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Biomedical subjects

W Behrens-Baumann

Publications and source records attributed to W Behrens-Baumann.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Illumination conditions of visually impaired people under private domestic circumstances - clinical study on 91 patients].

BACKGROUND: The illuminance and quality of illumination are important factors for visually impaired people to improve contrast sensitivity and reduce glare sensitivity at domestic reading places. The ability of visually impaired people to read can often be improved by simple strategies. At the onset of multiple ophthalmic diseases an optimum of lighting is often the tool of choice to restore reading capability. PATIENTS AND METHODS: 91 visually impaired people were included in this study. 76 were equipped with optical reading tools and 15 used a television reading aid. The illumination conditions of reading places were investigated. This included measurements of illuminance and information about the light source and localization, direction of light and modelling. The understanding of the importance of optimal illumination was judged by a graded scale from 1 - 5. RESULTS: Twenty-two of the 76 visually impaired people equipped with optimal reading tools were using an extra reading place. All others used livingroom or kitchen tables as their preferred reading place. 10 % of the reading places had a illuminance of above 5000 lx, whereas 63 % had less than 500 lx. Incandescent lamps dominated as artificial light sources. In 60 % of all reading places ceiling light sources were predominant. Only 40 % of the patients used an additional reading place illumination. For television reading aids the ceiling light caused a decrease of contrast sensitivity in 1 % - 7 %. If questioned, 90 % of the patients were highly sensitive to problems of good illumination of their reading places. This is, as our study revealed, in contrast to the conditions under which most of the visually impaired people read. CONCLUSIONS: Domestic reading places revealed considerable deficits concerning the illumination. Most visually impaired people do not realize this problem. Ophthalmologists, opticians, low-vision-, orientation- and mobility-trainers are recommended for rehabilitation.

Aged↗
PubMed2001

Ophthalmodynamometry: a reliable method for measuring intracranial pressure.

Under physiological conditions, the pressure in the central retinal vein is equal to or higher than the intracranial pressure (ICP) because the cerebrospinal fluid (CSF) passes the sheath of the optic nerve before draining into the cavernous sinus. The optic nerve sheath is where the ICP affects the retinal venous pressure. Ophthalmodynamometry (ODM) is a useful method for determining the central retinal artery pressure. While papilledema and a lack of venous pulsations are commonly used as a vague indication of the ICP, ODM may be advantageous for determining the pressure in the central retinal vein. Until now, however, the venous pressure has never been compared with the intracranial pressure. In the present study, the pressure in the central retinal vein was recorded in 31 patients while the ICP was simultaneously being recorded for various reasons. The results demonstrate a linear correlation (r = 0.968) between the pressure in the central retinal vein and the ICP. This correlation is of great practical value since until now, reliable intracranial pressure monitoring has only been possible by invasive means, by placing a probe either in the brain parenchyma or the ventricle. Ophthalmodynamometry is useful for momentary assessment of the ICP, can easily be repeated, and may be used whenever an elevated ICP is suspected in hydrocephalus, brain tumors and after head injury. However, it is not suitable for continuous ICP monitoring.

Adolescent↗
PubMed2001

Use of internet technologies for data acquisition in large clinical trials.

Data acquisition for automated processing is a central aspect of clinical trials with large numbers of cases because of their extensive demand for manpower. Scientific data can be collected using data forms, which are created in Hypertext Markup Language and published on the Internet. The completed data form can be returned via E-mail or Common Gateway Interface-Script and forwarded into a study database. For the Internet-based data acquisition of a prospective multicenter trial (e.g., on endophthalmitis incidence after cataract extraction), we developed two special HTML forms that can be opened in the ophthalmology department's homepage. A large number of acquired anonymous data has been collected via Internet and automatically transferred into the trial database. The Internet provides a fast and easy avenue for the acquisition of scientific data. This method of data acquisition and data processing will become more common place in multicenter clinical trials.

Clinical Trials as Topic↗
PubMed2000

[Ophthalmodynamometry. A reliable procedure for noninvasive determination of intracranial pressure].

BACKGROUND: Central vein pressure depends on intracranial pressure (ICP). Baurmann in 1925 therefore recommended measuring central vein pressure to determine ICP, but the accuracy of this method has not yet been verified. To test the method we measured venous outflow pressure (VOP) by noninvasive ophthalmodynamometry (ODM). METHODS AND MATERIALS: We studied 31 patients with suspected increased ICP. ICP was recorded continuously for a minimum of 24 h by intraventricular catheters, and ODM was performed during ICP measurement. The findings were compared with the results of conventional invasive ICP measurement. RESULTS: Pressure in the central retinal vein was highly correlated with ICP. CONCLUSION: Measuring VOP by ODM seems to be a reliable method for noninvasive recording of ICP. It is a useful screening test in all cases of presumed ICP elevation.

Adolescent↗
PubMed2000

[Penetrating re-keratoplasty a chaud using healon 5 for stabilizing the anterior chamber].

BACKGROUND: Penetrating keratoplasty in cases of perforated corneal ulcers is a technical challenge. The loss of anterior chamber volume during trephination causes irregularities of surgical margins and carries the risk of trauma to iris and crystalline lens. The highly viscous substance Healon 5 allows a deep anterior chamber to be maintained even in cases of rather large perforations. CASE REPORT: A 34-year-old man presented with acutely perforated ulcer on the transplant-host interface. Perforating minikeratoplasty (diameter 4.5 mm) including the corneal limbus had been performed 3 years previously because of a perforated ulcer after pterygium surgery. Corneal melting extending to the visual axis required a large-diameter transplant (8.0 mm), partially including the former transplant. Before trephination the anterior chamber was restored with Healon 5. Despite the fairly large perforation site we did not note any anterior chamber shallowing during trephination. Hardly any bleeding occurred perioperatively, although deep and superficial neovascularizations in the former transplant were cut. The postoperative course was uneventful with no rise in intraocular pressure. After 4 weeks, postoperative pinhole visual acuity with the preoperative correction (1.5 dpt. cyl.) was 0.7, with a topographic astigmatism of 6.5 dpt. CONCLUSION: In the case presented here, a regular recipient wound bed as a prerequisite for a relatively low postoperative astigmatism was created by the use of Healon 5 for anterior chamber stabilization during trephination.

Adult↗
PubMed2000

Laser iridocystotomy for bilateral acute angle-closure glaucoma secondary to iris cysts.

PURPOSE: To report laser iridocystotomy for bilateral acute angle-closure glaucoma secondary to peripheral iris cysts. METHOD: Case report. RESULTS: In a 55-year-old man with increased bilateral intraocular pressure, gonioscopy revealed varied angle narrowing. Bilateral angle-closure glaucoma secondary to peripheral iris cysts was diagnosed by ultrasound biomicroscopy. The peripheral iris cysts could not be seen in mydriasis by gonioscopy. Therefore, we decided to perform laser iridocystotomy with argon and Nd:YAG laser. Collapse of the cysts after laser treatment was demonstrated by ultrasound biomicroscopy. At follow-up, 9 months after laser treatment, intraocular pressure had dropped below 20 mm Hg in both eyes without further therapy. The iris cysts did not recur, which was demonstrated by ultrasound biomicroscopy. CONCLUSIONS: Peripheral iris cysts may produce angle closure and may cause secondary angle-closure glaucoma. If transpupillary laser cystotomy is not possible, laser iridocystotomy may produce collapse of the iris cysts and correction of secondary angle closure.

Acute Disease↗
PubMed2000

[Pseudoexfoliation (PEX) syndrome and intraoperative complications in cataract surgery].

BACKGROUND: Conventional wisdom holds that pseudoexfoliation syndrome (PEX) leads to an increased risk during cataract surgery with regard to zonular dialysis, rupture of the posterior capsule and luxation of the lens into the vitreous as a consequence of insufficient zonules. The present study is focused on the impact of pseudoexfoliation syndrome on the outcome of cataract surgery. PATIENTS AND METHODS: We included in a prospective study 1210 patients which underwent cataract surgery (phacoemulsification) and implantation of a posterior chamber lens in our department from October 1997 until June 1999. The course of surgery, relevant associated diagnoses, and intraoperative complications are described. The patients were divided in a PEX-group and non-PEX-group. RESULTS: There was no difference in the percentage of glaucoma patients between the PEX-group (16.2%) and non-PEX group (17.7%). There were statistically significant more women in the PEX-group and the average age was higher. Intraoperative complications, such as rupture of the posterior capsule, zonular dialysis and displacement of the lens into the vitreous body were similar in the two groups. CONCLUSION: This present study shows, that modern cataract surgery makes it possible to achieve good operative results, even in risk patients. Preoperative presence of PEX had no influence on the complication rate of cataract surgery.

Adult↗
PubMed2000

Venous opthalmodynamometry: a noninvasive method for assessment of intracranial pressure.

OBJECT: The goal of this study was to examine the potential use of ophthalmodynamometry in the noninvasive assessment of intracranial pressure (ICP). Under normal conditions, pressure within the central retinal vein is equal to or greater than ICP, because the central retinal vein basses through the optic nerve before it drains into the cavernous sinus. The optic nerve sheath is the place where ICP affects retinal venous pressure. Suction ophthalmodynamometry is an established method of investigation in ophthalmology to determine the pressure of the central retinal artery. Although observations of papilledema and lack of venous pulsations are commonly used to provide a vague assessment of ICP, ophthalmodynamometry may be used to determine the pressure of the central retinal vein. This venous pressure has never been compared with ICP. METHODS: In this study the pressure of the central retinal vein was recorded in 22 patients who underwent continuous simultaneous registration of ICP for various reasons, mainly for suspected hydrocephalus. A comparison of the two pressures was made. The results indicated a highly significant linear correlation between central retinal vein pressure and ICP. These results are of great practical value because up-to-date reliable ICP monitoring has only been possible by using invasive means, by placing a probe extradurally or subdurally into the brain parenchyma or a ventricle. CONCLUSIONS: Ophthalmodynamometry can be relevant for momentary assessment and is not suitable for continuous monitoring. However, this technique can easily be repeated and may be used whenever increased ICP is suspected in a patient suffering from hydrocephalus, brain tumors, or head injury.

Adolescent↗
PubMed1999

[At home utilization of low-vision aids by the visually impaired].

BACKGROUND: The increase of life expectancy causes a rising number of partially sighted. Therefore our Department of Ophthalmology has founded a laboratory for partially sighted 7 years ago. To optimize patient care, the results were now reinvestigated. MATERIALS AND METHODS: For the present study, 125 patients were selected by geographical aspects (home nearby clinic) from the lab's pool. After a 3 month minimum period of using the low-vision aid (LVA) patients were visited at their homes. Near visual acuity, distance visual acuity, magnification, and contrast sensitivity were studied under domestic and optimized conditions of illumination. Patients were interviewed in detail to investigate their habits of LVA use. RESULTS: An overall number of 94 patients (66 females and 28 males) could be evaluated. The most patients were between 80 and 84 years old. Vision impairment was attributable mostly to macular degeneration (55%) and diabetic retinopathy (21%). Visual acuity and contrast sensitivity decreased during the period of investigation. 79% of the patients had a unsatisfactory domestic illumination (< 1000 lx). Only 23% of the patients used their LVA at a fixed location. Main field of using LVA was reading (68%). The LVA were rarely used for writing and other fields of practice. 76% of LVA were used daily, more than 50% for a maximal duration of 1 h/d. Magnifiers were preferably used for short-time activities. Closed circuit television systems (CCTV) had a very good acceptance. Telescopes were characterized by a very high rate of rejection. The number of non-used LVA was approximately a fifth. Reasons were decreased visual acuity, impractical handling, missing introduction by delivering optician (54%) as well as unsatisfactory illumination. CONCLUSIONS: Improved patient care can be obtained by regular check-up visits (6 months), enhanced illumination, low-vision training, home visits, multi-disciplinary care and modified prescription of LVA.

Aged↗
PubMed1999

[Contrast enhancement in the public environment--improvement in orienting capacity of visually handicapped patients].

BACKGROUND: Partially sighted often experience problems in orientation in public areas. Individual visual aids can only be used with limitations. Improving light intensity and colour contrasts of timetables, information signs, direction symbols, etc. can provide remedies. Experimentally substantiated directives do not yet exist. PATIENTS AND METHODS: Experiments were conducted in 231 partially sighted subjects (binocular vision < 0.3) diagnosed as experiencing dullness when watching the media, having maculopathies, glaucomas, or dystrophic alterations of the retina or choroid, and in 43 normal subjects to determine the subjective assessment of colour and light-intensity contrasts. The presented contrast patterns were Hartmann-characters as infield (3.3 degrees) with a rectangular surround (19.5 degrees x 14.3 degrees). Three experimental series were carried out in which subjects assigned 14 non-coloured/non-coloured contrasts, 35 non-coloured/colour contrasts and 30 colour/colour contrasts to any of the five assessment classes of extremely poor, poor, optimal, sharp, extremely sharp. The colour contrasts consisted of combinations of yellow, green, red, purple, blue, and non-coloured. RESULTS: For non-coloured/non-coloured, the subjects preferred positive contrasts (bright infield, dark surround). Preferred contrast levels were 0.91 to 0.99 for positive contrasts and -0.96 to -0.99 for negative contrasts. For colour/non-coloured contrasts, 90% of the partially sighted preferred yellow as the foreground colour with a contrast level above 0.89. For colour/colour contrasts, optimal assessments of 90% of all partially sighted were yellow/purple and yellow/blue with contrast levels above 0.90. The determined results are applicable for the exact experimental contrast settings only. A field manual was prepared for planning and design of contrasts suited for the partially sighted in public areas. CONCLUSIONS: Partially sighted, in subjective contrasts assessment, prefer bright characters of signs on a dark background for both non-coloured and colour contrasts with contrast levels above 0.9. Yellow was the preferred infield colour.

Adolescent↗
PubMed1999

Effect of the cytostatic agent idarubicin on fibroblasts of the human Tenon's capsule compared with mitomycin C.

BACKGROUND/AIMS: To investigate the in vitro effect of a short time exposure to the anthracycline idarubicin on proliferation, protein synthesis, and motility of human Tenon's capsule fibroblasts in comparison with the antitumour antibiotic mitomycin C. METHODS: After determination of effective concentrations of idarubicin, fibroblasts of the human Tenon's capsule were exposed to idarubicin or mitomycin C at concentrations ranging from 0.1 microg/ml to 1 microg/ml or from 2.5 microg/ml to 250 microg/ml, respectively, for 0.5, 2, or 5 minutes and cultured for 60 days. Cell death by apoptosis caused by idarubicin treatment was confirmed by Hoechst 33258 staining. Further proliferation was explored by cell counting and by (3)H-thymidine uptake. Protein synthesis was measured by (3)H-proline uptake and motility was assessed by agarose droplet motility assay. RESULTS: Idarubicin is able to exert toxicity and to induce apoptosis during a short time exposure of 0.5 minutes at concentrations of 0.3-1 microg/ml resulting in a significant reduction in cell number compared with the control after 60 days. For mitomycin C, higher concentrations and longer expositions were necessary. Even after treatment with 1 microg/ml idarubicin or 250 microg/ml mitomycin C a few cells were able to incorporate (3)H-thymidine. (3)H-proline uptake up to 10 days after exposure to 0.3 microg/ml idarubicin was found not to be decreased. Cell motility was reduced after treatment with 1 microg/ml idarubicin for 5 minutes or with 250 microg/ml mitomycin C for 2 or 5 minutes. For low mitomycin C concentrations, an increase in motility was found during the first 10 days. CONCLUSION: Idarubicin reduces proliferation of human Tenons's capsule fibroblasts after incubation for 0.5 minutes at concentrations as low as 0.3-1 microg/ml. In comparison, mitomycin C requires longer exposure times and higher doses for equal results. Therefore, idarubicin may be useful in the prevention of glaucoma filtering surgery failure.

Antibiotics, Antineoplastic↗
PubMed1999

Changes in the epidemiology of ruptured globe eye injuries due to societal changes.

We studied 208 records of patients, who had undergone primary repair of a ruptured globe. A comparison of the periods 1987-1989 and 1993-1995 suggests epidemiological changes as a result of broad changes in occupational and social conditions after the German reunification in 1989. The rate of ruptured globe injuries caused by occupational accidents decreased from 38.8% in the first period to 31.4% in the second. We found an increase in comparable eye injuries as a consequence of leisure activities. Within the years from 1993 to 1995, in occupational accidents, we found a significant decrease in eye injuries in industry while accidents in small companies (e.g. garages, builders and constructors) increased significantly compared to 1987-1989.

Accidents, Occupational↗
PubMed1999

Population pharmacokinetics of 2% topical dorzolamide in the aqueous humor of humans.

PURPOSE: To evaluate the concentration and kinetics of dorzolamide in the aqueous humor after its topical application. METHODS: Samples of aqueous humor were collected at the beginning of routine cataract surgery at defined intervals after topical application of a 2% solution of dorzolamide. After deep-frozen storage of the samples, drug extraction was achieved with a mixture of solvents. Quantification was carried out by high-performance liquid chromatography on a reversed-phase column. RESULTS: Peak concentrations of dorzolamide in aqueous humor were reached approximately 2 hours after application with 1000 ng/ml. Average values were approximately 1000 to 700 ng/ml after 4 to 6 hours and approximately 200 ng/ml after 12 hours. Mean half-life of absorption was 1.2 hours and for elimination 3.0 hours. CONCLUSIONS: Pharmacokinetics of dorzolamide in the aqueous humor of humans are in comparable dimensions as previously reported in experimental trials in pigmented rabbits. There is a clear linear absorption and elimination kinetic, which is demonstrated using the Bateman function. A better knowledge of the distribution and kinetics of dorzolamide will help to explain its reported effects on intraocular hemodynamics, distinct from its intraocular pressure lowering effect.

Absorption↗
PubMed1999

Secretory peptides TFF1 and TFF3 synthesized in human conjunctival goblet cells.

PURPOSE: The objective of this study was to determine whether human conjunctival epithelium synthesizes TFF-peptides (formerly P-domain peptides, trefoil factors), a family of mucin-associated secretory peptides of the gastrointestinal tract. METHODS: Expression of TFF-peptides in human conjunctiva was monitored by reverse transcription-polymerase chain reaction analysis. Antisera specific for TFF-peptides were used for immunohistochemistry to determine the presence and distribution of TFF-peptides in human conjunctiva. RESULTS: mRNA expression of TFF1 and TFF3, but not TFF2, was detected in human conjunctiva. TFF1 and TFF3 but not TFF2 are stored in conjunctival goblet cells only as revealed by immunofluorescence. CONCLUSIONS: Goblet cells of the human conjunctiva synthesize TFF1 and TFF3. These peptides, together with the secretory ocular mucin MUC5AC, may contribute to the rheological properties of the tear film. They also may influence healing of corneal wounds due to their motogenic properties.

Aged↗
PubMed1998

Computer-based training for the treatment of partial blindness.

Partial blindness after brain injury has been considered non-treatable. To evaluate whether patients with visual-field defects can profit from computer-based visual restitution training (VRT), two independent clinical trials were conducted using patients with optic nerve (n = 19) or post-chiasmatic brain injury (n = 19). In post-chiasma patients, VRT led to a significant improvement (29.4%) over baseline in the ability to detect visual stimuli; in optic nerve patients, the effects were even more pronounced (73.6% improvement). Visual-field enlargements were confirmed by the observation of a visual-field expansion of 4.9 degrees-5.8 degrees of visual angle and improved acuity in optic nerve patients. Ninety five percent of the VRT-treated patients showed improvements, 72.2% confirmed visual improvements subjectively. Patients receiving a placebo training did not show comparable improvements. In conclusion, VRT with a computer program improves vision in patients with visual-field defects and offers a new, cost-effective therapy for partial blindness.

Blindness, Cortical↗