Sclerectomy with collagen implant.
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Collagen↗
Biomedical subjects
A Mermoud
Publications and source records attributed to A Mermoud.
Leber's hereditary optic neuropathy mitochondrial DNA mutations in normal-tension glaucoma.
BACKGROUND: in Leber's hereditary optic neuropathy, increased optic nerve cupping has been reported by several authors. Recently, a mitochondrial DNA (mtDNA) mutation at nucleotide 11778 typically associated with Leber's hereditary optic neuropathy (LHON) was identified in a patient treated for glaucoma but lacking typical signs of LHON. The question arises: should all normal-tension glaucoma patients be further evaluated for LHON? METHODS: we screened 54 unselected patients with normal-tension glaucoma (age range 20-96 years, 16 men and 38 women) for the primary mtDNA LHON mutations at nucleotides 3460, 11778 and 14484. RESULTS: none of the patients harboured the mtDNA mutations at nucleotides 3460, 11778 or 14484 (95% confidence intervals for each mutation ranged from 0% to 5.3%). CONCLUSIONS: primary LHON mtDNA mutations are rare or absent in unselected normal-tension glaucoma patients. Therefore, unselected normal-tension glaucoma patients should not be screened for these mutations. It is probable that only normal-tension glaucoma patients with atypical features (rapid progression, early deep central scotoma, pallor of neuroretinal rim, elevated disc, peripapillary teleangiectasia) or a positive family history of visual loss compatible with a matrilinear transmission should be further evaluated.
Adult↗
Degradation in soil and water and ecotoxicity of rimsulfuron and its metabolites.
The degradation and ecotoxicity of sulfonylurea herbicide rimsulfuron and its major metabolites were examined in batch samples of an alluvial sandy loam and in freshwater. An HPLC-DAD method was adapted to simultaneously identify and quantify rimsulfuron and its metabolites, which was successfully validated by GC-MS analysis. In aqueous solutions, pure rimsulfuron was rapidly hydrolyzed into metabolite 1 (N-(4,6-dimethoxypyrimidin-2-yl)-N-(3-(ethylsulfonyl)-2-pyridinylurea)), which itself was transformed into the more stable metabolite 2 (N-((3-(ethylsulfonyl)-2-pyridinyl)-4,6-dimethoxy-2-pyrimidineamine)), with half-life (t(1/2)) values of 2 and 2.5 days, respectively. Hydrolysis was instantaneous under alkaline conditions (pH = 10). In aqueous suspensions of the alluvial soil (pH = 8), formulated rimsulfuron had a half-life of 7 days, whereas that of metabolite 1 was similar to that in water (about 3.5 days). The degradation of the two major metabolites was also studied in soil suspensions with the pure compounds at concentrations ranging from 1 to 10 mg l(-1). The half-life of metabolite 1 ranged from 3.9 to 5 days, close to the previous values. Metabolite 2 was more persistent and its degradation is strongly dependent on the initial concentration (C0): half-life values ranged from 8.1 to 55 days at 2-10 mg l(-1), respectively. These values are higher than those determined from the kinetics of metabolite 1 transformation into metabolite 2 (t(1/2) = 8-19 days). The ecotoxicity of the three chemicals was evaluated through their effect on Daphnia magna and Vibrio fischeri (Microtox bioassay). No effect was observed on D. magna with 24 and 48 h acute toxicity tests. Similarly, no toxic effect was observed with the Microtox test for the three chemicals in the range of concentrations tested that included the field application dose. Thus, being of low persistence and lacking acute toxicity, these chemicals present a low environmental risk. However, chronic effects should be studied in order to confirm the safety of rimsulfuron and its major metabolites.
Animals↗
Deep sclerectomy with collagen implant in patients with glaucoma and high myopia.
PURPOSE: To study prospectively the success rate and complications of deep sclerectomy with collagen implant (DSCI), a nonpenetrating filtration procedure, in patients with glaucoma and high myopia. SETTING: Glaucoma Unit, Hôpital Ophtalmique Jules Gonin, Lausanne, Switzerland. METHODS: This nonrandomized prospective trial comprised 21 eyes of 21 highly myopic patients with medically uncontrolled primary or secondary open-angle glaucoma. Visual acuity, intraocular pressure (IOP), and slitlamp examinations were performed before as well as 1 and 7 days and 1, 3, 6, 9, 12, 18, 24, 30, 36, 42, 48, 54, 60, and 66 months postoperatively. Visual field examinations were repeated every 6 months. Exclusion criteria were known allergy to collagen, advanced lens opacity, and eye surgery or laser trabeculoplasty fewer than 6 months before enrollment. RESULTS: The mean follow-up was 44.0 months +/- 17.1 (SD). The mean preoperative IOP of 26.4 +/- 5.9 mm Hg dropped to 10.4 +/- 6.1 mm Hg at 48 months. Eighty-one percent of patients achieved an IOP below 21 mm Hg with or without medication at 48 months. Thirty-eight percent had an IOP below 21 mm Hg without medication. The mean number of medications per patient was reduced from 2.30 +/- 0.85 to 0.86 +/- 0.91. CONCLUSIONS: Deep sclerectomy with collagen implant provided reasonable control of IOP in patients with glaucoma and high myopia over a long-term follow-up. There were relatively few postoperative complications.
Adult↗
Five-year results of deep sclerectomy with collagen implant.
PURPOSE: To study prospectively the success rate and complications of deep sclerectomy with collagen implant (DSCI), a nonpenetrating filtration procedure. SETTING: Glaucoma Unit, Department of Ophthalmology, Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland. METHODS: This nonrandomized prospective trial comprised 105 eyes of 105 patients with medically uncontrolled primary or secondary open-angle glaucoma. Visual acuity, intraocular pressure (IOP), and slitlamp examinations were performed before and after surgery at 1 and 7 days and 1, 3, 6, 9, 12, 18, 24, 30, 36, 48, 54, 60, and 66 months. Visual field examinations were repeated every 6 months. A qualified success was defined as IOP below 21 mm Hg with or without medication. A complete success was defined as IOP lower than 21 mm Hg without medication. RESULTS: The mean follow-up was 43.2 months +/- 14.3 (SD). The mean IOP was 26.8 +/- 7 mm Hg preoperatively, 5.1 +/- 3 mm Hg 1 day postoperatively, and 11.8 +/- 3 mm Hg 60 months postoperatively. At 60 months, the qualified success rate was 94.8% and the complete success rate, 61.9%. The IOP was lower than 21 mm Hg with medication in 32.1% of patients at 60 months; 48 patients (45.7%) had an IOP of 15 mm Hg or lower without medication. No patient developed a shallow or flat anterior chamber, endophthalmitis, or surgery-induced cataract. However, 23 (21.9%) had progression of a preexisting senile cataract. Injections of 5-fluorouracil were given to 25 patients (23.8%) who had DSCI to salvage encysted blebs. The mean number of medications per patient was reduced from 2.30 +/- 0.76 to 0.49 +/- 0.72. CONCLUSION: Deep sclerectomy with collagen implant provided reasonable IOP over a long-term follow-up with few immediate postoperative complications.
Aged↗
Baerveldt implant in refractory glaucoma: long-term results and factors influencing outcome.
PURPOSE: To evaluate the clinical outcome of patients who received a Baerveldt implant for refractory glaucoma and to identify factors which may influence the outcome. METHODS: Retrospective study including 51 eyes of 51 patients with medically uncontrolled glaucoma who underwent Baerveldt implant surgery between June 1994 and December 1998. Criteria for success were intraocular pressure (IOP) < or = 21 mmHg and > 6 mmHg, necessity of further antiglaucoma medications, absence of additional glaucoma surgery and no loss of light perception. RESULTS: Over a mean follow-up of 37.6 (SD: +/-18.8) months, the mean intraocular pressure decreased from 34.8 (+/-12.5) mmHg to 14.0 (+/-4.3) mmHg at month 60. Qualified success rate, achieved when IOP was below 21 mmHg and higher than 6 mmHg with medications was 25/48 (52%), complete success rate (same IOP limits without medication) was 14/48 (29%). Seven eyes had major complications or lost light perception. Postoperative visual acuity improved or remained within one Snellen line of the preoperative visual acuity in 35 patients (73%). Factors associated with a better prognosis were a preoperative visual acuity better than 20/400 and etiology of glaucoma. CONCLUSION: The Baerveldt implant is effective in lowering intraocular pressure in most patients with refractory glaucoma. Long-term results are promising with satisfactory IOP control.
Adolescent↗
Ageing of Schlemm's canal in nonglaucomatous subjects.
AIM: to study age-related Schlemm's canal endothelial changes and evaluate consequences on the filtration function. MATERIAL AND METHODS: the inner wall endothelium of Schlemm's canal was examined in 9 non-glaucomatous subjects aged between 32 and 75 years, by a combined technique of light and electron microscopy (scanning and transmission). Quantitative analysis included counts of bulges, pores, nuclei, giant vacuoles and other protruding structures, as well as measures of pores, giant vacuoles and Schlemm's canal size parameters (diameter and inner wall width). Outflow facility calculations were realised using a modified previously described mathematical model. RESULTS: The main structures affected by ageing in Schlemm's canal appeared to be giant vacuoles. Their density but also their size is significantly reduced with increasing age. The intracellular pore population is also found to diminish with age and is correlated to that of giant vacuoles, suggesting that those pores are luminal openings of vacuoles. Outflow facility calculations revealed a global decrease of endothelial outflow facility of about 60% between the 3rd and 7th decades. The study also showed a different age-related pattern for the two subtypes of endothelial pores. CONCLUSIONS: Our study demonstrated that Schlemm's canal filtration function is significantly influenced by age, as the endothelial inner wall outflow facility is found to be widely reduced. This is partly the result of an age-related reduction in counts of giant vacuoles and intracellular pores. The second pore population (border or intercellular) doesn't follow the same evolution, but may have a more significant regulator role in transendothelial permeability.
Adult↗
New Tonopen XL: comparison with the Goldmann tonometer.
PURPOSE: To compare the intraocular pressure (IOP) values obtained using a Goldmann tonometer (Haag-Streit) with those obtained with the new Tonopen XL (Mentor), which has certain differences compared with first- and second-generation models. METHODS: The IOPs of 104 patients were assessed by Goldmann tonometer and Tonopen XL tonometer. Goldmann measurements was done first in 145 eyes and Tonopen measurements were done first in 53 eyes. Four observers measured the IOP. Observers A, B and C used the Goldmann tonometer first and then the Tonopen XL, while observer D used the Tonopen XL first and then the Goldmann tonometer. The results were analysed by descriptive analysis and, when the distribution of the data was normal, paired t-test and Pearson's r coefficient were used to compare and correlate IOP measurements between Goldmann and Tonopen measurements. When the distribution of the data was non-normal, the Wilcoxon matched-pair test and Spearman coefficient were used. The agreement between Goldmann and Tonopen values was also calculated. ANOVA test was used to compare the difference obtained by 'Goldmann minus Tonopen' measurements among the three different observers. RESULTS: A statistically significant difference (p < 0.0001) was found between the IOP readings obtained by Goldmann tonometer and the Tonopen XL and a significant correlation was found between the Goldmann values and Tonopen XL values (p < 0.001). When the Goldmann IOP was more than 20 mmHg the Tonopen XL measurements were lower than the Goldmann values. Also in this group this difference was statistically significant. No significant difference was found between Goldmann values and Tonopen values among the three observers, even though a significant difference was found between Goldmann values and Tonopen values for observer B. When the values obtained by first the Goldmann tonometer and then the Tonopen XL were compared with those obtained by first the Tonopen XL and then the Goldmann tonometer, no significant difference was found between the two groups. CONCLUSION: The new Tonopen XL provides similar results to the Goldmann tomometer in 62% of the cases and was slightly less accurate than the Goldmann tonometer for extreme values, just like the previous Tonopen. Nevertheless the precision is good enough for the purpose of adequate screening.
Analysis of Variance↗
[Analysis of filtration according to implant type after deep sclerectomy in the rabbit].
PURPOSE: The purpose of this study was to compare the aqueous humor outflow using three type of implants after deep sclerectomy. A numeric imaging system with ICG and fluorescein angiography was used. The evolution over time was recorded, while filtration and outflow facility were measured. MATERIAL AND METHODS: Numeric imaging system with ICG and fluorescein angiography were performed before and after deep sclerectomy at regular intervals after surgery. Both resorbable (collagen) and non-resorbable (hema) intrascleral devices have been tested in eight rabbits. The resorption time of the collagen implants has been monitored using UBM technique. The outflow facility was measured with the technique of anterior chamber canulation and constant pressure method. RESULTS: The resorbable collagen implants could be observed with UBM and angiography during the first six weeks post-operatively. The image of the non-resorbable Hema implant remained clearly visible over time. New drainage vessels were observed around the filtering bleb. The filtration significantly increased as the outflow facility improved after surgery, while the intraocular pressure remained stable over time. CONCLUSION: This conjunction of UBM, angiography and outflow measurement allowed us to study and compare three types of implants used as space maintainer after deep sclerectomy, and analyse their effect on the aqueous filtration and outflow facility.
Animals↗
MYOC mutation frequency in primary open-angle glaucoma patients from Western Switzerland.
PURPOSE: To determine MYOC gene mutation frequency in patients with primary open-angle glaucoma (POAG) from Western Switzerland. METHODS: A total of 117 unselected index patients with primary open-angle glaucoma were submitted to a full eye examination. DNA was extracted from blood and PCR amplicons of MYOC exon 3 were screened for mutations by single-strand conformation polymorphism (SSCP) analysis. Abnormal conformers were analyzed both by direct bidirectional sequencing and by enzymatic mutation detection (EMD) assay. RESULTS: Ten occurrences of four different sequence changes were detected, including: 1) five times the same disease-causing mutation (Q368X) in five unrelated POAG patients and 2) three distinct polymorphisms in five patients. The patients carrying an MYOC mutant allele were characterized by a broad clinical variability in terms of age of onset (34-77 years) and highest intraocular pressure (IOP) values (23-47 mmHg). CONCLUSIONS: A pathogenic MYOC mutation (Q368X) was identified in 4.27% (5/117) of the studied population from Western Switzerland, which corresponds to the highest frequency yet reported for this mutation.
Adult↗
Retinal nerve fiber layer and physiological central corneal thickness.
PURPOSE: To determine the relationship between central corneal thickness and the measurement of retinal nerve fiber layer thickness around the optic nerve head using a confocal scanning laser polarimeter such as the Nerve Fiber Analyzer (GDx). METHODS: Forty-four eyes were recruited for this study. Each patient had a normal visual field and a healthy optic nerve head, which was assessed by slit-lamp biomicroscopy with a 90-diopter lens and by a scanning laser ophthalmoscope (Heidelberg Retina Tomograph). Using the GDx, retinal nerve fiber layer thickness was calculated from 1.75 disc diameters together with some standard GDx parameters, including the number, symmetry, superior ratio, inferior ratio, maximum modulation, and ellipse modulation. Corneal thickness was measured with the DGH-1000 ultrasonic pachymeter. Descriptive analysis was used and Pearson's r coefficient of correlation was calculated. RESULTS: Corneal thickness was not significantly correlated to retinal nerve fiber layer thickness, but it was significantly (P < 0.05) correlated to the other GDx parameters. CONCLUSION: From these data. peripapillary retinal nerve fiber layer thickness is shown not to be significantly correlated to the corneal thickness, even if for the standard GDx parameters a significant correlation was found.
Aged↗
Normal retinal nerve fiber layer thickness in the peripapillary region measured by scanning laser polarimetry.
PURPOSE: To measure retinal nerve fiber layer thickness (RNFLT) as a function of distance from the optic nerve head using a confocal scanning laser polarimeter, such as the Nerve Fiber Analyzer (GDx). METHODS: Twenty eyes of 20 healthy patients were recruited for this study. Each patient had a normal visual field and a healthy optic nerve head, which was assessed by slit-lamp biomicroscopy using a 90-diopter lens and by a scanning laser ophthalmoscope. Using the GDx, RNFLT was calculated from 1.1 disc diameters (DD) to 2.5 DD in 0.1-DD increments from the outer edge of the optic disc rim. RNFLT was successively evaluated for the entire annulus surface, for each quadrant, and for every 10 degree sector. RNFLT was calculated in retardation degrees. Differences in RNFLT were calculated by analysis of variance. RESULTS: When the entire RNFLT was considered, the measurements close to the optic nerve head (at 1.1 and 1.2 DD) were found to be significantly (0.05 < or = P < or = 0.01) different from those measured far from the disc (at 2.4 and 2.5 DD). The inferior quadrant had the greatest RNFLT followed by the superior quadrant. When RNFLT was analyzed for every 10 degrees, RNFLT at 1.1 and 1.2 DD was significantly (P < or = 0.001) different from that measured at 2.4 and 2.5 DD in almost all 36 sectors. In the 36 considered sectors, no significant difference was found for all the RNFLT values that were calculated in all the positions of the annulus surface between 1.1 and 1.7 DD. CONCLUSION: From these data, peripapillary RNFLT is shown to be significantly (P < or = 0.001) thinner in the periphery (2.5 DD) than around the optic disc (1.1 DD). However, the lack of any difference in RNFLT from 1.1 to 1.7 DD suggested that the mild variations to locate the optic disc contour line do not change the results of the analysis if the RNFLT is calculated within 1.8 DD.
Aged↗
Aqueous outflow mechanisms and glaucoma surgery.
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Aqueous Humor↗
Recurrent transient visual loss after deep sclerectomy.
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Aged↗
Frequency doubling technique in patients with ocular hypertension and glaucoma: correlation with octopus perimeter indices.
PURPOSE: To ascertain whether frequency doubling technique (FDT) (Welch-Allyn, Skaneateles, NY; Zeiss-Humphrey, San Leandro, CA) indices provide results comparable with those of standard Octopus threshold perimeters (Interzeag AG, CH-8952 Schlieren, CH) in patients with glaucoma and in patients suspected of having ocular hypertension, glaucoma, or both. DESIGN: A comparative, consecutive, case series. PARTICIPANTS: Thirty-nine glaucomatous patients and 41 patients with ocular hypertension or suspected glaucoma were recruited consecutively. METHODS: The visual field of the study participants were assessed by FDT program C-20 full threshold and Octopus program dG1X. Only one eye of each participant was selected randomly. Pearson's r correlation coefficient was calculated among the FDT and Octopus indices. MAIN OUTCOME MEASURES: Using Octopus perimeter, mean defect (MD), mean sensitivity (MS), loss variance (LV), and corrected loss variance (CLV) were calculated and used for correlation. For the FDT, mean deviation (FDT-MD) and pattern standard deviation (FDT-PSD) were calculated and used for correlation. Also, the time required to perform the visual field test was considered. RESULTS: In the entire population, a statistically significant correlation (Pearson's r, P<0.001) was found between FDT-MD and both MS (0.77) and MD (-0.80) and between FDT-PSD and both LV (0.50) and CLV (0.45). When the glaucoma group was considered alone, similar significant correlation was found between the indices. In the suspected ocular hypertension and glaucoma suspect group, no significant correlation was found. A significant (P<0.001) difference was found between FDT and Octopus for the time needed to perform the visual field test. CONCLUSIONS: This new technique could be used both to screen populations and to observe glaucomatous visual field progression in early and moderate stages. The FDT is a faster way to analyze the visual field and captures threshold values for each point, but it is important to remember that this is a new technique and its limits are still unknown.
Aged↗
Sinusotomy and deep sclerectomy.
Non-penetrating filtering surgery (NPFS) started in 1962 with the first sinusotomy performed by Kraznov. At that time, the author of this new technique believed that the outflow resistance in the majority of cases of primary open-angle glaucoma was located at the level of scleral aqueous drainage veins and not in the trabeculum. He therefore developed a safe NPFS technique, leaving in place the trabeculum and the inner wall of Schlemm's canal. Because of difficulties with the microsurgical technique and the small reduction in intraocular pressure (IOP) compared with trabeculectomy, sinusotomy was abandoned. In the last decade, with the widespread use of operating microscopes, NPFS has been the subject of renewed interest. IOP reduction with the new NPFS techniques is comparable to that obtained with trabeculectomy, with significantly lower pre- and post-operative complications. The new NPFS techniques such as deep sclerectomy, ab externo trabeculectomy and viscocanalostomy present definitively different mechanisms of filtration compared with early sinusotomy. This article will review the history of NPFS as well as describing the different new non-penetrating filtering surgeries.
Filtering Surgery↗
[Intraocular hypotony: use of ultrasound biomicroscopy (UBM) for differential diagnosis and its schematic representation].
OBJECTIVES: To determine the use of high-frequency ultrasound biomicroscopy (UBM) in the assessment of hypotony and in particular to determine the proportion of cases for which UBM contributed significant additional hitherto unaccessible information. PATIENTS AND METHODS: Ultrasound biomicroscopy was performed in a standard manner, using a Humphrey UBM 840 system (Humphrey Instruments, Inc., San Leandro, CA). UBM findings were analysed and the clinical relevance of UBM information was determined for the whole collective. RESULTS: Twelve patients with hypotony were examined. UBM findings contributed essential information that allowed to reach a diagnosis or that determined the therapeutic attitude in 10 of the 12 hypotonic patients. In two cases the cause of hypotony was tractional ciliary body detachment, in 5 cases it was post-inflammatory atrophy of the ciliary body, in 3 cases it was post-traumatic irido and cyclodialysis, in one case it was supraciliary and suprachoroidal effusion and in the last case it was due to uveal effusion syndrome. Based on these findings we established a schematic approach for hypotony. CONCLUSIONS: This procedure enabled us to assess the morphological changes found in patients with hypotony. In a majority of cases UBM was useful either to orient therapeutic intervention or to establish a diagnosis. On the base of our findings a schematic approach for hypotony, using UBM, was established.
Algorithms↗
[Aqueous outflow pathway imaging in the rabbit with fluorescein and indocyanine green].
PURPOSE: The purpose of this study was to visualise the rabbit aqueous outflow pathway using a numeric imaging system with ICG and fluorescein injection in the anterior chamber. MATERIAL AND METHODS: We performed a simultaneous injection of Indocyanin Green (ICG) and Fluorescein into the anterior chamber of rabbit eyes. Using a digital camera, we took several sequenced pictures to visualize the distribution of the dyes within the outflow pathway. We observed the dynamics of the outflow over time. RESULTS: In the early phases, the shape of the outflow canal around the limbus was clearly seen. Several collecting veins close to the recti muscles were also identified. There was only slight fluorescein leakage during the early phases, allowing adequate visualization of the morphology of the outflow system. In the late phases, the sclera was stained with the fluorescein, and no details were thus visible. The ICG dye allowed better recognition of the fine details of the outflow structure. CONCLUSION: This method was relatively simple, safe and precise, and allowed us to visualise the details of the outflow pathways in the rabbit eyes. These results could be of great value in further evaluating the outcome of filtering surgeries in animal models.
Angiography↗