Biomedical subjects
Publications and source records attributed to R Guthoff.
Between 1983 and 1986 the authors studied 5 patients with idiopathically dilated episcleral vessels. All of them had unilateral open-angle glaucoma (25-38 mm Hg) and elevated episcleral venous pressure (22-38 mm Hg). Orbital venography showed normal venous outflow. It is presumed that the etiological mechanism was a localized venous obstruction in the region of the extraocular muscles.
In a large choroidal melanoma (prominence 12 mm, volume approx. 1,900 mm3) diagnostic sonography revealed an unusual compartmentation, corresponding to the internal reflectivity of the tumor. When NMR imaging was performed, marked differences in signal behavior were seen between the tumor's center and its periphery. Histopathology revealed a highly pigmented spindle B melanoma containing an amelanotic island with signs of necrosis. The ultrasound pattern was explained on the basis of well known physical phenomena, whereas the NMR signals are still not fully understood.
The present report describes clinical findings in 13 patients with Sturge-Weber syndrome, 11 of whom had glaucoma (22-52 mm Hg). The episcleral venous pressure (EVP) was high in all glaucomatous eyes (14-23 mm Hg). Tonography showed a marked decrease in outflow facility. The observations suggest that glaucoma in Sturge-Weber syndrome is caused by a) elevated episcleral venous pressure and b) secondary damage of the trabecular meshwork with reduction of outflow facility. The cause and pathogenesis of these lesions are discussed. In nine patients a diffuse angiomatosis involving most of the choroid (1.5-4.0 mm thick), as well as the episcleral perilimbal plexus, was demonstrated by ultrasonography.
Clinical features of posterior scleritis were noted in 12 eyes of nine patients followed up for one to seven years. The signs of this clinical entity varied from transitory choroidal folds in the fundus to extensive scleral and choroidal edema with associated edema of Tenon's space and of the optic nerve sheath. These were detected only by ultrasonography. Histopathologic examination of one eye disclosed granulomatous inflammatory reaction in the involved scleral and choroidal areas. Local and systemic treatment with corticosteroids seemed not to affect the clinical course or outcome.
In 75% of the patients with malignant melanoma of the choroid useful vision can be retained by beta-radiation with ruthenium-106/rhodium. Tumors with a prominence of more than 6 mm should be treated only for very special reasons. There is a statistically proven correlation between the initial tumor volume and the occurrence of residual tissue volume. Histopathological investigations have shown that residuals of the tumor do not permit any conclusions concerning the dignity or vitality of tumor cells. The risk to life is not increased by the conservative procedure, and it may even be reduced.
Diabetic retinopathy is the most important causative factor of all vitreous hemorrhages. Early vitrectomies improve the prognosis with regard to function and enable panretinal coagulation to be completed.
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The indications for and long-term results of about 200 Lester-Jones tube insertions are reported. Follow-up was possible in 165 patients, of which 83% ended up with a comfortable dry eye. Reimplantations had been necessary in a certain percentage, dependent upon the primary cause of epiphora. The best results were achieved after herpetic canalicular obstructions, and the highest ratio of complications occurred when unsuccessful lacrimal surgery had been the indication for bypass surgery.
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In various states of refraction axial eye length and thickness of the posterior ocular coats were measured echographically. As proved in previously performed experimental studies, retina, choroid and sclera were resolved in a considerable percentage of cases by combining the A- and B-mode techniques of modern ultrasonic equipment. The supposed close negative correlation between length of the globe and ocular coat dimensions was confirmed by statistical analysis of our data. This result should provide additional help, when interpreting the reflections of the ocular wall under normal and pathological conditions.
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The computed tomographic morphology of malignant choroidal melanoma and its perfusion characteristics are described. Thirty-three static and serial CT examinations made on 29 patients with choroidal melanoma, three with pseudotumors of the macula and one with choroidal metastasis revealed the choroidal melanoma to be usually a hyperdense, markedly perfused tumor, while the non-contrast diagnostically undifferentiable pseudotumors and the choroidal metastasis, revealed no significant change in density after the administration of contrast material. Density values of perfusion characteristics of choroidal melanoma that are outside of the normal range are a result of secondary changes within the immediate surroundings of the tumor, such as detachment of the retina, tumor-induced glaucoma, or tumor necrosis.
Clinical and experimental examinations are described for the localization of intra-ocular and intra-orbital foreign bodies by CT scan. The minimal detectable diameter size was 0.2 X 0.3 mm for metal, and 0.5 mm for glass. We had difficulty in distinguishing wood from air bubbles, mainly in the retrobulbar space. First clinical results have shown CT-localization to be useful in cases where conventional X-ray techniques led to doubtful results.