[Digital teaching 2020: Online teaching receives a better assessment than face-to-face teaching]. / Digitale Lehre 2020: Online-Unterricht erhält bessere Bewertung als Präsenzunterricht.

BACKGROUND: Due to the corona pandemic, face-to-face teaching was no longer permitted in the summer semester 2020 and online alternatives were quickly found. OBJECTIVE: In our article, we illustrate the switch from face-to-face to online teaching in ophthalmology at the University of Lübeck and compare online teaching with face-to-face teaching. METHODS: The central teaching evaluation takes place every semester with a standardized questionnaire. Based on the evaluation of these questions, a direct comparison of the attendance semester of the winter semester 2019/2020 with the online semester of the summer semester 2020 was carried out. RESULTS: The structure (p = 0.003), the organization (p = 0.001), the resources made available (p = 0.034), the attendance of the lectures (p < 0.001) and further dates (p = 0.041), the increase in interest (p = 0.039) and learning (p = 0.001) were rated better in the online semester than in the face-to-face semester. Overall, the digital summer semester 2020 (p < 0.01) received a significantly better overall grade than the face-to-face semester in winter 2019/2020. CONCLUSION: The structure of our courses has also been proven online. The theoretical content could be excellently mediated; however, practical exercises are not possible online. For the learning of practical skills, face-to-face instruction is still necessary.

[Digital teaching 2020: students assess attention during an online lecture as equivalent to a face-to-face lecture]. / Digitale Lehre 2020: Studenten schätzen die Aufmerksamkeit während einer Onlinevorlesung gleichwertig zu einer Präsenzvorlesung ein.

BACKGROUND: The corona pandemic has led to short-term adjustments of the procedures in medical courses. In many departments classroom teaching was no longer possible so that it was necessary to implement digital courses to provide an adequate medical training. METHODS: We developed a digital curriculum based on the contents of our established courses using primary in-house tools, such as Cisco WebEx and Moodle. We then performed a student survey to evaluate the implementation of the concept. RESULTS: The evaluation showed good ratings according to teaching content and didactics. The communication with the students and between each other was also considered good. Students assessed attention during the course to be equivalent in comparison to classroom teaching. As expected, the training of practical skills was evaluated as poor. For future courses most of the students could imagine a combination of digital and classroom teaching. DISCUSSION: Implementing a digital course was a sudden challenge for students and tutors. With suitable software solutions and good communication, it is possible to adequately teach theoretical content via digital courses. Students assessed the digital training in most parts to be a good and an equivalent option compared to classroom teaching. A remaining problem is the lack of practical training.

The effect of anakinra on retinal function in isolated perfused vertebrate retina.

PURPOSE: Blockage of the interleukin 1 (IL-1) signaling pathway has been proposed for treatment of inflammatory disorders like those affecting the retina and its adjacent tissue. Herein, we evaluated one of those inhibitory drugs, anakinra (Kineret®), based on its safety profile with emphasis on retinal function from an electrophysiological point of view. METHODS: Bovine retina preparations were perfused with two different concentrations of anakinra (1 mg/ml and 2 mg/ml). An electroretinogram (ERG) was recorded and b-wave recovery assessed. RESULTS: Exposure to anakinra at a concentration of 1 mg/ml did not decrease the b-wave amplitude, whereas 2 mg/ml resulted in a significant reduction. CONCLUSIONS: Based on these preliminary results, anakinra at a dose as low as 1 mg/ml could be regarded as safe for retinal function. However, dosages of 2 mg/ml and more do have toxic electrophysiological effects, at least for the short-term.

Testing the clinical value of multifocal electroretinography and microperimetry and the effects of intravitreal therapy with ranibizumab on macular function in the course of wet age-related macular degeneration: a 1-year prospective study.

PURPOSE: To investigate the clinical value of multifocal electroretinography (mfERG) and microperimetry and the effects of intravitreal therapy with ranibizumab (Lucentis®) on macular function in the course of neovascular age-related macular degeneration (nAMD). MATERIALS AND METHODS: We conducted a prospective single-arm interventional cohort study with 20 nAMD patients older than 50 years. Examinations were scheduled monthly for 1 year during intravitreal therapy with ranibizumab. The examinations included mfERG, microperimetry, spectral domain optical coherence tomography, and best-corrected visual acuity using ETDRS score. RESULTS: During the 12-month observation period, a significant positive linear correlation between the logarithm of minimum angle of resolution (logMAR) and scotoma area (r=0.28, 95% confidence interval [CI] 0.21-0.35), between logMAR and fovea thickness in optical coherence tomography (r=0.11, 95% CI 0.04-0.2), and a significant negative correlation between logMAR and mfERG (-0.37, 95% CI -0.43 to -0.31) were observed. A significant ranibizumab effect on logMAR was found (P=0.0065). From a total of 25 relapses, 14 were able to be predicted correctly by mfERG P1 decrease in the preceding month. However, there was no statistically significant relation between prediction and observed relapses (Fisher's exact test, P=0.6726). CONCLUSION: Our results indicate a possible role of mfERG and microperimetry in the monitoring of macular function and prediction of recurrence during intravitreal pharmacotherapy in wet AMD.

Biocompatibility of the vital dye Acid Violet-17 on retinal pigment epithelial cells.

PURPOSE: To examine the viability and differentiation of retinal pigment epithelial (RPE) cells after exposure to the vital dye Acid Violet-17 (AV-17). METHODS: Bovine RPE cells were incubated with AV-17 (0.0625-0.5 mg/mL) for 30 seconds or 5 minutes. Viability was determined by live/dead staining, cleaved CASP3 immunostainings, and MTT test. Actin cytoskeleton was visualized by Alexa 488-phalloidin. Immunocytochemistry was performed to determine the levels of ZO-1, CTNNB1, and KRT19. RESULTS: Exposure to AV-17 at the concentrations of 0.25-0.5 mg/mL resulted in a dose-dependent decrease in viability, the loss of ZO-1 from tight junctions, translocation of CTNNB1 into the cytoplasm and nucleus, disarrangement of the actin cytoskeleton, and a slight increase in KRT19. CONCLUSION: AV-17 at a concentration <0.125 mg/mL is likely to be well tolerated by the RPE cells, whereas the concentrations from 0.25 mg/mL onward can reduce viability and induce dedifferentiation particularly after long-term exposure.

Analysis of monosomy-3 in immunomagnetically isolated circulating melanoma cells in uveal melanoma patients.

Monosomy-3 in primary uveal melanoma (UM) is associated with a high risk of metastasis and mortality. Although circulating melanoma cells (CMC) can be found in most UM patients, only approximately 50% of the patients develop metastases. We utilized a novel immuno-FISH assay to detect chromosome-3 in intact CMC isolated by dual immunomagnetic enrichment. Circulating melanoma cells were detected in 91% of the patients (n = 44) with primary non-metastatic UM, of which 58% were positive for monosomy-3. The monosomy-3 status of CMC corresponded to the monosomy-3 status of the primary tumor in 10 of the 11 patients where this could be tested. Monosomy-3 in the CMC was associated with an advanced tumor stage (P = 0.046) and was detected in all four patients who developed metastasis within the follow-up period of 4 yr. This non-invasive technique may enable the identification of UM patients at risk for metastasis particularly when a primary tumor specimen is unavailable.

CD147 and matrix-metalloproteinase-2 expression in metastatic and non-metastatic uveal melanomas.

BACKGROUND: Extracellular matrix remodelling regulated by matrix-metalloproteinase (MMP) inducer (CD147) is a crucial process during tumor cell invasion and regulation of blood supply. In this study, we evaluated the correlation of CD147 and MMP-2 expression with major prognostic factors for uveal melanoma and the development of metastasis. METHODS: The expression of CD147 and MMP-2 was analyzed in 49 samples of uveal melanomas. Triple immunofluorescence stainings using markers against glial cells (GFAP), endothelial cells (CD34) and macrophages (CD68) were performed to further analyse the exact localisation of CD147 and MMP-2 positivity. In 28 cases clinical metastatic disease were found. The remaining 21 cases showed no signs of metastatic disease for an average follow-up of 10 years. Correlation analysis (Pearson correlation) was performed to analyse the association of CD147 and MMP-2 expression with known prognostic factors, vasculogenic mimicry (VM), the mature vasculature (von Willebrand Factor) and tumor induced angiogenesis (by means of Endoglin expression). RESULTS: CD147 and MMP-2 were expressed in 47 (96.0 %) of the uveal melanomas. CD147 up-regulation was significantly correlated with a higher MMP-2 expression. The overall expression analysis revealed no significant difference in the metastatic (p = 0.777) and non-metastatic subgroup (p = 0.585). No correlation of CD147 expression and any system of blood supply was evident. In the non-metastatic sub-group a significant correlation of clustered CD147 positive cells with largest basal diameter (p = 0.039), height (p = 0.047) and TNM-stage (p = 0.013) was evident. CONCLUSIONS: These data may indicate that CD147 regulates MMP-2 expression in uveal melanoma cells.

Analysis of caveolin-1 and phosphoinositol-3 kinase expression in primary uveal melanomas.

BACKGROUND: To evaluate the regulation of blood supply in primary uveal melanomas through caveolin-1 (Cav-1)/phosphoinositol-3 kinase (PI3K). METHODS: The expression of Cav-1 and PI3K was analysed in 51 paraffin sections of metastatic (n = 30) and non-metastastic uveal melanomas (n = 21). Two trained observers quantified Cav-1 and PI3K immunofluorescensce expression by determining intensity of staining and percentage of positive cells. The expression was correlated with known prognostic factors. Besides angiogenesis by means of endoglin expression, the normal vasculature (von Willebrand Factor expression) was evaluated semi-quantitatively. Vasculogenic mimicry (VM) was analysed by CD31/PAS staining. RESULTS: All examined specimens expressed Cav-1 with a mean of 90.34% Cav-1 positive cells (range, 3.23-100%). Metastatic disease was associated with a higher Cav-1 expression. The correlation of Cav-1 with well-established prognostic factors showed a significant association between Cav-1 expression and largest tumour diameter (P = 0.022), tumour node metastasis classification (P = 0.008) and invasion of optic nerve head (P = 0.048). PI3K was expressed by all uveal melanomas with a mean of 87.28% cells showing PI3K expression. A higher level of PI3K was significantly associated with larger height (P = 0.042) and progressed tumour node metastasis stage (P = 0.016). The percentage of PI3K and Cav-1 positive cells were significantly associated (P = 0.034). For PI3K and Cav-1 expression a non-significant association with VM was shown (P = 0.064 and P = 0.072, respectively). No correlation of PI3K or Cav-1 with angiogenesis or mature vasculature was seen (P > 0.05). CONCLUSIONS: Cav-1 expression may be especially up-regulated in larger uveal melanomas. As it was correlated with PI3K expression and VM in this series of uveal melanoma, Cav-1 might induce the formation of VM via the PI3K-signalling cascade.

Low concentrations of ethanol but not of dimethyl sulfoxide (DMSO) impair reciprocal retinal signal transduction.

BACKGROUND: The model of the isolated and superfused retina provides the opportunity to test drugs and toxins. Some chemicals have to be applied using low concentrations of organic solvents as carriers. Recently, E-/R-type (Cav2.3) and T-type (Cav3.2) voltage-gated Ca(2+) channels were identified as participating in reciprocal inhibitory retinal signaling. Their participation is apparent, when low concentrations of NiCl2 (15 µM) are applied during superfusion leading to an increase of the ERG b-wave amplitude, which is explained by a reduction of amacrine GABA-release onto bipolar neurons. During these investigations, differences were observed for the solvent carrier used. METHODS: Recording of the transretinal receptor potentials from the isolated bovine retina. RESULTS: The pretreatment of bovine retina with 0.01 % (v/v) dimethylsulfoxide did not impair the NiCl2-mediated increase of the b-wave amplitude, which was 1.31-fold ± 0.03 of initial value (n = 4). However, pretreatment of the retina with the same concentration of ethanol impaired reciprocal signaling (0.96-fold ± 0.05, n = 4). Further, the implicit time of the b-wave was increased, suggesting that ethanol itself but not DMSO may antagonize GABA-receptors. CONCLUSION: Ethanol itself but not DMSO may block GABA receptors and cause an amplitude increase by itself, so that reciprocal signaling is impaired.

Effect of different fixative solutions on eyes with experimental proliferative vitreoretinopathy.

The aim of this study was to evaluate the use of different fixatives on the reliability of histopathological changes in a rabbit model of proliferative vitreoretinopathy (PVR). Twenty eyes from 10 rabbits were divided into four groups. The right eyes were used in two experimental groups (each n = 5), and the left, in two control groups (each n = 5). Using a newly developed scleral incision marker, an oblique scleral incision was standardized in the experimental groups, followed by intravitreal injection of 0.4 ml autologous blood and the left for wound repair for four weeks. Eyes were enucleated at four weeks. The groups differed in the type of used fixative solution (formaldehyde 4% vs. 1% buffered formaldehyde and 1.25% glutaraldehyde). The eyes were evaluated for the development of fibrosis, retinal detachment (RD), and processed for histopathology. Fibrous ingrowth of a variable degree was present in the experimental groups originating from the trauma site. Experimental eyes fixed with formaldehyde 4% had RD extension that was greater than that fixed in formaldehyde/glutaraldehyde mixture; however, the difference did not reach statistical significance (P = 0.15). This difference was not fully explained by the fibrosis which developed. In addition, in control groups, formaldehyde 4% induced a fixative-dependent retinal separation that was absent in eyes fixed with formaldehyde/glutaraldehyde mixture (P = 0.03). In conclusion, a mixture of buffered formaldehyde 1% and glutaraldehyde 1.25% combined with standardized scleral incision resulted in consistent pathological changes. A reliable PVR model is a condition sine qua non to evaluate antifibrotic treatment strategies.

The effect of disease-modifying antirheumatic drugs on retinal function in the electrophysiological ex vivo model of the isolated perfused vertebrate retina.

BACKGROUND: Disease-modifying antirheumatic drugs (DMARDs) have been suggested in the treatment of inflammatory ophthalmological diseases. The aim of the present study was to investigate the effects of these DMARDs on bovine retinal function. METHODS: Bovine retina preparations were perfused with a standard solution. After recording stable electroretinograms the nutrient solution was substituted by a DMARD medium with varying concentrations of different drugs (etanercept and infliximab) for 30 min. Afterwards b-wave recovery was observed. RESULTS: Significant decreases in the b-wave amplitude (p < 0.05) were found for etanercept 0.5 mg/ml (p = 0.0022). Infliximab 2 mg/ml (p = 0.1276) did not result in any statistically significant b-wave reduction. CONCLUSION: The presented data suggest that infliximab might have the better safety profile than etanercept.

Serum cytokines as biomarkers for age-related macular degeneration.

PURPOSE: This study evaluates the potential of serum pro-inflammatory cytokines as AMD biomarkers. METHODS: Serum samples from 30 age-related macular degeneration (AMD) patients and 15 age-matched controls were examined for 16 inflammatory cytokines using multiplex ELISA. Patients were divided into three subgroups (improvement/no change/deterioration during anti-VEGF treatment) by OCT and funduscopy, and correlated to the cytokine levels. RESULTS: Serum concentrations of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 were significantly higher in AMD patients than in controls. None of the co-variables expressed a significant effect on the tested cytokines. Only IL-1a and IL-17 showed a statistically significant difference between groups (improved, unchanged, deteriorated) as determined by one-way ANOVA. Patients with increased macular thickness during treatment showed significantly lower levels of IL-17 compared to improved cases and to unchanged cases (p = 0.004, 0.03 respectively, Dunnett's T3 post hoc multiple test). TNF-α was significantly higher in improved cases compared to deteriorated cases (p =0.03, Dunnett's T3 post hoc multiple test). IL-17 was a significant predictor for macular oedema using linear regression (ß = -0.888, p <0.05). CONCLUSION: Elevation of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 in the serum of AMD patients supports the hypothesis of AMD as an inflammatory disease. Patients with high IL-17 and TNF-α serum levels were more likely to have a favourable course under VEGF therapy. These cytokines may be used as easy-to-obtain biomarkers.

A p38 MAPK inhibitor improves outcome after glaucoma filtration surgery.

PURPOSE: The aim of this study is to explore the effects of SB 202190, a highly selective p38 MAPK inhibitor, on bleb survival following glaucoma filtering surgery. MATERIALS AND METHODS: Human Tenon's fibroblasts were treated with SB 202190 (0 to 100 µM) to determine IC50, and cell proliferation and migration. Twenty rabbits were divided into 4 groups (G1-G4): G1 animals received only a trabeculectomy. G2-G4 animals had trabeculectomy plus one of the following subconjunctival adjuvants, given intraoperatively and postoperatively: G2=sham, G3=20 µM SB 202190, and G4=50 µM SB 202190. The blebs were assessed using the Indiana Bleb Appearance Grading Scale. The intraocular pressure (IOP) was expressed as the right to left eye ratio (R/L ratio). For morphometric bleb analysis the JMicrovision software was used. RESULTS: SB 202190 inhibits human Tenon's fibroblasts proliferation and migration in vitro (IC50=17.2 µM). In vivo subconjunctival application of SB 202190 after glaucoma filtration surgery significantly increases bleb height, bleb extension, and bleb survival time compared with the control. In all groups, the IOP ratio correlates with the fibrotic process. G3 shows a significantly reduced IOP ratio at day 14 compared with the control. Analysis of the bleb histology shows that G3 has a significant smaller fibrosis area compared with G1 and G2. Application of the highest dose (50 µM SB 202190) is associated with hyphema in 2 of 5 animals (40%). CONCLUSION: Application of SB 202190 significantly improves bleb characteristics and IOP control after filtering glaucoma surgery in a rabbit model.

Testing the effects of the dye acid violet-17 on retinal function for an intraocular application in vitreo-retinal surgery.

PURPOSE: To facilitate epiretinal or inner limiting membrane peeling, dyes like Indocyanine Green (ICG) as well as Trypan Blue (TB) were used so far. However, toxic effects on the retina were described for both dyes. The aim of our study was to investigate the effects of a novel vital dye Acid violet-17 (AV-17) on retinal histology and function to assess a possible application in vitreo-retinal surgery. METHODS: AV-17 was dissolved in a solvent with heavy water. An electroretinogram was recorded on perfused bovine retina. After reaching stable b-wave amplitudes, AV-17 (0.125-0.5 mg/ml) or the solvent was applied epiretinally for 30-300 seconds. The b-wave amplitudes were recorded before, during, and after treatment. Cultures of bovine retina were incubated for 30 or 300 seconds with the dye or solvent and processed for live/dead staining, immunohistochemistry, and immunoblotting. RESULTS: Reductions of the b-wave amplitudes were observed directly after the exposure to AV-17, which were rapidly and completely reversible within the recovery period for all exposure times at the concentrations of 0.125 and 0.25 mg/ml as opposed to the partial recovery after exposure to 0.5 mg/ml. A high degree of damage in the ganglion cell layer (GCL) and glial reactivity were detected at the concentrations of 0.25 and 0.5 mg/ml but not after exposure to lower concentrations or the solvent. CONCLUSION: Application of AV-17 at a concentration of up to 0.125 mg/ml was well tolerated in terms of retinal function, survival in the GCL, and glial reactivity whereas higher concentrations are not recommended.

Identification of circulating melanoma cells in uveal melanoma patients by dual-marker immunoenrichment.

PURPOSE: Despite successful local tumor control, uveal melanoma (UM) patients may develop lethal metastases. To reliably identify circulating melanoma cells (CMC) in UM patients, we set out to test a new immunomagnetic enrichment assay and screened UM patients for the presence of CMC. We also determined whether we could find CMC in culture; for example, for future drug testing. METHODS: A dual-immunomagnetic enrichment assay using antibodies against two melanoma markers (NKI/C3 and NKI/beteb) was used to determine the presence of UM cells in blood. The sensitivity of the assay was determined by spiking normal blood with 92.1 cells (concentration range, 1-10(4) cells/mL). Isolated cells were characterized by immunocytochemistry directly after immunoenrichment and after a 2-week culture. The presence of CMC was determined in the peripheral blood of 31 patients with UM, and results were compared to clinical prognostic factors at the time of presentation. RESULTS: The CMC were detected in 93.5% (n = 29 of 31) of the patients with primary nonmetastatic UM at a median density of 3.5 cells/10 mL blood (range, 0-10.2 cells), as well as in blood cultures. No significant association was observed between the presence or number of CMC and any clinical prognostic factors. CONCLUSIONS: The improved dual-immunoenrichment assay enabled the detection of intact and viable CMC in the majority of UM patients. We also were able to identify CMC after short-term culturing. Molecular characterization of the CMC rather than the prevalence of these cells is expected to provide relevant information on the individual risk of metastasis.

A TGF-ß receptor 1 inhibitor for prevention of proliferative vitreoretinopathy.

This study evaluates the use of the TGF-ß receptor 1 inhibitor LY-364947 (LY) to prevent proliferative vitreoretinopathy (PVR). For the in vitro experiments Human Tenon's Fibroblasts (HTFs) and retinal pigment epithelial (RPE) cells were treated with different concentrations of LY to determine HTF proliferation and RPE transdifferentiation. For in vivo testing 30 rabbits underwent a PVR trauma model. The animals received different concentrations of intravitreally injected LY, with or without vitrectomy. LY treatment reduced HTF proliferation and RPE transdifferentiation in vitro. In vivo intravitreal injection of LY prevented PVR development significantly. This positive effect was also present when LY injection was combined with vitrectomy. Intravitreal injection of LY prevented tractional retinal detachment in 14 out of 15 animals. In conclusion, treatment with the TGF-ß receptor 1 inhibitor LY reduces HTF proliferation and RPE transdifferentiation in vitro and prevents proliferative vitreoretinopathy and subsequent tractional retinal detachment in vivo.

The concentration-dependent effects of indocyanine green on retinal function in the electrophysiological ex vivo model of isolated perfused vertebrate retina.

BACKGROUND: Dye solutions such as indocyanine green (ICG) are used for the staining of intraocular structures. The aim of the presented study was to investigate the effects of ICG on bovine retinal function using different concentrations of ICG. METHODS: Bovine retina preparations were perfused with a standard solution and the electroretinogram was recorded. The nutrient solution was substituted by an ICG solution at varying concentrations for 45 min. Afterwards the preparations were reperfused with standard solution for at least 85 min. RESULTS: Significant reductions in b-wave amplitude were found for concentrations of 0.0025% (p = 0.0099) and 0.025% (p = 0.0378). For the concentration of 0.025%, the b-wave amplitude remained significantly decreased (p = 0.0082) after the observation period, but a full recovery of the b-wave was observed for the concentration of 0.0025% (p = 0.1917). CONCLUSION: Intraocular application of sufficient ICG concentrations for internal limiting membrane staining seems not possible without interfering with retinal function.

Electrophysiological toxicity testing of VEGF Trap-Eye in an isolated perfused vertebrate retina organ culture model.

PURPOSE: Age-related macular degeneration (AMD) is the leading cause of visual impairment in Western nations. Since the discovery of the importance of vascular endothelial growth factor (VEGF) in the pathogenesis of neovascular AMD, anti-VEGF agents including pegaptanib, ranibizumab and bevacizumab provide a treatment option to improve vision in affected persons. VEGF Trap-Eye (Aflibercept) is a new agent available for the treatment of exudative AMD. The molecule is a receptor decoy with a longer half-life and a higher affinity to VEGF compared with ranibizumab or bevacizumab. The presented study has been designed to evaluate the short-term toxic effects of VEGF Trap-Eye on retinal function during and after direct exposure to the drug. METHODS: Isolated bovine retinas were perfused with an oxygen-saturated nutrient solution, and the electroretinogram (ERG) was recorded using silver/silver chloride electrodes. A total of 0.5 mg or 2 mg VEGF Trap-Eye was added to the nutrient solution and retinas were exposed for 45 min, followed by a washout period of 100 min. The percentage of a- and b-wave reduction at the end of the washout was compared with the baseline values. Additionally, retinal whole mount cultures were exposed for 24 hr to VEGF Trap-Eye, and the amount of apoptotic cells were determined using the terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labelling (TUNEL) assay. RESULTS: During simulation of intraocular application, no significant reduction in the a-wave amplitude for 0.5 mg (2.70%, p = 0.37) and 2 mg (3.84%, p = 0.37) VEGF Trap-Eye and b-wave amplitude for 0.5 mg (19.68%, p = 0.17) and 2 mg (24.1%, p = 0.06) VEGF Trap-Eye was observed at the end of the washout. However, there were significant changes in a-wave and b-wave amplitudes directly after exposure to 0.5 mg VEGF Trap-Eye (18.4%, p = 0.004 and 43.1%, p = 0.006, respectively). CONCLUSIONS: The presented data suggest that intraocular application of up to 2 mg VEGF Trap-Eye does not induce irreversible toxic retinal damage. However, short-term results showed a negative effect directly after the application for 0.5 mg and 2 mg VEGF Trap-Eye.

The retinal biocompatibility of dyes in the ex vivo model of the isolated superfused vertebrate retina.

BACKGROUND: Peeling of the internal limiting membrane or epiretinal membranes is a successful principle in macular surgery to achieve a functional benefit. Different dyes are used to facilitate the identification of intraocular tissues. The aim of our work was to investigate the retinal tolerance to the different dyes and their solvent carriers to provide valuable data for surgeons in handling for an optimal intraoperative use. METHODS: Using the ex vivo model of the isolated superfused vertebrate retina technique, the effects of the dyes were tested on human and bovine retinal function. The retinas were perfused with an oxygen preequilibrated standard solution. The electroretinogram (ERG) was recorded using Ag/AgCl electrodes. After recording stable ERG amplitudes, the dyes brilliant blue G, indocyanine green, trypan blue, patent blue, triamcinolone and their solvent carriers were investigated. RESULTS: Reductions of the ERG amplitudes were found for each tested dye. The effects after application of the dyes were dependent on time and concentration of the applied dyes, which were different for each dye. CONCLUSION: In part, the ERG has shown strong effects already after a short period of dye application. Surgeons who rely on the intraocular use of the dyes should keep in mind our findings, and the use of some dyes should be limited to selected cases. The well-considered use of the dyes by the surgeons could lead to a better functional outcome and avoid a possible harmful outcome of the surgery after mishandling.

The neuroprotective potential of Rho-kinase inhibition in promoting cell survival and reducing reactive gliosis in response to hypoxia in isolated bovine retina.

AIMS: To investigate the outcomes of Rho-kinase inhibition in the electrophysiological ex vivo model of the isolated perfused vertebrate retina under hypoxia. METHODS: Bovine retinas were perfused with an oxygen saturated nutrient solution with or without the Rho-kinase inhibitor H-1152P. The retinas were stimulated repeatedly until stable amplitudes were reached and the electroretinogram was recorded at five minute intervals. Hypoxia was induced for 15, 30, and 45 minutes, after which the oxygen saturation was restored. The extent of the cell damage and glial reactivity was determined by Ethidium homodimer-1 staining, immunohistochemistry, and Western blot. RESULTS: Hypoxia caused a time-dependent reduction of the b-wave amplitudes, which could not be prevented by the H-1152P. Although the Rho-kinase inhibitor maintained higher b-wave amplitudes, these effects did not reach statistical significance. Hypoxia also resulted in an increase in cell damage and the activation of the glial cells in the untreated retinas whereas the administration of H-1152P significantly reduced the extent of these events. CONCLUSION: H-1152P exerted a neuroprotective effect against necrosis on the isolated bovine retina under hypoxia together with a reduction in glial cell reactivity. However, the inhibitor could not prevent the hypoxia induced retinal dysfunction possibly due to the interference with synaptic modulation.