Amniotic membrane transplantation for bullous keratopathy in eyes with poor visual potential

Human birth tissue products as a non-opioid medicine to inhibit post-surgical pain

Pain after surgery causes significant suffering. Opioid analgesics cause severe side effects and accidental death. Therefore, there is an urgent need to develop non-opioid therapies for managing post-surgical pain. Local application of Clarix Flo (FLO), a human amniotic membrane (AM) product, attenuated established post-surgical pain hypersensitivity without exhibiting known side effects of opioid use in mice. This effect was achieved through direct inhibition of nociceptive dorsal root ganglion (DRG) neurons via CD44-dependent pathways. We further purified the major matrix component, the heavy chain-hyaluronic acid/pentraxin 3 (HC-HA/PTX3) from human AM that has greater purity and water solubility than FLO. HC-HA/PTX3 replicated FLO-induced neuronal and pain inhibition. Mechanistically, HC-HA/PTX3 induced cytoskeleton rearrangements to inhibit sodium current and high-voltage activated calcium current on nociceptive neurons, suggesting it is a key bioactive component mediating pain relief. Collectively, our findings highlight the potential of naturally derived biologics from human birth tissues as an effective non-opioid treatment for post-surgical pain. Moreover, we unravel the underlying mechanisms of pain inhibition induced by FLO and HC-HA/PTX3.

The landscape of clinical trials in corneal regeneration: A systematic review of tissue engineering approaches in corneal disease

The limited availability of a healthy donor cornea and the incidence of allograft failure led researchers to seek other corneal substitutes via tissue engineering. Exploring the trend of clinical trials of the cornea with the vision of tissue engineering provides an opportunity to reveal future potential corneal substitutes. The results of this clinical trial are beneficial for future study designs to overcome the limitations of current therapeutic approaches. In this study, registered clinical trials of bio-based approaches were reviewed for corneal regeneration on March 22, 2024. Among the 3955 registered trials for the cornea, 392 trials were included in this study, which categorized in three main bio-based scaffolds, stem cells, and bioactive macromolecules. In addition to the acellular cornea and human amniotic membrane, several bio-based materials have been introduced as corneal substrates such as collagen, fibrin, and agarose. However, some synthetic materials have been introduced in recent studies to improve the desired properties of bio-based scaffolds for corneal substitutes. Nevertheless, new insights into corneal regenerative medicine have recently emerged from cell sheets with autologous and allogeneic cell sources. In addition, the future perspective of corneal regeneration is described through a literature review of recent experimental models.

Painful-blind eye: A forgotten palliative care

Painful-blind eye (PBE) is a challenging and debilitating condition that greatly affects the quality of life of patients. Although PBE can result from a variety of etiologies, currently there is no guideline or consensus on how to approach therapeutically these patients, and most treatments are experience-based. We summarized the evidence from available studies to investigate the current state of PBE treatment strategies. This review revealed that the information available about therapeutic approaches in patients with PBE is insufficient and outdated, therefore, new experimental and larger studies are needed to reach an agreement about this condition.

Clinical Outcomes of Amniotic Membrane/Umbilical Cord Particulate in Spinal Disorders: A Retrospective Study

Background

Musculoskeletal spinal disorders significantly impact patient populations from everyday workers to military soldiers. Effective treatment is critical to minimize the time between injury and returning to work and daily activities. Injection of amniotic membrane/umbilical cord (AMUC) tissue has demonstrated great potential in reducing patients' pain and has become an increasingly popular treatment option for painful orthopedic disorders.

Methods

A single-center, retrospective study was conducted on patients diagnosed with musculoskeletal spinal disorders and subsequently treated with AMUC via epidural and facet injections. Demographics and outcomes related to pain were assessed. Pain was verbally reported by the patient on a scale of 0-10 where 0 indicated no pain and 10 indicated worst imaginable pain. Complications and adverse events were also reported.

Results

A total of 52 patients (average age 40.8 ± 9.6 years) were included in the analysis with diagnoses of spondylosis (n = 44), intervertebral disc degeneration (n = 31), radiculopathy (n = 18), stenosis (n = 2), or other conditions. The cohort's average baseline pain score was 4.9 ± 2.2 with a mean duration of symptoms for 54.2 months (range: 1-300 months). After AMUC injection, pain significantly decreased to 3.4 ± 2.3 at two weeks (p < 0.0001) and 3.5 ± 2.2 at 3-4 weeks (p = 0.0023). For the mean follow-up period of 10.6 ± 5.4 weeks, pain was reduced to 2.8 ± 2.1 (p < 0.0001 vs baseline). No significant complications or adverse events were reported.

Conclusion

Use of an injectable AMUC, such as CLARIX FLO, may alleviate pain in patients with painful spinal indications of various pathologies. This study provides further evidence of its safety and efficacy in epidural and facet injections. Further studies are warranted to verify these promising results.

Impact of adjuvant amniotic membrane transplantation in infectious ulcerative keratitis

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Long-Term Outcomes of Phototherapeutic Keratectomy for Bullous Keratopathy

PURPOSE

To report the long-term outcomes after phototherapeutic keratectomy (PTK) for the treatment of bullous keratopathy.

METHODS

This is a retrospective medical record review of all patients with symptomatic bullous keratopathy who underwent PTK between June 2005 and March 2019 at the Royal Victorian Eye and Ear Hospital who were followed up for at least 12 months after the procedure. Medical records were used to extract demographic data, etiology of bullous keratopathy, complication rates, and subsequent procedures after PTK. The main outcomes recorded were pain and recurrence of bullae, which were assessed according to three time periods: 0 to 3 months, 4 to 12 months, and greater than 12 months after PTK.

RESULTS

During the study period, 64 eyes of 64 patients underwent PTK for bullous keratopathy. The mean follow-up duration was 51 months (range 12-140). The most common indication was pseudophakic bullous keratopathy (44% of cases). Pain had resolved in 88% of eyes within 0 to 3 months, 77% of eyes between 3 and 12 months (P = 0.031, compared with 0-3 months), and 70% of eyes with greater than 12-month follow-up (P = 0.131, compared with 3-12 months). Bullae recurred in 17% of eyes within 0 to 3 months, 22% of eyes between 3 and 12 months (P < 0.001 compared with 0-3 months), and 33% of eyes after the 12-month follow-up (P < 0.001 compared with 3-12 months). Eighty-six percent of patients undergoing PTK had no postoperative complications, and 73% of cases did not require subsequent procedures.

CONCLUSIONS

PTK is effective in providing long-term symptom relief from bullous keratopathy in most of the treated patients.

Use of Bowman's membrane electrocautery in blind eyes with painful bullous keratopathy not amenable to corneal transplantation: a retrospective case series

PURPOSE

This study evaluated the safety and efficacy of Bowman's membrane electrocautery in blind painful eyes with bullous keratopathy not amenable to corneal transplantation.

METHODS

Eleven eyes of 11 subjects with painful bullous keratopathy and poor visual potential who underwent electrocautery of Bowman's membrane at a tertiary referral ophthalmology clinic were reviewed retrospectively. Subject demographics and preoperative and postoperative data were collected, including description of pain, slit lamp biomicroscopy, best corrected visual acuity, topical medication use, and complications. Efficacy of the procedure on pain reduction, bullae resolution, and topical medication use were assessed at post-operative visits. Safety was also evaluated based on any complications.

RESULTS

Bowman's membrane electrocautery effectively resolved bullae in all eyes examined up to 6 months postoperatively; however, 2 eyes had recurrence by 1 year. Mean age at the time of surgery was 69.8 years and mean duration of follow-up was 15.4 months. Pain reduction was achieved in all eyes at 1 month, but 1 subject had pain recurrence by 6 months and another by 1 year. The median number of drops per day decreased from 6 preoperatively to 1.7 at 6 months. Two subjects who had underlying advanced ophthalmic disease had a mild reduction in vision.

CONCLUSION

Bowman's membrane electrocautery is a safe and minimally invasive procedure for the management of painful bullous keratopathy in eyes with low vision potential and not amenable to corneal transplantation. Duration of effect appears to last at least 6 months and up to 3 years post-procedure.

Corneal stromal mesenchymal stem cells: reconstructing a bioactive cornea and repairing the corneal limbus and stromal microenvironment

Corneal stroma-derived mesenchymal stem cells (CS-MSCs) are mainly distributed in the anterior part of the corneal stroma near the corneal limbal stem cells (LSCs). CS-MSCs are stem cells with self-renewal and multidirectional differentiation potential. A large amount of data confirmed that CS-MSCs can be induced to differentiate into functional keratocytes in vitro, which is the motive force for maintaining corneal transparency and producing a normal corneal stroma. CS-MSCs are also an important component of the limbal microenvironment. Furthermore, they are of great significance in the reconstruction of ocular surface tissue and tissue engineering for active biocornea construction. In this paper, the localization and biological characteristics of CS-MSCs, the use of CS-MSCs to reconstruct a tissue-engineered active biocornea, and the repair of the limbal and matrix microenvironment by CS-MSCs are reviewed, and their application prospects are discussed.

Review on the Use of Topical Ocular Hypertonic Saline in Corneal Edema

PURPOSE

To review the effectiveness of topical ocular hypertonic saline in corneal edema.

METHODS

Online literature search of published articles on the effectiveness of topical hypertonic saline in corneal edema, bullous keratopathy (BK), and other associated corneal conditions in humans was performed on April 16, 2020.

RESULTS

A total of 16 articles were reviewed after curation by the authors for relevance, with 4 randomized control trials, 6 prospective studies, 4 retrospective studies, and 2 case reports. Efficacy of hypertonic saline eye drops varied widely, depending on the specific corneal disorder being treated. Six of the studies involved BK (edema involves epithelium), 2 in corneal edema limited to the stroma, 5 in Fuchs dystrophy, 3 in filamentary keratitis (the presence of filaments attached to corneal epithelium), 2 in recurrent corneal erosion, and 1 in jellyfish stings. There was limited efficacy for hypertonic saline in BK, whereas clinical improvement was noted in most studies for corneal edema without epithelial involvement, especially if associated with Fuchs dystrophy or corneal hydrops in keratoconus. Hypertonic saline also seems to be beneficial for other corneal disorders, such as filamentary keratitis and jellyfish stings, but not in recurrent corneal erosion. Adverse effects from topical hypertonic saline include a mild stinging or burning sensation, with no serious complications having been reported.

CONCLUSIONS

Topical ocular hypertonic saline seems to be a safe and effective treatment in the management of less severe forms of corneal edema and other corneal disorders such as filamentary keratitis.

Amniotic Membrane Transplant for Bullous Keratopathy: Confocal Microscopy & Anterior Segment Optical Coherence Tomography

PURPOSE

To assess amniotic membrane retention after amniotic membrane transplant in bullous keratopathy patients and whether there were any corneal structural changes that may hinder further penetrating keratoplasty Methods: A retrospective study including 22 patients who have undergone amniotic membrane transplant from 1 Jan 1998 till 30 Jun 2016. Confocal microscopy and anterior segment optical coherence tomography (ASOCT) were performed to assess the retention of amniotic membrane and to detect any corneal structural changes. The comparison was made with 5 controls who had bullous keratopathy awaiting endothelial keratoplasty.

RESULTS

Patients had a mean follow-up of 61 ± 33.7 months. Pain reduction was significant (p < .001) although it did not significantly correlate with the regularity of the superficial, intermediate or basal epithelial layers, nor with the retention of the amniotic membrane. No long-term structural changes that may hinder future penetrating keratoplasty were detected.

CONCLUSION

This procedure is a safe and effective long-term treatment for symptomatic bullous keratopathy patients.

Effect of topical steroid instillation on central corneal thickness in eyes with bullous keratopathy

PURPOSE

To examine the effects of topical steroid instillation on central corneal thickness in eyes with bullous keratopathy (BK).

STUDY DESIGN

Retrospective case series METHODS: Consecutive patients with BK who did not wish to receive corneal transplantation and were treated with 0.1% betamethasone eyedrops were included. Patients with BK treated with 5% sodium chloride (hypertonic saline) eyedrops served as controls. Central corneal thickness (CCT), best-corrected visual acuity (BCVA), intraocular pressure (IOP), BK etiology, and clinical courses from medical records were retrospectively reviewed. We compared the two groups for differences in CCT, BCVA and IOP before treatment and 2 weeks, 1 month, and 3 months after treatment.

RESULTS

Eighteen eyes of 18 patients who were treated with betamethasone and 18 eyes of 18 patients who were treated with hypertonic saline were included. There was no significant difference in CCT between the two groups before treatment. The reduction of CCT in the betamethasone group was significantly larger than in the hypertonic saline group at 2 weeks (p = 0.002), 1 month (p = 0.02), and 3 months (p = 0.001) after treatment. Complications such as infectious keratitis and IOP rise did not occur during the observation period.

CONCLUSIONS

Topical steroid instillation reduced central corneal thickness in eyes with BK.

Corneal endothelial cell dysfunction: etiologies and management

A transparent cornea is essential for the formation of a clear image on the retina. The human cornea is arranged into well-organized layers, and each layer plays a significant role in maintaining the transparency and viability of the tissue. The endothelium has both barrier and pump functions, which are important for the maintenance of corneal clarity. Many etiologies, including Fuchs’ endothelial corneal dystrophy, surgical trauma, and congenital hereditary endothelial dystrophy, lead to endothelial cell dysfunction. The main treatment for corneal decompensation is replacement of the abnormal corneal layers with normal donor tissue. Nowadays, the trend is to perform selective endothelial keratoplasty, including Descemet stripping automated endothelial keratoplasty and Descemet’s membrane endothelial keratoplasty, to manage corneal endothelial dysfunction. This selective approach has several advantages over penetrating keratoplasty, including rapid recovery of visual acuity, less likelihood of graft rejection, and better patient satisfaction. However, the global limitation in the supply of donor corneas is becoming an increasing challenge, necessitating alternatives to reduce this demand. Consequently, in vitro expansion of human corneal endothelial cells is evolving as a sustainable choice. This method is intended to prepare corneal endothelial cells in vitro that can be transferred to the eye. Herein, we describe the etiologies and manifestations of human corneal endothelial cell dysfunction. We also summarize the available options for as well as recent developments in the management of corneal endothelial dysfunction.

Tissue remodeling after ocular surface reconstruction with denuded amniotic membrane

Amniotic membrane (AM) has been widely used as a temporary or permanent graft in the treatment of various ocular surface diseases. In this study, we compared the epithelial wound healing and tissue remodeling after ocular surface reconstruction with intact amniotic membrane (iAM) or denuded amniotic membrane (dAM). Partial limbal and bulbar conjunctival removal was performed on New Zealand rabbits followed by transplantation of cryo-preserved human iAM or dAM. In vivo observation showed that the epithelial ingrowth was faster on dAM compared to iAM after AM transplantation. Histological observation showed prominent epithelial stratification and increased goblet cell number on dAM after 2 weeks of follow up. Collagen VII degraded in dAM within 2 weeks, while remained in iAM even after 3 weeks. The number of macrophages and α-SMA positive cells in the stroma of remodelized conjunctiva in the dAM transplantation group was considerably less. In conclusion, dAM facilitates epithelial repopulation and goblet cell differentiation, further reduces inflammation and scar formation during conjunctival and corneal limbal reconstruction.

Amniotic Membrane Transplantation in Reconstructive and Regenerative Ophthalmology

Background

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

Material/Methods

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

Results

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

Conclusions

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

Management of a neurotrophic deep corneal ulcer with amniotic membrane transplantation in a patient with functional monocular vision: A case report

RATIONALE

Amniotic membrane transplantation (AMT) has been performed therapeutically in humans for over 100 years. In recent 2 decades AMTs have been used increasingly and successfully to treat various types of ophthalmic indications.

PATIENT CONCERNS

An 83-year-old man was referred to our eye hospital with a refractory neurotrophic deep corneal ulcer of the left eye.

DIAGNOSES

The best-corrected visual acuity of the left eye was 0.5 (0.3 logMAR) and of the right eye was 0.05 (1.3 logMAR), which was caused by a central retinal vein occlusion 5 years previously. In cases of binocular vision, a large amniotic membrane patch can cover the whole cornea, including the optical axis. However, in cases with functional monocular vision, as in the case reported here, the AMT has to be performed without the involvement of the optical axis to ensure vision for the patient. Otherwise the patient would have a massively restricted view like looking through waxed paper for at least 2-4 weeks until the overlay dissolved.

INTERVENTIONS

For this case, an AMT using a modified sandwich technique was applied without involvement of the optic axis to ensure vision for the patient. This case report illustrates this eye's course of healing over time.

OUTCOMES

A reduction in the inflammation and healing of the corneal ulcer could be seen. In addition, the corneal vascularization decreased. Six months after the AMT, a slit-lamp examination revealed stable findings. The best-corrected visual acuity of the left eye had increased to 0.8 (0.1 logMAR).

LESSONS

To the best of our knowledge, a case report on the management of a neurotrophic deep corneal ulcer with AMT in a patient with functional monocular vision has never been undertaken before.

Long-term symptomatic relief of bullous keratopathy with amniotic membrane transplant

The purpose of this study was to assess the long-term outcome of patients with symptomatic bullous keratopathy after amniotic membrane transplant. A retrospective cohort study includes that 20 patients with symptomatic bullous keratopathy, who have underwent amniotic membrane transplant at the Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital & Alice Ho Miu Ling Hospital, Hong Kong between 04/1998 and 06/2011, were invited back. Clinical examination was performed, including, pain score assessment (pain score out of 10), epithelial healing, and vision. A total of 21 eyes of 20 patients returned for our study. The majority of eyes experienced pain reduction (94 %), with a significant mean pain score difference of 6.8 ± 2.6, 2-tail p < 0.001 (99 % CI 4.9-8.7). The mean pre-operative and post-operative pain scores were 7.3 ± 2.9 and 0.5 ± 1.0, respectively. 16 eyes (76 %) were completely pain free, and 10 eyes (47 %) remained symptom free after a mean follow-up of 39.0 ± 36.3 months (range 5-171 months). The median epithelial healing time was 2 weeks (range 1-20 weeks). Amniotic membrane transplant may be considered as a longer-term treatment for bullous keratopathy patients, especially in patients with poorer visual prognosis, but it may also be used as an interim measure for patients awaiting corneal transplant.

Alternatives to corneal transplantation for the management of bullous keratopathy

PURPOSE OF REVIEW

Corneal transplantation remains the gold-standard treatment for bullous keratopathy patients as it provides symptomatic relief and visual rehabilitation. As corneas are not always available for transplant, alternative treatments have to be considered for alleviation of discomfort and pain.

RECENT FINDINGS

Various treatment options available in such cases include conjunctival flaps, anterior stromal puncture, amniotic membrane transplantation, phototherapeutic keratectomy, bandage contact lenses, and hypertonic saline eye drops. A combination of the above treatments can be employed depending upon the severity of bullous keratopathy and co-existing corneal edema. New potential treatments include collagen cross-linking (CXL), cultured endothelial cell injection, and topical treatment with Rho-associated kinase (ROCK) inhibitor.

SUMMARY

There is a lack of clinical trials comparing the safety and efficacy of the currently available treatment options for the management of bullous keratopathy. The effect of these treatments on subsequent corneal transplant has not been observed. CXL seems to offer short-term benefit for relief of pain. Newer potential treatment modalities such as ROCK inhibitors are claimed to be useful for the reversal of early edema associated with corneal endothelial dysfunction; however, long-term clinical trials are awaited.

Human amniotic membrane transplantation: Different modalities of its use in ophthalmology

The amniotic membrane (AM) is the inner layer of the fetal membranes and consist of 3 different layers: the epithelium, basement membrane and stroma which further consists of three contiguous but distinct layers: the inner compact layer, middle fibroblast layer and the outermost spongy layer. The AM has been shown to have anti-inflammatory, anti-fibrotic, anti-angiogenic as well as anti-microbial properties. Also because of its transparent structure, lack of immunogenicity and the ability to provide an excellent substrate for growth, migration and adhesion of epithelial corneal and conjunctival cells, it is being used increasingly for ocular surface reconstruction in a variety of ocular pathologies including corneal disorders associated with limbal stem cell deficiency, surgeries for conjunctival reconstruction, as a carrier for ex vivo expansion of limbal epithelial cells, glaucoma surgeries and sceral melts and perforations. However indiscriminate use of human AM needs to be discouraged as complications though infrequent can occur. These include risk of transmission of bacterial, viral or fungal infections to the recipient if the donors are not adequately screened for communicable diseases, if the membrane is not processed under sterile conditions or if storage is improper. Optimal outcomes can be achieved only with meticulous case selection. This review explores the ever expanding ophthalmological indications for the use of human AM.

Update on amniotic membrane transplantation

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

Autologous tragal perichondrium transplantation: a novel approach for the management of painful bullous keratopathy

PURPOSE

To introduce autologous tragal perichondrium transplantation as a novel surgical modality for the management of intractable symptomatic bullous keratopathy.

METHODS

In three eyes of three patients with painful bullous keratopathy, autologous tragal perichondria were transplanted on the corneal surface with the human amniotic membrane transplanted above. We included an additional three eyes of three patients with painful bullous keratopathy who received amniotic membrane transplantation only to serve as controls. Clinical symptom outcomes were assessed using a visual analogue scale at postsurgical months 1, 3, 5, 7, and 9. In addition, transplanted tragal perichondrium and amniotic membrane complex tissue button obtained from one patient who underwent penetrating keratoplasty was evaluated by immunohistochemical analysis of CD34, vimentin, and alcian blue staining.

RESULTS

All three patients who underwent autologous tragal perichondrium and human amniotic membrane co-transplantation showed improvements in pain and tearing. However, all three patients in the control group experienced aggravation of tearing and no further improvement of pain 3 months after surgery. In addition, one patient in the control group developed premature degradation of the amniotic membrane. Histopathologic and immunohistochemical analysis showed intact surface epithelization and positive CD34, vimentin and alcian blue staining of transplanted tragal perichondria.

CONCLUSIONS

The tragal perichondrium has a high mechanical structural force and high potency due to well-organized epithelization and the presence of mesenchymal stem cells. Autologous tragal perichondrium transplantation may be an effective modality for the management of painful bullous keratopathy.

Iridoschisis associated with nanophthalmos and bullous keratopathy

Iridoschisis is a rare condition in which the iris stroma splits into anterior and posterior layers. Iridoschisis is associated with anterior segment abnormalities including keratoconus, lens subluxation and angle-closure glaucoma. We describe the first case in which iridoschisis has occurred in association with nanophthalmos. We also report the rare complication of irido-corneal touch and subsequent corneal decompensation. Nanophthalmos and irido-corneal touch are sight-threatening associations of iridoschisis and should be excluded in all patients with this rare condition.

A controlled study of amniotic membrane transplantation for acute Pseudomonas keratitis

OBJECTIVE

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

DESIGN

Prospective interventional case series with retrospective controls.

PARTICIPANTS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Amniotic membrane transplantation: An option for ocular surface disorders

BACKGROUND

Ocular surface disorders (OSD) are challenging to treat. They can introduce serious morbidity and might even lead to visual loss. In such situations, keratoplasty remains the last option. Amniotic membrane transplantation (AMT) has been shown to be effective in the management of ocular surface pathologies. The aim of the study was to assess the efficacy of AMT for various indications of OSD.

MATERIALS AND METHODS

Experience of AMT in 65 patients with different OSD was evaluated. The aim of AMT was to achieve symptomatic relief, reduced inflammation, recurrence, and corneal haze; improve epithelization, stromal healing and visual acuity; and delay keratoplasty. Fresh amniotic membrane was used in all cases by a single surgeon. Follow-up and observations were done to evaluate success of achieving the goal.

RESULTS

Indications for AMT included primary and recurrent pterygium, various types of corneal ulcers (non-healing ulcer, descemetocele, corneal thinning and perforation), spheroidal degenerations, chemical burn and bullous keratopathy. The aim of AMT was different in different etiological indications. Postoperative follow-up was between 6 and 18 months. Success and complication rate were observed. Symptomatic relief (reduced pain and redness) was seen in patients with various corneal ulcers, chemical burn and bullous keratopathy. Improved epithelialization and stromal healing was noted in corneal ulcer cases. In spheroidal degenerations, keratectomy with AMT improved vision. Recurrence of pterygium was low (4.61%); graft failure in the form of graft rejection was seen in only 3.07% cases of acute keratitis. Corneal vascularization (4.61%) was present but not severe enough to hamper vision. Success in gaining intended effect was the most significant result with AMT.

CONCLUSION

AMT in various ocular surface pathologies shows success in achieving the goal of symptomatic relief, improved epithelialization, stromal healing and vision. Reduction in inflammation, corneal haze and recurrence of original disease is achieved with minimum complications.

Sutureless amniotic membrane transplantation for severe bacterial keratitis

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Evaluation of the role of ProKera in the management of ocular surface and orbital disorders

OBJECTIVES

To report the efficacy and safety profile of sutureless and adhesiveless amniotic membrane device (ProKera, Bio-Tissue, Inc., Miami, FL) in the management of various ocular surface and orbital disorders.

METHODS

Twenty eyes of 20 patients underwent placement of 21 ProKera implants between March 2006 and July 2007 at the University of Texas Southwestern Medical Center. Patient demographics, indications for placement, and duration of ProKera retention were recorded. Outcomes measured included corneal epithelial healing, visual acuity, patient tolerance, and adverse events.

RESULTS

ProKera was most commonly used in patients with corneal neovascularization with or without limbal stem-cell deficiency (10 eyes). Other indications included recurrent pterygium or pseudopterygium (three eyes), anophthalmic orbit contraction (two eyes), persistent epithelial defects (two eyes), severe thinning in a corneal ulcer (one eye), benign hereditary intraepithelial dyskeratosis (one eye), and band keratopathy (one eye). The mean duration of ProKera retention was 25.3 days (range, 0-125) visual acuity improved in 12 eyes (60%). Immediate adverse events included residual epithelial defects after removal (five eyes) and spontaneous extrusion of the implant (four eyes). Six patients (30%) reported eye pain or headache and four eyes (20%) had recurrence of the primary pathology.

CONCLUSIONS

Sutureless and adhesiveless amniotic membrane transplantation is a safe and effective method to promote healing and reconstruction of the ocular surface and orbit with minimal side effects. Recurrence of the underlying primary pathology remains a concern. The advent of a newer, softer conformer ring may improve patient tolerability and limit discomfort.

Cultivated autologous limbal epithelial transplantation for symptomatic bullous keratopathy

We report the clinical outcome of cultivated autologous limbal epithelial transplantation for symptomatic bullous keratopathy in an 87-year-old female patient presenting with recurrent corneal erosion and intractable ocular pain. The patient refused corneal transplantation, and transplantation of a cultivated autologous limbal epithelial sheet was carried out to free her of the symptoms associated with chronic pseudophakic bullous keratopathy. Both integrity of transplanted epithelium and relief from intolerable ocular pain were achieved and maintained immediately after surgery. No complications were noted in either the transplanted eye or donor eye during the 43-month follow-up period. Our findings support that patients with bullous keratopathy not consenting to procedures to improve visual acuity in whom the primary aim is relief of symptoms may benefit from cultivated autologous limbal epithelial transplantation.

Prospective comparison of two suturing techniques of amniotic membrane transplantation for symptomatic bullous keratopathy

PURPOSE

To determine the outcomes of a modified amniotic membrane transplantation (AMT) suturing technique for pain and discomfort relief in patients with symptomatic bullous keratopathy (BK).

DESIGN

Randomized, double-blind controlled clinical trial.

METHODS

setting: Ankara Research and Training Hospital 1st and 2nd Eye Clinics, Ankara, Turkey. study population: This prospective study included 39 eyes (39 patients) with BK presenting with intractable pain or discomfort and poor visual potential. intervention: Patients were randomly assigned into two groups: in group 1 (21 patients), patients underwent a modified AMT suturing technique; a groove was prepared by vacuum trephine on the recipient cornea and the edges of the punch-shaped amniotic membrane (AM) were sutured to this groove with the basement membrane side up. In group 2 (18 patients), patients underwent the standard AMT suturing to the cornea. main outcome measure: During a mean follow-up of 27.3 +/- 8.5 months (standard deviation) (range, 12 to 36 months), epithelial healing, persistence of AM, pain relief, and visual changes were analyzed and were compared between groups.

RESULTS

The mean age (P = .15), the mean follow-up (P = .73), and the mean preoperative visual acuity (P = .53) were similar in both groups. With the modified suturing technique, the postoperative visual acuity was better (P = .03), epithelialization time was shorter (P < .001), and the AM remained longer (P < .001). Successful epithelialization was achieved in 20 eyes (95.3%) in group 1, and in 16 eyes (88.9%) in group 2 (P = .586). The pain scores of patients in group 1 remained stable (P = .223) over time, however increased from the first week to the third month postoperatively in group 2 (P = .046).

CONCLUSIONS

The modified AMT suturing technique has a similar epithelialization rate to standard AMT suturing to cornea. Though technically more demanding, shorter epithelialization time, longer persistence of AM, and stable pain scores in the postoperative period makes this a promising method for the treatment of symptomatic BK.

Amniotic membrane in ophthalmology: indications and limitations

The amniotic membrane remains a useful tool in the treatment of several ophthalmic conditions, especially those related to the ocular surface. However, the 'success' reported in individual case reports and case series is not substantiated in the few published randomised controlled trials. More often than not, it is not as good as existing alternative options and, at best, is as good but with probably an increased cost. The variable outcomes could be related to inter and intra donor variations in the membrane and the depletion or alterations in its constituents subsequent to processing and storage. The membrane thus is a fairly 'non-standardised product' making comparisons of different applications and indications difficult. The potential for 'epidemic' infections, such as HIV, hepatitis B and C, is a serious issue as, in many parts of the world, fresh unquarantined membrane, at times with no tests for the above infectious agents, is being used. The exact mechanism of action of the membrane is not known but the consensus is that it acts as a substrate or scaffold for host cells to populate and thus facilitate healing and repair. The development of a standard 'synthetic membrane' using collagen or polymer matrices impregnated with putative beneficial ingredients, such as growth factors and antimicrobials, is being considered and may prove to be a step in the right direction.

Amniotic membrane transplantation: indications and results

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Amniotic membrane transplantation for persistent corneal epithelial defects in eyes after penetrating keratoplasty

PURPOSE

To determine the primary success and recurrence rate of amniotic membrane transplantation (AMT) for the treatment of persistent corneal epithelial defects (PEDs) in eyes after penetrating keratoplasty (PK).

DESIGN

Retrospective, non-randomized, observational case series.

METHOD

AMT was performed in 24 eyes of 24 patients with erosions (n=6) or ulcers (n=18), which were resistant to medical therapy. All eyes had undergone one (42%) or more PKs before AMT. After the removal of epithelium and pannus (if present), one or more layers of AM ('graft' (n=3), 'patch' (n=5), 'sandwich'=combination of graft/patch (n=16)) were transplanted. Main outcome measures included 'surgical success' (epithelium closed within 4 weeks after AMT), and 'recurrence' (new epithelial defect developing during follow-up after surgical success).

RESULTS

The rate of surgical success was 70% and was found to be inversely proportional to the number of previous PKs. Defects limited only to the centre of the graft had a higher success rate (central: 100%, non-central: 61%). A total of 44% successful eyes (erosions: 75% vs ulcers: 33%) had a recurrence after a mean follow-up of 16+/-13 months. The rate of surgical success was highest (81 vs 67 vs 25%) and the rate of recurrence was lowest (38 vs 90 vs 100%) with the sandwich technique in contrast to the graft or patch techniques used alone.

CONCLUSIONS

AMT may be beneficial in the treatment of PEDs after PK, especially when applying the sandwich technique. Recurrences seem to be more frequent, if PK preceded AMT.