Evidence against involvement of kynurenate branch of kynurenine pathway in pathophysiology of Fuchs' dystrophy and keratoconus.

Kynurenine aminotransferases (KAT) are enzymes catalyzing formation of kynurenic acid (KYNA) from kynurenine. KYNA is a Janus-faced molecule of high biological activity. On the one hand KYNA was identified as a UV filter and neuroprotectant with free radical scavenging properties, but on the other hand it may contribute to photodamage of lens proteins resulting in cataract formation. Fuchs endothelial corneal dystrophy (FECD) and keratoconus (KC) are common, vision threatening corneal dystrophies whose etiology is not fully understood. In our previous works, we confirmed the presence of KATs in the human cornea together with GPR35, a receptor for KYNA. This prompted us to investigate the potential changes in the expression of three isoforms: KAT I, KAT II, and KAT III in normal and FECD- and KC-affected corneas. Immunohistochemistry accompanied by gene expression data mining revealed that the levels of neither KAT I, KAT II, nor KAT III are affected in FECD and KC. This constitutes evidence against the involvement of KATs in the pathophysiology of FECD and KC.

Evaluation of Choroidal Melanoma Vascularization by Color Doppler Flow Imaging: An Option for Follow-Up Tumor Control Assessment after CyberKnife®?

Background and Objectives: Thus far, tumor control for choroidal melanoma after teletherapeutic radiation is clinically difficult. In contrast to brachytherapy, the tumor height does not necessarily have to shrink as a result of teletherapy. Therefore, the objective of this study was to evaluate tumor vascularization determined by color Doppler flow imaging (CDFI) as a possible approach for monitoring the therapy response after teletherapy of choroidal melanoma. Materials and Methods: A single-center retrospective pilot study of 24 patients was conducted, all of whom had been diagnosed with choroidal neoplasm, treated and followed up. Besides tumor vascularization, the following parameters were collected: age, gender, tumor entity, location, radiation dose, knowledge of relapse, tumor height, radiation-related complications, occurrence of metastases, visual acuity in logMAR. Results: The level of choroidal melanoma vascularization markedly decreased in all included subjects after treatment with the CyberKnife® technology. Initially, the level of vascularization was 2.1 (SD: 0.76 for n = 10); post-therapeutically, it averaged 0.14 (SD: 0.4). Regarding the tumor apex, CDFI sonography also demonstrated a significant tumor regression (mean value pre-therapeutically: 8.35 mm-SD: 3.92 for n = 10; mean value post-therapeutically: 4.86 mm-SD: 3.21). The level of choroidal melanoma vascularization declined in the patient collective treated with ruthenium-106 brachytherapy. The pre-therapeutic level of vascularization of 2 (SD: 0 for n = 2) decreased significantly to a level of 0 (mean: 0-SD: 0). The tumor height determined by CDFI did not allow any valid statement regarding local tumor control. In contrast to these findings, the patient population of the control group without any radiation therapy did not show any alterations in vascularization. Conclusions: Our data suggest that the determination of the tumor vascularization level using CDFI might be a useful and supplementary course parameter in the follow-up care of choroidal melanoma to monitor the success of treatment. This especially applies to robot-assisted radiotherapy using CyberKnife®. Further studies are necessary to validate the first results of this assessment.

Assessment of the Efficacy of Microinvasive Glaucoma Surgery Techniques using an Oculopression Stress Test. / Nicht invasiver Belastungstest zur Funktionsprüfung von mikroinvasiven Glaukomdrainage-Implantaten und Laserchirurgie.

BACKGROUND: Glaucoma is one of the most common causes of blindness worldwide. The only evidence-based treatment to slow down the progression of glaucoma is the reduction of intraocular pressure (IOP) using local medication or through surgery. During the last years, a large number of microinvasive glaucoma surgery techniques (MIGS) has been developed, in order to reduce the IOP in glaucoma patients safely and effectively. Until now, efficacy of MIGS has been assessed mainly according to the postoperative IOP and the number of medications used. Results from long-term studies are rare or not available in the majority of the cases. In order to better evaluate the functionality of MIGS, a new examination method has been developed with the help of a new oculopressor device. In this study the efficacy of different MIGS techniques will be examined using the new oculopressor. MATERIAL/METHODS: At first, glaucoma patients that had previously received a MIGS surgery (iStent inject, XEN Stent, ELT) were examined with the new oculopression test. Their results were compared with those of non-operated patients and healthy individuals. Overall, 38 healthy subjects (group 1), 10 non-operated patients (group 2), 19 patients after iStent inject implantation (group 3), 14 patients after XEN Stent implantation (group 4) and 5 patients after ELT (group 5) were examined. The new examination measures the IOP-reduction that occurs after oculopression and can be seen as an indirect measurement of the outflow facility of the eye. RESULTS: The IOP-reduction after oculopression differed among the study groups. Non-operated patients showed a significantly lower IOP-reduction compared to healthy individuals. Patients after iStent inject and XEN stent implantation showed a larger reduction of IOP after oculopression in relation to non-operated patients and their results approximated those of healthy individuals. These patients needed fewer medications postoperatively in relation to non-operated patients. Patients after ELT showed postoperatively a smaller reduction of IOP after oculopression compared to iStent inject and XEN stent patients. CONCLUSION: MIGS can increase the outflow facility of the eye in patients with glaucoma. Though ELT had the lowest impact on the aqueous outflow among the studied procedures in this study. The new test can help in the evaluation of current and further development of new MIGS in the future.

The presence and distribution of G protein-coupled receptor 35 (GPR35) in the human cornea - Evidences from in silico gene expression analysis and immunodetection.

We provide the evidence for G protein-coupled receptor 35 (GPR35) presence and distribution in the human cornea. The initial data on GPR35 gene expression were retrieved from microarray repositories and were further confirmed by western blotting and immunohistochemical analysis. Immunoblotting suggested that GPR35 exists predominantly as a dimer in corneal tissue. Moreover, corneal tissues were significantly richer in GPR35 compared to the adjacent sclera. Immunoreactivity for GPR35 was detected in normal corneas, keratoconus and Fuchs' dystrophy, mainly in the corneal epithelium and endothelium. In corneas with Fuchs' dystrophy, less intensive immunoreactivity for GPR35 in endothelium was revealed. The physiological relevance of this phenomenon requires further investigation.

Functional and morphological results of treatment of macula-on and macula-off rhegmatogenous retinal detachment with pars plana vitrectomy and sulfur hexafluoride gas tamponade.

BACKGROUND: To examine morphological and functional results after pars plana vitrectomy (PPV) with sulfur hexafluoride (SF6) gas tamponade due to macula-on and macula-off rhegmatogenous retinal detachment (RRD) during 6 months of the follow-up. METHODS: The study included 62 eyes that underwent successful PPV with SF6 tamponade with macula-on (34 eyes) and macula-off (28 eyes) RRD preoperatively. The best-corrected visual acuity (BCVA), Amsler test, M-charts, optical coherence tomography (OCT) and microperimetry were performed at 1, 3 and 6 months postoperatively. RESULTS: Results of the Amsler test were abnormal postoperatively in 54% of the patients in the group with macula-off and in 32% of the patients with macula-on RRD. Horizontal M-charts improved significantly from 0.33 to 0.2, vertical M-charts- from 0.29 to 0.17 during 6 months of the follow-up. There was a significant increase in the central retinal thickness (CRT) and average thickness (AT) between follow-up examinations only in the macula-off group. 29 of 62 eyes (47%) after surgery (equally with macula-on and macula-off RRD) showed morphological changes in OCT in the macular region, as epiretinal membrane, macular edema, subretinal fluid or alterations of the outer layers of the retina. The average threshold in microperimetry increased significantly within both groups during the follow-up. CONCLUSION: Both horizontal and vertical M-charts scores, as were as microperimetry sensitivity improved significantly during the 6 months of the follow-up both in macula-on and macula-off group. Although PPV with SF6 gas tamponade was successful, almost half of eyes revealed anatomical changes in the macular region in OCT both with macula-on and macula-off group. TRIAL REGISTRATION: Current Controlled Trials NCT03902795 registered on 03/04/2019. Retrospectively registered.

Examination of Kynurenine Toxicity on Corneal and Conjunctival Epithelium: In vitro and in vivo Studies.

Kynurenine (KYN) is a metabolite of tryptophan, proposed for the treatment of corneal diseases. Our goal was to evaluate the effects of KYN on normal human corneal and conjunctival epithelial cells in vitro and the re-epithelization of corneal erosion in rabbits. In our study, we used corneal (10.014 pRSV-T) and conjunctival (HC0597) epithelium cell cultures. KYN was applied at a concentration range of 1-100 µM for 24 and 48 h. We examined the effects on cellular metabolism, viability, interleukin-1ß (IL-1ß), IL-6, IL-10 secretion, cytoskeleton organization and transwell migration ability. Following a bilateral corneal de-epithelialization, the rabbits received drops containing 1% KYN and a saline solution to the contralateral control eye, 5 times daily. Digital images were analyzed using the EPCO 2000 software. The metabolic activity of cells was slightly decreased by KYN in the corneal but not in the conjunctival epithelium. The viability of both epithelia was improved by KYN; it caused alterations in the secretion of IL-6 and IL-10 but not IL-1ß. It had no impact on both epithelia morphology and the organization of the cellular cytoskeleton. KYN stimulated the formation of pseudopodia projections in both epithelia in vitro, which may be important in terms of wound healing. However, there were no differences in the re-epithelization rate in vivo. At the tested concentrations, KYN was not toxic for the corneal and the conjunctival epithelium in vitro and did not affect corneal re-epithelization in rabbits in vivo. Our results suggest that KYN may be taken into consideration for the treatment of ocular disorders.

[Systems Biology in Ophthalmology - Innovative Drug Identification for the Specific Prevention of Postoperative Fibrosis]. / Systembiologie in der Ophthalmologie ­ innovative Wirkstoffidentifikation zur spezifischen Vermeidung postoperativer Fibrose.

BACKGROUND: The long-term success of fistulating therapies for the treatment of glaucoma is essentially limited by excessive scarring reactions (fibrosis). Cytostatic agents such as mitomycin C can prevent fibrosis, but are often associated with side effects. Specific antifibrotics are not currently in clinical use. Therefore, this study describes a systems biology approach using a dedicated bioinformatics technology platform, with which active substances can be identified and repositioned as antifibrotics. MATERIALS AND METHODS: Differential gene expression data of human Tenon fibroblasts (hTF) were collected from untreated hTF and from hTF stimulated with TGF-ß1 ("fibrotic fibroblasts") by next-generation sequencing (NGS) and were used as the basis for the drug identification process. These data were filtered with the bioinformatic tool "FocusHeuristics". In comparison with the Connectivity Map database, antifibrotic agents were identified. The evaluation of a potentially promising drug as an antifibrotic was performed at hTF by indirect immunofluorescence in vitro. RESULTS: The analysis of the gene expression data led to the identification of several interaction networks of genes or proteins involved in fibrotic processes. One of these networks contains the cytokine bone morphogenic protein 6 (BMP6), interleukin 6 (IL6) and fibroblast growth factor 1 (FGF1). Another relevant network has been identified around the cluster of differentiation 34 (CD34) gene. The comparison of these data with those of the Connectivity Map allowed the identification of an inhibitory drug. Its evaluation in the fibrotic cell culture model in vitro using indirect immunofluorescence led to a significant reduction in the expression of the fibrotic marker proteins fibronectin and alpha-smooth muscle actin (α-SMA), which confirmed the predicted antifibrotic effect. CONCLUSION: Systems biological approaches can be used for the identification of antifibrotic drug candidates for the prevention of postoperative fibrosis and should be transferable by the investigating differential gene expression data of further ocular cells or tissues to other ophthalmological fields of application.

VIP changes during daytime in chicken intrinsic choroidal neurons.

PURPOSE: Ocular autonomic control is mediated by sympathetic and parasympathetic nerve fibres. Their interactions are complemented by primary afferent nerve fibers of and intrinsic choroidal neurons (ICN). As the vasodilatative neuropeptide, vasoactive intestinal peptide (VIP), is expressed in extrinsic and intrinsic ocular neurons, it is of special interest in ophthalmic research. Since circadian changes of ocular blood flow are known in humans and birds, this study aimed at investigating VIP expression at different daytimes in chicken choroid, the preferred model species in ICN research. METHODS: 12 eyes of 12 chickens were retrieved, slaughtered at 8.00-9.30 a.m. (n = 6) and 8.00 p.m. (n = 6), respectively, and choroidal wholemounts were prepared for immunofluorescence of VIP. VIP-positive ICN of both groups were quantified and density of VIP-positive axons assessed semi-quantitatively. In 28 additional eyes retrieved in the morning (n = 14) and evening (n = 14), choroidal VIP content was determined by ELISA. Morning and evening data were analyzed statistically. NADPH-diaphorase (NADPH-d, ICN cell marker) was done at additional 12 whole mount choroids of 12 chicken, retrieved in the morning (n = 6) and evening (n = 6). RESULTS: (1) Numbers of VIP positive neurons differed significantly between morning: (239.17 ±â€¯113.9) and evening: (550.83 ±â€¯245.7; p = 0.018). (2) Numbers of VIP-positive perikarya were significantly more accumulated in the temporal part of the choroid in the evening than in the morning (p = 0.026). (3) VIP positive axon density was found to be similar throughout the choroid in the morning and evening. (4) Number of NADPH-d positive neurons was not significantly different between morning (848.8 ±â€¯399.5) and evening (945.8 ±â€¯622.1, p > 0.05). (5) ELISA demonstrated a significant difference of VIP content (p = 0.012) in tissues harvested in the morning (145.41 ±â€¯43.3 pg/ml) compared to evening (221.44 ±â€¯106.3 pg/ml). CONCLUSIONS: As VIP positive axon density was similar in the morning and the evening throughout the choroid, PPG and ICN seemed to contribute equally to the axon network. Yet, changes in the total choroidal VIP content, the numbers of VIP positive perikarya, reflecting the intracellular VIP content, and their topographical distribution at two different days-times argue for a different status of activation of both neuronal sources in contrast to the equal amount of NADPHD-d positive neurons. The higher VIP content in the evening, compared to the morning, correlates with a known circadian rhythm of a lower IOP and a higher choroidal thickness at night. Thus, these changes may argue for a potential role of ICN in the regulation of ocular homeostasis and integrity.

Role of Corneal Stromal Cells on Epithelial Cell Function during Wound Healing.

Following injury, corneal stromal keratocytes transform into repair-phenotype of activated stromal fibroblasts (SFs) and participate in wound repair. Simultaneously, ongoing bi-directional communications between corneal stromal-epithelial cells also play a vital role in mediating the process of wound healing. Factors produced by stromal cells are known to induce proliferation, differentiation, and motility of corneal epithelial cells, which are also subsequently the main processes that occur during wound healing. In this context, the present study aims to investigate the effect of SFs conditioned medium (SFCM) on corneal epithelial cell function along with substance P (SP). Antibody microarrays were employed to profile differentially expressed cell surface markers and cytokines in the presence of SFCM and SP. Antibody microarray data revealed enhanced expression of the ITGB1 in corneal epithelial cells following stimulation with SP whereas SFCM induced abundant expression of IL-8, ITGB1, PD1L1, PECA1, IL-15, BDNF, ICAM1, CD8A, CD44 and NTF4. All these proteins have either direct or indirect roles in epithelial cell growth, movement and adhesion related signaling cascades during tissue regeneration. We also observed activation of MAPK signaling pathway along with increased expression of focal adhesion kinase (FAK), paxillin, vimentin, ß-catenin and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Additionally, epithelial-to-mesenchymal transition (EMT) regulating transcription factors Slug and ZEB1 expression were enhanced in the presence of SFCM. SP enriched the expression of integrin subunits α4, α5, αV, ß1 and ß3 whereas SFCM increased α4, α5, αV, ß1 and ß5 integrin subunits. We also observed increased expression of Serpin E1 following SP and SFCM treatment. Wound healing scratch assay revealed enhanced migration of epithelial cells following the addition of SFCM. Taken together, we conclude that SFCM-mediated sustained activation of ZEB1, Slug in combination with upregulated migration-associated integrins and ERK (Extracellular signal-regulated kinase)-FAK-paxillin axis, may lead to induce type 2 EMT-like changes during corneal epithelial wound healing.

Role of Bone Morphogenetic Protein 7 (BMP7) in the Modulation of Corneal Stromal and Epithelial Cell Functions.

In the cornea, healing of the wounded avascular surface is an intricate process comprising the involvement of epithelial, stromal and neuronal cell interactions. These interactions result to the release of various growth factors that play prominent roles during corneal wound healing response. Bone morphogenetic proteins (BMPs) are unique multi-functional potent growth factors of the transforming growth factor-beta (TGF-β) superfamily. Treatment of corneal epithelial cells with substance P and nerve growth factor resulted to an increase in the expression of BMP7 mRNA. Since BMP7 is known to modulate the process of corneal wound healing, in this present study, we investigated the influence of exogenous rhBMP7 on human corneal epithelial cell and stromal cell (SFs) function. To obtain a high-fidelity expression profiling of activated biomarkers and pathways, transcriptome-wide gene-level expression profiling of epithelial cells in the presence of BMP7 was performed. Gene ontology analysis shows BMP7 stimulation activated TGF-β signaling and cell cycle pathways, whereas biological processes related to cell cycle, microtubule and intermediate filament cytoskeleton organization were significantly impacted in corneal epithelial cells. Scratch wound healing assay showed increased motility and migration of BMP7 treated epithelial cells. BMP7 stimulation studies show activation of MAPK cascade proteins in epithelial cells and SFs. Similarly, a difference in the expression of claudin, Zink finger E-box-binding homeobox 1 was observed along with phosphorylation levels of cofilin in epithelial cells. Stimulation of SFs with BMP7 activated them with increased expression of α-smooth muscle actin. In addition, an elevated phosphorylation of epidermal growth factor receptor following BMP7 stimulation was also observed both in corneal epithelial cells and SFs. Based on our transcriptome analysis data on epithelial cells and the results obtained in SFs, we conclude that BMP7 contributes to epithelial-to-mesenchymal transition-like responses and plays a role equivalent to TGF-β in the course of corneal wound healing.

Central scotoma in tobacco-alcohol toxic optic neuropathy measured with semi-automated kinetic perimetry.

PURPOSE: To measure the area of central scotoma obtained with semi-automated kinetic perimetry (SKP) in patients suffering from tobacco-alcohol toxic neuropathy (TATN). METHODS: Twelve eyes of six patients with TATN were examined with SKP. Area of central scotoma was measured in square degrees (deg2). Additionally, static automated perimetry (SAP) within 60° was performed in each patient. RESULTS: Area of central scotoma was 41.8 deg2 for III4e isopter, 22.9 deg2 for I4e isopter and 16.1 deg2 for I2e isopter in TATN patients. SAP revealed central scotoma in all patients. There was 100% of accordance between two methods. CONCLUSION: SKP is comparable with SAP in assessing central scotoma. SKP offers advantage of measuring central scotoma and assessing remaining peripheral visual field in TATN, even with low incidence and prevalence of this clinical entity.

[Significance of Homocysteine in Glaucoma]. / Stellenwert vom Homocystein beim Glaukom.

Endothelial dysfunction and vascular dysregulation play a role in the multifactorial pathogenesis of glaucomatous optic nerve atrophy. Hyperhomocysteinemia is a risk factor for endothelial dysfunction and is associated with primary open-angle glaucoma as well as secondary open-angle glaucoma in the pseudoexfoliation syndrome. This paper reviews the literature on the association between homocysteine metabolism and glaucomatous disease and explains the possible role of hyperhomocysteinemia in the pathogenesis and progression of glaucoma. We discuss the role of exogenous modifiable risk factors for the prevention and therapy of glaucoma, as well as modification of these factors by changes in life style, such as weight reduction, changes in nutrition and physical activity. The roles of homocysteine in regulating the extracellular matrix, vasotoxicity, neurodegeneration, and epigenetics are explained. Prevention and therapy of glaucoma by regulation of homocysteine levels are discussed.

The presence of kynurenine aminotransferases in the human cornea: Evidence from bioinformatics analysis of gene expression and immunohistochemical staining.

PURPOSE: Kynurenine aminotransferases (KATs) catalyze the synthesis of kynurenic acid (KYNA), a compound of significant biological activity. The aim of this study is to investigate the presence and distribution of KAT immunoreactivity in the healthy human cornea. METHODS: Data on gene expression in human eye structures were extracted from public microarray experiments using Genevestigator software. Immunohistochemistry was conducted using polyclonal antibodies against KAT I, II, and III on sections of eight enucleated eyes from patients with choroidal melanoma. RESULTS: Bioinformatics analysis showed that all four KAT isoforms were actively transcribed in the cornea and the conjunctiva. Immunohistochemical analysis revealed the presence of KAT I, II, and III in all examined corneal sections. The corneal endothelium showed the strongest reactivity for all three KAT isoforms. There was a slight positive staining of the corneal stroma for KAT I and II. KAT III immunoreactivity was found only in the stroma of the limbal region. In the corneal epithelium, the expression of all three KAT isoforms showed a specific pattern of the stain with fine squatter granules throughout the cytoplasm. This reactivity was more pronounced in the basal cell layers. The intermediate cell layers showed only faint immunoreactivity, and occasionally, there was no staining. KAT I, II, and III were also present in the adjacent limbal conjunctiva. CONCLUSIONS: The results indicate that kynurenine can be metabolized to KYNA in the corneal epithelium, stroma, and endothelium.

[Measurement of the Strength of Human Musculus Orbicularis Oculi Using Video Analysis]. / Messaufbau zur videoanalysebasierten Bestimmung der Lidschlusskraft des humanen Musculus orbicularis oculi.

Introduction Current methods to measure the of strength of the musculus orbicularis oculi are limited by high proneness to examiner error or by their complex and impracticable set-ups. Our aim was to develop a simple and practicable method to measure eye lid power via video analysis. Methods 50 healthy subjects were included. A deformable single use lid speculum was used. Forced maximum lid closure was recorded via a video slit lamp. Analysis of the video data was performed with open source tracking software. The maximum and minimum distances of the inserted lid speculum were detected. The rigidity and mechanical characteristics of the lid speculum were tested separately. In this way, lid power could be determined by analysis of the maximum compression of the lid speculum. To explore the impact of age and sex on eye lid power, Pearson's correlation coefficient was evaluated. ICC (intra class correlation) was analysed as a measure of reliability. Results In three repeated measurements in 9 subjects, an ICC of α = 0.91 was detected. With 50 healthy subjects, the range of lid power was 0.62 - 4.72 N. No correlation was found between the age of the subjects and eyelid power (Pearson's correlation coefficient = 0.054). A weak correlation was found between the sex of the subjects and eyelid power. For female subjects, the mean power was 1.82 N and for male subjects 2.58 N (Pearson's correlation coefficient = 0.428). Discussion A test series of 50 healthy subjects exhibited a wide range of lid power. The wide range makes it difficult to distinguish between pathological and normal eyelid power. The major application field of the method may therefore be in inner-individual measurements of known eyelid pathologies, such as paresis of the facial nerve or ocular myasthenia.

[Visual Analysis of Retinal OCT Data]. / Visuelle Analyse von retinalen OCT-Daten.

Optical coherence tomography (OCT) enables noninvasive high-resolution 3D imaging of the human retina, and thus plays a fundamental role in ophthalmology. Via OCT examination, even subtle retinal changes can be captured, which occur in very early stages of different diseases (e.g., glaucoma, diabetes mellitus, or age-related macular degeneration). Yet, analyzing the resulting data is challenging. Conventionally, OCT data are strongly aggregated via automated methods. While this reduces the amount of information to be analyzed, it also makes it difficult, if not impossible, to identify small and localized retinal changes. This might lead to wrong diagnoses, since these methods do not account for patient-specific characteristics. We address this problem by providing new and efficient visual-interactive methods. Particularly, we introduce dedicated visualizations that show different aspects of the data. In addition, we support patient-specific selections of relevant data regions. Selected regions are emphasized, or separately visualized to inspect retinal substructures in detail. By visually comparing the regions to reference data, even very small retinal changes can be detected. We demonstrate the utility of our approach by applying it to data of a study with pediatric patients suffering from diabetes mellitus type 1. Our results show that visual-interactive methods indeed help to analyze subtle retinal changes and, thus, support the diagnosis of diseases in an early stage.

[Effect of the Age-Related Corneal Elasticity on Applanation Tonometry]. / Auswirkungen des altersbezogenen kornealen Elastizitätsmoduls auf die Applanationstonometrie.

Elevated intraocular pressure (IOP) is accepted to be one important criterion for glaucoma and is usually measured by applanation or rebound tonometry. The individual uncertainty due to central cornea thickness (CCT) is thereby corrected, while the error induced by age-related elastic modulus (EM) change of the cornea is ignored. To investigate its influence on IOP measurement, we derive a model including also the elastic modulus. Our approach is based on known equations from experimental physics and several assumptions being justified in this paper. Our correction values are in good agreement with the Dresden correction table for low CCT values up to 650 µm using a mean EM of 0.29 MPa. An EM variation from 0.2 to 0.5 MPa, which relates to ages from infancy to 90 years, results in an IOP error of up to 10 mmHg. A variation of the cornea curvature from 7.4 mm to 8.0 mm results in a total IOP change of about 3 mmHg, which is usually neglected. The derived model shows that established correction formulas can be insufficient for a reliable IOP determination. In many cases, the conventionally measured IOP may be precise enough, but the uncertainty in IOP determination due to CCT and EM influence are almost in the same range. Measuring the IOP using applanation methods with established correction formulas should not be overestimated without to respect the EM of the cornea.

Vancomycin in infusion during vitrectomy in surgical treatment of acute postoperative and posttraumatic endophthalmitis.

BACKGROUND: Endophthalmitis is potentially devastating intraocular inflammation following eye trauma or surgery. We describe the visual outcomes and causative pathogens in acute bacterial postoperative and posttraumatic endophthalmitis treated with immediate pars plana vitrectomy (PPV) with Vancomycin dissolved in the infusion fluid. METHODS: Clinical records of consecutive 30 patients with postoperative endophthalmitis and 15 patients with posttraumatic endophthalmitis were evaluated. Vancomycin was administered constantly in the infusion fluid at the time of complete PPV. Cultures were prepared from anterior chamber paracentesis. The mean follow-up period was 13 months. RESULTS: The visual acuities were improved in 38 cases (84 %) and remained stable in seven cases (16 %). Median post-PPV visual acuity was 1.0 logMAR in a group with postoperative endophthalmitis and 1.3 logMAR in a group with posttraumatic endophthalmitis (p < 0.05). Twenty cases (44 %) were culture-positive (Staphylococcus, Streptococcus, Enterococcus and Bacillus spp). CONCLUSIONS: Early PPV with Vanomycin in infusion leads to vision improvement in patients with both posttraumatic and postoperative endophthalmitis. In our series of 45 cases culture was positive only in half of the cases.

Visual outcomes of posterior chamber intraocular lens intrascleral fixation in the setting of postoperative and posttraumatic aphakia.

BACKGROUND: Several techniques for fixation of the posterior chamber intraocular lens (IOL) have been developed. We evaluate long-term functional outcomes and safety of posterior chamber IOL implantation using Hoffman scleral haptic fixation and sutureless Sharioth technique in patients with posttraumatic and postoperative aphakia. METHODS: This retrospective case-series included 42 eyes operated by one surgeon. The data including demographic data, ocular history, preoperative, early postoperative and final best corrected visual acuity (BCVA), rate of complications as well as postoperative IOL position were collected. The mean follow-up was 14.5 months. Hoffman haptic scleral fixation was performed in 31 eyes, Sharioth technique-in 11 eyes. Aphakia was due to eye trauma (19) or complicated cataract surgery (23). RESULTS: Overall, the final BCVA improved in 26 eyes, did not change in 5 eyes, and worsened in 11 eyes. No significant differences in BCVA were found between groups operated with Hoffman scleral fixation and Sharioth technique. Postoperatively, we noticed two dislocations of IOL fixated using Sharioth technique and none after Hoffman technique. No severe complications were observed. CONCLUSION: Both transscleral fixation techniques are feasible methods of secondary IOL implantation in posttraumatic and postoperative aphakia. with low incidence of complications, however visual outcomes are diverse.

Canaloplasty versus non-penetrating deep sclerectomy - a prospective, randomised study of the safety and efficacy of combined cataract and glaucoma surgery; 12-month follow-up.

PURPOSE: To compare outcomes of phaco-canaloplasty (PC) and phaco-non-penetrating deep sclerectomy (PDS) with a viscoelastic compound. METHODS: This study included 29 eyes after PC and 30 after PDS. Indications were uncontrolled primary open-angle glaucoma (POAG) and a cataract. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), and number of medications were evaluated. Follow-up examinations were performed on days 1 and 7, and after 1, 3, 6, and 12 months. Complete and qualified success was an IOP ≤ 18 mmHg. RESULTS: At the 12-month follow-up, mean IOP decreased in the PC group from 19.0 ±6.9 mmHg to 12.6 ±2.7 mmHg, and in the PDS group, from 19.1 ±5.8 mmHg to 14.3 ±3.5 mmHg (P < 0.05). Both groups preoperatively and at 12 months showed no significant differences in IOP (P > 0.05). There was no statistically significant difference between the number of medications used (P > 0.05). Complete and qualified success rates for both groups were 79.0 % and 76.9 % (P = 0.701). The most frequent postoperative PC complication was hyphema (58.0 %); for PDS, bleb fibrosis was most frequent (26.7 %). No PC patients required postoperative management. PDS patients required postoperative interventions 58.7 % of the time, including a 5-fluorouracil (5-FU) injection (58.7 %), suture lysis (48.3 %), and needling (27.6 %). CONCLUSIONS: Both PC and PDS lead to an effective decrease in IOP on a short-term follow-up basis and demonstrate similar efficacy and safety profiles. PDS patients required additional procedures including 5-FU injections, suture lysis, or needling. PC patients required no additional procedures.

Short-term fluctuation of intraocular pressure is higher in patients with pseudoexfoliation syndrome despite similar mean intraocular pressure: a retrospective case-control study.

PURPOSE: Higher levels of short-term fluctuation of intraocular pressure (IOP) are characteristic of pseudoexfoliation syndrome (PEX). However, it is not known whether they are just a side effect of the higher mean intraocular pressure (IOP) or an independent feature. The purpose of this study was to compare short-term fluctuation of IOP between eyes with PEX and control eyes that were matched as closely as possible for mean IOP. METHODS: In this retrospective case-control study, all patients with confirmed PEX were identified from the database of the Erlangen Glaucoma Registry. From the same database, matched control eyes with similar treatment, age, glaucoma stage, and mean IOP were identified. For each patient, data from multiple extended diurnal IOP profiles were available. RESULTS: Seventy-eight eyes were included in the study (39 with PEX and 39 matched control eyes). Although a very close match was achieved, a small but statistically significant difference in mean IOP was still present, but this did not seem to explain the differences in IOP fluctuation levels. Eyes with PEX had significantly higher short-term IOP fluctuations (SD of IOP and range of IOP). CONCLUSIONS: The higher levels of short-term fluctuation in IOP appear to be an independent feature of PEX and not merely a secondary effect of the higher mean IOP. We suggest that this may have practical implications, even if IOP fluctuation levels should not prove to be an independent risk factor for development/progression of glaucoma, because more frequent measurements are needed in these patients to obtain good estimates of mean IOP and changes in IOP under treatment.