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O Schwenn

Publications and source records attributed to O Schwenn.

At least 19 recordsLinked to original sources
PubMed2005

[Reproducibility of measurements of the peripapillary retinal nerve fibre layer thickness. Optical coherence tomography versus retinal thickness analyzer].

PURPOSE: The aim of this study was to compare the intra- and inter-examiner reproducibility of measurements obtained by optical coherence tomography (OCT) and retinal thickness analyzer (RTA). PATIENTS AND METHODS: During a period of 2 months, 22 eyes of 16 patients and 6 healthy subjects were included. Two examiners (EMH, RK) successively performed three measurements of the peripapillary retinal nerve fibre layer (RNFL) thickness with RTA and OCT. The reproducibility of three individual measurements of one examiner (intra-examiner) as well as the reproducibility of the measurements between both examiners (inter-examiner) was evaluated using the Friedman test and sign test. RESULTS: The average thickness of the peripapillary RNFL was 154.4 microm for the first investigator (EMH) and 155.1 microm for the other investigator (RK) measured with RTA. The results obtained by OCT were 137.3 microm (EMH) and 138.9 microm (RK), respectively, generally indicating a threefold smaller range. Comparing the three measurements of one single examiner, no appreciable intra-observer dependency neither for RTA (EMH: p=0.19, RK: p=0.95) nor for OCT (EMH: p=0.51, RK: p=0.62) was observed. Inter-examiner analysis for RTA and OCT also revealed an acceptable reproducibility. CONCLUSIONS: Measurements of peripapillary RNFL thickness using RTA and OCT exhibited intra- and inter-observer agreement.

Adolescent↗
PubMed2005

Transpalpebral tonometry: reliability and comparison with Goldmann applanation tonometry and palpation in healthy volunteers.

BACKGROUND/AIM: TGDc-01 is a new, portable, transpalpebral tonometry device. The aim of this study was to evaluate the reproducibility of this method, including intraobserver and interobserver deviations, and to compare the results with those of Goldmann applanation tonometry and palpation of intraocular pressure (IOP). METHODS: A total of 40 eyes of 20 healthy volunteers were included. Two independent parallel observers (1 and 2) performed three replicate measurements per eye, respectively, both using TGDc01 tonometry, one observer (3) performed three replicate measurements using Goldmann applanation tonometry, and one observer (4) measured the IOP via palpation. Intraindividual deviations within and between both observers using TGDc-01 tonometry and between all three methods were investigated about clinically relevance by comparison of medians and quartiles, statistically significance by pairwise sign tests. Comparisons between observers and methods were based on averaged IOP values of the three individual measurements for each observer and each patient. Intraobserver deviations were analysed by means of Friedman tests. RESULTS: Observers 1 and 2 showed a statistically significant intraobserver deviation when using TGCc-01 (Friedman p = 0.007 for observer 1 and p = 0.002 for observer 2). There was no statistically significant interobserver deviation between observers 1 and 2 (sign test p = 0.200); however, in 45% of the eyes interobserver deviations were larger than plus or minus 3 mm Hg. The median intraindividual deviation between TGDc-01 and Goldmann (TGDc-01 minus Goldmann) was 0 mm Hg (interquartile range -1; 2 mm Hg; sign test p = 0.522); but deviations were larger than plus or minus 3 mm Hg for 38% of the 40 eyes. Median intraindividual deviation between TGDc-01 and palpation (TGDc-01 minus palpation) was -2 mm Hg (interquartile range -4; 1 mm Hg; sign test p = 0.018), but deviations were larger than plus or minus 3 mmHg for 43% of eyes. Median intraindividual deviation between Goldmann and palpation (palpation minus Goldmann) was 2 mm Hg (interquartile range -2; 4 mm Hg; p = 0.429), but deviations were larger than plus or minus 3 mm Hg in 48% of the eyes. CONCLUSION: Interobserver deviations using TGDc-01 tonometry and intraindividual deviations between TGDc-01 tonometry, Goldmann applanation tonometry, and palpation of IOP were found to be clinically relevant. Thus, according to our results TGDc-01 could not be established as a substitute or diagnostic alternative method for Goldmann applanation tonometry. But as deviations between TGDc01 and Goldmann turned out smaller than between palpation of IOP and Goldmann, TGDc-01 seems to provide a better choice for tonometry in patients, in whom Goldmann applanation tonometry is not possible.

Adult↗
PubMed2004

[Deep sclerectomy using a hyaluronate implant versus trabeculectomy. A comparison of two glaucoma operations using mitomycin C].

BACKGROUND: It was investigated whether a very low target pressure could be achieved by modification of deep sclerectomy without losing the advantages of non penetrating surgery in comparison to conventional filtration surgery. PATIENTS AND METHODS: A total of 22 eyes from 22 patients with advanced open angle glaucoma were randomly assigned to receive a deep sclerectomy or a trabeculectomy. Both groups received 0.02% mitomycin C under the conjunctiva prior to preparation of the scleral flap. In the deep sclerectomy group at least parts of the outer trabecular meshwork were removed until an apparent filtration was achieved. A dry cross-linked hyaluronate served as an implant. In the other group a classical trabeculectomy was performed. RESULTS: The median intraocular pressure 12 months post-operation was 11.5 mm Hg in the deep sclerectomy group compared to 11 mm Hg in the trabeculectomy group; the median of the relative IOP reduction was -47% in the deep sclerectomy group, and -57% in the trabeculectomy group. The best corrected visual acuity was unchanged 12 months postoperatively in both groups. DISCUSSION: As a more aggressive IOP-lowering procedure (intended filtration, use of antimetabolites) deep sclerectomy proved to be as effective as trabeculectomy. Nevertheless, the advantages of the more difficult surgical procedure concerning visual acuity, complications and surgical interventions were lost postoperatively.

Adult↗
PubMed2004

[Agreement between clinical evaluation, Heidelberg-Retina-Tomograph (HRT) and Nerve Fiber Analyzer (GDx) in glaucoma diagnosis].

BACKGROUND: We have made a comparison of clinical evaluation, Heidelberg-Retina-Tomograph (HRT) and Nerve Fiber Analyzer (GDx) in diagnosing glaucoma. MATERIALS AND METHODS: One eye of 38 glaucoma patients and 26 non-glaucoma patients was examined with HRT and GDx. Assignment of the patients into the two groups by clinical evaluation was performed on the basis of visual field and optic disc results. As classification criterion for glaucoma/non-glaucoma by means of the instruments we employed the statistical classification of the HRT and "the number" of the GDx. Statistical analysis was performed with Cohen's kappa and McNemar tests. Additionally, ROC curves for evaluation of the sensitivity and specificity of the glaucoma classification are demonstrated for HRT and GDx. RESULTS: Agreement between clinical evaluation and HRT was moderate (Cohen's kappa = 0.43), there was no significant over- or underdiagnosis by HRT (p = 0.48). Agreement between clinical evaluation and GDx (diagnosis of glaucoma when "the number" > 50) was bad (Cohen's kappa = 0.27) with a significant overdiagnosis by GDx compared to clinical evaluation (p < 0.05). Agreement between clinical evaluation and GDx (diagnosis of glaucoma when "the number" > 40) was better (Cohen's kappa = 0.54), there was no significant over- or underdiagnosis by GDx (p = 0.79). ROC curves for glaucoma classification showed no difference between HRT and GDx (area under the curve: HRT = 0.8, GDx = 0.78). CONCLUSIONS: Because of the only moderate agreement between clinical evaluation on the one hand and HRT and GDx classification on the other hand for the discrimination between glaucoma and non-glaucoma, the clinician should not completely rely on the instrument-derived glaucoma classification.

Aged↗
PubMed2003

[Nd-YAG laser iridotomy in pigment dispersion syndrome and pigment dispersion glaucoma].

Pigment dispersion syndrome is characterized by iris transillumination defects, Krukenberg spindels, and dense trabecular pigmentation. Additional features are bilaterality, myopia, concavity of the peripheral iris, a higher incidence in men than in woman,and young age of onset. A mechanism of reverse pupillary block causes iridozonular friction. Laser iridotomy is recommended as treatment to prevent further pigment dispersion and pigmentary glaucoma.

Accommodation, Ocular↗
PubMed2002

Ocular pulse amplitude in patients with open angle glaucoma, normal tension glaucoma, and ocular hypertension.

BACKGROUND/AIM: Intraocular pressure (IOP) is not a fixed constant value but rather has pulsatile components associated with cardiac action. The SmartLens dynamic observing tonometer (odc, Ophthalmic Development Company AG, Zurich, Switzerland) can measure and record simultaneously IOP and ocular pulse amplitude (OPA). It was the aim of this study to evaluate OPA in patients with primary open angle glaucoma (POAG) and high IOP, normal tension glaucoma (NTG), and ocular hypertension (OHT). Furthermore, the authors examined whether there were any correlations with blood pressure. METHODS: 80 subjects were divided into four groups (n=20): 20 patients each with POAG, NTG, and OHT and 20 volunteers without any ocular pathology except for cataract served as a control group. RESULTS: The OPA of the POAG group was not statistically significant different from the control group and from the OHT group. However, OPA was statistically significant lower (p<0.01) in the NTG group compared with all other groups. The OPA of the OHT group was slightly higher compared to the healthy volunteers (p=0.09) and to the POAG patients (p=0.09). No statistically significant correlations with blood pressure could be detected. A logistic regression model was established which identified OPA as an independent risk factor for NTG. CONCLUSIONS: The study demonstrated a decrease in OPA of patients suffering from NTG. Thus, measuring of OPA by the SmartLens dynamic observing tonometer could be helpful in the detection of NTG patients.

Adult↗
PubMed2001

[Prevention of early postoperative increase in intraocular pressure after phacoemulsification. Comparison of different antiglaucoma drugs].

PURPOSE: To compare the ocular hypotensive effect of different antiglaucomatous eye drops. PATIENTS AND METHODS: This double-blind, randomized study included 119 eyes of 119 patients without other ocular pathology undergoing standardized (one surgeon, Healon) small incision cataract surgery with foldable intraocular lens implantation. The patients were assigned to one of five groups: group 1: 0.25% timolol in Gelrite (extended efficacy, n = 23); group 2: 2% dorzolamide (n = 24); group 3: combination of 0.5% timolol plus 2% dorzolamide (n = 22); group 4: brimonidine (n = 26); group 5: gentamicin (control, n = 24). Intraocular pressure (IOP) was measured preoperatively and at 3 +/- 1, 6 +/- 1, 9 +/- 1, 24 +/- 3, and 48 +/- 3 h postoperatively. Statistical interference was determined by nonparametric group comparisons using Wilcoxon's tests. Absolute values (static comparison) and intraindividual differences from preoperative measurements (dynamic comparisons) were evaluated. All p values should be regarded as descriptive values since they were not formally adjusted for multiplicity. A p value lower than 0.05 therefore indicates local statistical significance. RESULTS: There were no differences between the groups with regard to age, phacoemulsification time, axial length, and preoperative IOP. A statistically significant IOP decrease was measured in group 1 at 24 (p = 0.028) and 48 h (p = 0.007) and in group 3 at 3 (p = 0.001), 6 (p = 0.001), 24 (p = 0.001), and 48 h (p = 0.001) after surgery. A statistically significant IOP increase occurred in group 4 at 3 (p = 0.001), 6 (p = 0.001), and 9 h (p = 0.001) and in group 5 at 3 (p = 0.001), 6 (p = 0.001), 9 (p = 0.001), and 24 h (p = 0.002) postoperatively. Groups 1, 2, and 3 demonstrated lower IOPs at different time points in comparison to groups 4 and 5. Furthermore, group 3 had lower IOPs at 3 h (compared to group 1) and at 6 h (compared to group 2) postoperatively. No statistical differences in IOP were found after 48 h. CONCLUSION: The results favor a combination of 0.5% timolol plus 2% dorzolamide to control postoperative IOP elevation.

Adrenergic alpha-Agonists↗
PubMed2001

[Reproducibility of measurement of ocular pulse amplitude and intraocular pressure using Smartlens].

BACKGROUND: SmartLens (ODC Ophthalmic Development Company AG, Zürich) is a contact lens tonometer, which allows continuous registration of intraocular pressure (IOP) and ocular pulse amplitude (OPA) and simultaneous ophthalmoscopy. The purpose of this study was to evaluate the intra- and interobserver variability and reliability of intraocular pressure and ocular pulse amplitude measurements using SmartLens. METHODS: To evaluate the intraobserver variability, intraocular pressure (IOP) and ocular pulse amplitude (OPA) were both measured 5 times in 10 healthy eyes by one observer. To evaluate the interobserver variability, intraocular pressure and ocular pulse amplitude were measured by 3 different observers in 10 healthy eyes. Data description is based on coefficients of variation (SD/mean in %), statistical inference on ANOVA-based reliability estimation. RESULTS: The coefficient of the intraobserver variation was 9.57% for the IOP and 14.5% for the OPA (SD IOP: +/- 1.64 mmHg, SD OPA: +/- 0.39 mmHg). The coefficient of the interobserver variation with 5 replicate measurements was 10.16% for the IOP and 14% for the OPA (SD IOP: +/- 1.83 mmHg, SD OPA: +/- 0.4 mmHg). The interobserver reliability was 87% for the IOP and 86% for the OPA. One of the three observers obtained significantly higher IOP and OPA values. CONCLUSIONS: SmartLens is a reasonably precise and reliable device for IOP as well as OPA measurements but the results were not found to be observer independent.

Analysis of Variance↗
PubMed2001

[Keratopathy as a sign of multifocal congenital sensory polyneuropathy. A case report].

PATIENT: A 63-year-old female with bilateral recurrent corneal ulcerations for 10 years, suffered from vascularisation of the cornea and absence of corneal sensitivity. Other symptoms were multifocal hypoaesthesia with hypalgesia of hands and legs, generalised lack of deep tendon reflexes, absence of somato-sensory evoked potentials (SSEP) and of sensory nerve action potentials (SNAP) in these regions. A sural biopsy demonstrated extreme lack of myelinated fibres. Acquired causes for polyneuropathy were excluded. THERAPY: Subsequent to local ocular treatment we carried out a perforating corneal transplantation of the left eye because of corneal scars. This had to be repeated 2 years later because of vascularisation of the transplant. The visual function of the left eye could be stabilised at values between 0.2 and 1/50. CONCLUSION: Anamnesis and clinical symptoms of the patient are compatible with the diagnosis of hereditary sensory neuropathy type II (HSN II) affecting the trigeminal nerves. In patients with neuropathy and impaired corneal sensitivity, a favourable prognosis may be achieved by a corneal transplant.

Cornea↗
PubMed2001

[Refraction, anterior chamber depth, decentration and tilt after implantation of monofocal and multifocal silicone lenses].

BACKGROUND: We prospectively investigated changes in refraction, anterior chamber depth, decentration and tilt after implantation of multifocal (MIOL) and monofocal (MONO) intraocular lenses (IOL). PATIENTS AND METHODS: We examined 103 cataractous eyes from 103 patients receiving either a three-piece monofocal or multifocal silicone IOL. Anterior chamber depth (ACD), amount of IOL decentration, and degree of IOL tilt were quantified using retroillumination and Scheimpflug photographs. Examinations, including subjective refraction, were performed preoperatively, one week and 6 months postoperatively. RESULTS: All eyes were within 2 dpt (spherical equivalent) from the target refraction, and 93% of eyes with a MIOL were within 1 dpt. No significant refractive shift or ACD change occurred during the postoperative course. Median tilt in the MIOL group at 6 months was 1.1 degrees (0-2.6) and that in the MONO group 1.0 degree (0-2.5). There was no statistically significant change in intraindividual IOL decentration or tilt. CONCLUSION: Three-piece silicone MIOLs and MONOs with polymethylmethacrylate haptics implanted in the capsular bag after circular capsulorhexis provide good centration and very little tilt without statistically significant change up to 6 months after surgery. Postoperative refractive shift is of minor concern for 6 months after surgery.

Adult↗
PubMed2001

Clinical comparison of two intraocular pressure measurement methods: SmartLens dynamic observing tonography versus Goldmann.

PURPOSE: To compare intraocular pressure measurements obtained with SmartLens, a gonioscopic contact lens, to those from Goldmann applanation tonometry. METHODS: Eighty volunteers (20 healthy individuals and 60 glaucoma patients from the university eye hospital's outpatient department) were examined using conventional Goldmann tonometry and the new SmartLens tool. For each device three replicate measurements were performed. A paired t-test and the corresponding mean difference confidence interval approach were used to assess deviations in location of the two tonometric methods; the test procedure of Maloney and Rastogi was used for comparison of precision in paired data. Intraindividual differences were evaluated according to the approach of Altman and Bland. RESULTS: There was a mean difference of 5.6 mmHg (95% CI: 4.3 mmHg; 6.8 mmHg; P<0.01) in intraocular pressure between the two methods with a significant overestimation by SmartLens tonometry compared to Goldmann tonometry (P<0.01). The 95%-limits of agreement ranged from -5.4 mmHg to +16.6 mmHg for individual patients. The measurement method variance of SmartLens was higher (Maloney-Rastogi test; P <0.01). The mean coefficients of variation for intraindividual replicates were 10.1% (SmartLens) and 3.8% (Goldmann; P <0.01). CONCLUSIONS: Accepting Goldmann tonometry as gold standard for intraocular pressure measurement, the SmartLens method shows considerable variation and therefore is not proven to be an adequate substitute for Goldmann tonometry.

Adult↗
PubMed2001

Correlation of postoperative axial length growth and intraocular pressure in congenital glaucoma--a retrospective study in trabeculotomy and goniotomy.

BACKGROUND: This paper investigates the correlation of postoperative intraocular pressure (IOP) with axial length growth in children who underwent either trabeculotomy (TO) or goniotomy (GO) as primary surgery for congenital glaucoma. METHODS: Thirty-seven eyes of 21 children with congenital glaucoma who underwent one or two TOs from 1992 to 1997 and 26 eyes of 16 children with congenital glaucoma who underwent one or more GOs from 1974 to 1993 were retrospectively analyzed. None of the eyes had undergone other surgery previously. Thirteen of the TOs were combined with a small trabeculectomy. IOP was measured by handheld applanation tonometry (Perkins). Axial length was measured by ultrasound. The data were analyzed for correlation of postoperative IOP reduction with postoperative axial length growth. RESULTS: Mean duration of follow-up was 27.3 months in the TO eyes and 37.1 months in the GO eyes. Mean pretreatment IOP before surgery was 28.4+/-6.9 mmHg in the TO eyes and 30.8+/-8.5 mmHg in the GO eyes. Mean IOP at the end of follow-up was 17.5+/-5.8 mmHg in the TO eyes and 17.4+/-10.2 mmHg in the GO eyes. Axial length growth was normalized (proportional or slowed down compared with the nomogram of axial length growth) in 31 of the 37 TO eyes and in 20 of the 26 GO eyes, and was increased in 6 of the TO eyes and 6 of the GO eyes at the end of follow-up. Regarding axial length growth, 6 of 37 TO eyes had increased axial length growth at the end of follow-up. Three of these eyes also did not fulfill the IOP success criterion; 2 of the 3 eyes with normalized IOP had only borderline increased axial length growth. Six of 26 GO eyes had increased axial length growth at the end of follow-up. Five of these eyes did not fulfill the IOP success criterion; 1 eye with normalized IOP had only borderline increased axial length growth. CONCLUSION: The data show remarkably good correlation of postoperative IOP with postoperative axial length growth. Axial length measurements can therefore help to ascertain halting or progression of congenital glaucoma and thus are considered an important parameter for congenital glaucoma follow-up.

Child↗
PubMed2001

Effects of intraocular cefotaxime on the human corneal endothelium.

PURPOSE: To ascertain whether 0.4 mL of cefotaxime 0.25% applied intracamerally causes toxic alteration of the human corneal endothelium. METHODS: In this prospective randomized masked study, 66 patients had cataract extraction using phacoemulsification, a frown incision, and implantation of a poly(methyl methacrylate) intraocular lens. This was followed by intraocular injection of 0.4 mL of cefotaxime 0.25% or balanced salt solution (BSS(R)). Contact specular microscopy and photography were performed preoperatively and 1 to 4 days and 3 months postoperatively. RESULTS: In the cefotaxime group, the mean endothelial cell count was 2729 cells/mm(2) +/- 474 (SD) preoperatively, 2520 +/- 462 cells/mm(2) 1 to 4 days postoperatively, and 2560 +/- 495 cells/mm(2) 3 months postoperatively. The mean endothelial cell count in the BSS (control) group was 2657 +/- 413 cells/mm(2), 2475 +/- 384 cells/mm(2), and 2486 +/- 427 cells/mm(2), respectively. There was no significant difference in cell count or morphology between groups (P <.05). CONCLUSIONS: Intraocular application of cefotaxime produced no significant changes in endothelial cell count or morphology when compared with application of a control substance. With its broad spectrum of antibiotic activity, cefotaxime might be an appropriate alternative to other intraocularly administered antibiotics in anterior segment surgery for prophylaxis and management of infection.

Adult↗
PubMed2001

Intraocular pressure after small incision cataract surgery: temporal sclerocorneal versus clear corneal incision.

PURPOSE: To compare intraocular pressure (IOP) after phacoemulsification and foldable intraocular lens (IOL) implantation using a temporal sclerocorneal or clear corneal incision. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: One hundred patients (100 eyes) with cataract having phacoemulsification with posterior chamber IOL implantation were randomly assigned to receive a temporal sclerocorneal or clear corneal tunnel incision. Intraocular pressure was measured preoperatively and 6 hours, 1, 2, and 3 days, and 5 months postoperatively. Statistical significance was determined by nonparametric group comparisons using 2-sample random Wilcoxon tests. RESULTS: Six hours postoperatively, the median IOP increase was significantly higher in the sclerocorneal tunnel group (57%) than in the clear corneal incision group (18%) (P <.001). No significant between-group difference in IOP was found at 1, 2, or 3 days or 5 months. At 5 months, IOP was 0.6 mm Hg lower than preoperatively in the sclerocorneal tunnel group and 1.5 mm Hg lower in the clear corneal group. CONCLUSIONS: After phacoemulsification and foldable IOL implantation, the immediate postoperative IOP increase was higher in eyes having a sclerocorneal incision than in those having a clear corneal tunnel incision. These results could be important in eyes with decreased outflow facility or preexisting optic nerve damage.

Adult↗
PubMed2001

[Near vision after implantation of monofocal versus multifocal intraocular lenses].

AIM: Object of this study was to compare the near visual acuity between eyes with monofocal intraocular lens (MONO) and myopic target refraction in comparison with eyes after refractive multifocal intraocular lens (MIOL) implantation and emmetropic to slight hyperopic target refraction. PATIENTS AND METHOD: 89 eyes of 83 patients underwent cataract surgery, in 49 eyes a MONO (SI-40NB, Allergan) was implanted, in 40 eyes a refractive MIOL (SA-40N, Allergan). At day 2 after surgery and after 5 months the uncorrected near visual acuity, the near visual aculty with distance correction and with an addition of +3 diopters (D) were determined. The refractive outcome targeted in case of MIOL implantation was emmetropia to slight hyperopia and myopia for the MONO subjects. The eyes with MONO were classified in 4 categories depending on their postoperative refractive error (spherical equivalent, SE): category 1 with SE +1 to > 0 D, category 2 with SE 0 to > -1 D, category 3 with SE -1 to > -2 D and category 4 with a SE -2 to > -3 D. RESULTS: We found a statistically significant better uncorrected near visual acuity in eyes with MIOL than in MONO subjects for category 1-3. In category 4 there was no statistically significant difference between MONO and MIOL. With best distance correction near visual acuity in MIOL was statistically significant better than in all 4 MONO categories. After adding 3 D, there was no statistically significant difference between the groups. CONCLUSION: Even in case of a myopic target refraction near visual acuity in eyes of the MONO group was statistically significant worse than in the eyes of the MIOL group. Only in case of postoperative SE of < or = -2 D eyes of the MONO group had a near visual acuity similar to the eyes of the MIOL group. This advantage is accomplished with a decrease in the uncorrected distance visual acuity.

Aged↗