Amniotic membrane transplantation for painful bullous keratopathy

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 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.

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.

Augmented dried versus cryopreserved amniotic membrane as an ocular surface dressing

Purpose

Dried amniotic membrane (AM) can be a useful therapeutic adjunct in ophthalmic surgery and possesses logistical advantages over cryopreserved AM. Differences in preservation techniques can significantly influence the biochemical composition and physical properties of AM, potentially affecting clinical efficacy. This study was established to investigate the biochemical and structural effects of drying AM in the absence and presence of saccharide lyoprotectants and its biocompatibility compared to cryopreserved material.

Methods

AM was cryopreserved or dried with and without pre-treatment with trehalose or raffinose and the antioxidant epigallocatechin (EGCG). Structural and visual comparisons were assessed using electron microscopy. Localisation, expression and release of AM biological factors were determined using immunoassays and immunofluorescence. The biocompatibility of the AM preparations co-cultured with corneal epithelial cell (CEC) or keratocyte monolayers were assessed using cell proliferation, cytotoxicity, apoptosis and migration assays.

Results

Drying devitalised AM epithelium, but less than cryopreservation and cellular damage was reduced in dried AM pre-treated with trehalose or raffinose. Dried AM alone, and with trehalose or raffinose showed greater factor retention efficiencies and bioavailability compared to cryopreserved AM and demonstrated a more sustained biochemical factor time release in vitro. Cellular health assays showed that dried AM with trehalose or raffinose are compatible and superior substrates compared to cryopreserved AM for primary CEC expansion, with increased proliferation and reduced LDH and caspase-3 levels. This concept was supported by improved wound healing in an immortalised human CEC line (hiCEC) co-cultured with dried and trehalose or raffinose membranes, compared to cryopreserved and fresh AM.

Conclusions

Our modified preservation process and our resultant optimised dried AM has enhanced structural properties and biochemical stability and is a superior substrate to conventional cryopreserved AM. In addition this product is stable and easily transportable allowing it to be globally wide reaching for use in clinical and military sectors.

"Swiss roll" amniotic membrane technique for the management of corneal perforations

PURPOSE

To describe a novel technique for using amniotic membrane in the management of corneal perforations.

METHODS

Interrupted 10-0 nylon sutures are passed across the perforation site. A roll of amniotic membrane is then placed across the row of preplaced sutures, and the sutures are tied to secure the membrane. An amniotic membrane patch is placed over the graft, which is then protected by a bandage contact lens.

RESULTS

We illustrate the results of our 2 most recent patients.

CONCLUSIONS

Amniotic membrane has been widely used in ocular surgery. We recommend the "Swiss roll" amniotic membrane graft technique in cases of severe corneal thinning or localized perforations.

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 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.