotizing scleritis in an otherwise "healthy" patient after uncomplicated cataract surgery, can be the first manifestation of a serious occult systemic disease. Therefore, an aggressive approach regarding the diagnosis, workup and treatment should be initiated by the ophthalmologist in order to maximize a successful ophthalmic and medical outcome.

Transplantation of human limbal epithelium cultivated on amniotic membrane for the treatment of severe ocular surface disorders

PURPOSE

To study the short-term clinical results of transplanting of cultivated corneal/limbal epithelial cells on human amniotic membrane (AM) for limbal deficiency.

DESIGN

Noncomparative, retrospective interventional case series.

PARTICIPANTS

Thirteen eyes of 13 patients with severe limbal deficiency (Stevens-Johnson syndrome in eight eyes, ocular cicatricial pemphigoid in three eyes, and chemical burns in two eyes) were treated at the department of Ophthalmology, Tokyo Dental College, Japan.

INTERVENTION

Cultivated allo-limbal epithelium was transplanted onto the ocular surface of patients with severe limbal deficiency.

MAIN OUTCOME MEASURES

Ocular surface reconstruction with corneal epithelialization, changes in visual acuity, and postoperative complications were studied. Histologic examinations were also performed on cultivated epithelium.

RESULTS

Cultivated corneal epithelium on AM formed two to three layers with the formation of basement membrane-like structures. After the surgery, the epithelium regenerated and covered the ocular surface in eight eyes (61.5%). However, three of the eight eyes developed partial conjunctival invasion, and two eyes later developed epithelial defects. At last examination, corneal epithelialization was achieved in six eyes (46.2%). Five eyes had conjunctivalization, one eye had dermal epithelialization, and one eye was not epithelialized. Complications were corneal perforation in four eyes and infectious keratitis in two eyes.

CONCLUSIONS

This study demonstrates that the success rate for transplanting cultivated allo-limbal epithelium on the AM is not different from the conventional limbal and AM transplantation for the treatment of severe limbal stem cell dysfunction.

Histopathology of human corneas after amniotic membrane and limbal stem cell transplantation for severe chemical burn

PURPOSE

To describe the histopathologic changes in the cornea following amniotic membrane transplantation (AMT) combined with limbal transplantation.

METHODS

Four eyes with complete limbal stem cell deficiency after severe chemical burn underwent AMT with either a living-related conjunctival limbal allograft (lr-CLAL) (three eyes) or a conjunctival limbal autograft (CLAU) (one eye) for ocular surface reconstruction. Penetrating keratoplasty was performed several months after the initial procedure for further visual rehabilitation. Mean follow up time was 20 months. Light and transmission electron microscopy (TEM) and indirect immunofluorescence microscopy of the excised corneal buttons were performed.

RESULTS

All specimens displayed a multilayered epithelium without conjunctival goblet cells over the entire corneal surface. Basal epithelial cells demonstrated a firm connection to the remnants of the transplanted amniotic membrane (AM), which at some places appeared to be in a state of "modification" or "remodeling" in the collagen layers. The basement membrane zone displayed a positive staining when using antibodies against collagen IV and VII, integrin alpha6 and beta4, laminin 5, and bullous pemphigoid antigen 2. Remnants of the AM in the specimen showed staining of collagen IV, which was found also in cross-sections of cryopreserved AM. The recipients Bowman's membranes that were only partially present after the initial trauma were significantly disturbed.

CONCLUSION

Within the time frame studied, the transplanted AM apparently survives and integrates into the host tissue being modified or remodeled by recipient cells. AMT in combination with a CLAU or lr-CLAL is a useful technique in promoting a rapid and stable reepithelialization of a corneal surface following severe chemical or thermal damage.

Amniotic membrane graft for late-onset glaucoma filtering leaks

PURPOSE

To evaluate the effectiveness and safety of amniotic membrane graft in the management of late-onset filtering bleb leaks after trabeculectomy with mitomycin C.

DESIGN

Prospective, noncomparative, interventional case reports.

METHODS

Two eyes of two patients with late-onset filtering bleb leak received an amniotic membrane graft.

RESULTS

In both patients, bleb leaks were closed successfully with amniotic membrane graft, and bleb function was maintained during the follow-up period of 34 and 14 months, respectively.

CONCLUSION

Amniotic membrane graft may be considered an alternative method for treating late-onset filtering bleb leaks while maintaining bleb function. As the number of cases was small, more cases need to be accumulated to verify the usefulness of this technique.

Thygeson lecture. Amniotic membrane transplantation: why is it effective?

PURPOSE

To review the uses and previously proposed mechanisms of action of amniotic membrane transplantation (AMT) and to suggest a new mechanism of action for the effectiveness of AMT in resolving a persistent epithelial defect (PED).

METHODS

Significant clinical and experimental publications are reviewed.

RESULTS

Evidence from the scientific literature suggests a new hypothesis for the effectiveness of AMT in the reepithelialization of a PED and the reduction of corneal stromal inflammation and continued fibrosis.

CONCLUSION

It is suggested that reepithelialization of a PED, and hence the reduction of stromal inflammation and continued fibrosis following reepithelialization, is aided by the combination of oxygenation, moisture and protection of the fragile epithelium by the amniotic membrane.

Symptomatic management of postoperative bullous keratopathy with nonpreserved human amniotic membrane

PURPOSE

To report the results of the management of painfully symptomatic postoperative bullous keratopathy (PBK) by performing a nonpreserved human amniotic membrane (NP-AMT) transplantation in nine eyes with poor visual potential.

METHODS

A prospective, comparative, nonrandomized management of symptomatic PBK was done by performing a complete corneal de-epithelialization followed by a NP-AMT transplantation (NP-AMT group) or no NP-AMT transplantation (control group). We evaluated time for re-epithelialization, patient's symptoms, and appearance of new bullae.

RESULTS

In the NP-AMT group, mean follow-up time was 40 weeks. Mean re-epithelialization time was 11.2 days. Symptoms of PBK resolved completely in eight patients (88%), who were asymptomatic and showing very quiet eyes from postoperative day 1, and resolved partially in one patient in whom we observed barely symptomatic bullae at the peripheral NP-AMT border (sixth postoperative week) and an asymptomatic one at the corneal center under the NP-AMT (seventh postoperative week). In the control group, mean follow-up time was 18 weeks; there were recurrences of symptomatic bullae in four of five patients at a mean time of 6.3 days.

CONCLUSIONS

NP-AMT is a good alternative for the management of painful PBK in eyes with poor visual potential; NP-AMT is widely available, the technique is easy to perform, and it has good results from both the symptomatic and esthetic standpoint.

The stamler lid splint: a new short-term technique for achieving therapeutic ptosis

PURPOSE

To provide an introduction to a new device, the Stamler lid splint (SLS), a disposable appliance designed to create a temporary total therapeutic ptosis. We also describe the indications for its use and analyze its limitations.

METHODS

The utility of the SLS in effecting complete ptosis was examined in 33 patients. Outcome parameters examined were mean duration of (induced) ptosis, success (and failure) rate, and the incidence of side effects.

RESULTS

The most common indications for using the SLS were lid closure abnormalities (n = 6) and epithelial defects after keratoplasty (n = 5). The induced ptosis lasted for a mean of 3.3 days (range, 1.5-6). The success rate of the SLS in achieving a total ptosis was 90.9%. Failure was attributed to the presence of atypical lid or orbital anatomy. No patient developed a complication specifically related to the SLS itself.

CONCLUSIONS

The SLS is an inexpensive, quick, and technically straightforward means of treating a variety of ocular surface disorders in compliant patients with normal lid and orbital anatomy. The SLS is best suited to patients who require short-term therapy only.

Amniotic membrane graft for the management of scleral melting and corneal perforation in recalcitrant infectious scleral and corneoscleral ulcers

PURPOSE

To study the efficacy and safety of using cryopreserved human amniotic membrane (AM) graft as a patch graft to reduce stromal melting and promote reepithelialization in extensive infectious scleral and corneoscleral ulcers.

METHODS

Four cases of infectious scleral ulcers with persistent scleral melting and no sign of reepithelialization and three cases of corneoscleral ulcers with corneal perforation were studied. All patients had previously undergone pterygium excision, and infections were caused by Pseudomonas (n = 4), fungi (n = 2), and atypical Mycobacterium (n = 1). The area of limbus involved ranged from 3 to 9 (mean, 4.7) o'clock positions. Repeated debridements were performed, the causative microorganisms were identified, and the appropriate topical and systemic antibiotics were given to all patients before AM grafting. Postoperatively, the speed of reepithelialization, changes in the severity of scleral melting and inflammation, recurrence of infection, and visual acuity were documented.

RESULTS

Melting and inflammation at the lesion site decreased after AM grafting. Reepithelialization of the scleral lesions was complete at an average 15.7 +/- 8.7 days (range, 5-31) postoperatively. Focal melting of the AM graft occurred in two cases, and in one case, it was necessary to perform further corneoscleral graft. No recurrent infection was encountered, but sterile abscess occurred in three cases that were located away from the original lesion. Useful vision above 20/400 was maintained in all patients at the end of follow-up.

CONCLUSION

The AM graft is effective in promoting conjunctival reepithelialization and reducing scleral melting and inflammation and can be considered as an alternative biomaterial to improve wound healing in scleral and corneoscleral ulcerations.

Expansion of conjunctival epithelial progenitor cells on amniotic membrane

Amniotic membrane (AM) reconstructed human conjunctival surfaces recover a goblet cell density higher than normal. Cultured rabbit conjunctival epithelial cells (RCE) on AM preferentially exhibit non-goblet epithelial differentiation. It was thus wondered if conjunctival progenitor cells that might have been preserved during ex vivo expansion on AM can still differentiate into conjunctival non-goblet epithelial and goblet cells under the influence of mesenchymal cells. Fourteen day old AM cultures of RCE were subcutaneously implanted in Balb/c athymic mice for 11 days and processed for PAS staining and immunostaining with monoclonal antibodies to conjunctival goblet cell mucin (MUC5AC, AM3), glycocalyx (AMEM2), cornea specific cytokeratins K3 (AE5) and K12 (AK2) and basal cell specific cytokeratin K14. Cell cycle kinetics were measured by BrdU labelling for 1 or 7 days. The 7 day labelled RCE were chased for 14 days in the same primary culture. After subcutaneous implantation, conjunctival non-goblet epithelial cells increased stratification and formed occasional cysts. The resultant epithelial phenotype was conjunctival with many PAS-positive, MUC5AC-positive, and AM3-positive goblet cells, AMEM2-positive suprabasal and superficial cells, and K14-positive basal cells, but was not corneal (negative to AE5 and AK2 staining). Twenty four hr BrdU labelling showed a labelling index of 42.5%. A higher labelling index or 69% was noted after continuous BrdU labelling for 7 days. A large number of label retaining basal cells with a labelling index of 84% were noted following 14 days of chase. Conjunctival epithelial progenitor cells for goblet and non-goblet cell differentiation are preserved by AM in vitro as evidenced by being able to differentiate into goblet cells in a permissive stromal environment, and being slow-cycling, and label retaining. This information is useful for future ex vivo expansion of conjunctival epithelial stem cells for conjunctival surface reconstruction.

Amniotic membrane grafts for nontraumatic corneal perforations, descemetoceles, and deep ulcers

PURPOSE

To describe the clinical outcome of amniotic membrane transplantation (AMT) for nontraumatic corneal perforations, descemetoceles, and deep ulcers.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Thirty-four eyes of 33 consecutive patients operated on for nontraumatic corneal perforations or descemetoceles at four academic departments of ophthalmology. Associated autoimmune disorders included rheumatoid arthritis (n = 6), Stevens-Johnson syndrome (n = 3), ocular cicatricial pemphigoid (n = 2), systemic lupus erythematosus (n = 1), and one eye with Mooren's ulcer, as well as neurotrophic, or exposure keratopathy (n = 10), postinfectious nonhealing ulcers (n = 6), and postsurgery (n = 5).

INTERVENTION

Three or four layers of amniotic membrane (AM) were applied over the ulcer bed and anchored with 10-0 nylon interrupted or running sutures. A large AM piece was used as a patch to cover the entire corneal surface.

MAIN OUTCOME MEASURES

Formation of anterior chamber depth, epithelialization of the AM grafts, and stability of the corneal stromal thickness.

RESULTS

The mean follow-up period was 8.1 +/- 5.7 (ranging from 2-23) months. A successful result was observed in 28 of 34 eyes (82.3%). Of the successful cases, 23 eyes needed one AMT procedure, whereas 5 eyes needed two procedures to achieve a successful result. In five eyes, a subsequent definitive surgical procedure such as penetrating keratoplasty or lid surgery was needed. Failure was observed in six eyes with rheumatoid arthritis, neurotrophic keratopathy, or graft melting.

CONCLUSIONS

AMT is an effective method for managing nontraumatic corneal perforations and descemetoceles. It can serve as either a permanent therapy or as a temporizing measure until the inflammation has subsided and a definitive reconstructive procedure can be performed. This treatment option is also beneficial in those countries where corneal tissue availability is limited.

Limbal stem cell transplantation for the treatment of subepithelial amyloidosis of the cornea (gelatinous drop-like dystrophy)

PURPOSE

Subepithelial amyloidosis of the cornea, or gelatinous drop-like corneal dystrophy (GDD), is a severe form of corneal stromal amyloidosis predominantly found in the Japanese population. GDD causes severe visual disturbances with irritating symptoms, and keratoplasty is inevitably complicated by early recurrence. This study was conducted to evaluate the efficacy of limbal stem cell transplantation (LSCT) for the treatment of GDD.

METHODS

Nine consecutive eyes of seven patients with GDD were treated with LSCT. Limbal grafts were obtained from cadaver eyes. All eyes underwent lamellar or penetrating keratoplasty simultaneously with LSCT. Intensive epithelial management and immunosuppression therapy was performed.

RESULTS

With a mean observation period of 4 years, eight (88.9%) of nine eyes did not show any signs of recurrence. Five grafts remained clear, and seven eyes had an improvement in vision. Glaucoma and rejection were observed in five and three eyes, respectively, and two eyes with glaucoma required surgical intervention.

CONCLUSIONS

Limbal stem cell transplantation is effective for the prevention of recurrence in GDD. Control of intraocular pressure and rejection are the keys to long-term maintenance of clear grafts.

Histologic findings after amniotic membrane graft in the human cornea

OBJECTIVE

To describe the histopathologic findings in the human cornea several months after a stromal amniotic membrane graft. To show the clinicopathologic correlation after the graft in two cases with different follow-up times.

DESIGN

Two interventional case reports with clinicopathologic correlation.

PARTICIPANTS

Two patients with neurotrophic corneal ulcer unresponsive to medical treatment (one with stromal vascularization and the other without stromal vascularization).

INTERVENTION

Amniotic membrane graft was performed in both patients to treat the neurotrophic ulcer. Three and 7 months after amniotic membrane grafting, a penetrating keratoplasty was needed, and the removed corneas were analyzed.

MAIN OUTCOME MEASURES

Clinical and histopathologic examinations, including routine histopathologic and immunohistochemical studies.

RESULTS

Complete epithelialization was observed on histologic examination over the basement membrane of the amniotic membrane graft. The amniotic membrane was slowly reabsorbed in the cornea without stromal vascularization with no inflammatory reaction produced. In the cornea that had stromal vascularization the amniotic membrane was rapidly reabsorbed because of the presence of abundant inflammatory cells. Once reabsorbed, the amniotic membrane was replaced by new fibrotic stroma, that was different from that found in the rest of the cornea but that helped to maintain corneal thickness.

CONCLUSIONS

The amniotic membrane graft allows for correct epithelialization in cases of neurotrophic corneal ulcer. Once the amniotic membrane is reabsorbed, it is replaced by a new fibrotic stroma, which can reduce corneal transparency. In corneas that have no stromal vascularization, the graft may remain in the stroma for many months, compromising corneal transparency during this period.

Nonpreserved human amniotic membrane transplantation in acute and chronic chemical eye injuries

PURPOSE

To evaluate the safety and efficacy of nonpreserved amniotic membrane transplantation (AMT) with or without limbal autograft transplantation (LAT) in management of acute and chronic chemical eye injuries.

METHODS

Amniotic membrane transplantation or AMT + LAT was performed on nine eyes of seven consecutive patients, five eyes with acute chemical burn and four eyes with limbal stem cell deficiency secondary to previous chemical burn. Nonpreserved amniotic membrane was used in all procedures.

RESULTS

Five patients (71.5%) were men and two (28.5%) were women. The average age at the time of surgery was 32.7 +/- 10.9 years (range, 20-45). Mean follow-up after last surgery was 8.9 +/- 3.2 months (range, 6-14). The average epithelial healing time was 24.6 +/- 17.3 days (range, 3-45). At the end of the follow-up period, visual acuity improved in all eyes, inflammation subsided, and the subjective complaints decreased remarkably.

CONCLUSION

AMT with nonpreserved amniotic membrane promoted epithelial healing, reduced surface inflammation, increased patient comfort, and decreased the extent and severity of vascularization when used in patients with acute chemical burns. When used in limbal stem cell deficiency owing to past chemical burns, AMT alone or in combination with LAT aided in ocular surface reconstruction. Infectious, inflammatory, or toxic/allergic reactions were not encountered in any patient owing to the use of nonpreserved amniotic membrane. Further studies are required to establish the safety and efficacy of preserved and nonpreserved AMT in ocular surface reconstruction.

Amniotic membrane in the surgical management of acute toxic epidermal necrolysis

OBJECTIVE

To report a new surgical technique to manage severe acute toxic epidermal necrolysis.

DESIGN

Two interventional case reports.

PARTICIPANTS

Two patients. Case 1: A 6-year-old boy had severe toxic epidermal necrolysis develop after being treated with trimethoprim and sulfamethoxazole for chronic otitis media. Both eyes and eyelids were affected. He underwent bilateral lysis of symblepharon and all adhesions and bilateral amniotic membrane transplantation to the entire ocular surface except the cornea. Loss of eyelid skin required transplantation of amniotic membrane to all four eyelids and strips of amniotic membrane at the eyelid margins. Case 2: An 8-year-old girl with severe toxic epidermal necrolysis associated with mycoplasma pneumonia had bilateral, diffuse keratoconjunctivitis, diffuse corneal epithelial defects, and bilateral symblepharon. Amniotic membrane transplantation was performed bilaterally, using a symblepharon ring in the left eye.

INTERVENTION

Amniotic membrane transplantation.

MAIN OUTCOME MEASURES

Preservation of normal ocular and eyelid surfaces and prevention of blindness.

RESULTS

Case 1: Thirty-six months after bilateral ocular surgery, there is no symblepharon, good ocular surface wetting, and an uncorrected bilateral vision of 20/20. Case 2: Amniotic membrane transplantation protected both ocular surfaces and prevented conjunctival contracture without adhesion of the eyelids to the ocular surface. The central vision was preserved. There was minimal peripheral corneal vascularization and mild conjunctival scarring of the tarsal conjunctival surface 34 months postoperatively.

CONCLUSIONS

These are the first cases of acute toxic epidermal necrolysis treated with amniotic membrane transplantation and the first use of the procedure on external eyelid surfaces with good healing of the eyelids. This new treatment for acute toxic epidermal necrolysis preserves normal ocular and eyelid surfaces and may prevent blindness.

Amniotic membrane implantation as a therapeutic contact lens for the treatment of epithelial disorders

PURPOSE

To evaluate the efficacy and safety of amniotic membrane implantation as a therapeutic contact lens in the treatment of different epithelial defects without stromal ulceration.

METHODS

We used amniotic membrane implantation as a therapeutic contact lens in 20 consecutive patients with epithelial defects. Group 1 included 10 patients with persistent epithelial defects that did not respond to medical treatment. Group 2 included 10 patients with surgically induced epithelial defects.

RESULTS

No intra- or postoperative complications were observed. The amniotic membrane implant remained in place for a mean of 12.5 days (range, 3-34). In 11 of the 20 patients, the amniotic membrane implant became detached within the first 8 days. When the corneal implant was postoperatively covered with a soft contact lens, this time increased. In group 1, complete epithelialization was achieved in three of the four cases in which the amniotic membrane remained in place for 2 or more weeks. There were no cases of complete epithelialization in which the implant remained in place for less than 1 week. In group 2, epithelialization was achieved in all cases, regardless of the time that the implant remained in place.

CONCLUSION

Amniotic membrane implanted as a therapeutic contact lens can be an effective and safe option for the treatment of different epithelial defects. In patients with persistent epithelial defects, the number of cases with complete postoperative epithelialization was higher when the amniotic membrane remained in place longer. The early detachment of the amniotic membrane implant remains a major problem, even with the use of multiple fixation sutures.