Corneal transplantation

La peau et la cornée sont deux tissus de revêtement constitués d'un épithélium fermement ancré à un tissu conjonctif, le derme pour la peau et le stroma pour la cornée. Les cellules souches de la peau ont pu être amplifiées grâce à la technique de Rheinwald et Green en 1975 et utilisées dès 1981 sous forme de feuillets épidermiques pour le traitement des grands brûlés. Plus tard, cette technique de culture a été reprise pour amplifier les cellules épithéliales limbiques. La couche basale de l'épithélium limbique se situe dans la zone transitionnelle entre la cornée et la conjonctive et contient les cellules souches de l'épithélium cornéen [J Cell Biol 1 (1986) 49-52 et Cell 57 (1989) 201-209] appelées cellules souches limbiques (CSL). Elles assurent le renouvellement de l'épithélium cornéen en générant des cellules d'amplifications transitoires qui migrent de façon centripète à partir de la couche basale limbique vers la couche basale de la cornée. Le génie tissulaire permet de reconstruire des tissus en trois dimensions (3D), associant l'épithélium à son tissu conjonctif sous-jacent. Pour reconstruire le tissu conjonctif, notre modèle associe des cellules et un polymère biodégradable et naturel à base de collagène. Ce substrat poreux sert d'échafaudage à la culture de fibroblastes pour donner un derme/ stroma équivalent vivant, qui secondairement épithélialisé aboutit à une peau/hémicornée reconstruite. Nous présentons ici : la reconstruction des épithélia dans les pathologies de surface de la peau et de la cornée et le développement de nos modèles tridimensionnels de peau et de cornées à base de collagène-GAG-chitosane et leurs applications.

To document the 1-year safety, efficacy, and stability results of 355 eyes treated in the multicenter study of conductive keratoplasty (CK) used to correct low to moderate hyperopia. Design: Nonrandomized comparative (self-controlled) trial. Participants: Twenty surgeons at 13 centers performed CK on the eyes of all patients enrolled in a multicenter, 2-year, U.S. phase III clinical trial. Treated eyes had ϩ0.75 to ϩ3.00 diopters (D) of hyperopia and Յ0.75 D of cylinder. Patients were 40 years of age or older. Intervention: Low-energy, high-frequency current was applied directly into the peripheral corneal stroma through a delivery tip inserted at 8 to 32 treatment spots. The number of treatment spots was increased for increasing levels of hyperopia, but the amount of radiofrequency energy remained constant. Emmetropia was intended. All eyes were treated once (there were no retreatments). Main Outcome Measures: Data from 355 eyes with 1 year of follow-up were analyzed for safety and stability, and data from 318 eyes were analyzed for efficacy and predictability, as well as stability and safety. All patients reported on satisfaction and quality of vision after surgery. Results: At 1 year, uncorrected visual acuity was Յ20/20 in 56%, Յ20/25 in 75%, and Յ20/40 in 92% of eyes. The manifest refractive spherical equivalent refraction was within 0.50 D in 63%, within Ϯ1.00 D in 89%, and within Ϯ2.00 D in 99%. Seven of 355 eyes lost 2 lines of best spectacle-corrected visual acuity at 1 year, but no eye lost Ͼ2 lines. One eye of 355 had induced cylinder of Ͼ2.00 D. The cycloplegic refractive spherical equivalent changed a mean of 0.25 Ϯ 0.50 D between months 3 and 6, 0.11 Ϯ 0.41 D between months 6 and 9, and 0.11 Ϯ 0.35 D between months 9 and 12. Refractive stability seemed to be attained by 6 months and remained stable through 12 months. Histology and confocal microscopy showed deep penetration of the treatment into the stroma. Endothelial cell counts were not changed by the treatment. Conclusions: CK seems to be safe, effective, and stable for correcting low to moderate spherical hyperopia in patients 40 years old or older. Treatment penetration is deep and cylindrical in shape, and it does not damage the corneal endothelium. Uncorrected visual acuity, predictability, and stability are as good as or better than those obtained with other techniques used to correct hyperopia.

To assess the potential of a short pulsed laser to cut a posterior graft and bed for posterior lamellar keratoplasty (PLAK). Experimental study. Using the laser FEMTEC (20/10 Perfect Vision, Heidelberg, Germany), posterior lamellar dissections (wave length approximately 1 microm, pulse energy < 10 microJ, spot size <10 microm, repetition rate 12.5 kHz, 6-mm-7 mm diameter, 31 s and 90 s) were performed in 18 freshly enucleated porcine eyes and 10 human donor corneas starting from the anterior chamber and ending with the lamellar bed. Before removal, 50 microm to 500 microm-thick flaps were delineated by partly confluent gas bubbles (maximum 2-mm long) with minute tissue bridges (typically 5- to 10 microm) in between. Scanning electron microscopy displayed smooth cut surfaces and rectangular corners with minor remaining tissue bridges (approximately 5 microm). By transmission electron microscopy, the cut edges were lined by a delicate, electron-dense layer (5 nm-10 nm in width) and essentially normal adjacent collagen fibers. Femtosecond laser technology seems to offer a promising approach to minimally invasive posterior lamellar keratoplasty (femto-PLAK) through small tunnel incisions in corneal endothelial diseases.

To identify the incidence of and risk factors for intraocular pressure (IOP) elevation after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: Retrospective review was conducted of 68 consecutive DSAEK procedures alone, or in combination with phacoemulsification with intraocular lens implantation or exchange, performed by two surgeons at the University of Texas Southwestern Medical Center between 2005 and 2009. Eyes that developed IOP elevation above 21 mm Hg after DSAEK and requiring initiation or escalation of glaucoma therapy were evaluated. Results: Thirty-seven (54%) eyes showed IOP elevation responsive to medical treatment by a mean follow-up of 11.38 Ϯ 7.81 months. Six (8.8%) eyes required glaucoma surgery. In the eyes, which developed elevated IOP, gonioscopy did not reveal any new peripheral anterior synechiae formation. Prolonged topical steroid usage, rebubbling, combined DSAEK/cataract surgery, or repeat DSAEK were not significant factors (PϾ0.05) for development of elevated IOP, but history of previous glaucoma or ocular hypertension (OHTN) was significant (Pϭ0.007). Conclusions: Intraocular pressure elevation is not uncommon in eyes after DSAEK, but most cases can be controlled with conservative management. Intraocular pressure elevation post-DSAEK occurred by mechanisms other than peripheral anterior synechial angle closure. The only significant risk factor for development of elevated IOP in our series was a previous history of glaucoma or OHTN.

Zusammenfassung Ist die Erfolgsprognose für eine Hornhauttransplantation schlecht und/oder ist eine Keratoplastik wiederholt gescheitert, bieten Keratoprothesen die einzige Chance zur visuellen Rehabilitierung. Die Boston-Keratoprothese, welche seit 50 Jahren kontinuierlich fortentwickelt worden ist, wird heute bei weitem am häufigsten angewandt, mit in den letzten Jahren auch international erheblich zunehmenden Implantatzahlen.

This is a case report of Acanthamoeba as a causative agent of keratitis at the Department of Ophthalmology, University Hospital Rijeka. Delay in treatment led to an advanced stage of the disease with multiple complications. Initially, presented symptoms were similar to those of herpetic keratitis. In the mean time progression of the disease led to a cloudy cornea with a stromal ring infiltrate, poor vision, elevated intraocular pressure, a mature cataract and finally corneal melt. Corneal scrapings were obtained from a 28 years old female patient, wearing soft contact lenses and with poor lens hygiene. Acanthamoeba cysts were identified by the cytological examination. Culture of the corneal scraping had confirmed Acanthamoeba as the etiological agent. Making the diagnosis of Acanthamoeba is difficult. We presented this case of delayed diagnosis and unfavorable outcome as a reminder that clinical suspicion remains the most important diagnostic tool. Contact lens wears with a new diag...

New corneal storage techniques and legislative changes have transformed conditions for corneal grafting in Sweden. Since 1995, the Swedish Corneal Surgery Society has registered the number of grafts, the size of waiting lists for surgery as well as changes in the capacity of the banks. Since 1995 the number of procedures per year has declined while the waiting list has grown. The required number of procedures is 650 rather than the 448 performed in 1999. The decline is due to a lack of donor corneas, priority accorded to other surgery, efforts to adapt contact lenses to keratoconus, and further indications for excimer laser surgery. The four established corneal banks as well as two opening in 2001 will increase the number of grafts available for surgery.

Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections.

Human corneal transplantation to date suffers from the shortage of good-quality donor tissue, and in some conditions, allografting is contraindicated. A range of arti fi cial replacements to donor allograft corneas have been developed. These range from keratoprostheses (KPro) that replace basic corneal functions of light transmission and protection to regenerative medicine strategies for regenerating one or more layers of the human cornea. This chapter reviews the advances made in developing arti fi cial corneas or more accurately, arti fi cial alternatives to donor allograft corneas for ocular application.

AbstractÐKeratoprosthesis research has been a gradual, rather fragmentary process with advances being made by isolated groups of researchers. This has arisen partly because of poor funding in the area; research groups which have achieved commercial support have often had constraints upon the full disclosure of their ®ndings. Despite these diculties there has been real progress over the last decade by several independent groups. This article concentrates upon our own development of a hydrogel core-and-skirt keratoprosthesis, the Chirila KPro, in order to illustrate the scienti®c and clinical problems common to keratoprosthesis research. Pilot data from a clinical trial is presented and the priorities for future research are discussed. #

To evaluate and compare the outcomes of therapeutic keratoplasty (TKP) and optical keratoplasty (OKP) in the management of medically unresponsive Acanthamoeba keratitis and post-keratitis scarring, respectively. Retrospective, nonrandomized, comparative, interventional case series. Thirty patients with Acanthamoeba keratitis treated at a single center. Retrospective review of all cases of penetrating keratoplasty (PKP) or lamellar keratoplasty (LKP) performed for Acanthamoeba keratitis at a single center between January 1, 1980, and December 31, 2007. Inclusion criteria included histopathologic confirmation of Acanthamoeba organisms in the surgical specimen and at least 6 months of postoperative follow-up. Postoperative complications, microbiological cure, graft survival, and visual acuity. Thirty-one eyes of 30 patients met the inclusion criteria. This included 22 eyes (22 patients) that were initially treated with TKP (20 PKP/2 LKP) and 9 eyes (8 patients) treated with OKP (8 OKP/...

After penetrating keratoplasties for different congenital or acquired corneal diseases, the presence of characteristic cataracta glaucomatosa lens opacities was noted in 9 cases of fixed, dilated pupil iris atrophy of Urrets-Zavalia. This association--rarely mentioned in the literature--is an opportunity to study again the different physiopathological theories on this syndrome (pupillary block by mydriasis with hypertony, upsetting of iris neurovegetative balance, particular sensitivity of ocular tissues to the surgical aggression in keratoconus), to analyze their arguments, and the preventive measures that proceed from them. The almost complete extinction of this type of complication of the corneal graft surgery, since the routine use of these preventive measures, proves the multifactorial origin of this syndrome.

Corneal perforation may be associated with prolapse of ocular tissue and requires prompt diagnosis and treatment. Although infectious keratitis is an important cause, corneal xerosis and collagen vascular diseases should be considered in the differential diagnosis, especially in cases that do not respond to conventional medical therapy. Although medical therapy is a useful adjunct, a surgical approach is required for most corneal perforations. Depending on the size and location of the corneal perforation, treatment options include gluing, amniotic membrane transplantation, and corneal transplantation. (Surv Ophthalmol 56:522--538, 2011. Ó 2011 Elsevier Inc. All rights reserved.) Key words. corneal perforation diagnosis keratoplasty management patch graft therapeutic keratoplasty 522

The authors have recently treated a case of Parinaud's oculoglandular syndrome due to Chlamydia trachomatis serotype L2, a causative agent of lymphogranuloma venereum (LGV). The ocular manifestations included a mixed papillary-follicular conjunctivitis with fleshy superior limballesions in both eyes. A superior marginal corneal perforation requiring a therapeutic corneal graft was present in the right eye. The patient had vaginitis, inguinal lymphadenopathy, a history of Sjogren's syndrome, and seropositivity to human immunodeficiency virus (HIV). The ocular disease resolved completely after 6 weeks of oral tetracycline therapy. [

Hintergrund In den letzten Jahren wurden gewaltige Fortschritte im Verständnis neovaskulärer Erkrankungen des Auges gemacht. Neue antiangiogene Medikamente habe in die Therapie der AMD und der diabetischen Retinopathie Einzug gehalten. Ziel dieser Arbeit ist es, aktuelle und zukünftige Möglichkeiten der lokalen antiangiogenen Therapie an Hornhaut, Bindehaut und Vorderkammer aufzuzeigen. Methoden Literaturübersicht aus PUBMED und eigene klinische und experimentelle Daten. Ergebnisse Es gibt erste Erfolg versprechende Erfahrungen mit topischen Inhibitoren der Angiogenese (v. a. Bevacizumab) an der Hornhaut und Bindehaut sowie beim intrakameralen Einsatz. Schlussfolgerungen Neue topische antiangiogene Therapieoptionen zum lokalen Einsatz an Hornhaut und Bindehaut sind derzeit bereits off-label verfügbar und werden die Therapie angiogener Erkrankungen am vorderen Augenabschnitt deutlich verbessern. Background Recent years have seen tremendous progress in our understanding of the mechanisms of neovascular diseases of the eye. Antiangiogenic treatment options are now widely used in the management of age-related maculopathy (AMD) and diabetic retinopathy. The aim of this article is to highlight some novel methods of local antiangiogenic treatment of the cornea and conjunctiva and in the anterior chamber of the eye. Methods The study took the form of a literature review (PUBMED) and a review of the authors’ own data. Results Initial experience with novel inhibitors of angiogenesis, especially bevacizumab, used locally on cornea and conjunctiva is promising. Intracameral injections of VEGF inhibitors can be used to ameliorate neovascular glaucoma. Conclusion Novel antiangiogenic drugs are available for topical use in the anterior segment of the eye (as off-label use) and will improve the management of neovascular diseases affecting cornea and conjunctiva and in the anterior chamber of the eye.

PURPOSE: To compare the visual and refractive results in eyes with advanced keratoconus having deep anterior lamellar keratoplasty (DALK) with those having intrastromal corneal ring segment (ICRS) implantation. SETTING: Dr. L € utfi Kırdar Kartal Training and Research Hospital, Istanbul, Turkey. DESIGN: Comparative case series.

PURPOSE: To evaluate postoperative corneal deturgescence after Descemet stripping endothelial keratoplasty (DSAEK) using the Visante anterior segment optical coherence tomography (OCT) system (Carl Zeiss Meditec Inc, Dublin, California, USA). • DESIGN: Retrospective case series. • METHODS: We included 21 eyes (9 males and 12 females; mean age ؎ standard deviation, 76.3 ؎ 12 years). The Visante OCT system was used to determine the central and peripheral endothelial keratoplasty graft thickness and total central and peripheral corneal thickness. • RESULTS: Central graft thickness decreased from the first day (243.3 ؎ 92 m) to the last visit (147.8 ؎ 44 m; P ‫؍‬ .0001). The rate of central graft thinning slowed during the following intervals: during the first week (47 m), at 1 week to 1 month (40 m), and at 1 to 6 months (25 m), with a mild increase at 6 to 9 months (5 m). Peripheral graft thickness continued to decrease from postoperative day 1 (318.5 ؎ 99 m) to the last visit (196.7 ؎ 50 m; P ‫؍‬ .0001). There was a decrease in total central corneal thickness from day 1 (903.8 ؎ 179 m) to the last visit (671 ؎ 93 m; P ‫؍‬ .0001). All patients were imaged with the Visante OCT at the first 4 defined postoperative intervals; however, only 9 eyes were imaged at the last interval of 6 to 9 months. • CONCLUSIONS: After DSAEK, there is a greater thinning of the central graft compared with the peripheral graft. The central cornea thickness decreases and peripheral corneal thickness increases. Central corneal graft deturgescence stabilizes by 6 months after surgery. (Am J Ophthalmol 2009;148:32-37.

Endothelial keratoplasty (EK) has recently emerged as an alternative to penetrating keratoplasty (PK) for patients with endothelial diseases, including Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy, and corneal graft failure. EK provides distinct advantages over PK, in that it is a less invasive procedure and leads to more rapid recovery of vision. Additionally, this procedure does not require long-term corneal sutures, eliminating problems with suture breakage, suture abscesses, astigmatism, and wound dehiscence. Disadvantages of EK include the need for specially prepared donor tissue and additional surgeon training or experience. In this review we discuss the history of EK, recent advances that have led to its widespread use, limits and complications of the procedure, and areas for future improvement.

Objective. The aim of this study was to evaluate the frequency and main risk factors for corneal graft rejection. Patients and Methods. This retrospective study included 285 eyes in 256 patients who underwent a penetrating keratoplasty (KPT) from January 1995 to December 2004. The minimum follow-up was 12 months to evaluate graft evolution. Except for complications, the follow-up was weekly, then monthly for 6 months, and ultimately quarterly during the first year. Thereafter the follow-up was performed semi-annually. Patients were informed about the functional signs for which they have to urgently consult. Results. Immunologic rejection of the corneal graft occurred in 128 KPT in 112 patients (rejection frequency ϭ 41%). The identified main risk factors were new vascularization of the recipient cornea over 2 or more quadrants, corneal opacity due to an infectious origin, posttraumatic corneal opacity or congenital glaucoma, graft diameter Ͼ8 mm, and therapeutic KPT. Conclusions. Rejection of the corneal graft is the primary cause of KPT failure. One out of 2 graft failures was due to rejection. Two criteria are unanimously recognized as risk factors for rejection: neovascularization of recipient cornea and antecedents of corneal rejection. The rejection must be treated early to not endanger graft success, which imposes a close follow-up for grafted patients.

Fuchs endothelial dystrophy (FED), first described by Ernst Fuchsis in 1910, is a condition in which there is premature degeneration of corneal endothelial cells. When the number of endothelial cells is reduced to a significant degree fluid begins to accumulate within the cornea. As a result the cornea loses its transparency and the individual suffers a reduction in vision. The only successful surgical treatment for this condition is replacement of part or all of the cornea with healthy tissue from a cadaveric donor. The established procedure, penetrating keratoplasty (PKP), has been used for many years and its safety and efficacy are well known. Endothelial keratoplasty (EK) is a relatively new surgical procedure and the safety and efficacy relative to PKP are unknown.

To evaluate the accuracy of the thickness and diameter of corneal disks obtained with the Femtec femtosecond laser (20/10 Perfect Vision) for Descemet-stripping endothelial keratoplasty (DSEK). Singapore National Eye Centre, Singapore. A femtosecond laser was used to create posterior stromal ablations at varying depths, producing donor lenticules 150 to 200 microm thick with diameters of 7.0 to 9.5 mm (n = 40). After stromal ablation, the central corneal thickness was measured by anterior segment optical coherence tomography and the diameters were measured using imaging software. The mean deviation from the attempted thickness was 15 +/- 14 microm. No correlation was found between the preoperative corneal thickness and the accuracy of the laser ablation (P = .91). No statistically significant differences were found in the accuracy of the laser ablation with multiple-pass nomograms (P = .15). The laser was accurate in producing circular diameters with an arc length between 7.0 mm and 9.5 mm (r2 = 0.935, P = .001). The femtosecond laser produced posterior stromal ablations that were accurate in depth of ablation and circularity.

To evaluate the efficacy of deep lamellar keratoplasty using the big-bubble technique in patients with keratoconus. • DESIGN: Interventional case series. • METHODS: Thirteen eyes of 12 patients (eight male and four female subjects) with moderate to advanced keratoconus and intolerance to contact lens wear were included in this study. Deep lamellar keratoplasty was performed by the intrastromal air injection technique. Full-thickness donor tissue devoid of Descemet membrane and endothelium was then sutured into place. Best-corrected visual acuity, refractive results, surgical technique, and complication rates were analyzed. • RESULTS: Big bubble was successfully achieved in nine eyes (69.2%). Average postoperative best-corrected visual acuity was 20/25 (range 20/50 to 20/20) at a mean follow-up of 5 months. Intraoperative microperforation of Descemet membrane occurred in two eyes (15.3%). Three eyes (23%) developed a steroid-induced increase in intraocular pressure, which responded to medical therapy. • CONCLUSIONS: Deep lamellar keratoplasty that uses the big-bubble technique is safe and effective in patients with keratoconus. Visual outcome is comparable to standard penetrating keratoplasty, without the risk of endothelial rejection.

Infection of the eye caused by Acanthamoeba species constitutes a burgeoning and unsolved problem. Of individuals with Acanthamoeba keratitis, 85% wear contact lenses; abrasion of the cornea is implicated. Corneal infection often can be prevented by good lens care and hygiene. Severe Acanthamoeba keratitis often can be very difficult to treat; surgery can be less than successful and may lead to further problems. The encysted stage in the life cycle of Acanthamoeba species appears to cause the most problems; many biocides are ineffective in killing the highly resistant cysts. Combination therapy-that is, use of 2 or 3 biocides, sometimes with antibacterial antibiotics-appears to work best. Recurrence is common if treatment is stopped prematurely. Immunologic methods are being investigated as a form of prevention, and oral immunization of animals recently has been successful in the prevention of Acanthamoeba keratitis by inducing immunity before infection occurs. Immunization thus may eventually become the best approach for reduction of the incidence of amebic infection in humans.

Introduction: Infectious keratitis following penetrating keratoplasty is a common postoperative complication. Intensive topical and systemic treatments do not always prevent the risk of graft failure. In this report we demonstrate the beneficial anti-microbial effect of corneal collagen cross-linking in a late-onset, sight-threatening, corneal graft ulcer.