Thierry Zeyen

Universiteit Hasselt, Hasselt, Flanders, Belgium

Are you Thierry Zeyen?

Claim your profile

Publications (77)154.62 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To test whether retinal oxygen metabolism is different in glaucoma patients compared with healthy subjects. This was a two-centre study where retinal vessel oxygen saturation was measured in glaucoma patients and healthy individuals with a non-invasive spectrophotometric retinal oximeter. Visual fields were obtained in the glaucoma patients. No statistical difference was found in retinal oxygen saturation in arterioles (p=0.16), venules (p=0.16) and arteriovenous difference (p=0.24) when all glaucoma patients (n=74) were compared with healthy individuals (n=89). When patients with advanced glaucoma (visual field mean defect (MD ≥ 10 dB, n=21)) were compared with healthy individuals, the oxygen saturation in venules was higher in glaucoma patients (58.2%±5.4% vs 53.8%±6.4%; p=0.0054, mean±SD) and the arteriovenous difference was lower in glaucoma patients (36.4%±4.7% vs 39.5%±5.7%; p=0.021). In glaucoma patients with mild glaucoma (visual field MD ≤ 5 dB, n=33), no statistical differences were found in retinal oxygen saturation compared with healthy individuals. Glaucoma patients with advanced glaucoma have higher oxygen saturation in venules and lower arteriovenous difference in oxygen saturation compared with healthy individuals. The decreased arteriovenous difference in severe glaucoma may be related to lower oxygen consumption secondary to neuropathy.
    The British journal of ophthalmology 01/2014; · 2.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the efficacy and safety of a single intracameral bevacizumab injection to improve the outcome of trabeculectomy. A 12-month, prospective, randomised, double-masked, placebo-controlled trial. Patients with medically uncontrolled open-angle glaucoma scheduled for a primary trabeculectomy were recruited and randomised to receive 50 µL of either bevacizumab (1.25 mg) or placebo (balanced salt solution) peroperatively. Absolute success was defined as intraocular pressure (IOP) ≤18 mm Hg and >5 mm Hg with at least 30% reduction from baseline and no loss of light perception. Success through the use of additional medical and/or surgical IOP-lowering treatments was defined as qualified success. 138 patients completed a 12-month follow-up, 69 of whom were in the bevacizumab treated group. IOP at 1 year postoperatively was significantly lower than baseline (placebo: 25.6±9.9 mm Hg vs 11.5±3.9 mm Hg, p<0.01; bevacizumab: 24.8±8.1 mm Hg vs 11.9±3.8 mm Hg, p<0.01), with no difference between treatment groups (p=0.69). However, absolute success was higher in the bevacizumab group (71% vs 51%, p=0.02), with the need for IOP-lowering interventions (needlings) being lower in this group (12% vs 33%, p=0.003). Complication rates were low and comparable between groups. Peroperative administration of intracameral bevacizumab significantly reduces the need for additional interventions during the follow-up of patients undergoing trabeculectomy.
    The British journal of ophthalmology 10/2013; · 2.92 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the ability of ophthalmologists across Europe to match stereoscopic optic disc photographs to visual fields of varying severity. Evaluation and comparison of 2 diagnostic tests. A total of 109 of 260 invited ophthalmologists in 11 European countries. These had participated in the previous European Optic Disc Assessment Trial (EODAT), a trial on glaucoma diagnostic accuracy based on optic discs only. Each participant matched stereo optic disc photographs of 40 healthy and 48 glaucomatous eyes to a visual field chosen from 4 options per disc. The 4 presented visual fields included the corresponding one and 3 other visual fields, varying in severity. The matching accuracy and any inaccuracy per disease severity were calculated. Classification accuracy (as glaucomatous or healthy) was compared with EODAT data. Duplicate slides allowed for the assessment of intraobserver agreement. Accuracy of matching optic discs with their corresponding visual field and of classifying them as healthy or glaucomatous; intraobserver agreement (κ). The overall accuracy of ophthalmologists for correctly matching stereoscopic optic disc photographs to their visual fields was 58.7%. When incorrectly matched, the observers generally overestimated the visual field severity (P < 0.001), notably in eyes with early glaucoma. The intraobserver agreement was, on average, moderate (0.52). European ophthalmologists correctly matched stereoscopic optic disc photographs to their corresponding visual field in only approximately 59% of cases. In most mismatches, the clinicians overestimated the visual field damage. Proprietary or commercial disclosure may be found after the references.
    Ophthalmology 06/2013; · 5.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To describe the study design and baseline factors of the Heidelberg Retina Tomograph ancillary study within the EGPS. Furthermore, to examine the relationship between HRT optic disc topographic measurements and baseline demographic and ocular factors. Methods: Four hundred and eighty-nine ocular hypertensive participants were included. Each participant completed HRT imaging at least annually. The associations between HRT measurements and IOP, central corneal thickness (CCT), baseline photographic estimates of vertical CDR ratio (CDR), asymmetry between the two eyes in CDR ratio and baseline visual field indices were assessed using regression analysis. Results: Associations between HRT measurements and vertical CDR by photographs were found for almost all stereometric optic disc parameters in both univariate and multivariate analysis. The strongest association was found between vertical CDR measurements and disc, cup and rim area; cup and rim volume, CDR area, linear CDR, mean and maximum cup depth and cup shape measure (all p < 0.0001). In multivariate analysis, pattern standard deviation (PSD) and HRT disc area had significant associations with several HRT optic disc measurements. Furthermore, CCT was significantly associated with reference height and the glaucoma probability score (GPS, outside normal limits). Conclusions: The EGPS is the first multicentre, placebo-controlled randomized clinical trial to use HRT for monitoring optic disc changes in participants with ocular hypertension. We found strong associations between stereophotographic vertical CDR estimates, HRT disc area, PSD and several HRT parameters. We found, furthermore, that the parameters reference height and GPS were significantly related to central corneal thickness.
    Acta ophthalmologica 05/2013; · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To compare the rates of change in the visual field (VF) in patients with glaucoma before and after trabeculectomy. Methods: Of 52 eyes of 52 patients with different types of chronic glaucoma who underwent first trabeculectomy were evaluated retrospectively. Pre- and postoperative-automated visual fields measured by the same technique were compared to detect differences in rates of change. Rates of VF loss before and after trabeculectomy were calculated using mean deviation (MD). Linear mixed models were used to compare the rates of change in the VF before and after trabeculectomy. Results: The mean follow-up period pre- and post-trabeculectomy was 3.9 years (min 0.9, max 10.7) and 3.8 years (min 2.0, max 8.0), respectively. The intraocular pressure (IOP) decreased from 18.1 mmHg (SD = 4.7) before trabeculectomy to 11.1 mmHg (SD = 2.9) at the last follow-up after trabeculectomy. The rate of MD loss was reduced with 56% on average, from -0.36 dB/year before surgery to -0.16 dB/year after surgery (p = 0.15). Conclusion: Trabeculectomy considerably decreased the rates of change in the glaucomatous visual field.
    Acta ophthalmologica 04/2013; · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Acta ophthalmologica 01/2013; · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE:: To assess the long-term outcomes of trabeculectomy using an anterior chamber maintainer and a combination of adjustable and releasable sutures compared with trabeculectomy using a viscoelastic and solely releasable sutures. METHODS:: In a prospective, randomized, single-center study, 2 different trabeculectomy techniques were compared. One eye of each patient was randomly assigned to trabeculectomy with an anterior chamber maintainer and a combination of 2 adjustable and 2 releasable flap sutures (technique 1), whereas the other eye had trabeculectomy with viscoelastic and 2 releasable flap sutures (technique 2). The postoperative management was comparable in both groups except for the manipulation of the adjustable sutures. The main outcome measures were the postoperative intraocular pressure (IOP), the frequency of early postoperative complications and interventions, and the number of glaucoma medications. RESULTS:: Thirty-two patients were included and had a follow-up of at least 18 months. The preoperative and postoperative IOP at 18 months was 22.1±8 and 13.3±2 mm Hg in the group using technique 1 and 22.7±7 and 13.3±3 mm Hg in the group using technique 2, respectively (mean±SD; P=0.18 for IOP reduction between both techniques). Early postoperative complications and interventions were infrequent and comparable in both techniques. The reduction in number of medications was not significantly different between the 2 groups (mean±SD from 2.4±1.0 to 0.4±0.8 in the group using technique 1 and from 2.3±1.0 to 0.2±0.5 in the group using technique 2; P=0.50). CONCLUSIONS:: There is no significant difference in IOP reduction, in frequency of postoperative complications and interventions, or in reduction of medications between the 2 techniques.
    Journal of glaucoma 08/2012; · 1.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To report a case of anterior segment ischemia (ASI) with rubeosis iridis after circular buckling surgery in a highly-myopic patient which was successfully treated with a second intravitreal bevacizumab injection. Case report and review of the literature. ASI is a rare but potentially serious complication of posterior segment surgery. Finally it leads to neovascular glaucoma as a result of rubeosis iridis. An encircling band can compromise anterior segment circulation in different ways: by manipulation or disinsertion of the recti muscles, by occlusion of the vortex veins through compression or by changes in the blood supply of iris and ciliary body. This patient developed rubeosis iridis secondary to ASI. There was a remarkable regression of rubeosis iridis one month after a second intravitreal bevacizumab injection. Other case reports of bevacizumab use in neovascular glaucoma have shown clinical improvements of these patients, with intraocular pressure control and reduction of the neovascularization process. We describe a highly-myopic patient who developed ASI with rubeosis iridis after a circular buckling operation. Slit-lamp examination and gonioscopy can show very little rubeosis iridis and can be misleading. Iris fluorescein angiography is the most sensitive technique for evaluation of iris vessel abnormalities and is of considerable value in the early detection of rubeosis iridis. This report demonstrates the rapid resolution of rubeosis iridis on iris fluorescein angiography after a second intravitreal injection of bevacizumab. How long this regression will persist is unknown and repeated injections of bevacizumab may be necessary if rubeosis reappears.
    Bulletin de la Société belge d'ophtalmologie 01/2012;
  • T ZEYEN
    [Show abstract] [Hide abstract]
    ABSTRACT: A combined Phaco-Trabeculectomy will often not have the same result as both procedures separately. The IOP lowering effect of a combined procedure is usually less than that of Trabeculectomy alone. Likewise, post-operative fluctuations of the anterior chamber depth after a combined procedure will influence the post-operative refraction, especially in the early post-operative period and/or if additional procedures (e.g. needling) are necessary to rescue a failing bleb. Therefore, most surgeons will prefer to stage both procedures. Since cataract surgery might compromise an existing filtering bleb, it is recommended to perform Phaco first if the IOP is not too elevated. If the glaucoma is at risk to deteriorate in the short term, filtering surgery should be performed first. It is advisable to wait 6 months between the cataract and glaucoma surgery.
    Acta ophthalmologica 09/2011; 89(s248). · 2.44 Impact Factor
  • T ZEYEN
    [Show abstract] [Hide abstract]
    ABSTRACT: Deep sclerectomy claims to be safer than trabeculectomy. This might have been true in the past but, with modern techniques, “safe trabeculectomy” can be performed with few complications. Deep sclerectomy claims to be a “non-perforating” procedure. It is probably more correct to name it a two-stage perforating procedure since post-operative Yag-laser goniopuncture is necessary in > 50% of the cases. Since an iridectomy is not performed during deep sclerectomy, iris incarceration can occur after goniopuncture and can be easily missed. Furthermore, it is puzzling that new modifications of deep sclerectomy include using an Express implant, converting it right away to a perforating procedure. Finally, a trabeculectomy usually provides lower post-operative IOPs than a deep sclerectomy. Since one of the reasons to operate is to obtain a low target IOP, it is advisable to perform a trabeculectomy.
    Acta ophthalmologica 09/2011; 89(s248). · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose To compare the rates of change in the visual field (VF) in patients with glaucoma before and after trabeculectomy.Methods 52 eyes of 52 patients over 35 years of age with different types of chronic glaucoma who underwent primary trabeculectomy were evaluated retrospectively. Pre- and postoperative automated visual fields measured by the same technique were compared to detect differences in rates of progression. Rates of VF loss before and after trabeculectomy were calculated using global indices, mean defect (MD) and pattern standard deviation (PSD) and linear regression analysis per cluster. Linear mixed models were used to compare the evolution of the VF before and after trabeculectomy.Results The mean follow-up period pre-trabeculectomy was 3.88 years (min 0.92, max 10.72) and post-trabeculectomy 3.82 years (min 2.03, max 8.02). The intraocular pressure (IOP) decreased significantly from 18.12 ± 4.71 mmHg before trabeculectomy to 11 ± 2.87 mmHg at the last follow-up after trabeculectomy (P < 0.0001). The rate of progression of MD decreased with 55%, from –0.36 dB/year before surgery to –0.16 dB/year after surgery (P = 0.15). The rates of progression of PSD decreased from –1.69 dB/year before to –0.018 dB/year after surgery (P = 0.03). Of the 10 predefined clusters, only in cluster 10, situated infero-temporally, the difference between the slopes was statistically significant (0.64 dB/year, P = 0.0021).Conclusion Trabeculectomy significantly decreased the rates of glaucomatous VF progression.
    Acta ophthalmologica 09/2011; 89(s248). · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess the outcomes of the various medical and surgical treatment options for malignant glaucoma. Design Retrospective, comparative case series. Participants Twenty-four eyes of 21 patients with malignant glaucoma. Intervention Nine eyes were treated medically. Twenty-one eyes underwent surgery, 15 of which had the full vitrectomy-(phaco)-iridectomy-zonulectomy procedure. Main outcome measures Intraocular pressure (IOP), best-corrected visual acuity (BCVA) and number of glaucoma medications were measured. The relapse rate was 100% after medical therapy, 75% after a Yag laser capsulotomy and a hyaloidotomy, 75% after a conventional vitrectomy and 66% after an anterior vitrectomy in combination with an iridectomy-zonulectomy. All patients who underwent a full vitrectomy combined with an iridectomy and a zonulectomy (and phacoemulsification if phakic) had postoperative relief of malignant glaucoma without relapse within the follow-up period. After this vitrectomy-tunnel technique, the IOP ranged from 10 to 22 mmHg (mean 16 mmHg) after a mean follow-up of 61 days. Mean BCVA improved by 5 Early Treatment Diabetic Retinopathy Study (ETDRS) lines, and mean number of glaucoma medications decreased from two to one. Complete vitrectomy combined with iridectomy and zonulectomy (and phacoemulsification, if applicable) most successfully managed aqueous misdirection syndrome in our retrospective case series.
    Albrecht von Graæes Archiv für Ophthalmologie 08/2011; 250(1):131-41. · 1.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this review was to summarize literature in view of patient-reported outcome (PRO) instruments for glaucoma and provide guidance on how outcomes are best assessed based on evidence about their content and validity. A systematic literature review was performed on papers describing the developmental process and/or psychometric properties of glaucoma or vision-specific PRO-instruments. Each of them was assessed on their adherence to a framework of quality criteria. Fifty-three articles were identified addressing 27 PRO-instruments. In all, 18 PRO's were developed for glaucoma and 9 for diverse ophthalmologic conditions. Seven instruments addressed functional status, 11 instruments quality of life and 9 instruments disease and treatment-related factors. Most of the instruments demonstrated only partially adherence to predefined quality standards. The tools for assessing functional status were of poor quality, while the Glaucoma Quality of Life Questionnaire and the Vision Quality of Life Index were well-developed QoL measures, yet only validated using classical techniques. The Rasch-scaled QoL-tools, IVI and VCM1 need to improve their item-content for glaucoma patients. The questionnaires to measure adherence should improve their validity and the Treatment Satisfaction Survey for Intra Ocular Pressure pops out as the highest quality tool for measuring topical treatment side effects. This review revealed that most PRO-instruments demonstrated poor developmental quality, more specifically a lack of conceptual framework and item generation strategies not involving the patients' perspective. Psychometric characteristics were mostly tested using classical validation techniques.
    Eye (London, England) 03/2011; 25(5):555-77. · 1.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed to investigate (1) the prevalence of nonadherence with eye drop treatment; (2) selected correlates of nonadherence at the patient and health-care organization level; and (3) the diagnostic value of the ophthalmologists' ratings, using patients' self-reports as standard. This cross-sectional multicenter survey used questionnaires for ophthalmologists and their patients to assess self-reported nonadherence and its correlates. One item, using a 4-point scale [never (ie, adherent) to daily], asked the patients whether they had forgotten to administer eye drops during the past 2 weeks. Ophthalmologists rated their patients as adherent or nonadherent. Nonadherence was also determined by combined methods, whereby either could indicate nonadherence. Given the nested structure of the data, multilevel modeling was used to investigate self-reported nonadherence-correlates. Diagnostic values of ophthalmologists' report were calculated. Of 663 patients (48% female, 44% >69 years), nonadherence was indicated in 39.2% (n=260) through self-reporting, 2.1% (n=14) through ophthalmologists' ratings, and 40% (n=266) through combined measures. The multivariable, multilevel model showed following significant nonadherence-correlates: Male sex (P=0.01), younger age (P=0.027), and higher-dose frequency (P=0.001). No significant correlation with treating ophthalmologist (P=0.21) could be seen. Yet, the patients visiting their ophthalmologists at least every 3 months were less nonadherent than patients with fewer consultations (P=0.01). The ophthalmologists' report showed a sensitivity and specificity of 3% and 98.5%, respectively. The prevalence of self-reported nonadherence was congruent with literature. The patients visiting their ophthalmologists at least every 3 months have a lower risk of nonadherence. Ophthalmologist report is an insensitive method for detecting nonadherence.
    Journal of glaucoma 11/2010; 20(7):414-21. · 1.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare the interobserver agreement in detecting glaucomatous optic disc changes using serial stereophotography between a large group of non-expert ophthalmologists and glaucoma specialists; to assess the accuracy of non-experts; to investigate whether the interobserver agreement and the accuracy of non-experts changed after a training session. Masked interobserver agreement study. Serial optic disc stereophotos from 40 patients with glaucoma. Three independent experienced glaucoma specialists (readers of the European Glaucoma Prevention Study) evaluated a set of 2 serial optic disc color stereo-slides for glaucomatous change, obtained with a delay varying from 2 to 7 years of 40 patients, masked from the temporal sequence of the slides. Each patient was graded as changed or stable by agreement of 2 of 3 of the experts (the reference standard). Thirty-seven non-expert ophthalmologists independently evaluated the same set of serial optic disc stereo-slides twice, with the second evaluation on the same day, masked from the results of the previous evaluation, after a training session on a separate slide set. Interobserver agreement of non-experts and experts in detecting glaucomatous optic disc changes (expressed as kappa coefficient); agreement of non-experts with the reference standard (accuracy) before and after a training session. The interobserver kappa coefficient (κ) of the non-experts and experts was 0.20 (95% confidence interval [CI], 0.19-0.21) and 0.51 (95% CI, 0.33-0.69), respectively (P<0.0001). The mean κ of the non-experts with the reference standard was 0.33 (95% CI, 0.27-0.39). After a training session, the interobserver agreement of the non-experts increased from 0.20 to 0.27 (95% CI, 0.26-0.28) (P<0.0001). The percentage agreement of the non-experts with the reference standard improved from 68.5% before to 71.4% after the training session (Wilcoxon signed-rank test, P=0.034). The interobserver agreement of non-expert ophthalmologists in detecting glaucomatous optic disc changes using serial stereophotos was significantly lower than that of experts, which was moderate. After a training session, the interobserver agreement and the accuracy of the non-experts showed a small but statistically significant improvement.
    Ophthalmology 11/2010; 118(4):742-6. · 5.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose Glaucoma surgery fails in 30% due to excessive scar formation of the constructed channel. Our group found that vascular endothelial growth factor (VEGF) is upregulated in the aqueous humor of glaucoma patients and postoperatively in a rabbit model for trabeculectomy, that VEGF stimulates fibroblast proliferation in vitro whereas bevacizumab can inhibit their growth, and that a single peroperative intracameral injection of bevacizumab improves the surgical outcome of trabeculectomy in a rabbit model. Based on these findings, we set up a clinical trial to study the potential of bevacizumab as an anti-scarring agent after trabeculectomy.Methods This is a prospective, randomized, placebo-controlled, double-blinded experimental study. The effect of peroperative administration of 50 µl of bevacizumab (25mg/ml) on intraocular pressure, bleb characteristics, as well as number of postoperative IOP-lowering medications and surgical interventions is investigated. Patients with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) who are scheduled for primary trabeculectomy are included.Results Inclusions started on April 2009 and are still ongoing. Based on a priori calculations we need to include 124 patients. We already included 97 patients, 54 of which are POAG and 43 are NTG patients. By the end of September the majority will have ended the study. The preliminary results of this group will be presented at EVER.Conclusion This study will provide evidence on effectiveness and safety of single administration of bevacizumab during trabeculectomy to reduce the risk of surgical failure, avoiding or reducing the need for long-term medication use or secondary surgical intervention.
    Acta ophthalmologica 09/2010; 88(s246). · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose Some patients questioned us whether diving and mountaineering can have an effect on their intraocular pressure (IOP). Since the results in the literature concerning mountaineering are often contradictory and the data concerning diving are very limited; we investigated if an increase in atmospheric pressure influences the IOP in a normal population. Since we clinically experienced higher pressures in the summer, we checked the temperature influence on the IOP simultaneously.Methods Twenty-seven healthy volunteers (aged 18 to 44) were placed in a hyperbaric chamber. Their IOP was measured with a Perkins tonometer at baseline (normal atmospheric pressure of 1 Bar and 24°C), after increasing the atmospheric pressure to 2 Bar both at 14°C and 28°C, and finally at baseline again. A multivariate regression analysis was used to evaluate the results of both eyes.Results The IOP significantly decreased from 11.75mmHg to 10.50mmHg at 2 Bar. The IOP decrease remained constant during the atmospheric pressure rise (40 minutes) and was independent of the temperature change. The IOP returned back to the baseline value when exiting from the hyperbaric chamber.Conclusion A small increase of atmospheric pressure to 2 Bar (= equal effect to diving at 10m below sea level) is sufficient to lead to a significant reduction in IOP independent of temperature changes in a healthy young population. The IOP decrease sustains for the whole hyperbaric chamber period.
    Acta ophthalmologica 09/2010; 88(s246). · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to compare the intra-ocular pressure (IOP) obtained by ocular response analyzer (ORA), dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT). In 102 patients (47 with primary open-angle glaucoma and 55 healthy controls) IOP was measured with GAT, ORA and DCT in one eye. The agreement between GAT, DCT and ORA values was assessed using Bland-Altman plots. The discrepancy between the methods was related to central corneal thickness (CCT), corneal hysteresis (CH) and corneal resistance factor (CRF) using linear regression models. Significant differences were observed amongst DCT, corneal compensated ORA (ORAcc) and GAT (P < 0.01). Only the ORAcc and DCT were comparable. ORAcc and DCT significantly over-estimated IOP compared to GAT and for ORAcc this difference depended on the height of IOP. A significant correlation was found between CCT and the deviation of DCT and ORAcc from corrected GAT (both P < 0.0001). Our study showed a low degree of agreement between IOP measured by ORA, DCT and GAT. DCT and ORAcc over-estimated the IOP compared to GAT.
    International Ophthalmology 05/2010; 30(6):651-9.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine the diagnostic accuracy of judging optic disc photographs for glaucoma by ophthalmologists. Evaluation of diagnostic test and technology. A total of 243 of 875 invited ophthalmologists in 11 European countries. We determined how well each participant classified 40 healthy eyes and 48 glaucomatous eyes with varying severity of the disease on stereoscopic slides. Duplicate slides were provided for determining intraobserver agreement. All eyes were also imaged with the GDx with variable corneal compensation (GDx-VCC) (Carl Zeiss Meditec AG, Jena, Germany) and the Heidelberg Retina Tomograph (HRT) I (Heidelberg Engineering GmbH, Heidelberg, Germany). Diagnostic accuracies of clinicians were compared with those of the best machine classifiers. Accuracy of classification, expressed as sensitivity, specificity, and overall accuracy. Intraobserver agreement (kappa). The overall diagnostic accuracy of ophthalmologists was 80.5% (standard deviation [SD], 6.8; range, 61.4%-94.3%). The machine classifiers outperformed most observers in diagnostic accuracy; the GDx-VCC nerve fiber indicator and the HRT's best classifier correctly classified 93.2% and 89.8% of eyes, respectively. The intraobserver agreement (kappa) varied between -0.13 and 1.0 and was on average good (0.7). In general, ophthalmologists classify optic disc photographs moderately well for detecting glaucoma. There is, however, large variability in diagnostic accuracy among and agreement within clinicians. Common imaging devices outperform most clinicians in classifying optic discs. Proprietary or commercial disclosure may be found after the references.
    Ophthalmology 04/2010; 117(4):717-23. · 5.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the benefit of preoperative treatment with either topical nonsteroidal anti-inflammatory drug (NSAID) or steroid in terms of clinical outcomes following trabeculectomy. Prospective, randomized placebo-controlled trial. Sixty-one patients. Between July 2005 and October 2007, 61 consecutive medically uncontrolled glaucoma patients scheduled for first-time trabeculectomy were randomized to 1 of 3 study topical medication groups: nonsteroidal anti-inflammatory drugs (ketorolac), steroids (fluorometholone), or placebo (artificial tears). Patients instilled 1 drop 4 times daily for 1 month before the procedure and were examined on days 1 and 2, at weeks 1, 2, and 4, and at months 3, 6, 12, 18, and 24 after trabeculectomy. Incidence of postoperative surgical or medical interventions (needling, laser suture lysis, needling revision, and intraocular pressure [IOP]-lowering medication). Fifty-four patients (54 eyes) were entered for analysis. The mean number of preoperative medications was 2.3+/-0.9. The mean baseline IOP was 21.0+/-6.0 mmHg. The mean postoperative target IOP was 16.5+/-1.8 mmHg. The mean follow-up was 23.6+/-4.0 months. The percentage of patients requiring needling within the first year was 41% in the placebo group, 6% in the NSAID, and 5% in the steroid group (P = 0.006). The percentage of patients requiring IOP-lowering medication to reach the target IOP at 1 year was 24% in the placebo group, 18% in the NSAID group, and 0% in the steroid group (P = 0.054 overall; P = 0.038 for steroids vs. others). The log-rank test showed a significant (P = 0.019) difference in medication-free survival curves between the different groups. More specifically, patients in the steroid group needed significantly less medication over the total follow-up (P = 0.007). Topical ketorolac or fluorometholone for 1 month before surgery was associated with improved trabeculectomy outcomes in terms of likelihood of postoperative needling. In the steroid group, there was a significantly reduced need for additional postoperative IOP-lowering medication compared with the other groups. The author(s) have no proprietary or commercial interest in any materials discussed in this article.
    Ophthalmology 04/2010; 117(7):1324-30. · 5.56 Impact Factor

Publication Stats

632 Citations
154.62 Total Impact Points

Institutions

  • 2013
    • Universiteit Hasselt
      Hasselt, Flanders, Belgium
    • Centro Hospitalar de Lisboa Central
      Lisboa, Lisbon, Portugal
  • 2005–2013
    • Universitair Ziekenhuis Leuven
      • Department of Ophthalmology
      Louvain, Flanders, Belgium
  • 2012
    • Leiden University Medical Centre
      Leyden, South Holland, Netherlands
  • 2010
    • Het Oogziekenhuis Rotterdam
      Rotterdam, South Holland, Netherlands
  • 2005–2010
    • KU Leuven
      • Division of Ophthalmology
      Leuven, VLG, Belgium
  • 2009
    • Jules Stein Eye Institute
      Maryland, United States
  • 2008
    • National Technical University of Athens
      • School of Electrical and Computer Engineering
      Athens, Attiki, Greece
  • 2007
    • Università degli Studi di Milano-Bicocca
      Milano, Lombardy, Italy