New Normative Database of Inner Macular Layer Thickness Measured by Spectralis OCT Used as Reference Standard for Glaucoma Detection

Purpose: This study examines the capacity to detect glaucoma of inner macular layer thickness measured by spectral-domain optical coherence tomography (SD-OCT) using a new normative database as the reference standard. Methods: Participants (N = 148) were recruited from Leuven (Belgium) and Zaragoza (Spain): 74 patients with early/moderate glaucoma and 74 age-matched healthy controls. One eye was randomly selected for a macular scan using the Spectralis SD-OCT. The variables measured with the instrument's segmentation software were: macular nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) volume and thickness along with circumpapillary RNFL thickness (cpRNFL). The new normative database of macular variables was used to define the cutoff of normality as the fifth percentile by age group. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) of each macular measurement and of cpRNFL were used to distinguish between patients and controls. Results: Overall sensitivity and specificity to detect early-moderate glaucoma were 42.2% and 88.9% for mRNFL, 42.4% and 95.6% for GCL, 42.2% and 94.5% for IPL, and 53% and 94.6% for RNFL, respectively. The best macular variable to discriminate between the two groups of subjects was outer temporal GCL thickness as indicated by an AUROC of 0.903. This variable performed similarly to mean cpRNFL thickness (AUROC = 0.845; P = 0.29). Conclusions: Using our normative database as reference, the diagnostic power of inner macular layer thickness proved comparable to that of peripapillary RNFL thickness. Translational Relevance: Spectralis SD-OCT, cpRNFL thickness, and individual macular inner layer thicknesses show comparable diagnostic capacity for glaucoma and RNFL, GCL, and IPL thickness may be useful as an alternative diagnostic test when the measure of cpRNFL shows artifacts

AMA0076, a Novel, Locally Acting Rho Kinase Inhibitor, Potently Lowers Intraocular Pressure in New Zealand White Rabbits with Minimal Hyperemia

PURPOSE. To determine whether ROCK inhibition for the treatment of glaucoma can be improved by using novel, locally acting Rho kinase (ROCK) inhibitors, such as AMA0076, that lower IOP without inducing hyperemia. METHODS. On-target potency of AMA0076 was compared with other ROCK inhibitors (Y-27632 and Y-39983) and conversion of AMA0076 into its functionally inactive metabolite was evaluated in rabbit eye tissues. Human trabecular meshwork (HTM) cell morphology, actin filaments, and focal adhesion were studied in vitro after exposure to AMA0076. The effect of AMA0076 on IOP was investigated in normotensive rabbits and a new, acute hypertensive rabbit model. Intraocular pressure lowering efficacy of AMA0076 was compared with pharmacologic treatments. Hyperemia after single topical dosing of AMA0076 and Y-39983 was scored. RESULTS. AMA0076 and Y-39983 showed similar on-target potency. AMA0076 was most stable in aqueous humor and converted into its metabolite in other eye tissues. Exposure of HTM cells to AMA0076 led to significant and reversible changes in cell shape and a decrease in actin stress fibers and focal adhesions. Both AMA0076 and Y-39983 provided an equivalent IOP control. Compared with latanoprost and bimatoprost, AMA0076 was more potent in preventing the IOP elevation in the acute hypertensive rabbit model. The degree of hyperemia was significantly lower in rabbits treated with AMA0076 then with Y-39983. CONCLUSIONS. AMA0076 is a locally acting ROCK inhibitor that is able to induce altered cellular behavior of HTM cells. Administration of AMA0076 effectively reduces IOP in ocular normotensive and acute hypertensive rabbits without causing distinct hyperemia

Macrophage miR-210 induction and metabolic reprogramming in response to pathogen interaction boost life-threatening inflammation

Unbalanced immune responses to pathogens can be life-threatening although the underlying regulatory mechanisms remain unknown. Here, we show a hypoxia-inducible factor 1α–dependent microRNA (miR)–210 up-regulation in monocytes and macrophages upon pathogen interaction. MiR-210 knockout in the hematopoietic lineage or in monocytes/macrophages mitigated the symptoms of endotoxemia, bacteremia, sepsis, and parasitosis, limiting the cytokine storm, organ damage/dysfunction, pathogen spreading, and lethality. Similarly, pharmacologic miR-210 inhibition improved the survival of septic mice. Mechanistically, miR-210 induction in activated macrophages supported a switch toward a proinflammatory state by lessening mitochondria respiration in favor of glycolysis, partly achieved by downmodulating the iron-sulfur cluster assembly enzyme ISCU. In humans, augmented miR-210 levels in circulating monocytes correlated with the incidence of sepsis, while serum levels of monocyte/macrophage-derived miR-210 were associated with sepsis mortality. Together, our data identify miR-210 as a fine-tuning regulator of macrophage metabolism and inflammatory responses, suggesting miR-210–based therapeutic and diagnostic strategies

Glaucoma: refining diagnosis and treatment.

Glaucoma is a chronic progressive disease characterised by specific structural abnormalities of the optic nerve head and patterns of visual field loss. Currently, lowering intraocular pressure (IOP) is the main pillar in the treatment of glaucoma and filtering surgery is the most efficient approach for doing so. However, in 30% of the cases, the constructed channel closes due to excessive scar formation, resulting in surgical failure. Therefore, a need for refinement of the surgical technique and for adjunctive therapeutic strategies to improve surgical outcome and to prevent filtration failure, remains.The first project of this doctoral thesis focuses on the improvement of the surgical technique and the development of adjunctive anti-fibrotic strategies to fight postoperative fibrosis and surgical failure in an attempt to optimise the surgical technique and thus improve the surgical outcome. This project consists of the following three studies which will be discussed below. In the first study, two different trabeculectomy techniques were compared in a prospective, randomised, single-centre study. One eye of each patient was randomly assigned to a trabeculectomy with an anterior chamber maintainer and a combination of 2 adjustable and 2 releasable flap sutures (technique 1), while the other eye underwent a trabeculectomy with a viscoelastic and 2 releasable flap sutures (technique 2). The remainder of the operation was similar in both eyes. There was no significant difference in IOP reduction, in frequency of postoperative complications and interventions, nor in the reduction of medications between the two techniques. In conclusion, using an anterior chamber maintainer might add safety when operating eyes at risk, while in most cases the classic technique 2, which is less sophisticated and faster, guaranteed excellent results if it was performed meticulously by an experienced surgeon. Therefore, technique 2 was used for the subsequent studies.In the second study, microplasmin, a truncated form of the human plasmin, was tested as an anti-scarring agent in a rabbit model for filtration surgery. The pilot experiments revealed promising data that the anterior chamber injections alone showed a trend to increase bleb area during the first week, but the combination of anterior chamber injection and 4 times daily topical eye drops were needed to improve bleb survival and increase bleb area in a rabbit model for filtration surgery. Therefore, in an attempt to extended ocular delivery, microplasmin was added to poloxamer and hydroxypropylmethylcellulose (HPMC) gels. The gel formulations developed were not able to improve the outcome after trabeculectomy, despite the fact that the activity of microplasmin lasted at least 24 hours. Strikingly, poloxamer 17% (w/w) gel alone could increase bleb area and prolong bleb survival, probably due to a mechanical effect. Further optimisation of the delivery method to achieve a longer release of active microplasmin over several weeks is necessary and could prove to be beneficial. In the last part of the surgical project, translational research was conducted based on the favourable effects of bevacizumab in the prevention of fibrosis in vitro and in vivo which we demonstrated previously. In a prospective, randomized, double-masked and placebo-controlled study, the effect of a single, preoperative, intracameral administration of bevacizumab (1.25mg/ml; Avastin ) in terms of clinical outcome following trabeculectomy in patients with either primary open-angle glaucoma (POAG) or normal tension glaucoma (NTG) was investigated. Interestingly, a single intracameral administration of bevacizumab at the end of trabeculectomy was associated with increased absolute success rates, reduced need for postoperative interventions in order to reach the target IOP, and more diffuse blebs with a lower degree of vascularity. Despite a successful IOP reduction, glaucoma continues to progress in some patients. Indeed, besides a raised IOP, other risk factors related to ocular ischemia have been associated with the pathogenesis of glaucoma. Currently, very little is known about the metabolic alterations in the retina of glaucoma patients, as only surrogate measurements of metabolism were available until recently. The second component of this doctoral thesis focuses on the change of oxygen metabolism in the glaucomatous retina measured by non-invasive retinal oximetry and to gain more insights into the vascular aspects of this disease. During the first phase of this project, the protocol and the analysis were fine-tuned in accordance with the group of Professor Stefánsson (Reykjavik, Iceland). The quality of the retinal vessel oximetry images were improved by the addition of topical phenylephrine 5% after tropicamide 0.5% for dilation, without influencing the retinal oxygen saturation values or the retinal vessel diameter in glaucoma patients. In the second phase, retinal vessel oximetry measurements were compared between glaucoma patients and healthy subjects, and between different types of glaucoma groups. Oxygen saturation values were similar in POAG and NTG patients. Healthy subjects had a greater oxygen consumption compared to glaucoma patients, which could be related to tissue atrophy in glaucoma.In the third phase, the association between retinal vessel oxygen saturation in glaucoma patients with structural optic disc and retinal nerve fiber layer (RNFL) changes and visual field defects was determined. Severe glaucoma damage was associated with increased oxygen saturation in venules and decreased arteriovenous difference in retinal oxygen saturation. These data confirm that in eyes with severe glaucomatous damage, oxygen consumption was decreased due to tissue loss. In conclusion, two different surgical techniques were compared and the technique with viscoelastics and 2 releasable flap sutures was chosen for further use. Two anti-fibrotic strategies were evaluated. Microplasmin looked promising in pilot experiments but the developing for extended ocular drug delivery needed further optimisation. Furthermore, a single intracameral administration of bevacizumab at the end of trabeculectomy proved to be beneficial for the outcome after trabeculectomy. In addition, retinal oximetry was different between healthy subjects and glaucoma patients and our data suggested that oxygen consumption was decreased in glaucoma patients due to tissue loss.nrpages: 190status: publishe

The iStent trabecular micro-bypass stent: a case series

PURPOSE: To evaluate the safety and effectiveness of a trabecular micro-bypass stent, the iStent (Glaukos, USA), for reduction of intraocular pressure in patients with open angle glaucoma. METHODS: In this prospective case series, ten eyes of eight patients underwent a gonioscopically-guided implantation of an iStent. Six eyes underwent combined surgery: cataract surgery followed by iStent implantation, and the remaining four eyes underwent iStent implantation only. The primary outcome measure was intraocular pressure and the secondary outcome measures were the reduction in number of glaucoma medications, and the number of complications. RESULTS: Mean intraocular pressure dropped from 19.6 mmHg preoperatively to 16.3 mmHg (range 12-27) after one month (p = 0.04), to 15.4 mmHg (range 8-23) after six months (p = 0.03) and 15.8 mmHg (range 9-25 mmHg) after one year (p = 0.03). There was a significant reduction in number of hypotensive medications between baseline and 12 months postoperatively from 2.7 to 1.7 medications. No vision-threatening complications were observed. CONCLUSIONS: The Glaukos iStent trabecular micro-bypass implantation is a safe procedure that is not associated with complications traditionally associated with filtering surgery. This trabecular bypass results in significant mid-term reduction of intraocular pressure as well as the number of medications.status: publishe

Disturbed correlation between arterial resistance and pulsatility in glaucoma patients

(i) To investigate whether pulsatility index (PI) and mean flow velocities (MFV) are altered in glaucoma patients. (ii) To evaluate the significance of PI in retrobulbar autoregulation capacity.status: publishe

Comparison of ICare, Dynamic Contour Tonometer, and Ocular Response Analyzer with Goldmann Applanation Tonometer in Patients with Glaucoma

PURPOSE: To compare the intraocular pressure (IOP) readings taken by ICare, Pascal dynamic contour tonometer (DCT), and ocular response analyzer (ORA) with those taken by Goldmann applanation tonometer (GAT). We sought to evaluate the influence of central corneal thickness (CCT) on IOP measurements and to compare patients' preferences for the four tonometers. METHODS: In this prospective study, 93 eyes from 93 patients were examined. Patients were randomly divided into 4 groups to vary the order in which the tonometers were applied. CCT was measured with an ultrasound pachymeter. RESULTS: The average CCT was 558+/-47.4 microm. The mean +/- standard deviation IOP for GAT, ICare, DCT, and ORA (Goldmann-correlated IOP) (ORA(GC)) were 15.1+/-4.8, 15.7+/-5.7, 18.2+/-5.1, and 18.3+/-6.6 mmHg, respectively. There was no significant difference between the mean IOP obtained with GAT and ICare (p=0.14). There was also no difference in IOP levels between the mean IOP obtained with DCT and ORA (p=0.26). There was no correlation between IOP measurements and CCT for the 4 instruments. Bland-Altman graphs showed disagreement between the measurements taken by GAT and the other instruments. There was no significant difference in patients' preference among the 4 instruments (p=0.48). CONCLUSIONS: IOP readings from ICare were consistent with those from GAT, whereas DCT readings correspond well to ORA(GC) measurements. DCT and ORA readings both overestimated the GAT readings. There was no correlation between the IOP measurements and the CCT for the 4 instruments. There was no significant difference in patients' preference among the 4 instruments.status: publishe

The Effect of Trabeculectomy on Astigmatism

To investigate the change in corneal astigmatism after trabeculectomy.status: publishe

Intraocular pressure correlates with optic nerve sheath diameter in patients with normal tension glaucoma

PURPOSE: 1. Identify differences in optic nerve sheath diameter (ONSD) as an indirect measure of intracranial pressure (ICP) in glaucoma patients and a healthy population. 2. Identify variables that may correlate with ONSD in primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) patients. METHODS: Patients with NTG (n = 46) and POAG (n = 61), and healthy controls (n = 42) underwent B-scan ultrasound measurement of ONSD by an observer masked to the patient diagnosis. Intraocular pressure (IOP) was measured in all groups, with additional central corneal thickness (CCT) and visual field defect measurements in glaucomatous patients. Only one eye per patient was selected. Kruskal-Wallis or Mann-Whitney were used to compare the different variables between the diagnostic groups. Spearman correlations were used to explore relationships among these variables. RESULTS: ONSD was not significantly different between healthy, NTG and POAG patients (6.09 ± 0.78, 6.03 ± 0.69, and 5.71 ± 0.83 respectively; p = 0.08). Visual field damage and CCT were not correlated with ONSD in either of the glaucoma groups (POAG, p = 0.31 and 0.44; NTG, p = 0.48 and 0.90 respectively). However, ONSD did correlate with IOP in NTG patients (r = 0.53, p  0.25 in all groups). CONCLUSIONS: Indirect measurements of ICP by ultrasound assessment of the ONSD may provide further insights into the retrolaminar pressure component in glaucoma. The correlation of ONSD with IOP solely in NTG patients suggests that the translaminar pressure gradient may be of particular importance in this type of glaucoma.status: publishe

Complementary effects of bevacizumab and MMC in the improvement of surgical outcome after glaucoma filtration surgery

PURPOSE: To determine the optimum administration route of bevacizumab after glaucoma filtering surgery (GFS) and to investigate whether a reduced dose of mitomycin-C (MMC) in combination with bevacizumab could improve surgical outcome with a reduced incidence of side-effects. METHODS: Plasma levels of bevacizumab were determined via ELISA after intracameral (IC), subconjunctival (SC) and intravitreal (IV) injections in mice, subjected to a mouse model of GFS. Application of MMC was compared to bevacizumab (SC, 25 μg) and to the combined use of both adjuvants. Surgical sponges soaked in MMC 0.02% or 0.01% were exposed to the sclera for 1 or 2 min. Treatment outcome was studied by bleb investigation. RESULTS: The three administration routes of bevacizumab equally improved surgical outcome. The VEGF antibody was detected at relatively high levels in plasma shortly after IV injection, whereas it was minimally absorbed after IC and SC injections. Both bevacizumab (SC) and MMC 0.02% (2 min) similarly increased bleb area. As compared to MMC, the combined injection with bevacizumab induced an additional effect on surgical outcome. Exposure of MMC 0.02% for 1 or 2 min together with bevacizumab equally improved surgical outcome, but 2 min application induced corneal toxicity. The combined use of bevacizumab and 1-min MMC 0.01% also improved surgical outcome compared to monotherapy, although to a lesser extent than the combination with 1-min MMC 0.02%. CONCLUSIONS: Adjunctive bevacizumab not only enhances the beneficial effect of MMC on surgical outcome, but also allows reducing the administration time of MMC 0.02%, thereby eliminating its toxic effects on the cornea.status: publishe