Biomedical subjects
Publications and source records attributed to F Daxecker.
A nomogram for determining the refraction of intraocular lenses was developed to define the following diagnoses: emmetropizing lens, residual refraction of a given lens refraction and desired postoperative refraction. The nomogram makes an approximation solution possible to determine the refractive power of intraocular lenses from the basic refraction and the refractive power of the cornea.
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The necessity of calculating the refractive power of intraocular lenses in advance is emphasized and the authors' procedure described: Measurement of corneal radii with the Zeiss ophthalmometer, measurement of the bulb length with the A-Scan method, calculation of refractive power and the desired dioptric aniseikonia with the authors' own pocket calculator program using the formulas cited by Gernet. In 74% of the cases the postoperative difference from the pre-calculated refractions is less than 1 D, in 22% up to 2 D and in 4% up to 3 D.
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It was tried to demonstrate the laser-test simultaneously great groups of persons and thus to divide them roughly into prospective emmetropes and different ametropes. For that an interference-phenomenon of laser-light on a screen is used to determine the refractive status. If the head is moved slowly in one direction, myopes register a movement of the interference-pattern in the contrary sense, hyperopes a movement in the same sense, while emmetropes do not recognize a direction of movement. The refractive status of 139 students was investigated. The results of the laser-test with a small group of 24 students were compared with the results of retinoscopia, in the course of which the laser-test proved to be very sensitive. In 86% of the cases laser correction and retinoscopic correction were identical within a variation of +/- 0.25 dpt. All ametropic patients were detected with great certainty. Even negligible, subjectively not perceptible ametropia could be detected. Thus it was shown, that only 60% of those, who have been found to be ametropic by the laser-test, really do need glasses or a better correction. For determination of astigmatism further experiments are necessary.
Conjunctivitis follicularis is characterized by the appearance of cellular infiltrates consisting of lymphocytes, eosinophils and mast cells; this has led to the assumption of an allergic etiology in many cases. In a first attempt to prove this hypothesis three cases of conjunctivitis follicularis were investigated using the following immunological methods: (1) determination of immunoglobulins in the lacrimal fluid by means of quantitative precipitation (IgG, IgA, IgM), and by a direct radioimmunoassay for IgE; (2) direct immunofluorescence test on cryostat sections of biopsy specimens of diseased conjunctiva to detect immunoglobulin-producing plasma cells. According to initial results the infiltrated conjunctiva contains considerable numbers of plasma cells producing mainly IgA, and IgM. Plasma cells positively stained with anti-IgG and notably with anti-IgE were only rarely found. These findings, which were also supported by the quantitative Ig determinations in the lacrimal fluids, tend to rule out an allergic, IgE-mediated pathomechanism in these cases.
Elevated protein concentrations in the aqueous humor, without Tyndall phenomenon, were found in a case of Coats' Disease. In particular, proteins of smaller size were involved. The permeability of the retinal vessels was presumed to be impaired. The resulting increase in protein concentrations in the aqueous humor could be the cause of the secondary glaucoma in Coats' Disease.
Partial evulsion of the optic nerve is observed in very few cases. How difficult a diagnosis can be, and the possible causes of such an injury, are discussed.
Hereditary angioedema is caused by a deficiency of the C 1 esterase inhibitor (a component of complement). It is manifested by attacks of swelling of the extremities, face, eyelids, trunk, respiratory tract or abdominal viscera. The ophthalmological significance, diagnosis, symptoms and treatment of the condition are discussed.
Diagnostic tapping of the anterior chamber to determine the CEA count in aqueous humor is discussed. Taking the serum aqueous humor barrier (filtration index) into account, it is possible to determine how much of this tumor antigen is produced locally. A case report illustrates the relevance of the method in a case of bilateral metastases of breast cancer in the choroid.