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Biomedical subjects

J von Eicken

Publications and source records attributed to J von Eicken.

6 recordsLinked to original sources
PubMed2006

[The role of pachymetry in routine glaucoma diagnosis].

The influence of corneal thickness on the precision of Goldman applanation tonometry is highly disputed. Goldmann and Schmidt assumed that the physiological variation of corneal thickness does not influence the measurement. But they indicated that an "abnormal" deviation of corneal thickness can lead to a false measurement. In the last 30 years many investigations have reliably demonstrated that thick corneas produce elevated applanation values and thin corneas lower values. The correction value is 1 mm Hg per 25 microm change in corneal thickness. The accuracy of intraocular pressure measurement is important for the detection and monitoring of glaucoma. Therefore it is necessary to recalculate applanation values based on corneal thickness in every patient, especially after refractive surgery. It is also necessary to keep in mind that with applanation tonometry we measure a force. From the force readings we deduce the value of the intraocular pressure. This conclusion is only correct if the theory of Goldmann applanation tonometry is right. But between force measurement and intraocular pressure there is the individual cornea with special properties like thickness, rigidity and astigmatism which can influence the correctness of the measurement. So we can understand why knowledge of corneal thickness can improve the deduction from force measurement of intraocular pressure. It is also reasonable that other individual corneal properties we do not measure or do not know so far can influence the deduction. This means that the corneal thickness is not the only variable. Pachymetry allows us to estimate the intraocular pressure with higher precision. Therefore it should be clinically used.

Artifacts↗
PubMed2005

[Glaucoma diagnostics and corneal thickness].

In recent years the role of pachymetry in the correction of applanation tonometry values was controversially disputed. At the present time it is undoubtedly proven that central corneal thickness affects the accuracy of applanation tonometry. The dimension of this influence is 1 mmHg of pressure per 25 microm of change in corneal thickness. It is important to remember that Goldmann and Schmidt calibrated the applanation tonometer according to the central corneal thickness of their population by using the optical method. Therefore, it is first necessary to determine the corneal thickness for each examiner and his methods. The linear correction formula should be used only in the range of corneal thickness in which the formula was determined. The correction according to Orssengo and Pye and further developments in tonometry may offer alternatives for better estimation of intraocular pressure.

Cornea↗
PubMed2004

[Potentially fatal orbital disorder].

Fulminant processes of the orbit can cause considerable diagnostic difficulties with regards to the clinical, radiological and microbiological appearance. Rhino-orbito-cerebral mucormycosis is a rare but, when untreated, fatal orbital disease capable of destructive infiltration of soft tissue and bone. It occurs preferably in the ill adjusted diabetic or in the course of an immunodeficiency. The following case report describes a leukaemia patient developing a severe rhino-orbito-cerebral mucormycosis which was initially not recognised. Since untreated mucormycosis is fatal, an aggressive surgical approach with excision of the whole necrotic area is necessary even if the diagnosis cannot be confirmed with certainty.

Adult↗
PubMed2000

[Transient blindness after subconjunctival anesthesia for diode laser cyclophotocoagulation].

BACKGROUND: Retro- and parabulbar anaesthesia can be associated with severe sight-threatening and life-threatening complications and may compromise optic nerve function, especially in eyes with advanced optic neuropathy. Subconjunctival anaesthesia usually does not influence optic nerve function. We report on two patients who developed transient amaurosis after subconjunctival anaesthesia. PATIENTS: In two patients (75 and 77 years old) with advanced refractory glaucoma a diode laser cyclophotocoagulation was performed to lower the increased IOP. For local anaesthesia, 2 ml of 2% mepivacaine was placed beneath the conjunctiva. The needle was placed at least 6 mm from the limbus to avoid bleeding at the injection site near the limbus. After 10 minutes, both patients observed a decrease of their vision of the treated eyes. A few minutes later, an amaurosis of the treated eyes was found in both patients, which was fully reversible after 2 to 3 hours. At fundus examination, no vessel occlusion was seen. CONCLUSIONS: Subconjunctival anaesthesia may cause transient blindness in patients with advanced optic neuropathy. The incidence of this side effect seems very low.

Aged↗
PubMed1999

A human arterial organ culture model of postangioplasty restenosis: results up to 56 days after ballooning.

BACKGROUND: Restenosis is a reparative process that is activated in response to injury induced by angioplasty. Despite numerous experimental models of restenosis the number of human arterial organ culture systems is very limited and long-term experiences do not exist. METHODS AND RESULTS: During routine nephrectomies parts of the renal arteries of 88 patients were extracted, 47 were suitable for organ culture preparations. Sections were made at 3 mm intervals perpendicular to the vessel wall axis. The arterial segments were treated with 3 mm standard balloon-catheters (Medtronic 14K2030E) for 60 s with 3, 6, 9, and 12 bar. After angioplasty, the organ segments were cultured in a mixture of Waymouth's MB 752/1 and Ham F-12, supplemented with 15% fetal calf serum. After 0, 4, 14, 21, 28, and 56 days the organ cultures were fixed in 4% para-formaldehyde and embedded in paraffin. After staining with a modified elastica-van Gieson technique the intimal wall thickening was analyzed with a computerized morphometric system. For the identification of smooth muscle cells (SMC) a monoclonal antibody against smooth muscle alpha-actin was used. Endothelial cells were identified using an anti-human von Willebrand factor. To determine the number of cells undergoing DNA synthesis, bromodeoxyuridine (BrdU), a thymidine analogue, was added to the culture media 18 h prior to fixation. BrdU was detected with a monoclonal antibody, as secondary antibody a biotinylated horse-anti-mouse antibody was used. After 14, 21, and 28 days in culture BrdU-positive cells were detected in the neointima of the organ cultures, indicating mitotic activity in this area. After 28 and 56 days in culture a clear increase of neointimal thickening was found in the morphometric analysis. By positive reaction with antibodies against smooth muscle alpha-actin these cells were partly identified as SMC. CONCLUSIONS: The organ culture model offers opportunities for in vitro investigations of postangioplasty restenosis. The data emphasize the importance of a relatively late proliferative response of SMC in the human arterial organ culture model.

Adult↗