Factors that influence the suitability of human organ-cultured corneas.

PURPOSE: The purpose was to assess the influence of donor and storage factors on the suitability of organ-cultured corneas for transplantation. METHODS: Data from 1340 donor corneas stored between 2009 and 2015 were analyzed retrospectively. Logistic regression analysis was used to assess the influence of different factors on the suitability of grafts for transplantation. RESULTS: Forty-one percent (553/1340) of corneas were discarded. The leading causes were medical contraindication (20.2 %) and poor endothelial quality (19.3 %). Donor age influenced suitability for transplantation significantly. Corneas from donors aged 80 years and older were more likely to be discarded because of endothelial insufficiency (P < 0.0001). The cause of donor death including infection and multiple organ dsyfunction syndrom (MODS) increased the risk of bacterial or fungal contamination during organ culture (P = 0.007 and P = 0.014, respectively). Prolonged time between death and enucleation was associated with an increased risk of unsuitability for transplantation (P < 0.0001). The amount of time between death and corneoscleral disc excision and duration of storage influenced the suitability for transplantation (P = 0.0007 and P < 0.0001, respectively). CONCLUSION: Donor age, cause of death, storage time, death to enucleation and death to disc excision times influenced transplantation suitability. The percentage of discarded corneas may be reduced by shortening storage time, death to enucleation, and death to corneoscleral disc excision times. Setting a maximum donor age could reduce the percentage of discarded corneas. However, as long as there is a lack of donor corneas, we do not recommend any donor age limit.

[Refractive changes after Descemet membrane endothelial keratoplasty]. / Refraktionsänderung nach der Descemet-Membran-Endothelkeratoplastik.

Penetrating keratoplasty has different refractive disadvantages in contrast to posterior lamellar keratoplasty. For example, a decentered corneal trephination and a tilted trephination or unevenly tightened corneal sutures can cause an uncontrolled high astigmatism as well as a refractive change. Also the postoperative refraction may change over time as a result of wound healing, suture loosening or suture removal. The aim of this retrospective study was to investigate a possible refractive change after Descemet membrane endothelial keratoplasty (DMEK). A total of 139 pseudophakic eyes from 125 patients with endothelial decompensation had undergone DMEK surgery at the Tübingen Eye Clinic. After a mean postoperative time of 13.15 ± 2.98 months after DMEK discreet mean changes in the spherical equivalent of + 0.37 ± 0.87 diopters and the cylinder to - 0.45 ± 0.57 diopters were observed. The mean central corneal thickness decreased from 670 ± 70 µm to 544 ± 55 µm. In conclusion after DMEK a discreet induced hyperopic refractive shift due to the reversal of stromal swelling was observed.

[Management of corneal endothelial decompensation with Descemet's membrane endothelial keratoplasty in a patient with Ahmed glaucoma valve implant]. / Behandlung einer Endotheldekompensation mit der Descemet-Membran-Endothelkeratoplastik bei einem Patienten mit Ahmed-Implantat.

BACKGROUND: Currently, the main causes for developing bullous keratopathy are from problems related to intraocular surgery, trauma, infection, Fuchs' endothelial dystrophy and chronically elevated intraocular pressure. In the 1990s penetrating keratoplasty was once considered the therapy of choice for treatment of bullous keratopathy but in recent years it has been replaced by posterior lamellar keratoplasty. The Descemet membrane endothelial keratoplasty (DMEK) procedure represents the final development of posterior lamellar keratoplasty. The question now arises whether DMEK can be used in patients with bullous keratopathy and Ahmed glaucoma valve implant. CASE REPORT: A 72-year-old man was referred to our hospital for further evaluation with the diagnosis of bullous keratopathy and pseudoexfoliative glaucoma. The bullous keratopathy was caused by a variety of previous operations as well as decompensation of intraocular pressure. This article describes the therapy of bullous keratopathy by DMEK with existing Ahmed glaucoma valve implant. After surgery the cornea became clear and the best-corrected visual acuity improved from hand movement to 0.2. The intraocular pressure remained normal (10-14 mmHg) without antiglaucoma medication and the endothelial cell count decreased only slightly over a follow-up of 13 months. No complications were encountered. CONCLUSIONS: The DMEK surgical procedure seems to be possible in patients with Ahmed glaucoma valve implant and endothelial decompensation. However, further studies with a larger number of patients should follow to validate the replacement of penetrating keratoplasty and other posterior lamellar procedures by DMEK.

[Clinical results after Descemet membrane endothelial keratoplasty]. / Klinische Ergebnisse nach Descemet-Membran-Endothelzelltransplantation.

BACKGROUND: Diseases of the endothelial cell layer represent a common indication for perforating keratoplasty. In recent years posterior lamellar keratoplasty techniques have undergone a revival. The latest and most promising advancement is the isolated transplantation of Descemet's membrane (DM) with the endothelial layer - also known as Descemet's membrane endothelial keratoplasty (DMEK). This study was conducted to evaluate the clinical results of our DMEK patients and to assess the perioperative management. PATIENTS AND METHODS: 70 patients (75 eyes) with endothelial cell decompensation (50 eyes with Fuchs endothelial dystrophy and 25 eyes with bullous keratopathy) had undergone DMEK surgery at the Tübingen Eye Clinic. Visual acuity, refractive error, intraocular pressure, slit lamp examination, pachymetry and endothelial cell density were considered and re-examined at intervals of 1, 2 and 4 weeks postoperatively with further 3 monthly follow-ups. RESULTS: The mean age of the 45 female and 25 male patients at time of surgery was 73 years (36 to 91 years). The mean follow-up period was 12.1 months. One patient received an autologous and 4 patients a triple procedure. The mean preoperative LogMAR visual acuity was 0.87 ± 0.41. After 1 week a LogMAR visual acuity of 0.82 ± 0.4 was observed (p = 0.544). At the final examination the LogMAR visual acuity was 0.32 ± 0.35 (p < 0.001, a highly significant result as compared to the preoperative value). The most common and important complication was the dislocation of the transplant which was seen in 23 eyes (31 %). The use of intracameral air pressurisation re-appositioned most transplants. Complications such as highly elevated intraocular pressure, epithelial inclusions or endophthalmitis were not noted in any patient. CONCLUSIONS: DMEK surgery lead to a significant visual rehabilitation in a majority of patients in a relatively short postoperative period. It may be considered as a gold standard to treat isolated endothelial diseases as has been implicated by other studies. Thus, the safety and efficiency of this new type of posterior lamellar keratoplasty technique has been confirmed.

[Precut technique for Descemet's membrane endothelial keratoplasty, preparation and storage in organ culture]. / Precut Verfahren für Descemet-Membran-Endothelzelltransplantation, Präparation und Aufbewahrung in Kultur.

BACKGROUND: The preparation of the Descemet's membrane (DM) with the endothelial cell layer may be performed directly prior to surgery or as a precut tissue procedure. The purpose of the current study was the evaluation of the preparation technique and the tissue culture of 10 days regarding potential endothelial cell loss. MATERIALS AND METHODS: Ten corneoscleral rims with an average age of 64.3 years were dissected to obtain 8.5 mm in diameter endothelial-DM complexes, which subsequently were organ cultured for 10 days. The endothelial cell density (ECD) was assessed during the cell culture period at days 1., 4., 7. and 10. In addition, time of preparation and transplant morphology were evaluated. RESULTS: The DM with the endothelial cell layer could successfully be dissected from all corneoscleral rims. The average preparation time was 8.3 min. The average ECD count was 2183 ± 77 cells/mm2 prior to, 2094 ± 110 cells/ mm2 at day 1, 2078 ± 134 cells/mm2 at day 4, 1977 ± 107 cells/mm2 at day 7 and 1898 ± 170 cells/mm2 at day 10 after preparation, respectively. Endothelial cell loss was 4.1 %, 4.8 %, 9.4 % and 13.1 % after preparation, respectively. None of the transplants exhibited large, centrally-located cell deficits. CONCLUSION: The isolated storage of DM with the endothelial layer, without any stromal remnants, showed gratifying results under storage conditions in organ culture with a moderate ECD decrease. Hence, the implementation of a precut DMEK is conceivable.

[Histological and ultrastructural analysis of the Descemet's membrane after descemetorhexis in DMEK surgery]. / Histologische und ultrastrukturelle Untersuchung der Descemet-Membran nach Descemetorhexis bei der DMEK- Operation.

BACKGROUND: In order to obtain an optimal visual outcome in the isolated transplantation of Descemet's membrane (DM) with the endothelial cell layer, a regular interface between the receiver cornea and the graft is important for the prognosis. The purpose of this histological and ultrastructural study was to investigate how precise the descemetorhexis works using the Sinskey hook and whether the precision of DM removal depends on the clinical and pathological diagnosis of the underlying corneal endothelial disease. PATIENTS AND METHODS: 22 DM specimens of 22 patients obtained after descemetorhexis in DMEK using a Sinskey hook were examined using histological analyses and transmission electron microscopy for the presence of residual stroma, thickness of the DM, endothelial cell count, and presence of guttae. 17 patients had a Fuchs corneal dystrophy, 5 pseudophakic bullous keratopathy. RESULTS: Light and electron microscopy showed no evidence of adherent stroma in all 22 specimes after descemetorhexis independent of the different underlying endothelial pathological abnormalities. The mean total thickness of the DM was 20.58 ± 4.23 µm in patients with Fuchs endothelial dystrophy and 21.31 ± 5.41 µm in patients with bullous keratopathy. There was no significant difference between both pathological abnormalities. The anterior banded layer measured a mean of 3.04 ± 0.40 µm and 3.25 ± 0.22 µm thick; the posterior non-banded layer 17. 63 ± 4.07 µm and 17.60 ± 5.0 µm thick in each case of Fuchs corneal dystrophy and pseudophakic bullous keratopathy. There was no significant difference between the two diseases. CONCLUSIONS: Descemetorhexis allows a selective removal of the DM without adherent stroma in different underlying endothelial pathological abnormalities and in different variability of disease expression.

[Clinical results after cataract surgery in patients with Behçet's disease]. / Ergebnisse nach Kataraktchirurgie bei Patienten mit Behçet-Erkrankung.

BACKGROUND: Behçet's disease is a systemic vasculitis disorder of unknown aetiology. Ocular involvement, especially with vasculitis, is detected in up to 80 % of the cases. Anterior segment involvement such as cataract is also seen in the follow-up of patients who are then treated surgically. In this study, we aimed to analyze the outcomes of cataract surgery in patients with Behçet's disease retrospectively. PATIENTS AND METHODS: The records of 9 patients (12 eyes) with Behçet's disease who underwent phacoemulsification with IOL implantation in 11 eyes and extracapsular cataract extraction (ECCE) with IOL implantation in one eye between June 2001 and September 2009 were evaluated retrospectively. The visual outcome and complications were analysed. RESULTS: The mean follow-up was 33.8 months (range 3 to 88 months). The mean preoperative LogMAR BCVA was 1.15 ± 0.53 (95 % CI: 0.81 - 1.49) and increased to 0.36 ± 0.32 (95 % CI: 0.15 - 0.56) at last medical visit (p < 0.001). The most frequent postoperative complication was posterior capsular opacification, which developed in 2 eyes (17 %). Other complications were mild fibrinous reaction in 1 eye (8 %). CONCLUSIONS: The outcomes of cataract surgery in patients with Behçet's disease were satisfactory. The great majority of the patients regained and retained a good visual outcome and had fewer postoperative complications.

[The influence of the HIV pandemic on the incidence of malignant ocular tumours in Southern Malawi (Blantyre)]. / Einfluss der HIV-Pandemie auf die Inzidenz maligner Augentumoren im südlichen Malawi (Blantyre).

BACKGROUND: The HIV pandemic in Southeast Africa is a challenge to the poorly staffed and poorly financed health systems of the affected countries. A dramatic increase of HIV-associated ocular malignancies has been observed in Malawi. This study investigated the frequency of malignant ocular tumours at the only eye hospital in the south of Malawi. METHODS: A retrospective analysis of all patients who underwent removal of conjunctival growth suspicious for malignancy was performed for the period from 1989 to 2006. In addition a consecutive group of 49 patients with malignant ocular tumours was offered an HIV test. RESULTS: The number of patients undergoing surgery for suspected ocular surface squamous neoplasia (OSSN) increased from 32 cases in 1989 to 467 in 2006. Of the patients with malignant ocular tumours, 80% (39 of 49) had OSSN, and 76% of the patients with OSSN were HIV positive. CONCLUSIONS: OSSN has become the most frequent malignant ocular tumour in the south of Malawi. The incidence of OSSN seems to have increased dramatically from 1989 to 2006--in parallel to increasing HIV infection rates.

Implications of bevacizumab on vascular endothelial growth factor and endostatin in human choroidal neovascularisation.

AIM: To evaluate the implications of intravitreal bevacizumab on proangiogenic vascular endothelial growth factor (VEGF) with regard to the endogenous angiogenesis inhibitor endostatin in human choroidal neovascularisation (CNV) secondary to age-related macular degeneration. METHODS: Retrospective review of an interventional case series of 48 patients who underwent full macular translocation surgery with removal of CNV. Twenty-five patients were treated with intravitreal bevacizumab injection 1 to 154 days prior to surgery (bevacizumab CNV). Twenty-three CNV without any kind of previous treatment were used as controls (control CNV). CNV were stained for CD34, cytokeratin18, VEGF, endostatin and E-selectin. A "predominance score of VEGF over endostatin" (PS) was defined by the difference between VEGF and endostatin staining scores. RESULTS: Bevacizumab CNV revealed a weaker VEGF expression in endothelial cells (p = 0.0245) but significantly more intense endostatin in retina pigment epithelium (RPE) (p = 0.0001) and stroma (p<0.0001). Consequently, PS was significantly lower in RPE (p = 0.02), vessels (p = 0.03) and stroma (p = 0.0004) in bevacizumab CNV. The intensity of E-selectin expression in bevacizumab CNV was comparable with that in control CNV. CONCLUSIONS: A shift within the angiogenic balance in terms of decreased VEGF predominance over endostatin is detected in human CNV treated with bevacizumab.

[Scleromalacia associated with varicella-zoster virus]. / Varizella-zoster-Virus-assoziierte Skleromalazie.

BACKGROUND: Scleromalacia usually appears following vasculitis in systemic rheumatoid diseases, especially as a late symptom of rheumatoid arthritis. CASE REPORT: A 67-year-old woman was referred to our hospital for further evaluation with the diagnosis of a "fast-growing tumor" of the left eye. Sixteen months ago she had suffered from herpes zoster ophthalmicus-associated keratouveitis and trabeculitis in the same eye. Scleromalacia associated with varicella-zoster virus (VZV) was diagnosed after the biomicroscopic and gonioscopic examination of the eye was completed and a systemic disease had been ruled out. One week after beginning systemic application of acyclovir (5 x 800 mg daily) and prednisolone (30 mg daily), the anterior chamber inflammation regressed and a fibrosis seemed to appear in the atrophic scleral area. CONCLUSION: Although scleral atrophy mostly appears as a late sign of systemic rheumatoid diseases, it might also develop secondary to infectious diseases. Scleromalacia associated with varicella-zoster virus has been previously described only in a few cases. Scleromalacia is a vision-threatening complication of zoster ophthalmicus which responds well to combination therapy with systemic antiviral and anti-inflammatory agents.

Antiproliferative and cytotoxic properties of bevacizumab on different ocular cells.

AIM: To evaluate the antiproliferative and cytotoxic properties of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), on human retinal pigment epithelium (ARPE19) cells, rat retinal ganglion cells (RGC5), and pig choroidal endothelial cells (CEC). METHODS: Monolayer cultures of ARPE19, RGC5, and CEC were used. Bevacizumab (0.008-2.5 mg/ml), diluted in culture medium, was added to cells that were growing on cell culture dishes. Cellular proliferative activity was monitored by 5'-bromo-2'-deoxyuridine (BrdU) incorporation into cellular DNA and the morphology assessed microscopically. For cytotoxicity assays ARPE19, RGC5, and CEC cells were grown to confluence and then cultured in a serum depleted medium to ensure a static milieu. The MTT test was performed after 1 day. The "Live/Dead" viability/cytotoxicity assay was performed and analysed by fluorescence microscopy after 6, 12, 18, 24, 30, 36, and 48 hours of incubation. Expression of VEGF, VEGF receptors (VEGFR1 and VEGFR2) and von Willebrand factor was analysed by immunohistochemistry. RESULTS: No cytotoxicity of bevacizumab on RGC5, CEC, and ARPE19 cells could be observed after 1 day. However, after 2 days at a bevacizumab concentration of 2.5 mg/ml a moderate decrease in ARPE19 cell numbers and cell viability was observed. Bevacizumab caused a dose dependent suppression of DNA synthesis in CEC as a result of a moderate antiproliferative activity (maximum reduction 36.8%). No relevant antiproliferative effect of bevacizumab on RGC5 and ARPE19 cells could be observed when used at a concentration of 0.8 mg/ml or lower. CEC and ARPE 19 cells stained positively for VEGF, VEGFR1, and VEGFR2. More than 95% of the CEC were positive for von Willebrand factor. CONCLUSIONS: These experimental findings support the safety of intravitreal bevacizumab when used at the currently applied concentration of about 0.25 mg/ml. Bevacizumab exerts a moderate growth inhibition on CEC when used in concentrations of at least 0.025 mg/ml. However, at higher doses (2.5 mg/ml) bevacizumab may be harmful to the retinal pigment epithelium.