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Purpose: To evaluate bleb morphology features of different glaucoma drainage devices (GDD) using magnetic resonance imaging (MRI)., Materials and Methods: Prospective cohort study of GDD and bleb morphology in consecutive glaucoma patients implanted with Ahmed Glaucoma Valve (AGV), Paul Glaucoma Implant (PGI), Baerveldt Glaucoma Implant (BGI) and Ahmed ClearPath (ACP) devices. Thirty-six eyes from 30 consecutive patients underwent standardized GDD implantation followed by MRI at least 1 month after surgery. Main outcomes included bleb volume and endplate position relative to the optic nerve. Secondary outcomes included intraocular pressure (IOP), medication and surgical complications during a 12-month follow-up., Results: Seven eyes were implanted with the AGV (19%), 5 with BGI (14%), 16 with PGI (44%) and 8 with ACP (22%). MRI scans were obtained 85 ± 66 days after surgery. Mean total bleb volume was 563 ± 390 mm 3 . This bleb volume was inversely correlated with early post-operative IOP (day 7; r s  = -0.3326, p = 0.0475) but positively correlated with IOP at 12 months (r s  = 0.3592, p = 0.0341). No significant difference in total bleb volume was found between GDD types (p = 0.1223). A double-layered bleb was observed in 34 eyes (94%). The inferior bleb volume was significantly larger in PGI devices versus other GDD types (380 ± 205 vs. 193 ± 161 mm 3 ; p = 0.0043). Distance from the endplate to the optic nerve was 9.5 ± 4.0 mm, similar across GDDs (p = 0.2519)., Conclusions: Double-layered blebs are a common finding with GDDs. Bleb volume showed different correlations with IOP at distinct timepoints and the PGI device formed larger blebs. A standardized GDD implantation technique ensures a safe distance from the GDD endplate to the optic nerve., (© 2023 The Authors. Acta Ophthalmologica published by John Wiley & Sons Ltd on behalf of Acta Ophthalmologica Scandinavica Foundation.)

Purpose: The Baerveldt-XEN technique is intended to reduce the risk of early hypotony after Baerveldt implant, while keeping a good long-term intra-ocular pressure (IOP) control. The aim of this study is to discuss the surgical success rate of the Baerveldt-XEN and compare it with the commercially available flow-restrictor device (Ahmed glaucoma valve - AGV)., Methods: Single-centre, cohort study. Consecutive glaucoma patients with uncontrolled IOP > 21 mmHg on maximum tolerated medical therapy, and who had an aqueous shunt as the planned surgical procedure. Patients underwent implantation of Baerveldt-XEN. An age-, gender- and glaucoma aetiology-matched database of AGV patients was used for comparison. Complete surgical success was defined as a final IOP between 6 and 21 mmHg, and 20% reduction from baseline with no need for IOP-lowering medication. Qualified success was the same criteria but resorting to medications., Results: Twenty-four eyes from 24 subjects with glaucoma were included in this study, 12 patients underwent Baerveldt-XEN implantation and 12 AGV. Twelve months after the Baerveldt-XEN implant, the IOP reduced from 33 ± 9 mmHg to 14 ± 3 mmHg (p < 0.001). The qualified and complete success rate was 50% and 25%, respectively. With the AGV, the IOP reduced from 29 ± 7 mmHg to 16 ± 7 mmHg (p = 0.001). The matched AGV group compared to the Baerveldt-XEN, presented a higher complete success rate (58.3%) and a qualified success rate of 33.3% (p = 0.72). No sight-threatening complications were recorded in both groups., Conclusions: The Baerveldt-XEN disclosed a low complete success rate at 1 year of follow-up, although with no major safety concerns. While studies with a longer follow-up are needed to demonstrate the potential advantages and disadvantages of the Baerveldt-XEN, this technique may be less likely to achieve drop-free efficacy when compared to other flow-restrictor strategies., (© 2020 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: Glaucoma studies have long taken into account the blood pressure (BP) status of patients. This study summarizes and evaluates the impact of the different criteria that have been used for BP-related variables in glaucoma research., Methods: Studies included in two meta-analyses that reviewed the role of BP in glaucoma were analyzed. Additional studies published after the search periods of the meta-analyses were also included. Criteria for the definition of arterial hypertension and other BP-related variables, such as mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP), were retrieved., Results: Sixty-four studies were evaluated. One-third used 140 mmHg as a systolic BP cut-off to define hypertension, 20% used 160 mmHg and the remaining half used various other criteria. Less than 20% of studies reported MAP and/or MOPP. While eight of the ten studies reporting MAP used a correct formula that only happened for five of the eleven studies reporting MOPP. Using as an example average blood pressure values, incorrectly used formulas could have led to an overestimation of more than 100% of the expected values., Conclusion: Considerable heterogeneity exists in BP-related variables in glaucoma research and different definitions can lead to large disparities. Glaucoma research would benefit from a consensus regarding blood pressure parameters., (© 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To investigate the vitreopapillary interface (VPI) in health and glaucoma according to the different stages of posterior vitreous detachment (PVD) formation., Methods: Prospective single centre study including healthy subjects and glaucoma patients. PVD staging was performed with spectral domain optical coherence tomography. Gender, age, lens status and refractive error were assessed in both groups. Glaucoma patients additionally had a comprehensive ophthalmological investigation including intraocular pressure measurement, visual field testing and confocal imaging of the optic nerve head., Results: Data on 523 subjects (993 eyes) were included from the VPI study (clinicaltrials.gov NCT02290795) database (493 eyes of 258 healthy subjects and 500 eyes of 265 glaucoma patients). Healthy subjects were significantly younger than primary open angle glaucoma patients (59.7 ± 14.81 versus 70.0 ± 10.78 years, p < 0.001), but were otherwise matched for refractive error and gender. Significantly more glaucomatous eyes were pseudophakic (26.6% versus 5.1%). Including only phakic nonoperated eyes from subjects between 50 and 80 years old decreased the age difference between healthy and open angle glaucoma (64.1 ± 8.0 versus 65.9 ± 6.7 years, p = 0.051). Comparing these subgroups rendered similar average ages for PVD stages 0 and 4, in contrast to the significant older age for the glaucoma subgroup in stage 1 (64.1 ± 6.01 versus 61.4 ± 8.38 years, p < 0.001) and a trend towards significance in stage 3 (70.8 ± 69.8 versus 67.5 ± 5.92 years, p = 0.051)., Conclusion: The VPI study is a large clinical trial investigating the VPI in health and glaucoma. A subset of glaucoma patients seems to experience stages 1-3 of PVD formation at older age compared to healthy subjects., (© 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

. Purpose: To determine whether retinal vessel oxygen saturation in patients with glaucoma is associated with structural optic disc and retinal nerve fibre layer (RNFL) changes and visual field (VF) defects. Methods: Fifty-nine patients with confirmed glaucoma were recruited at University Hospitals Leuven. Retinal oxygen saturation in patients with glaucoma was measured with a noninvasive spectrophotometric retinal oximeter (Oxymap ehf, Reykjavik, Iceland). VF and Heidelberg retinal tomographies (HRTs) were performed on the same day. Statistical analysis was performed using Student's t-test and Pearson's or Spearman correlation coefficient. Results: The mean oxygen saturation in venules was higher in patients with severe VF defects compared to those patients with mild VF defects (69 ± 3% versus 65 ± 6% respectively; p = 0.0003; n = 59). Accordingly, the arteriovenous (AV) difference in oxygen saturation was lower in patients with worse VF compared to those with better VF (29 ± 3% versus 33 ± 6% respectively; p = 0.002). The oxygen saturation in venules correlated with the VF mean defects ( r = −0.42; p = 0.001; n = 59) as well as with the structural HRT parameters rim area and RNFL thickness ( r = −0.39; p = 0.008 and r = −0.26; p = 0.05 respectively; n = 53). The AV difference decreased significantly as the VF defect worsened ( r = 0.38; p = 0.003), as the rim area diminished ( r = 0.29; p = 0.03) and as the RNFL thickness decreased ( r = 0.27; p = 0.05). No correlation was found between the oxygen saturation in retinal arterioles and either of these parameters. Conclusion: Severe glaucomatous damage is associated with increased oxygen saturation in retinal venules and decreased AV difference in oxygen saturation. These data suggest that in eyes with severe glaucomatous damage, reduced retinal oxygen consumption is consistent with tissue loss. [ABSTRACT FROM AUTHOR]

Purpose Glaucoma patients are known to have an underlying vascular dysfunction and General anesthesia ( GA) significantly decreases blood pressure, which might decrease ocular perfusion. This study was conducted to investigate the effects of GA on ophthalmic flow velocities and blood pressure. Methods Prospective, case-control study. Glaucoma patients were scheduled for trabeculectomy or drainage device implantation; non-glaucomatous patients undergoing vitrectomy for macular hole or epiretinal membrane peeling were recruited as control subjects. Color Doppler imaging of the ophthalmic artery ( OA) was performed immediately before and 1 minute after GA induction. The following parameters were analyzed: OA blood velocities and resistivity index, as well as cardiovascular parameters (diastolic and systolic blood pressure and heart rate). Statistical analysis was performed using Student’s paired t test, Mann-Whitney, Fisher's exact test and Spearman's correlation. Results 53 patients were included (glaucoma group: 25; control group: 28). The magnitude in blood pressure decrease after GA induction was similar between the two groups (p value 0.61-0.70). However, the decrease in OA blood velocities was significantly larger in the glaucoma groups than in the control group (p < 0.03 in all comparisons). Unlike the control subjects, in the glaucoma group there was a significant association between the magnitude of blood pressure decrease and the lowering of the OA mean blood velocity ( r = 0.69, 95% IC: 0.36-0.87, p < 0.001). Conclusions These results suggest that glaucoma patients are unable to keep a stable blood velocity in the OA when subjected to acute significant decreases in blood pressure (such as the ones seen after GA induction). [ABSTRACT FROM AUTHOR]

Purpose Glaucoma is known to be associated with vascular dysfunction. However, integrating this knowledge in the clinical setting has been limited, considering the majority of vascular oriented studies have been either underpowered or only addressed a small segment of the vascular parameters in strictly selected patients. The Leuven Eye Study aims at bridging this gap by prospectively collecting the largest amount of vascular oriented data in a large real-life glaucoma clinic setting. Methods Prospective, cross-sectional, case-control hospital-based study. Patients with primary open-angle glaucoma ( POAG), normal tension glaucoma ( NTG), glaucoma suspect or ocular hypertension ( OHT) and healthy volunteers were recruited. In addition to an ophthalmological examination, a vascular-oriented questionnaire was completed and ocular blood flow assessment (color Doppler imaging of retrobulbar vessels, retinal oximetry, dynamic contour tonometry, optical coherent tomography enhanced depth imaging of the choroid) was performed in each subject. Results 620 subjects (297 male) were recruited between March and December 2013 ( POAG: 214, NTG: 192; glaucoma suspect: 41; OHT: 27; healthy controls: 146). Mean age was 68.4 ± 12.9 years. Other than IOP, there was no difference in demographic variables between glaucoma groups and healthy volunteers. Values for the ocular blood flow parameters are in line with the current literature. Conclusions The Leuven Eye study stands as the largest clinical trial on ocular blood flow in glaucoma. The creation of this vast database may help integrate the vascular aspects of glaucoma into the clinical practice of glaucoma. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the difference in assessment between fundoscopic and confocal scanning vertical cup-disc-ratio (VCDR) in open angle glaucoma patients. Methods Data from a single eye of normal tension (NTG) and primary open angle glaucoma (POAG) patients from the Leuven Eye Study were included: age, gender, visual field mean deviation (MD), fundoscopic and HRT III VCDR assessment as well as mean retinal nerve fiber layer thickness (mRNFL). Differences within groups were assessed by paired sample t-tests. Receiver operator curves (ROC) were constructed to assess and compute the likelihood ratio and positive predictive value. Results 303 eyes (161 POAG and 142 NTG) were included. The average VCDR clinically assessed was significantly larger than the value derived from the HRT III software (0.81 ± 0.14 versus 0.61 ± 0.16, p < 0.001) and this difference remained statistically significant in both groups. In advanced glaucoma (MD > −12 dB), the area under the curve for HRT III and fundoscopic VCDR was respectively 0.80 ± 0.05 versus 0.84 ± 0.04 for NTG and 0.66 ± 0.044 versus 0.82 ± 0.033 for POAG. To predict a MD of maximum -12 dB with 80% certainty in NTG patients the VCDR needs to be at least 0.79 and 0.88 for HRT III and fundoscopic VCDR values, whereas in POAG patients these numbers are 0.88 and 0.93, respectively. Conclusions Clinical assessment of VCDR renders significantly higher values than HRT III derived values. Fundoscopic assessment of the optic nerve can predict better the visual field damage compared to the HRT III assessment. [ABSTRACT FROM AUTHOR]