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Demetrios Vavvas

Publications and source records attributed to Demetrios Vavvas.

4 recordsLinked to original sources
PubMed2004

Two cases of orbital lymphangioma associated with vascular abnormalities of the retina and iris.

PURPOSE: To report 2 patients with combined intraocular and orbital vascular abnormalities. DESIGN: Two interventional case reports. MAIN OUTCOME MEASURES: Clinical and pathologic findings. INTERVENTION/TESTING: Orbitotomy, fluorescein angiography, magnetic resonance imaging, and radiation therapy. RESULTS: Two patients presented with vision loss, intermittent proptosis, and cosmetic deformity. These patients had orbital lymphangioma, ipsilateral retinal and iris vascular malformations, and smaller corneal diameter on the affected side. CONCLUSIONS: The coexistence of these diverse vascular anomalies supports the established hypothesis of pluripotential orbital vascular anlagen. Disruptive influences of various types during embryogenesis or development may produce a variety of congenital orbital and intraocular vascular malformations.

Adult↗
PubMed2004

Preface.

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Boric Acids↗
PubMed2002

Mechanisms of disease: cataracts.

Studying the mechanisms that are responsible for the transparency of the lens we see that multiple factors are involved in the maintenance of lens clarity as well as in cataractogenesis. Is there a unifying mechanism? Since the function of the lens is the transmission of electromagnetic radiation in the visible spectrum, fundamental physical laws should apply. Attenuation of a light beam that passes through a medium happens by two major processes: absorption and scattering. In absorption, light energy is dissipated into heat as the result of energy-absorbing electronic transitions. In scattering, radiation is redirected away from the incident pathway, thereby reducing the transmitting power. Depending on the angular dependence of the scattered light, the wave front of the transmitted light is distorted. In the case of cataract, the primary factor is turbidity secondary to scattering. A perfectly uniform medium exhibits no light scattering; thus a continuous medium can scatter light only when it contains spatial fluctuations around the mean density governed by specific equations. These equations simply state that the amplitude of scattering is proportional to the Fourier amplitude of the density fluctuations in the medium [12]. Electron micrograph analysis using Fourier transformation has shows an increase in the fluctuation of spatial density of the opaque fiber [12,26,37,93]. Thus, all transparency mechanisms and all cataractogenic factors can be thought of as opposing effectors of spatial density fluctuation affecting scatter and antithetical producers of light absorbing moieties.

Cataract↗