Lamellar keratoplasty in the management of inflammatory corneal ulceration and perforation

Prognosis and etiology of traumatic and non-traumatic corneal perforations in a tertiary referral hospital: a 30-year retrospective study

PURPOSE

To clarify the prognosis of corneal perforation, we compared the etiology and characteristics of patients with traumatic and non-traumatic corneal perforations.

METHODS

This retrospective observational study included patients treated for traumatic or non-traumatic corneal perforations at a single tertiary hospital from 1989 to 2019. The variables collected included the primary cause of corneal perforation, final best-corrected visual acuity (BCVA), and treatment administered. The initial treatment administered and treatment success rates were compared between the traumatic and non-traumatic groups. Multivariate linear regression analysis was performed to determine the predictors of final visual acuity.

RESULTS

Ninety eyes of 90 patients (mean age, 61.1 ± 19.7 years) were included. Traumatic and non-traumatic corneal perforations occurred in 40 (44.4%) and 50 eyes (55.6%), respectively. Among non-traumatic causes, infection and autoimmune disease were the causes for corneal perforation in 18 (20.0%) and 12 eyes (13.3%), respectively. The success rate for the closure of the perforated site with the initial procedure was significantly higher in traumatic corneal perforations than in non-traumatic corneal perforations (90.0% and 72.2%, respectively; p = 0.038). Patients with traumatic corneal perforation had significantly better final BCVA than those with non-traumatic corneal perforation (0.71 ± 1.18 and 1.52 ± 1.12, respectively; p = 0.0016). On multivariate analysis, older age and non-traumatic corneal perforation were significantly related to the final lower BCVA (p < 0.001 and p = 0.029, respectively).

CONCLUSION

Traumatic corneal perforation demonstrated a significantly better prognosis than non-traumatic corneal perforation. It is critical to consider the primary cause of corneal perforation to anticipate prognosis.

Lamellar corneal patch grafts in the management of corneal thinning and perforations without using extra corneas

OBJECTIVES

To report the tectonic role of circular and square-shaped lamellar grafts without using extra corneas.

MATERIALS AND METHODS

We retrospectively reviewed 23 lamellar patch grafts performed over a six-year period for various tectonic indications in corneal thinning and perforations. The anterior stroma of corneal endothelium peeled for Descemet Membrane Endothelial Keratoplasty were used to prepare circular lamellar corneal grafts. After punch trepanation of donor corneas for penetrating keratoplasty, the remaining rim of the cornea was used to prepare square-shaped grafts.

RESULTS

Circular lamellar grafts were used in 13 eyes that had paracentral or central corneal thinning or perforations. Square-shaped grafts were used in 10 eyes, nine of which had peripheral corneal thinning or perforations, and one, limbal. Anatomical success after tectonic grafts was achieved in 22 of 23 eyes (95.6%) at a mean follow-up of 9.83 ± 6.27 months. The mean of the best-corrected visual acuity improved from logMAR 2.29 ± 0.23 preoperatively to logMAR 1.35 ± 0.2 postoperatively, at the final follow-up.

CONCLUSIONS

The main disadvantage of patch grafts is the shortage in corneal supply due to insufficient cornea donation in developing countries like Turkey. By evaluating unused corneal rims, extra corneas will not be required.

Extensive autoimmune keratolysis with subsequent corneal perforation managed with tectonic endothelial keratoplasty

Purpose

To report a case of corneal perforation secondary to an extensive rheumatologic corneal melt, that was successfully managed via systemic immunosuppression and internal tectonic endothelial keratoplasty (TEK).

Observations

A 55-year-old male with undiagnosed rheumatoid arthritis presented with a progressively enlarging area of peripheral ulcerative keratitis with extensive keratolysis which subsequently perforated despite treatment with oral steroids. The structural integrity of the globe was restored via a combination of cyanoacrylate glue and tectonic endothelial keratoplasty (TEK). This technique provided long term structural support and improved visual acuity.

Conclusions and Importance

TEK grafts represent a viable treatment option in a subset of patients with corneal perforation secondary to an extensive corneal melt. The familiarity and relative ease of the surgical technique along with a lack of corneal sutures represents an alternate technique when compared to full thickness or lamellar keratoplasty. Further, through the use of anterior segment spectral domain optical coherence tomography (SD-OCT) we demonstrate that the donor graft integrated within the host cornea. To our knowledge, this represents the first case in the literature of corneal perforation secondary to an inflammatory corneal melt that was successfully managed with internal tectonic endothelial keratoplasty.

Effect of Stem Cell-Derived Extracellular Vesicles on Damaged Human Corneal Endothelial Cells

Purpose

Human corneal endothelial cells (HCECs) are essential to visual function; however, since they have limited proliferative capacity in vivo, they are prone to corneal endothelial dysfunction. At present, the only treatment is a corneal transplantation from donor cadavers. Also, due to a global shortage of donor corneas, it is important to find alternative strategies. Recent studies highlight that stem cell–derived extracellular vesicles (EVs) play a relevant role in stem cell-induced regeneration by reprogramming injured cells and inducing proregenerative pathways. The aim of this work is to evaluate whether EVs derived from mesenchymal stem cells (MSC-EVs) are able to promote regeneration of damaged HCECs.

Methods

We isolated HCECs from discarded corneas in patients undergoing corneal transplantation or enucleation (N = 23 patients). Bone marrow mesenchymal stem cells (MSCs) were obtained from Lonza, cultured, and characterized. MSC-EVs were obtained from supernatants of MSCs. In order to establish a valid in vitro damage model to test the regenerative potential of EVs on HCECs, we evaluated the proliferation rate and the apoptosis after exposing the cells to serum-deprived medium at different concentrations for 24 hours. We then evaluated the HCEC migration through a wound healing assay.

Results

In the selected serum deprivation damage conditions, the treatment with different doses of MSC-EVs resulted in a significantly higher proliferation rate of HCECs at all the tested concentrations of EVs (5‐20 × 10³ MSC-EV/cell). MSC-EVs/cell induced a significant decrease in number of total apoptotic cells after 24 hours of serum deprivation. Finally, the wound healing assay showed a significantly faster repair of the wound after HCEC treatment with MSC-EVs.

Conclusions

Results highlight the already well-known proregenerative potential of MSC-EVs in a totally new biological model, the endothelium of the cornea. MSC-EVs, indeed, induced proliferation and survival of HCECs, promoting the migration of HCECs in vitro.

Corneal transplantation after failed grafts: Options and outcomes

Corneal transplantation is the most commonly performed human tissue transplantation procedure worldwide. Because of the large number of transplants, corneal graft failure has become one of the most common indications for corneal transplantation. The relatively recently developed lamellar transplant techniques have brought about specific potential complications leading to graft failure that may require different approaches to repeat transplantation other than penetrating keratoplasty. On the other hand, these new lamellar techniques also provide novel ways of rescuing failed penetrating grafts, with potential advantages over successive penetrating keratoplasties, such as reduced intraoperative risks and faster visual rehabilitation. We summarize the incidence and risk factors of graft failure for penetrating and lamellar (stromal and endothelial) corneal transplants and discuss the various surgical alternatives currently available to rescue such failed grafts, with a focus on the reported outcomes and limitations.

Shaped corneal transplantation surgery

Since its inception in 1905, keratoplasty techniques have continuously evolved. Shaped keratoplasty procedures have allowed corneal surgeons to use complex graft-host junctions and non-circular graft designs to optimise wound strength and healing, facilitate early suture removal and expedite visual rehabilitation. While this was initially limited to penetrating procedures, shaped lamellar keratoplasty techniques have since emerged. Furthermore, the arrival of femtosecond laser has dramatically increased the range of graft designs available to surgeons, due to the technology's ability to precisely cut complex wound edges. This review describes the broad range of shaped keratoplasty grafts currently available and elaborates on their respective advantages and disadvantages in relation to conventional keratoplasty.

Corneal transplantation in the modern era

Corneal blindness is one of the major causes of reversible blindness, which can be managed with transplantation of a healthy donor cornea. It is the most successful organ transplantation in the human body as cornea is devoid of vasculature, minimizing the risk of graft rejection. The first successful transplant was performed by Zirm, and since then, corneal transplantation has seen significant evolution. It has been possible because of the relentless efforts by researchers and the increase in knowledge about corneal anatomy, improvement in instruments and advancements in technology. Keratoplasty has come a long way since the initial surgeries wherein the whole cornea was replaced to the present day where only the selective diseased layer can be replaced. These newer procedures maintain structural integrity and avoid catastrophic complications associated with open globe surgery. Corneal transplantation procedures are broadly classified as full-thickness penetrating keratoplasty and partial lamellar corneal surgeries which include anterior lamellar keratoplasty [sperficial anterior lamellar keratoplasty (SALK), automated lamellar therapeutic keratoplasty (ALTK) and deep anterior lamellar keratoplasty (DALK)] and posterior lamellar keratoplasty [Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK)] broadly.

Corneal grafting for the treatment of full-thickness corneal defects in dogs: a review of 50 cases

OBJECTIVE

To describe corneal grafting for the treatment of full-thickness corneal defects in dogs and to determine its effectiveness in preserving vision.

METHODS

A review of the medical records of dogs that underwent corneal grafting following corneal perforations (≥3 mm) at the VTH-UAB from 2002 to 2012 was carried out.

RESULTS

Fifty dogs of different breed, age and gender were included. Brachycephalic breeds were overrepresented (37/50;74%). All cases were unilateral, with euryblepharon being the most common concurrent ocular abnormality (20/50;40%). Full-thickness penetrating keratoplasties (FTPK) were performed in 21/50 eyes (42%) and lamellar keratoplasties (LK) in 29/50 eyes (58%). Frozen grafts (FroG) were used in 43/50 eyes (86%) and fresh homologous grafts (FreHoG) in 7/50 (14%). Of the former group, 26 were homologous (FroHoG:60%) and 17 heterologous (FroHeG:40%). A combination of topical medication (antibiotics, corticosteroids, cycloplegics, and 0.2% cyclosporine A) and systemic mycophenolate mofetil was administered. Median follow-up time was 200 days. Postsurgical complications included wound dehiscence (6/50;12%) and glaucoma (4/50;8%). Clinical signs of graft rejection were diagnosed as follows: FroHoG (13/26;50%), FroHeG (11/17;65%), FreHoG (4/7;57%), FTPK (12/21;57%), and LK (16/29;55%). Medical treatment successfully controlled graft rejection in 11/28 eyes (39%). Good anatomical outcome was achieved in 86% (43/50), of which 95% (41/43) were visual at last examination, with moderate opacification to complete transparency of the graft present in 48.2%.

CONCLUSIONS

Corneal grafting is an effective surgical treatment for full-thickness corneal defects in dogs. If graft rejection is present, additional medical or surgical therapy may be necessary, achieving a highly satisfactory visual outcome.

Clinical study of therapeutic ocular surface medium for persistent epithelial defect

PURPOSE

To investigate therapeutic ocular surface medium (TOSM), a potential physiological tear replacement therapy, for persistent epithelial defect (PED).

METHODS

11 eyes of 10 patients with PED for ≥ 2 weeks without improvement despite conventional treatment were enrolled in a prospective pilot study of TOSM over 1 month.

RESULTS

Healing of the PED occurred in 3 out of the 11 eyes at 1, 2 and 4 weeks, respectively. At week 4, 2 eyes were almost healed (PED area ≤ 0.5 mm(2)). In 4 of the remaining 6 eyes, the PED area was reduced. Failure occurred in 1 case with end-stage ocular cicatricial pemphigoid and severe dry eye, and 1 patient withdrew due to a mild allergic reaction. There were no serious or irreversible side effects with TOSM.

CONCLUSIONS

TOSM is a potential novel physiological therapy for PED that, unlike autologous serum, has the potential to be easily manufactured and widely available.

Lamellar corneal transplantation

Penetrating keratoplasty (PK) has been the gold standard for the surgical treatment of most corneal pathologies; lamellar keratoplasty that only replaces the diseased corneal layers has recently evolved as an alternative, however. Innovations in surgical technique and instrumentation provide visual outcomes comparable to PK. We review the indications and outcomes of various techniques of anterior lamellar surgery developed to treat stromal disorders. Similarly, we discuss posterior lamellar keratoplasty techniques such as Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty. Posterior lamellar keratoplasty provides faster visual rehabilitation than PK in cases of Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. In addition, for medically unresponsive infectious keratitis, therapeutic anterior lamellar keratoplasty yields similar graft survival to PK without an increased risk of disease recurrence.

Validation of tissue quality parameters for donor corneas, designated for emergency cases: corneal graft survival

PURPOSE

To validate tissue quality parameters for donor corneas designated for emergency grafting for corneal graft survival.

METHODS

In a longitudinal cohort follow-up study, 131 emergency penetrating grafts were studied. Grafts were performed with a pool of organ-cultured donor corneas designated for emergency grafting and prepared for immediate use with all safety tests performed. Assignation criteria were: corneas with a small superficial stromal opacity but meeting all selection criteria for PKP tissue and corneas without stromal opacity, but an endothelial cell density from 1800 to 2300 cells/mm(2) or mild polymegathism or pleomorphism. Cox multivariate regression analysis, Kaplan-Meier survival and log rank test were applied.

RESULTS

Of the 131 keratoplasties, 115 could be followed. One eye was lost during surgery because of an expulsive bleeding. In 15 cases, a conjunctival transplantation finished off the penetrating graft. Corneal graft survival was not significantly related to the presence of PKP quality of the donor endothelium, neither with a cloudy graft nor with endothelial decompensation as the cause of failure. Main risk factors for a failed graft were vascularization of the host cornea (p=0.0001), the presence of a systemic auto immune disease in the recipient (p=0.003) and the disease leading to the (imminent) perforation and emergency graft (p=0.021).

CONCLUSION

A selected pool of donor corneas designated for emergency grafting that does not interfere with the scheduled procedures allows more efficient and safe use of donor tissue in case of a(n) (imminent) perforation. Corneal graft survival rates justify the criteria for selection.

Deep anterior lamellar keratoplasty: indications, surgical techniques and complications

The concept of lamellar keratoplasty (LK) is not new. However, it had been abandoned and largely replaced by the time-honored technique of penetrating keratoplasty (PK) because LK is technically demanding, time consuming and gives suboptimal visual outcomes due to interface irregularity arising from manual lamellar dissection. Recent improvements in surgical instruments and introduction of new techniques of maximum depth of corneal dissection as well as inherent advantages such as preservation of globe integrity and elimination of endothelial graft rejection have resulted in a re-introduction of LK as an acceptable alternative to conventional PK. This review article describes the indications, different techniques, clinical outcomes and complications of deep anterior LK.

Multilayered Gore-Tex patch for temporary coverage of deep noninfectious corneal defects: surgical procedure and clinical experience

PURPOSE

To evaluate the multilayer Gore-Tex patch as temporary coverage of deep, noninfectious corneal defects.

DESIGN

Retrospective, interventional case series.

METHODS

SETTING

University Medical Center Schleswig-Holstein, Kiel, Germany.

PATIENT POPULATION

Thirty-nine eyes of 38 patients with noninfectious, deep corneal defects. Underlying disorders included neurotrophic or immunologic ulcers in 37 eyes (94.9%) and traumatic defects in 2 eyes (5.1%). Intervention procedures: Corneal defects were covered with multiple Gore-Tex layers, of which the uppermost was sutured to the cornea. The Gore-Tex patch was kept in place until an appropriate corneal transplant was obtained and effective systemic immunosuppression was initiated.

MAIN OUTCOME MEASURES

Long-term preservation of the eye, frequency of resuturing of the Gore-Tex patch, and best-corrected visual acuity.

RESULTS

In 38 cases, the eye could be preserved. In 10 eyes, additional sutures were required. Before surgery, the mean best-corrected visual acuity (logMAR) was 1.14 ± 0.45 (20/250), and that at final follow-up was 1.13 ± 0.41 (20/250). The Gore-Tex patch remained in place 4 days to 32 months (mean, 6.4 ± 8.3 months) until corneal transplantation (27 eyes) or until an alternative way of defect coverage could be performed. Three eyes did not require further coverage after explantation of the Gore-Tex patch. In 6 eyes, either the Gore-Tex patch was kept in place or the patients died.

CONCLUSIONS

Temporary coverage of deep corneal defects with multilayer Gore-Tex patches allows time until an appropriate corneal transplant is obtained. The technique is particularly useful in patients with underlying autoimmune disorders, because an effective systemic immunosuppression can be initiated before corneal transplantation.

Deep anterior lamellar keratoplasty versus penetrating keratoplasty for keratoconus: a clinical trial

PURPOSE

To compare deep anterior lamellar keratoplasty (DALK) using the big-bubble technique to penetrating keratoplasty (PK) in patients with keratoconus.

MATERIALS AND METHODS

In this clinical trial, patients with moderate to advanced keratoconus with poor spectacle-corrected visual acuity and intolerant to contact lens wear were enrolled. DALK was performed using the big-bubble technique, and a full-thickness donor cornea without Descemet membrane was sutured to the recipient bed. PK was performed conventionally with a Hessburg-Barron suction trephine. Three types of suturing were used for both groups. Postoperative refractive errors, best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and higher order aberrations (HOAs) were compared between the study groups.

RESULTS

The study included 81 eyes of 81 patients. Forty-six eyes underwent DALK from which 4 were excluded because of failure to achieve bared Descemet membrane. Thirty-five eyes received PK. Mean patient age was 26.91 ± 7.9 versus 30.89 ± 10.3 years in the DALK and PK groups, respectively (P = 0.06). Mean follow-up period was 22.0 ± 7.9 months in the DALK group and 24.6 ± 3.5 months in the PK group (P = 0.32). Mean postoperative spherical equivalent refractive error was -3.23 ± 3.4 diopters in the DALK group versus -2.22 ± 4.6 diopters in the PK group (P = 0.28), and mean postoperative BCVA was 0.18 ± 0.08 and 0.15 ± 0.10 logarithm of the minimum angle of resolution, respectively (P = 0.12). CSF and total aberrations and HOAs were comparable in the study groups.

CONCLUSIONS

DALK is an effective alternative surgical procedure for patients with keratoconus; the outcomes are comparable to PK in terms of refractive errors, BCVA, CSF, and HOAs.

Validation of tissue quality parameters for donor corneas designated for emergency use in preservation of the globe

PURPOSE

To validate tissue quality parameters for donor corneas designated for emergency grafting to preserve the globe.

METHODS

In a longitudinal cohort follow-up study, 151 emergency grafts in the Netherlands were studied. Grafts were performed with a pool of organ-cultured donor corneas designated for emergency grafting and prepared for immediate use with all safety tests performed. Assignation criteria were corneas with a small superficial stromal opacity but meeting all selection criteria for penetrating keratoplasty tissue and corneas without stromal opacity but an endothelial cell density from 1800 to 2300 cells per square millimeter or mild polymegethism or pleomorphism. Cox multivariate regression analysis, Kaplan-Meier survival, and log rank test were applied.

RESULTS

All requests for corneal tissue were honored within 24 hours. Ninety-one patients showed a complete and 60 an imminent perforation. One hundred thirty-one penetrating grafts and 20 lamellar grafts have been used. The globes were saved in 140 of the 151 patients (92.7%). Globe preservation was not significantly related to the absence of penetrating keratoplasty quality of the donor endothelium, the type of grafting, the degree of vascularization in the host cornea, or diabetic disease in the recipient. The main risk factor for globe preservation was the presence of a systemic autoimmune disease in the recipient (P = 0.0021).

CONCLUSIONS

A selected pool of donor corneas designated for emergency grafting, that does not interfere with the scheduled procedures, allows more efficient and safe use of donor tissue in case of an imminent perforation. Globe preservation rates justify the quality criteria for designation of this tissue.

Patterns of rejection after deep lamellar keratoplasty

PURPOSE

To describe 7 patients with keratoconus who underwent graft rejection after deep lamellar keratoplasty (DLK).

DESIGN

Retrospective case series and literature review.

PARTICIPANTS

Seven patients who underwent DLK for keratoconus between 1997 and 2001. These cases were compared with a previously reported case series of DLK for keratoconus between 1994 and 2001.

METHODS

The clinical records of patients with rejection after DLK for keratoconus were examined to obtain details of the surgery, the interval to the rejection episode and its treatment, best-corrected visual acuity (BCVA), and presence of potential risk factors for rejection. The clinical features and course of rejection were compared with reports of corneal graft rejection in the literature. Patient characteristics were compared with the reported series of patients who had DLK for keratoconus.

MAIN OUTCOME MEASURES

Final BCVA and number, type, and features of rejection episodes.

RESULTS

The mean age was 28 years, with a median follow-up of 40 months after DLK. Rejection occurred between 3 and 41 months postoperatively. Four patients were atopic, 4 had a penetrating keratoplasty in the fellow eye, and 1 had deep stromal vessels in the host cornea. Isolated epithelial rejection occurred in 1 patient and stromal rejection in 3 cases, and there were 3 cases of mixed stromal and epithelial rejection. Topical steroid therapy led to reversal of rejection in 5 cases. Two patients had progressive vascularization with graft failure and poor vision. The median final BCVA was 6/9 (range, 6/6-6/36).

CONCLUSIONS

Deep lamellar keratoplasty avoids the risk of endothelial rejection, but epithelial or stromal rejection may still occur. Recognition and appropriate treatment are needed to prevent graft failure with subsequent visual loss.

Lamelläre Keratoplastik

In 1840 Mühlbauer was the first to describe a technique for anterior lamellar keratoplasty (LKP). However, in the second half of the twentieth century penetrating keratoplasty (PKP) became the gold standard. Although it is associated with a higher risk for serious complications -- it is technically easier to perform and avoids wound healing reactions in the lamellar interface and thus resulting in better visual acuity. In view of the pathology, replacing all layers of the cornea including healthy parts can be considered therapeutic "overkill" for many corneal graft indications. Several innovative surgical techniques have recently been described which allow the lamellar dissection of recipient and donor cornea with good reproducibility in almost every desired depth. This now allows the recipient endothelium and Descemet's membrane to be selectively replaced or preserved and to avoid formation of an optical barrier in the lamellar interface in eyes undergoing lamellar keratoplasty for optical indications. The most important principal advantage of an anterior LKP -- to minimize the risk of an immune reaction in the graft -- is even more important in tectonic indications. From the large number of variations, the surgical technique, results, and problems with anterior and posterior LKP for optical indications as well as lamellar segment keratoplasty and epikeratoplasty for tectonic indications are discussed.

Microsurgical treatment of Mooren's corneal ulcer

This study evaluated the effect of microsurgery of lamellar keratoplasty (LKP) on Mooren's corneal ulcer. The surgical effect, postoperative astigmatism, postoperative vision, postoperative ulcer recurrence, and surgical complications of 2 groups of consecutive Mooren's ulcer inpatients treated respectively by non-microsurgery of LKP and microsurgery of LKP were analyzed. There were significant differences of the effect, postoperative astigmatism, postoperative vision, postoperative ulcer recurrence, and surgical complications between the 2 groups. The effect and postoperative vision of the microsurgery-treated group were better than those of the non-microsurgery-treated group. The postoperative astigmatism, postoperative ulcer recurrence, and surgical complications of the microsurgery-treated group were less than those of the non-microsurgery-treated group. Microsurgery of LKP of Mooren's corneal ulcer can greatly improve the cure rate of the disease and postoperative vision, and reduce surgical complication and postoperative ulcer recurrence.

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.

[Severe Moorens ulcer: efficacy of monthly cyclophosphamide intravenous pulse treatment]

PURPOSE

Mooren's ulcer (MU) is a chronic peripheral corneal ulceration featuring conjunctival immunoglobulin deposits. It is considered as the result of a limbic immune process with hyperactivation of T and B lymphocytes. The etiology remains unknown. The response to topical steroid therapy and surgical procedures usually poor and the visual outcome can be devastating.

METHODS

Clinical follow-up of 3 patients who had rebel MU to conventional therapy, and were treated with 1g monthly intravenous cyclophosphamide.

RESULTS

First patient was a 24-years-old man who had MU in his left eye. The response to surgical procedure and intravenous steroid treatment was poor and corneal perforation occurred. The affected cornea healed after 9 months of Cy treatment. The second patient was a 50-years-old man who had MU in his left eye, which did not improved with lamellar keratoplasty and topical steroid therapy. Corneal healing was obtained after 20 months of Cy treatment. The third patient was a 70-years-old man who presented with a furrowed MU in his right eye which healed with conjunctival resection and 4 months of Cy perfusion. No adverse effects of Cy was noted as opposed to Cy given orally.

CONCLUSION

We report the effectiveness of 1g monthly intravenous cyclophosphamide (Cy) treatment in rebel MU. We suggest that immunosuppressive therapy using IV monthly Cy may be proposed in severe rebel MU.

Tectonic grafts for corneal thinning and perforations

PURPOSE

To evaluate the success of tectonic grafts in cases of corneal thinning and perforations.

METHODS

We performed 42 tectonic grafts in 41 eyes of 40 patients. Three types of tectonic grafts were used in our treatment protocol. These were (a) full-thickness grafts, (b) mushroom grafts, and (c) lamellar grafts. The parameters evaluated were indications, visual acuity, location, size and type of graft, postoperative outcome, and complications, if any.

RESULTS

The most common indication for tectonic grafts was corneal thinning and perforation subsequent to infection (12 eyes) followed by those due to immunologic causes (six eyes) and trauma (six eyes). Twenty-four full-thickness tectonic grafts, nine mushroom grafts, and nine lamellar patch grafts were performed. Anatomical success was achieved in 35 of 41 (85.4%) eyes. Visual acuity of 6/24 or better was obtained in 29 of 41 (70.73%) eyes. The mean of best-corrected visual acuity (expressed in decimal) improved from 0.2 +/- 0.26 to 0.34 +/- 0.26 at an average follow-up of 10.83 +/- 6.27 months. The major complications were peripheral anterior synechiae in four eyes (9.76%) and graft melting in five eyes (12.2%).

CONCLUSIONS

Tectonic graft is a useful therapeutic option in selected cases of corneal thinning and perforations because it effectively restores the integrity of the eye and allows acceptable visual rehabilitation.

Amniotic membrane, tear film, corneal, and aqueous levels of ofloxacin in rabbit eyes after amniotic membrane transplantation

PURPOSE

We evaluated ocular penetration and drug levels in tears after topical ofloxacin instillation in rabbit eyes with amniotic membrane transplantation (AMT).

METHODS

Forty-eight New Zealand White rabbits were used. In the first set of experiments, 24 rabbits (24 eyes) were divided into four groups according to the epithelial removal or AMT. Topical ofloxacin was instilled four times every 15 minutes. One hour after the last eyedrop, the concentration of ofloxacin in the amniotic membrane, cornea, and aqueous humor was evaluated. In the second set of experiments, 24 rabbits were divided into six groups according to AMT (transplantation of lyophilized or fresh amniotic membrane) or duration of application. Ofloxacin ointment or two drops of ofloxacin were applied to the right eye, and then tear samples were collected after 0.5, 1, 2, 4, and 6 hours for the analysis of ofloxacin concentration.

RESULTS

Mean ofloxacin concentrations in the cornea and aqueous humor were statistically higher in deepithelialized cornea regardless of AMT (p < 0.05). The mean tear levels of ofloxacin in the AMT groups were statistically higher than those in non-AMT groups (p < 0.05). There was no statistical significance in the tear level of ofloxacin between lyophilized amniotic membrane groups and fresh amniotic membrane groups nor between 1-hour amniotic membrane-attached groups and 6-hour amniotic membrane-attached groups.

CONCLUSION

Amniotic membrane transplantation seems to interfere with the ocular penetration of topical ofloxacin in normal rabbit corneas but enhances ofloxacin penetration in corneas with epithelial defects. The ofloxacin level in tears was higher in eyes with AMT up to 1 hour after topical ofloxacin use. Therefore, it seems that amniotic membrane has some potential to act as an effective drug delivery system.

The evolution of lamellar grafting techniques over twenty-five years

The history of lamellar keratoplasty (LK) surgery spans over 100 years, and the advantages of lamellar surgery have long been known. The surgery is usually used for tectonic purposes; however, new techniques and technology over the past 25 years have expanded the applications of LK in optical rehabilitation. Instrumentation such as viscoelastics, diamond knives, ultrasonic pachymetry, artificial anterior chambers, advanced microkeratomes, and the excimer laser have enhanced our ability to work more safely in the tedious microsurgical environment of the lamellar procedure. Advances in surgical techniques such as deep lamellar anterior keratoplasty and deep lamellar endothelial keratoplasty have expanded the application of lamellar surgery to endothelial replacement and have achieved visual results approaching those of penetrating keratoplasty while reducing the rate of rejection and improving the long-term graft stability. As research continues, LK promises to be an increasingly important option for the corneal surgeon.

Lamellar corneal patch grafts in the management of corneal melting

PURPOSE

To evaluate the clinical indications and results of reconstructive (tectonic) lamellar keratoplasty in corneal melting.

METHODS

A nonrandomized, uncontrolled retrospective case series of 64 consecutive patients (80 eyes) who underwent lamellar keratoplasty for corneal melting at our institution over a 17-year period. We reviewed the (a) clinical indications, (b) visual acuities, (c) postoperative corneal clarity, and (d) post-operative complications. Comparisons in visual acuity were made between central and peripheral corneal melts. The statistical influence of patient age, diagnosis, and corneal graft size on pre- and postoperative visual acuity values also was studied.

RESULTS

Although reconstructive lamellar keratoplasty for active corneal melting was effective in saving the integrity of the globes in all but four patients, the postoperative visual acuity remained poor in the majority of cases because of the often devastating nature of the underlying ocular diseases. Only 14 patients had best postoperative visual acuities of 20/100 or better. Repeated lamellar keratoplasties were necessitated by corneal opacification, infection, or progressive postoperative corneal dissolution in 14 cases. Subsequent vision-restoring surgeries, consisting of penetrating keratoplasties or cataract extractions, were done in 11 eyes with modest improvement of visual acuity. Postoperative visual acuity was significantly better in peripheral corneal melts than in central melts (p = 0.004).

CONCLUSION

Lamellar keratoplasty is an effective method of restoring the integrity of the eye ravaged by corneal melting. It is less invasive and consequently safer than penetrating keratoplasty in actively inflamed and unstable eyes. The primary purpose for this surgery is to salvage the integrity of the globe during the acute phase of disease and not so much to achieve visual improvement per se. It allows time for systemic immunosuppression to take effect and for the eye to quiet down before possible future vision-restoring surgery.

The future of lamellar keratoplasty

New surgical techniques in lamellar keratoplasty, including phototherapeutic keratectomy, automated lamellar keratectomy, plano-epikeratoplasty, deep anterior lamellar keratoplasty, combined amniotic membrane and limbal transplantation, large-diameter corneoscleral lamellar keratoplasty, and posterior lamellar keratoplasty, have recently become available. These procedures broaden the array of treatments for corneal disorders and may be used as alternatives to penetrating keratoplasty.

A new surgical technique for deep stromal, anterior lamellar keratoplasty

AIMS

To describe a new surgical technique for deep stromal anterior lamellar keratoplasty.

METHODS

In eye bank eyes and sighted human eyes, aqueous was exchanged by air, to visualise the posterior corneal surface--that is, the "air to endothelium" interface. Through a 5.0 mm scleral incision, a deep stromal pocket was created across the cornea, using the air to endothelium interface as a reference plane for dissection depth. The pocket was filled with viscoelastic, and an anterior corneal lamella was excised. A full thickness donor button was sutured into the recipient bed after stripping its Descemet's membrane.

RESULTS

In 25 consecutive human eye bank eyes, a 12% microperforation rate was found. Corneal dissection depth averaged 95.4% (SD 2.7%). Six patient eyes had uneventful surgeries; in a seventh eye, perforation of the lamellar bed occurred. All transplants cleared. Central pachymetry ranged from 0.62 to 0.73 mm.

CONCLUSION

With this technique a deep stromal anterior lamellar keratoplasty can be performed with the donor to recipient interface just anterior to the posterior corneal surface. The technique has the advantage that the dissection can be completed in the event of inadvertent microperforation, or that the procedure can be aborted to perform a planned penetrating keratoplasty.

Vasculitic peripheral ulcerative keratitis

The onset of peripheral ulcerative keratitis in the course of a connective tissue disorder, such as rheumatoid arthritis, relapsing polychondritis, or systemic lupus erythematosus, may reflect the presence of potentially lethal systemic vasculitis. Moreover, peripheral ulcerative keratitis may be the first sign of systemic necrotizing vasculitis in patients with Wegener's granulomatosis, polyarteritis nodosa, microscopic polyangiitis, or Churg-Strauss syndrome. Although the exact pathogenesis of this severe corneal inflammation and destruction is not well understood, evidence points to a dysfunction in immunoregulation with immune complexes formed in response to autoantigens or to some unknown microbial antigen depositing in scleral and limbal vessels. These events lead to changes that are mainly responsible for the resulting tissue damage. In pauci-immune vasculitides positive for antineutrophil cytoplasmic antibodies, cell-mediated cytotoxicity may play an important role in the pathogenesis of peripheral ulcerative keratitis. Untreated systemic conditions such as those mentioned above may carry a grave prognosis for the eye and may also be life-threatening. Immunosuppressive therapy with corticosteroids and cytotoxic agents is, we believe, mandatory in the treatment of these multisystem disorders associated with vasculitic peripheral ulcerative keratitis.

Management of conjunctival cicatrizing diseases and severe ocular surface dysfunction

Physical or chemical injuries, infections, immunologic oculocutaneous disorders, drugs, and various systemic disorders may cause scarring of the conjunctiva and disturbances of the ocular surface. Trichiasis, lid margin malposition, and dry eye may result in persistent ocular irritation. The cornea may be primarily or secondarily involved. If severe, disturbances of the ocular surface may lead to significant visual impairment. Thorough evaluation of patients and of the underlying disease process is required for optimal management. Treatment may be challenging and should be comprehensive, combining medical measures and surgical correction of structural changes. Suppression of exogenous irritants, treatment of dry eye, antiinflammatory therapy, and immunosuppressants are paramount to control the underlying disease and allow optimal surgical results. Surgical correction of trichiasis and lid margin malposition, conjunctival grafting, mucous membrane transplantation, limbal stem cell transplantation, amniotic membrane transplantation, and penetrating keratoplasty help reestablish a physiologic ocular surface. Severe cases may require keratoprosthetics for visual rehabilitation. Corneal ulceration or perforation requires prompt attention to maintain ocular integrity. Special measures should be considered for patients who require cataract or glaucoma surgery.

Amniotic membrane transplantation for persistent epithelial defects with ulceration

PURPOSE

To determine whether preserved human amniotic membrane can be used as an alternative substrate for treating persistent corneal epithelial defects with sterile ulceration.

METHODS

Amniotic membrane transplantation was performed in 11 eyes of 11 consecutive patients with corneal ulcers of different causes that had persisted for a mean +/- SD of 17.5 +/- 13.9 weeks.

RESULTS

Ten patients healed in 3.9 +/- 2.3 weeks (P < .01) without recurrence for 9.0 +/- 5.9 months. One patient failed to heal because of preexisting corneal perforation pursuant to severe rheumatoid arthritis.

CONCLUSION

Amniotic membrane transplantation may be considered an alternative method for treating persistent epithelial defects and sterile ulceration that are refractory to conventional treatment and before considering treatment by conjunctival flaps or tarsorrhaphy.

The management of corneal perforations associated with rheumatoid arthritis. An analysis of 32 eyes

BACKGROUND

Sterile corneal ulceration is a rare complication of rheumatoid arthritis and may lead to corneal perforation. Surgical management for visual restoration frequently is unsuccessful. The authors analyze the factors that may determine the failure of corneal surgery in perforations associated with rheumatoid arthritis.

METHOD

The management of 29 patients with rheumatoid arthritis with corneal perforations requiring surgical intervention was reviewed. The corneal lesions were classified either as necrotizing keratitis (n = 20) or as ulcers secondary to surface disease (n = 12), depending on the most evident primary pathology. The outcome of different methods for primary repair (i.e., application of tissue adhesive, lamellar graft, or penetrating keratoplasty) and graft survival in penetrating keratoplasties were analyzed.

RESULTS

Fifty-seven corneal procedures were performed in 32 eyes. Primary repair was successful (i.e., no further corneal surgery within 6 months was required) in five eyes (25%) with necrotizing keratitis and in eight eyes (67%) with perforations secondary to surface disease. The application of tissue adhesive, when planned as long-term treatment, was unsuccessful in all five eyes. Immunosuppression significantly improved the survival of first penetrating grafts (42% graft survival after 1 year versus 11% without immunosuppression, P = 0.02). Of 25 graft failures, 20 (80%) were caused by recurrent melts up to 6 months after penetrating keratoplasty. Ocular surface infection was responsible for failure in six of ten grafts after that time.

CONCLUSION

Complications of corneal surgery in rheumatoid corneal perforations are frequent. The type of surgical procedure, the predominant pathogenic mechanism, and the perioperative immune status influence the outcome. The control of corneal melting and the prevention of surface infection are critical for graft survival.